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Salinity represents a considerable environmental risk, exerting deleterious effects on horticultural crops. Nanotechnology has recently emerged as a promising avenue for enhancing plant tolerance to abiotic stress. Among nanoparticles, cerium oxide nanoparticles (CeO2 NPs) have been demonstrated to mitigate certain stress effects, including salinity. In the present study, the impact of CeO2 NPs (0, 25, and 100 mg L−1) on various morphological traits, photosynthetic pigments, biochemical parameters, and the essential oil profile of spearmint plants under moderate (50 mM NaCl) and severe (100 mM NaCl) salinity stress conditions was examined. As expected, salinity reduced morphological parameters, including plant height, number of leaves, fresh and dry weight of leaves and shoots, as well as photosynthetic pigments, in comparison to control. Conversely, it led to an increase in the content of proline, total phenols, malondialdehyde (MDA), hydrogen peroxide (H2O2), and antioxidant enzyme activities. In terms of CeO2 NP applications, they improved the salinity tolerance of spearmint plants by increasing chlorophyll and carotenoid content, enhancing antioxidant enzyme activities, and lowering MDA and H2O2 levels. However, CeO2 NPs at 100 mg L−1 had adverse effects on certain physiological parameters, highlighting the need for careful consideration of the applied concentration of CeO2 NPs. Considering the response of essential oil compounds, combination of salinity stress and CeO2 treatments led to an increase in the concentrations of L-menthone, pulegone, and 1,8-cineole, which are the predominant compounds in spearmint essential oil. In summary, foliar application of CeO2 NPs strengthened the resilience of spearmint plants against salinity stress, offering new insights into the potential use of CeO2 NP treatments to enhance crop stress tolerance. [ABSTRACT FROM AUTHOR]

Nitrogen use efficiency (NUE) is important for the growth and development of rice and is significant in reducing the costs of rice production. OsNRT1.1b is involved in nitrate assimilation, and the alleles at position 21,759,092 on chromosome 10 clearly separate indica (Pathum Thani 1 (PTT1) and Homcholasit (HCS)) and japonica (Azucena and Leum Pua (LP)) rice varieties. Rice morphological and physiological traits were collected at three nitrogen levels (N0 = 0 kg ha−1, N7 = 43.75 kg ha−1, and N14 = 87.5 kg ha−1). Leaf and tiller numbers in PTT1 and HCS at N7 and N14 were two to three times higher than those at N0. At harvest, the biomass yield in PTT1 was the highest, while the total grain number in HCS was the maximum. The leaf widths and total chlorophyll contents (SPAD units) of Azucena and LP increased with nitrogen application as well as photosynthetic pigment parameters; for example, plant senescence reflectance indices (PSRIs), structure-insensitive pigment indices (SIPIs), and modified chlorophyll absorption ratio indices (MCARIs) were highly related in the japonica varieties. PTT1 and HCS, both carrying the A allele at OsNRT1.1b, had better NUE than Azucena and LP with the G allele. HCS, overall, had better NUE than PTT1. The translation to grain yield of assimilates was remarkable in PTT1 and HCS compared with Azucena and LP. In addition, HCS converted biomass for a 75% higher yield than PTT1. The ability of HCS to produce high yields was achieved even at N7 nitrogen fertilization, manifesting efficient use of nitrogen. [ABSTRACT FROM AUTHOR]

Salt stress can seriously affect the growth and development of maize (Zea mays L.), resulting in a great yield loss. Melatonin (MT), an indole hormone, is a potential enhancer of plant tolerance against salt stress. However, the complex mechanisms of MT application in enhancing maize salt tolerance are still unclear. Herein, three-leaf seedlings of salt-susceptible P138 and its salt-resistant ethyl methane sulfonate (EMS)-104 mutant were cultured with or without 150 μM MT application under 0 and 100 mM Na2CO3 treatments for seven days, to systematically explore the response mechanisms of exogenous MT in improving the salt tolerance of maize. The results showed that salt stress triggered an escalation in reactive oxygen species production, enhanced multiple antioxidant enzymes' activities, impaired cellular membrane permeability, inhibited photosynthetic pigment accumulation, and ultimately undermined the vigor and photosynthetic prowess of the seedlings. While suitable MT application counteracted the detrimental impacts of Na2CO3 on seedlings' growth and photosynthetic capacity, the seedling length and net photosynthetic rate of P138 and EMS-104 were increased by 5.5% and 18.7%, and 12.7% and 54.5%, respectively. Quantitative real-time PCR (qRT-PCR) analysis further showed that MT application activated the expression levels of antioxidant enzyme-related genes (Zm00001d025106, Zm00001d031908, Zm00001d027511, and Zm00001d040364) and pigment biosynthesis-related genes (Zm00001d011819 and Zm00001d017766) in both maize seedlings under Na2CO3 stress; they then formed a complex interaction network of gene expression, multiple physiological metabolisms, and phenotype changes to influence the salt tolerance of maize seedlings under MT or Na2CO3 stress. To sum up, these observations underscore that 150 μM MT can alleviate salt injury of maize seedlings, which may provide new insights for further investigating MT regulation mechanisms to enhance maize seedlings' salt resistance. [ABSTRACT FROM AUTHOR]

Soil salinization, especially in arid and semi-arid regions, is one of the major abiotic stresses that affect plant growth. To mediate and boost plant tolerance against this abiotic stress, arbuscular mycorrhizal fungi (AMF) symbiosis is commonly thought to be an effective tool. So, the main purpose of this study was to estimate the role of AMF (applied as a consortium of Claroideoglomus etunicatum, Funneliformis mosseae, Rhizophagus fasciculatum, and R. intraradices species) symbiosis in mitigating deleterious salt stress effects on the growth parameters (shoot length (SL), root length (RL), shoot dry weight (SDW), root dry weight (RDW), root surface area (RSA), total root length (TRL), root volume (RV), root diameter (RD), number of nodes and leaves) of Cenchrus ciliaris L. plants through improved accumulations of photosynthetic pigments (chlorophyll a, chlorophyll b, total chlorophyll), proline and phenolic compounds. The results of this experiment revealed that the roots of C. ciliaris plants were colonized by AMF under all the applied salinity levels (0, 75, 150, 225, and 300 mM NaCl). However, the rate of colonization was negatively affected by increasing salinity as depicted by the varied colonization structures (mycelium, vesicles, arbuscules and spores) which were highest under non-saline conditions. This association of AMF induced an increase in the growth parameters of the plant which were reduced by salinity stress. The improved shoot/root indices are likely due to enhanced photosynthetic activities as the AMF-treated plants showed increased accumulation of pigments (chlorophyll a, chlorophyll b and total chlorophyll), under saline as well as non-saline conditions, compared to non-AMF (N-AMF) plants. Furthermore, the AMF-treated plants also exhibited enhanced accumulation of proline and phenolic compounds. These accumulated metabolites act as protective measures under salinity stress, hence explaining the improved photosynthetic and growth parameters of the plants. These results suggest that AMF could be a good tool for the restoration of salt-affected habitats. However, more research is needed to check the true efficacy of different AMF inoculants under field conditions. [ABSTRACT FROM AUTHOR]

The phenotype of albino tea plants (ATPs) is significantly influenced by temperature regimes and light conditions, which alter certain components of the tea leaves leading to corresponding phenotypic changes. However, the regulatory mechanism of temperature-dependent changes in photosynthetic pigment contents and the resultant leaf colors remain unclear. Here, we examined the chloroplast microstructure, shoot phenotype, photosynthetic pigment content, and the expression of pigment synthesis-related genes in three tea genotypes with different leaf colors under different temperature conditions. The electron microscopy results revealed that all varieties experienced the most severe chloroplast damage at 15 °C, particularly in albino cultivar Baiye 1 (BY), where chloroplast basal lamellae were loosely arranged, and some chloroplasts were even empty. In contrast, the chloroplast basal lamellae at 35 °C and 25 °C were neatly arranged and well-developed, outperforming those observed at 20 °C and 15 °C. Chlorophyll and carotenoid measurements revealed a significant reduction in chlorophyll content under low temperature treatment, peaking at ambient temperature followed by high temperatures. Interestingly, BY showed remarkable tolerance to high temperatures, maintaining relatively high chlorophyll content, indicating its sensitivity primarily to low temperatures. Furthermore, the trends in gene expression related to chlorophyll and carotenoid metabolism were largely consistent with the pigment content. Correlation analysis identified key genes responsible for temperature-induced changes in these pigments, suggesting that changes in their expression likely contribute to temperature-dependent leaf color variations. [ABSTRACT FROM AUTHOR]

Tea plant calli (Camellia sinensis L.) are characterized by the accumulation of various phenolic compounds (PC)—substances with high antioxidant activity. However, there is still no clarity on the response of tea cells to light exposure of varying intensity. The purpose of the research was to study tea callus cultures grown under the influence of primary exposure to different light intensities (50, 75, and 100 µmol·m−2·s−1). The cultures' growth, morphology, content of malondialdehyde and photosynthetic pigments (chlorophyll a and b), accumulation of various PC, including phenylpropanoids and flavanols, and the composition of catechins were analyzed. Primary exposure to different light intensities led to the formation of chloroplasts in tea calli, which was more pronounced at 100 µmol·m−2·s−1. Significant similarity in the growth dynamics of cultures, accumulation of pigments, and content of malondialdehyde and various phenolics in tea calli grown at light intensities of 50 and 75 µmol·m−2·s−1 has been established, which is not typical for calli grown at 100 µmol·m−2·s−1. According to data collected using high-performance liquid chromatography, (+)-catechin, (−)-epicatechin, epigallocatechin, gallocatechin gallate, epicatechin gallate, and epigallocatechin gallate were the main components of the tea callus culture's phenolic complex. Its content changed under the influence of primary exposure to light, reaching the greatest accumulation in the final stages of growth, and depended on the light intensity. The data obtained indicate changes in the morphophysiological and biochemical characteristics of tea callus cultures, including the accumulation of PC and their individual representatives under primary exposure to light exposure of varying intensity, which is most pronounced at its highest values (100 µmol·m−2·s−1). [ABSTRACT FROM AUTHOR]

Capsicum annuum L. has worldwide distribution, but drought has limited its production. There is a lack of research to better understand how this species copes with drought stress, whether it is reversible, and the effects of mitigating agents such as salicylic acid (SA). Therefore, this study aimed to understand the mechanisms of action of SA and rehydration on the physiology of pepper plants grown under drought conditions. The factorial scheme adopted was 3 × 4, with three water regimes (irrigation, drought, and rehydration) and four SA concentrations, namely: 0 (control), 0.5, 1, and 1.5 mM. This study evaluated leaf water percentage, water potential of shoots, chlorophylls (a and b), carotenoids, stomatal conductance, chlorophyll a fluorescence, and hydrogen peroxide (H2O2) concentration at different times of day, water conditions (irrigation, drought, and rehydration), and SA applications (without the addition of a regulator (0) and with the addition of SA at concentrations equal to 0.5, 1, and 1.5 mM). In general, exogenous SA application increased stomatal conductance (gs) responses and modified the fluorescence parameters (ΦPSII, qP, ETR, NPQ, D, and E) of sweet pepper plants subjected to drought followed by rehydration. It was found that the use of SA, especially at concentrations of 1 mM in combination with rehydration, modulates gs, which is reflected in a higher electron transport rate. This, along with the production of photosynthetic pigments, suggests that H2O2 did not cause membrane damage, thereby mitigating the water deficit in pepper plants. Plants under drought conditions and rehydration with foliar SA application at concentrations of 1 mM demonstrated protection against damage resulting from water stress. Focusing on sustainable productivity, foliar SA application of 1 mM could be recommended as a technique to overcome the adverse effects of water stress on pepper plants cultivated in arid and semi-arid regions. [ABSTRACT FROM AUTHOR]

N6–methyladenosine (m6A) is a widespread post–transcriptional modification in eukaryotic mRNAs. Proteins with the YTH structural domain act as m6A–binding proteins by recognizing the m6A modification and regulating mRNA through this recognition. In this study, SlYTHDF2, a prototypical m6A –binding protein gene in the YTH family was expressed in various tissues, and subcellular localization analyses indicated that the SlYTHDF2 protein was localized in the nucleus and cytoplasm. SlYTHDF2 knockout lines were obtained using CRISPR/Cas9 technology and showed the senesced leaves prematurely increased endogenous ABA accumulation compared with the wild type. Moreover, we found that dark promoted leaf senescence in SlYTHDF2 knockout lines and exogenous ABA further accelerated leaf senescence under dark conditions. The qRT–PCR analysis revealed significant alterations in the expression of genes associated with the ABA pathway. Relative to the wild type, the CR–slythdf2 plants exhibited reduced levels of photosynthetic pigments, higher accumulation of reactive oxygen species, and increased damage to cell membranes. Additionally, we discovered that SlYTHDF2 interacts with the chloroplast–binding protein SlRBCS3 through yeast two–hybrid and BiFC experiments. Overall, our data suggest the important role of SlYTHDF2 in regulating tomato leaf senescence. [ABSTRACT FROM AUTHOR]

Water scarcity leads to significant ecological challenges for global farming production. Sustainable agriculture depends on developing strategies to overcome the impacts of drought on important crops, including soybean. In this present study, seven promising soybean genotypes were evaluated for their drought tolerance potential by exposing them to water deficit conditions. The control group was maintained at 100% field capacity (FC), while the drought-treated group was maintained at 50% FC on a volume/weight basis. This treatment was applied at the second trifoliate leaf stage and continued until maturity. Our results demonstrated that water shortage exerted negative impacts on soybean phenotypic traits, physiological and biochemical mechanisms, and yield output in comparison with normal conditions. Our results showed that genotype G00001 exhibited the highest leaf area plant−1 (483.70 cm2), photosynthetic attributes like stomatal conductance (gs) (0.15 mol H2O m−2 s−1) and photosynthetic rate (Pn) (13.73 μmol CO2 m−2 s−1), and xylem exudation rate (0.25 g h−1) under drought conditions. The G00001 genotype showed greater leaf greenness by preserving photosynthetic pigments (total chlorophylls (Chls) and carotenoids; 4.23 and 7.34 mg g−1 FW, respectively) in response to drought conditions. Soybean plants accumulated high levels of stress indicators like proline and malondialdehyde when subjected to drought stress. However, genotype G00001 displayed lower levels of proline (4.49 μg g−1 FW) and malondialdehyde (3.70 μmol g−1 FW), indicating that this genotype suffered from less oxidative stress induced by drought stress compared to the other investigated soybean genotypes. Eventually, the G00001 genotype had a greater yield in terms of seeds pod−1 (SP) (1.90) and 100-seed weight (HSW) (14.60 g) under drought conditions. On the other hand, BD2333 exhibited the largest decrease in plant height (37.10%), pod number plant−1 (85.90%), SP (56.20%), HSW (54.20%), gs (90.50%), Pn (71.00%), transpiration rate (59.40%), relative water content (34.40%), Chl a (79.50%), total Chls (72.70%), and carotenoids (56.70%), along with the maximum increase in water saturation deficit (290.40%) and malondialdehyde content (280.30%) under drought compared to control conditions, indicating its higher sensitivity to drought stress. Our findings suggest that G00001 is a promising candidate to consider for field trials and further evaluation of its molecular signature may help breeding other elite cultivars to develop drought-tolerant, high-yielding soybean varieties. [ABSTRACT FROM AUTHOR]

Salinity restricts the growth of irrigated fruit crops in semi-arid areas, making it crucial to find ways to reduce salt stress. One effective strategy is using eliciting substances like ascorbic acid. In this context, the objective of this study was to evaluate the effects of application methods and concentrations of ascorbic acid on the morphophysiology and production of sour passion fruit irrigated with saline water. The experiment was organized using a factorial randomized block design (3 × 3 × 2) with three application methods (soaking, spraying, and soaking and spraying), three concentrations of ascorbic acid (0, 0.8, and 1.6 mM) and two levels of electrical conductivity of irrigation water—ECw (0.8 and 3.8 dS m−1). Foliar spraying of ascorbic acid at a concentration of 0.8 mM mitigated the effects of salt stress on the relative water content of leaves, the synthesis of photosynthetic pigments, gas exchange, and total production of sour passion fruit when irrigated with ECw of 3.8 dS m−1. Plants grown with water of 0.8 dS m−1 and under foliar application of 0.8 mM of ascorbic acid achieved the maximum growth in stem diameter and the greatest volume of pulp in the fruits. [ABSTRACT FROM AUTHOR]

Rhodiola linearifolia Boriss., a perennial alpine plant from the Crassulaceae family, is renowned for its unique medicinal properties. However, existing research on this species is limited, particularly regarding the impact of altitude on its physiological and medicinal compounds. The current study employed morphophysiological and anatomical methods to explore the adaptive mechanisms of R. linearifolia across different altitudinal gradients, while also examining photosynthetic pigments and metabolomic changes. Our results indicate that despite the simultaneous effects of various mountain abiotic factors, significant correlations can be identified between altitude and trait variation. An optimal growth altitude of 2687 m above sea level was identified, which is pivotal for sustainable ecosystem management and potential species introduction strategies. It is noted that increasing altitude stress enhances the synthesis of secondary antioxidant metabolites in R. linearifolia, enhancing its pharmaceutical potential. [ABSTRACT FROM AUTHOR]

This study examined the impact of organic manures from different sources (poultry, sheep, and cattle) on lemon balm (Melissa officinalis L., Lamiaceae) during different harvests. Manure application increased the photosynthetic pigments levels (chlorophyll-a, 9–41%; chlorophyll-b, 24–60%), biomass (41–60%), and essential oil yield (60–71%). Sheep manure treatment exhibited the highest antioxidant capacity among all the manures tested. Through GC-MS and GC-FID analysis, 10 chemical constituents were identified in the essential oil, accounting together for 91–95% of the total composition. The primary chemical component was geranial (39–46%), followed by neral (28–35%), (E)-caryophyllene (4.7–11%), geranyl acetate (2.7–5.9%), and caryophyllene oxide (1.7–4.8%). The utilization of livestock manures significantly improved the quality of the essential oil in terms of neral and geranial percentages compared to the control. Notably, during mid-August and early October, there was a substantial rise in these valuable compounds. However, a decrease in geranyl acetate and oxygenated monoterpenes resulted in a decline of the antioxidant capacity to 3%. Consequently, it is recommended to utilize essential oils from the second and third harvests for industrial purposes. Overall, the use of livestock manures, especially sheep manure, as a nutrient source for lemon balm cultivation, proves to be a viable approach for producing high-quality essential oils. [ABSTRACT FROM AUTHOR]

Insect infestation triggers multiple defense responses in plants, both locally at the infection site and systemically throughout the plant, including the production of feeding deterrents, toxins, defensive proteins, enzymes, and secondary metabolites. Our study aimed to compare the endogenous levels of antioxidative enzymes, photosynthetic pigments, phytohormones, total phenols, and flavonoids in bark-beetle-infested and uninfested trees. We evaluated the surviving trees in bark-beetle-infested stands, assessing both the condition and defense of uninfested and infested beech (Fagus sylvatica), pine (Pinus sylvestris), and fir (Abies alba) trees. Sampling was performed at six affected sites in the Czech Republic, targeting trees that were resilient to significant health deterioration caused by abiotic and biotic factors. The results showed different levels of most of the measured compounds in the three species. Among all the tested species, photosynthetic pigment levels showed the strongest association with infestation status, which was generally lower in the infested plants. For chlorophyll a, extremely significant reductions were observed from 123 ± 20.6 to 101 ± 17.9 μg/g dry weight (DW) in pine, from 231 ± 33.1 to 199 ± 22.2 μg/g DW in beech, and from 60 ± 5.66 to 51.3 ± 6.27 μg/g DW in fir. In contrast, enzymatic activities indicated only isolated instances of significant association, whereas antioxidative properties (total phenolic content, flavonoids, and 2,2-diphenyl-1-picrylhydrazyl radical scavenging capacity) were not significantly associated with infestation status. There was a statistically significant increase in glutathione reductase activity in infested fir and pine trees. However, this difference was not statistically significant in beech. In contrast, a significant increase in superoxide dismutase activity was detected in infected beech trees. Phytohormones have emerged as the most diverse group of analyzed compounds. Cytokinins were the most distinct, with many of them being significantly increased in infested pines, whereas both beech and fir showed only one significant association. Additionally, derivatives of jasmonic acid also showed a distinct pattern of change associated with bark beetle infestation, with the levels of three out of the four analyzed jasmonates being significantly decreased in infested pines, whereas no effects were observed in beeches and firs. Notably, many phytohormones were significantly elevated in the infested pine, whereas both beech and fir exhibited only one significant association. Overall, the data showed that pines responded differently to bark beetles than to beeches or firs. The greatest changes in phytohormones were observed in pine, whereas the most significant changes in photosynthetic pigments were observed in beech and fir trees. [ABSTRACT FROM AUTHOR]

This study explores the encapsulation in alginate/bentonite beads of two metal(loid)-resistant bacterial consortia (consortium A: Pseudomonas sp. and Bacillus sp.; consortium B: Pseudomonas sp. and Bacillus sp.) from the Atacama Desert (northern Chile) and Antarctica, and their influence on physiological traits of Chenopodium quinoa growing in metal(loid)-contaminated soils. The metal(loid) sorption capacity of the consortia was determined. Bacteria were encapsulated using ionic gelation and were inoculated in soil of C. quinoa. The morphological variables, photosynthetic pigments, and lipid peroxidation in plants were evaluated. Consortium A showed a significantly higher biosorption capacity than consortium B, especially for As and Cu. The highest viability of consortia was achieved with matrices A1 (3% alginate and 2% bentonite) and A3 (3% alginate, 2% bentonite and 2.5% LB medium) at a drying temperature of 25 °C and storage at 4 °C. After 12 months, the highest viability was detected using matrix A1 with a concentration of 106 CFU g−1. Further, a greenhouse experiment using these consortia in C. quinoa plants showed that, 90 days after inoculation, the morphological traits of both consortia improved. Chemical analysis of metal(loid) contents in the leaves indicated that consortium B reduced the absorption of Cu to 32.1 mg kg−1 and that of Mn to 171.9 mg kg−1. Encapsulation resulted in a significant increase in bacterial survival. This highlights the benefits of using encapsulated microbial consortia from extreme environments, stimulating the growth of C. quinoa, especially in soils with metal(loid) levels that can be a serious constraint for plant growth. [ABSTRACT FROM AUTHOR]

Background: Boron is an essential micronutrient for plant growth and productivity, yet excessive boron leads to toxicity, posing significant challenges for agriculture. Fragrant rice is popular among consumers, but the impact of boron toxicity on qualitative traits of fragrant rice, especially aroma, remains largely unexplored. The individual potentials of melatonin and salicylic acid in reducing boron toxicity are less known, while their synergistic effects and mechanisms in fragrant rice remain unclear. Methods: Thus, this study investigates the combined application of melatonin and salicylic acid on fragrant rice affected by boron toxicity. One-week-old seedlings were subjected to boron (0 and 800 µM) and then treated with melatonin and salicylic acid (0 and 100 µM, for 3 weeks). Results: Boron toxicity significantly impaired photosynthetic pigments, plant growth, and chloroplast integrity while increasing oxidative stress markers such as hydrogen peroxide, malondialdehyde, methylglyoxal, and betaine aldehyde dehydrogenase. Likewise, boron toxicity abridged the precursors involved in the 2-acetyl-1-pyrroline (2-AP) biosynthesis pathway. However, individual as well as combined application of melatonin and salicylic acid ameliorated boron toxicity by strengthening the antioxidant defense mechanisms—including the enzymes involved during the ascorbate–glutathione (AsA–GSH) cycle and glyoxalase system—and substantially improved 2-AP precursors including proline, P5C, Δ1-pyrroline, and GABA levels, thereby restoring the 2-AP content and aroma. These findings deduce that melatonin and salicylic acid synergistically alleviate boron toxicity-induced disruptions on the 2-AP biosynthesis pathway by improving the 2-AP precursors and enzymatic activities, as well as modulating the physio-biochemical processes and antioxidant defense system of fragrant rice plants. Conclusions: The findings of this study have the potential to enhance rice productivity and stress tolerance, offering solutions to improve food security and sustainability in agricultural practices, particularly in regions affected by environmental stressors. [ABSTRACT FROM AUTHOR]

Drug overuse harms the biosphere, leading to disturbances in ecosystems' functioning. Consequently, more and more actions are being taken to minimise the harmful impact of xenopharmaceuticals on the environment. One of the innovative solutions is using biosorbents—natural materials such as cells or biopolymers—to remove environmental pollutants; however, this focuses mainly on the removal of metal ions and colourants. Therefore, this study investigated the biosorption ability of selected pharmaceuticals—paracetamol, diclofenac, and ibuprofen—by the biomass of the cyanobacteria Anabaena sp. and Chroococcidiopsis thermalis, using the LC-MS/MS technique. The viability of the cyanobacteria was assessed by determining photosynthetic pigments in cells using a UV–VIS spectrophotometer. The results indicate that both tested species can be effective biosorbents for paracetamol and diclofenac. At the same time, the tested compounds did not have a toxic effect on the tested cyanobacterial species and, in some cases, stimulated their cell growth. Furthermore, the Anabaena sp. can effectively biotransform DCF into its dimer. [ABSTRACT FROM AUTHOR]

Maize (Zea mays L.) is sensitive to salt stress, especially during seed germination and seedling morphogenesis, which limits maize growth and productivity formation. As a novel recognized plant hormone, melatonin (MT) participates in multiple growth and developmental processes and mediates biotic/abiotic stress responses, yet the effects of salt stress on maize seedlings remain unclear. Herein, we investigated the effects of 150 μM exogenous MT on multiple phenotypes and physiologic metabolisms in three-leaf seedlings across eight maize inbred lines under 180 mM NaCl salt stress, including growth parameters, stomatal morphology, photosynthetic metabolisms, antioxidant enzyme activities, and reactive oxygen species (ROS). Meanwhile, the six gene expression levels controlling antioxidant enzyme activities and photosynthetic pigment biosynthesis in two materials with contrasting salt resistance were examined for all treatments to explore the possible molecular mechanism of exogenous MT alleviating salt injury in maize. The results showed that 150 μM exogenous MT application protected membrane integrity and reduced ROS accumulation by activating the antioxidant system in leaves of maize seedlings under salt stress, their relative conductivity and H2O2 level average reduced by 20.91% and 17.22%, while the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) averaged increased by 13.90%, 17.02%, 22.00%, and 14.24% relative to salt stress alone. The improvement of stomatal size and the deposition of photosynthetic pigments were more favorable to enhancing photosynthesis in leaves when these seedlings treated with MT application under salt stress, their stomatal size, chlorophyll content, and net photosynthetic rate averaged increased by 11.60%, 19.64%, and 27.62%. Additionally, Gene expression analysis showed that MT stimulation significantly increased the expression of antioxidant enzyme genes (Zm00001d009990, Zm00001d047479, Zm00001d014848, and Zm00001d007234) and photosynthetic pigment biosynthesis genes (Zm00001d011819 and Zm00001d017766) under salt stress. At the same time, 150 μM MT significantly promoted seedling growth and biomass accumulation. In conclusion, our study may unravel crucial evidence of the role of MT in maize seedlings against salt stress, which can provide a novel strategy for improving maize salt stress resistance. [ABSTRACT FROM AUTHOR]

Water stress (drought and waterlogging) is one highly important factor affecting food security in China. Investigating the effects of soil moisture stress on the morphological and physiological characteristics of maize seedlings is crucial for ensuring food production. The use of spectral monitoring to observe crop phenotypic traits and assess crop health has become a focal point in field crop research. However, studies exploring the contribution of crop phenotypic and physiological data to the Normalized Difference Vegetation Index (NDVI) are still limited. In this study, a 35-day pot experiment was conducted with seven soil moisture gradients: 50%, 60%, 70%, 80% (control group, CK), 90%, 100%, and 110% treatment. In order to investigate the effects of soil moisture stress on seedling phenotypes, antioxidant enzyme activities, and NDVI, an ASD FieldSpec 4 Hi-Res NG portable spectrometer was used to collect spectral data from maize (Zea mays L. B73) leaves. The contributions of maize phenotypic and physiological traits to NDVI were also examined. The results indicated that (1) the 50% and 110% treatments significantly affected maize seedling phenotypes compared to the CK group; (2) the activities of superoxide dismutase (SOD) and peroxidase (POD) in the leaves increased under water stress, while the activities of glutathione peroxidase (GSH-PX) and ascorbate peroxidase (APX) decreased; (3) soil moisture stress (drought and waterlogging) reduced photosynthetic pigments, chlorophyll content (SPAD), and NDVI, with inhibitory effects intensifying as the stress level increased; (4) Redundancy analysis showed that antioxidant enzymes explained 69.87% of the variation in seedling height, leaf area, and NDVI. Soil moisture stress, chlorophyll, and SPAD explained 58.14% of the variation in these parameters. The results demonstrated that maize seedlings were highly sensitive to soil moisture changes, and the SPAD value contributed significantly to NDVI (p < 0.01). This study provides valuable insights for future research in precision agriculture management [ABSTRACT FROM AUTHOR]

In this work, we assessed the effects of increasing ozone (O3) on four petunia varieties with different floral pigmentation (pink, red, rose-red, and white). Plants were exposed, in open-top chambers located in China, to three O3 concentrations, i.e., (i) ambient air (AA), (ii) AA + 60 ppb O3 (AA + 60), and (iii) AA + 120 ppb O3 (AA + 120), for 85 days (9 h day−1). Flower diameter and duration were assessed, together with leaf chlorophyll and flavonoid contents. White petunia showed a reduced flower diameter and longevity under AA + 60 (−7 and −6%, respectively, in comparison to AA), whereas pink and red petunias only showed this under AA + 120 (−8 and −7%, on average, respectively). Chlorophyll loss occurred in all varieties under AA + 60 (−30%, on average), and at AA + 120 in white and red petunias (−54%, on average). The total flavonoid content in the pink and white varieties increased only under AA + 120 (around +85%), while it grew at both AA + 60 and AA + 120 (+92% and two-fold higher, respectively) in the red variety. Increasing O3 concentrations did not affect particularly the red-rose variety. The white variety showed the strongest correlations among flower and leaf properties, confirming a variety-related O3 response, as well as demonstrating that it had the highest O3 sensitivity. [ABSTRACT FROM AUTHOR]

Chemical desiccation is widely used in agriculture to anticipate harvest and mitigate the effects of adverse environmental conditions. It is applied to both grains and seeds. Although this practice is widely used, there are still significant gaps in understanding the effects of different herbicide application times on seed quality and plant physiological responses. The objective of this study was to evaluate the effects of different herbicide application times on cowpea, focusing on seed quality, physiological responses, and biochemical composition, including chlorophylls, carotenoids, sugars, and proline, under nocturnal desiccation. In the first experiment, eight herbicides and two mixtures were applied at night: diquat, flumioxazin, diquat + flumioxazin, glufosinate ammonium, saflufenacil, carfentrazone, diquat + carfentrazone, atrazine, and glyphosate. All of the tested herbicides caused a reduction in normal seedling formation, with the diquat + carfentrazone combination resulting in 100% abnormal seedlings. A significant decrease in chlorophyll levels (chlorophyll a: 63.5%, chlorophyll b: 50.2%) was observed using diquat, which indicates damage to photosynthetic processes, while the carotenoid content increased. Total soluble sugars and proline were also negatively impacted, reflecting physiological stress and metabolic changes in seedlings. In the second experiment, three application times were tested with diquat, diquat + flumioxazin, and diquat + carfentrazone. Nocturnal application showed the most significant reduction in chlorophyll levels and increased carotenoid levels. Application at noon and late afternoon also significantly changed the soluble sugar and proline levels. These results indicate that the herbicide application time directly influences the seeds' physiological quality. [ABSTRACT FROM AUTHOR]

Simple Summary: This study looked at how three different shrub species in an urban setting were affected by aphid colonisation. Analyses of fourteen factors that describe the photosynthetic pigment concentration and gas exchange to the carbon, nitrogen, and hydrogen partition were conducted. Aphid colonisation had the greatest impact on nitrogen partition and the C/N ratio, parameters that could be recommended in other studies of a similar kind. The studied shrub species had varying responses. Spiraea × vanhouttei and Cydonia japonica demonstrated the strongest responses in terms of nitrogen partition and the C/N ratio. Shrubs are a significant component of urban vegetation found in parks, but they experience various influences from biotic and abiotic agents, among which aphids play an important role. In this work, the effects of aphid colonisation on three shrub species in urban environments were examined. Fourteen parameters were analysed, describing the photosynthetic pigment content and gas exchange to carbon, nitrogen, and hydrogen partitions. While no significant effect of colonisation was found on photosynthetic pigment parameters, the effect was significant on gas exchange parameters. The strongest effect of aphid colonisation achieved was on nitrogen partition and the C/N ratio, parameters that could be suggested for further similar studies. All parameters were classified into two groups according to their principal component analysis, suggesting a correlation between nitrogen and carbon content, the C/N ratio, measured gas exchange parameters, and chlorophyll a content. The ratio between net photosynthesis and dark respiration (A/K) was classified in the second group, suggesting that this parameter provides additional information on the effect of aphid colonisation and deserves special attention in further studies. There were differences in the effect of aphid colonisation on the physiology of the examined shrub species, especially in cases where a decrease in the C/N ratio was achieved in Spirea trilobata and Cydonia japonica, while an increase in the same parameter was recorded in Hybiscus syriacus. [ABSTRACT FROM AUTHOR]

Water deficit and heat are the primary abiotic stresses affecting plants. We conducted in vitro experiments to investigate how citron watermelon seedlings respond to water deficit and heat, focusing on growth, water status, reserve mobilization, hydrolase activity, and metabolite partitioning, including non-structural carbohydrate availability, during the vulnerable stage of seedling establishment crucial for crop production. To reveal the involvement of phytosterols (stigmasterol, sitosterol, and campesterol) in combined stress tolerance, four citron watermelon genotypes were investigated under varying osmotic potential [−0.05 MPa, −0.09 MPa and −0.19 MPa] and temperature (26 °C and 38 °C). Phytosterols were analyzed by gas chromatography–mass spectrometry (GC–MS). Seedlings subjected to osmotic stress from polyethylene glycol (PEG) exhibited reduced growth, linked to relative water content (RWC) changes, delayed starch mobilization in cotyle-dons, and decreased non-structural carbohydrate availability in roots. High temperature retarded the photosynthetic apparatus's establishment and compromised photosynthetic pigment activity and dry matter production. The results suggest that inherent stress tolerance in citron watermelon is characterized by the increased accumulation of lipids, mainly sterols, especially in heat/drought-stressed plants. This study provides valuable information about the metabolic response of citron watermelon to combined stress and metabolites identified, which will encourage further study in transcriptome and proteomics to improve drought tolerance. [ABSTRACT FROM AUTHOR]

Low temperature is a major environmental factor that negatively affects the growth and productivity of plants, such as the tropical fruit Cape gooseberry (Physalis peruviana L.), which is susceptible to cold stress. Therefore, to investigate the effect of the amino acid L-phenylalanine (Phe), L-cysteine (Cys), or sodium selenite (Se) on enhancing antioxidant activities, experiments were conducted on the phenolic compounds, proline content, and membrane stability of Cape gooseberry seedlings under low-temperature stress. The seedlings were exposed for 48 h to a low temperature (4 °C) followed by 24 h of optimal growth conditions. In seedlings treated with Se, we found a high relative water content, good membrane integrity, low ion leakage, and hydrogen peroxide. Additionally, this treatment led to the improvement of photosynthetic pigments and antioxidant activity. The analysis of seedlings under cold stress showed that the Phe enhanced the stomatal conductance and phenol content. Furthermore, low concentrations of Cys resulted in the production of proline and flavonoids, which reduced the negative effects of environmental stress on seedlings and maintained cell membrane integrity. Overall, in this experiment, the use of Se and low concentrations of Cys had a positive effect on the amount of antioxidant compounds, which improved seedling growth under stress conditions. [ABSTRACT FROM AUTHOR]

Light treatment is an innovative method to enhance the synthesis of secondary metabolites in plants and improve the quality of plant-based food ingredients. This study investigated the effects of red light treatment on the physiological and biochemical changes during wheat germination, aiming to produce high-quality wheat sprouts with strong antioxidant capacity. Using response surface methodology, the study optimized the conditions for phenolic accumulation in wheat sprouts under red light treatment and explored the molecular mechanisms behind the enhancement of total phenolic content (TPC) and quality. The results indicated that red light treatment significantly increased the TPC in wheat sprouts. The highest TPC, reaching 186.61 μg GAE/sprout, was observed when wheat sprouts were exposed to red light at an intensity of 412 μmol/m²/s for 18.2 h/d over four days. Compared to no light, red light treatment significantly increased the content of photosynthetic pigments (chlorophyll and carotenoids). Red light treatment notably heightened the levels of both free and bound phenolic in the germinating wheat. Red light treatment markedly boosted the activities and relative gene expression levels of enzymes related to phenolic biosynthesis, including phenylalanine ammonia-lyase, cinnamate-4-hydroxylase, and 4-coumarate-CoA ligase. Additionally, red light treatment enhanced the antioxidant capacity of wheat sprouts by improving the activity and gene expression of four key antioxidant enzymes, thereby promoting growth and germination. This research suggested that red light treatment is an effective strategy for stimulating total phenolic biosynthesis, enhancing antioxidant capacity, and producing highly nutritious wheat sprouts, thus laying the groundwork for developing total phenolic-enriched wheat sprouts as valuable food ingredients in the future. [ABSTRACT FROM AUTHOR]

Urban trees are known for their ability to settle fine particulate matter (PM2.5), yet the effects of historical pollution exposure on their dust-retention capacity and stress memory remain underexplored. Therefore, we selected Euonymus japonicus Thunb. var. aurea-marginatus Hort. and Photinia × fraseri Dress, which are two common urban greening tree species in the Yangtze River Delta, a highly urbanized region in China facing severe air pollution challenges, characterized by dense urban forests, and we employed an aerosol generator to perform controlled experiments aiming to simulate PM2.5 pollution exposure in a sealed chamber. The experiments encompassed a first pollution treatment period P1 (15 days), a recovery period R (15 days), and a second pollution treatment period P2 (15 days). The study investigates the historical impacts of pollution exposure by simulating controlled environmental conditions and assessing the morphological and physiological changes in trees. The main results are as follows: Vd of Euonymus japonicus Thunb. var. aurea-marginatus Hort. significantly decreased on the 10th day during P2 compared with that on the same day during P1, whereas Vd of Photinia × fraseri Dress significantly decreased on the 15th day. Compared with those during P1, the specific leaf area of both plants significantly decreased, the specific leaf weight significantly increased, the wax layer significantly thickened, the stomata decreased, and the content of photosynthetic pigments remained stable during P2. Furthermore, the air pollution tolerance index (APTI) generally increased during both P1 and P2. This study contributes to international knowledge by examining stress memory in urban trees and underscores the role of stress memory in enhancing plant resistance to periodic particulate pollution, offering insights into the adaptive mechanisms that can be applied globally, not just regionally. [ABSTRACT FROM AUTHOR]

Salt stress is a key environmental factor altering rice plant growth. Strigolactones (GR24) play a vital role in responding to various abiotic stresses and regulating plant growth. However, the regulatory mechanisms of SLs on rice seedlings under salt stress have not yet been clarified. A pot experiment was undertaken to evaluate the effects of GR24 soaking on the rice variety 'Huanghuazhan' (salt-sensitive) seedling growth, antioxidant metabolism, and endogenous hormones under NaCl stress. Results showed that NaCl stress significantly inhibited rice growth; disrupted antioxidant enzymes activity; and increased the content of soluble proteins (SPs), proline (Pro), malondialdehyde (MDA) and hydrogen–peroxide (H2O2). GR24 significantly improved photosynthetic pigments and antioxidant–enzyme activities, including superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate–peroxidase (APX); increased SP, ascorbic acid (AsA); and reduced glutathione (GSH) content and MDA, H2O2, and Pro content, resulting in the mitigation of oxidative injury caused by NaCl stress. Moreover, GR24 significantly increased the content of strigolactones (SLs), cytokinin (CTK), auxin (IAA), Gibberellin A3 (GA3), and IAA/ABA and CTK/ABA ratios and decreased the abscisic acid (ABA). Findings indicated that GR24 alleviated oxidative damage caused by NaCl stress by increasing photosynthetic and antioxidant capacity and maintaining the balance of endogenous hormones, thus improving the salt tolerance of rice seedlings. [ABSTRACT FROM AUTHOR]

Anti-hail nets have been employed in viticulture to reduce the damage caused by hailstorms, but whether this strategy may have detrimental effects on grape quality in the Mediterranean region is still unknown. This study was carried out in the Salento region during the 2023 harvest to evaluate the grape microclimate and fruit quality attributes of 'Fiano' white grapes grown uncovered or covered with either crystal or black nets. The nets had a small but significant effect on the air temperature (about 0.3 °C and 0.1 °C higher with black and crystal nets, respectively) and relative humidity (about 1% lower with both black and crystal nets) in the grape zone. However, no significant variation was recorded for grape colouration (except for the chromaticity coordinate a*) nor for the main skin photosynthetic pigments (chlorophyll a, chlorophyll b, carotenoids), the total polyphenolic content, and the total soluble solids. Our preliminary results suggest that anti-hail nets can be effective to protect the grapevines against hailstorms and other adverse weather conditions, without having negative impacts on the colour development and bioactive compounds of white grapes in the Mediterranean region. [ABSTRACT FROM AUTHOR]

The Coulomb coupling between transition densities of the pigments in photosynthetic pigment-protein complexes, termed excitonic coupling, is a key factor for the description of optical spectra and energy transfer. A challenging question is the quantification of the screening of the excitonic coupling by the optical polarizability of the environment. We use the equivalence between the sophisticated quantum chemical polarizable continuum (PCM) model and the simple electrostatic Poisson-TrEsp approach to analyze the distance and orientation dependence of the dielectric screening between chlorophylls in photosystem I trimers. On the basis of these calculations we find that the vacuum couplings V m n (0) and the couplings in the dielectric medium V m n = f m n V m n (0) are related by the empirical screening factor f m n = 0.60 + 39.6 θ (| κ m n | − 1.17) exp (− 0.56 R m n / Å) , where κ m n is the usual orientational factor of the dipole-dipole coupling between the pigments, R m n is the center-to-center distance, and the Heaviside-function θ (| κ m n | − 1.17) ensures that the exponential distance dependence only contributes for in-line type dipole geometries. We are confident that the present expression can be applied also to other pigment-protein complexes with chlorophyll or related pigments of similar shape. The variance between the Poisson-TrEsp and the approximate coupling values is found to decrease by a factor of 8 and 3–4 using the present expression, instead of an exponential distance dependent or constant screening factor, respectively, assumed previously in the literature. [ABSTRACT FROM AUTHOR]

Rising temperature is a major threat to the normal growth and development of maize, resulting in low yield production and quality. The mechanism of maize in response to heat stress remains uncertain. In this study, a maize mutant Zmhsl-1 (heat sensitive leaves) with wilting and curling leaves under high temperatures was identified from maize Zheng 58 (Z58) mutant lines generated by ethyl methanesulfonate (EMS) mutagenesis. The Zmhsl-1 plants were more sensitive to increased temperature than Z58 in the field during growth season. The Zmhsl-1 plants had lower plant height, lower yield, and lower content of photosynthetic pigments. A bulked segregant analysis coupled with whole-genome sequencing (BSA-seq) enabled the identification of the corresponding gene, named ZmHSL, which encodes an endo-β-1,4-xylanase from the GH10 family. The loss-of-function of ZmHSL resulted in reduced lignin content in Zmhsl-1 plants, leading to defects in water transport and more severe leaf wilting with the increase in temperature. RNA-seq analysis revealed that the differentially expressed genes identified between Z58 and Zmhsl-1 plants are mainly related to heat stress-responsive genes and unfolded protein response genes. All these data indicated that ZmHSL plays a key role in lignin synthesis, and its defective mutation causes changes in the cell wall structure and gene expression patterns, which impedes water transport and confers higher sensitivity to high-temperature stress. [ABSTRACT FROM AUTHOR]

Salinity poses a significant challenge to tomato plant development and metabolism. This study explores the use of biostimulants as eco-friendly strategies to enhance tomato plant tolerance to salinity. Conducted in a greenhouse, the research focuses on the Solanum lycopersicum L. behavior under saline conditions. Tomato seeds were treated with arbuscular mycorrhizal fungi (AMF), compost, and their combination under both non-saline and saline conditions (0 and 150 mM NaCl). Plant height, number of flowers and fruits, shoot fresh weight, and root dry weight were negatively impacted by salt stress. The supplementation with compost affected the colonization of AMF, but the application of stress had no effect on this trait. However, the use of compost and AMF separately or in combination showed positive effects on the measured parameters. At the physiological level, compost played a beneficial role in increasing photosynthetic efficiency, whether or not plants were subjected to salinity. In addition, the application of these biostimulants led to an increase in nitrogen content in the plants, irrespective of the stress conditions. AMF and compost, applied alone or in combination, showed positive effects on photosynthetic pigment concentrations and protein content. Under salt stress, characterized by an increase in lipid peroxidation and H2O2 content, the application of these biostimulants succeeded in reducing both these parameters in affected plants through exhibiting an increase in antioxidant enzyme activity. In conclusion, incorporating compost, AMF, or their combined application emerges as a promising approach to alleviate the detrimental impacts of salt stress on both plant performances. These findings indicate optimistic possibilities for advancing sustainable and resilient agricultural practices. [ABSTRACT FROM AUTHOR]

We studied the recovery of the growth and physiological parameters of Scots pine seedlings after long-term zinc toxicity. The removal of excess zinc from the nutrient solution resulted in the rapid recovery of primary root growth but did not promote the initiation and growth of lateral roots. The recovery of root growth was accompanied by the rapid uptake of manganese, magnesium, and copper. Despite the maximum rate of manganese uptake by the roots, the manganese content in the needles of the recovering plants did not reach control values during the 28 days of the experiment, unlike magnesium, iron, and copper. In general, the recovery of ion homeostasis eliminated all of the negative effects on the photosynthetic pigment content in the needles. However, these changes, along with recovery of the water content in the needles, were not accompanied by an increase in the weight gain of the recovering seedlings compared with that of the Zn-stressed seedlings. The increased accumulation of phenolic compounds in the needles persisted for a long period after excess zinc was removed from the nutrient solution. The decreased lignin content in the roots and needles is a characteristic feature of Zn-stressed plants. Moreover, the removal of excess zinc from the nutrient solution did not lead to an increase in the lignin content in the organs. [ABSTRACT FROM AUTHOR]

In the relay intercropping system of maize/sweet potato, the growth of the sweet potatoes is seriously limited by weak light stress in the early stage due to shade from maize plants. However, it is not clear how the weak light affects sweet potatoes and causes tuberous root loss. By setting two light intensity levels (weak light = 30% transmittance of normal light), this study evaluated the responses of two sweet potato cultivars with different tolerances to weak light in a field-based experiment and examined the divergence of gene expression related to light and photosynthesis in a pot-based experiment. The results showed that under weak light, the anatomic structure of functional leaves changed, and the leaf thickness decreased by 39.98% and 17.32% for Yuhongxinshu-4 and Wanshu-7, respectively. The ratio of S/R increased, and root length, root superficial area, and root volume all decreased. The photosynthetic enzyme rubisco was weakened, and the net photosynthetic rate (Pn) declined as well. The level of gene expression in Wanshu-7 was higher than that of Yuhongxinshu-4. The KEGG analysis showed that differentially expressed genes from the two cultivars under weak-light stress used the same enrichment pathway, mainly via glutathione metabolism and flavonoid biosynthesis. After full light levels were restored, the differentially expressed genes were all enriched in pathways such as photosynthesis, photosynthetic pigment synthesis, and carbon metabolism. These findings indicated that weak light changed the plant morphology, photosynthetic physiology and gene expression levels of sweet potatoes, which eventually caused losses in the tuberous root yield. The more light-sensitive cultivar (Wanshu-7) had stronger reactions to weak light. This study provides a theoretical basis and strategy for breeding low-light-tolerant varieties and improving relay intercropping production in sweet potatoes. [ABSTRACT FROM AUTHOR]

The olive oil from the Royal cultivar has not been studied in depth, especially its relationship between analytical and sensory parameters. Currently, it is a minority cultivar, but due to its excellent organoleptic properties, it is constantly growing. The research objective is to obtain excellent-quality olive oil from the Royal cultivar at an industrial extraction plant and characterize the oil sensory and analytically. For this purpose, three important factors were set: very early olives; very low-time olive paste malaxation; and environmental temperature. The analytical parameters studied were volatile and phenolic compounds, fatty acids, photosynthetic pigments, and other quality parameters. Fourteen phenolic compounds were identified and found in significantly higher concentrations in Royal olive oil, including the oleacein compound. Moreover, volatile compounds from the LOX pathway, such as hexenal, (E)-2-hexenal, and (Z)-3-hexen-1-ol, had significantly higher concentrations, which were related to organoleptic characteristics: very fruity, not very spicy, and very low bitterness. The highest values obtained were 74.98% extraction efficiency at 30 min; 71.31 mg/kg chlorophyll content at 30 min; 156.38 mg/kg phenolic compound at 30 min; 18.98 mg/kg volatile compounds at 15 min; and better organoleptic characteristics at 15 min. The oil extraction efficiency was lower than that of other olive cultivars; nevertheless, the content of volatile compounds is higher. [ABSTRACT FROM AUTHOR]

Simple Summary: Macroalgae in natural marine areas play an important role in mitigating ocean climate change. The complexity of natural conditions also makes it necessary to study macroalgae not only by considering the effects of changes in a single factor but also by exploring the coupled effects of different environmental conditions on macroalgae. Therefore, in this study, two species of macroalgae were used as experimental subjects to observe their growth processes under different co-treatments of temperature and CO2 concentration. The results of this study can provide a reference for how natural macroalgae can cope with future changes in ocean climate. To investigate the ecological impacts of macroalgae in the framework of shifting global CO2 concentrations, we conducted a study utilizing Ulva fasciata and Sargassum horneri specimens sourced from the Ma'an Archipelago in Zhejiang Province on how ocean acidification (OA) and temperature changes interact to affect the photosynthetic physiological responses of macroalgae. The results of the study showed that OA reduced the tolerance of U. fasciata to bright light at 20 °C, resulting in more pronounced photoinhibition, while 15 °C caused significant inhibition of U. fasciata, reducing its growth and photosynthetic activity, but OA alleviated the inhibition and promoted the growth of the alga to a certain extent. The tolerance of S. horneri to bright light was also reduced at 20 °C; the inhibition was relieved at 15 °C, and the OA further improved the algal growth. The Relative Growth Rate (RGR), photosynthetic pigment content, and the release of the dissolved organic carbon (DOC) of U. fasciata were mainly affected by the change in temperature; the growth of the alga and the synthesis of metabolites were more favored by 20 °C. A similar temperature dependence was observed for S. horneri, with faster growth and high metabolism at 15 °C. Our results suggest that OA reduces the tolerance of macroalgae to high light at suitable growth temperatures; however, at unsuitable growth temperatures, OA effectively mitigates this inhibitory effect and promotes algal growth. [ABSTRACT FROM AUTHOR]

Salt stress is a critical abiotic factor that adversely affects plant growth and productivity by impairing photosynthesis. This study explores the impact of exogenous ascorbic acid (AsA) on the photosynthetic performance of tomato seedlings (Solanum lycopersicum L. cv. Ligeer 87-5) under salt stress. Hydroponic experiments were conducted in a solar greenhouse, where tomato seedlings were subjected to the following five treatments: Control, NaCl, NaCl + AsA, NaCl + lycorine (LYC), and NaCl + LYC + AsA. Our findings demonstrate that salt stress significantly reduced chlorophyll and carotenoid contents, levels of chlorophyll synthesis precursors (5-aminolevulinic acid (ALA), porphobilinogen (PBG), uroporphyrinogen III (Urogen III), protoporphyrin IX (Proto IX), magnesium protoporphyrin IX (Mg-Proto IX), protochlorophyllide (Pchl)), and essential elements (Mg, Fe, Mn, Zn, Mo, and P) in both roots and leaves. These reductions led to a substantial decline in net photosynthetic rate (Pn) and compromised photosystem II (PSII). In contrast, exogenous AsA application significantly enhanced the content of photosynthetic pigment precursors and essential elements, improved stomatal aperture and gas exchange efficiency, and boosted the photosynthetic performance of tomato seedlings under salt stress. Furthermore, AsA treatment mitigated the negative effects of salt stress by protecting PSII, increased light energy utilization efficiency, and alleviated both stomatal and non-stomatal limitations. The application of the AsA synthesis inhibitor LYC exacerbated the detrimental effects of salt stress, further reducing chlorophyll content and photosynthetic efficiency. In conclusion, exogenous AsA plays a vital role in enhancing the photosynthetic performance and stress tolerance of tomato seedlings under salt stress by stabilizing chlorophyll biosynthesis, facilitating essential element absorption, and optimizing stomatal function. This study provides a new approach and feasible measures for improving tomato resistance and yield, which is significant for enhancing crop productivity, managing saline soils, and promoting sustainable agricultural practices. [ABSTRACT FROM AUTHOR]

Rising atmospheric CO2 levels, a significant consequence of anthropogenic activities, profoundly impact global agriculture and food security by altering plant physiological processes. Despite extensive research, a comprehensive understanding of the specific effects of elevated CO2 on maize (Zea mays L.)'s primary and secondary metabolism remains elusive. This study investigated the responses of maize seedlings cultivated in open-top chambers (OTCs) under three CO2 concentrations: ambient (380 ppm), elevated (600 ppm), and high (1800 ppm). Key growth parameters, including plant height, leaf area, and aboveground biomass (leaf and stem), were assessed alongside metabolic profiles encompassing nonstructural and structural carbohydrates, syringyl (S) and guaiacyl lignin, the syringyl-to-guaiacyl (S/G)-lignin ratio, photosynthetic pigments, total soluble protein, and malondialdehyde (MDA) levels. The results demonstrated that exposure to 600 ppm CO2 significantly enhanced plant height, leaf area, and aboveground biomass compared to ambient conditions. Concurrently, there were notable increases in the concentrations of primary metabolites. In contrast, exposure to 1800 ppm CO2 severely inhibited these growth parameters and induced reductions in secondary metabolites, such as chlorophyll and soluble proteins, throughout the growth stages. The findings underscore the intricate responses of maize metabolism to varying CO2 levels, highlighting adaptive strategies in primary and secondary metabolism under changing atmospheric conditions. This research contributes to a nuanced understanding of maize's physiological adaptations to future climate scenarios characterized by elevated CO2, with implications for sustainable agriculture and food security. [ABSTRACT FROM AUTHOR]

Hollyhock (Alcea rosea L.) is an aromatic, ornamental/medicinal plant species for which the selection of drought-tolerant varieties based on physio-chemical traits is desirable. The data presented resulted from a field experiment. This experiment was designed as a split-plot, based on a randomized complete block design, in which the main plots consisted of the three irrigation regimes (30, 60 and 80% permissible discharge moisture available in the soil), and the subplots consisted of nine hollyhock varieties. Photosynthetic pigments, Fv/Fm, proline content and selected antioxidant enzymes were measured throughout the period of induced drought stress. The data obtained illustrate the nature of the physiological response of hollyhock to drought stress. Based on the measured traits the varieties Isfahan 1, Shiraz 1 and Tabriz were shown to display the highest degree of resistance to drought stress. These data suggest that the effect of drought stress is dependent upon the drought level, variety and the trait in question. In this regard, future plant breeders for this species may find it useful to utilize ascorbate peroxidase (APX), catalase (CAT) and guayacol peroxidase (POX) activities as biochemical markers to select for drought-tolerant genotypes. As such, hollyhock can be considered a promising ornamental/medicinal species for cultivation in semi-arid environments. [ABSTRACT FROM AUTHOR]

Temporary immersion system (TIS) cultures are reported to be superior when compared to semi-solid (SS) and liquid (LQ) cultures for the in vitro plant regeneration of many plant species. In the present study, we used a TIS for plant regeneration of Gerbera jemesonii "Shy Pink" and compared the results with that of SS and LQ cultures. The number of shoots regenerated in the SS, LQ, and TIS cultures was 6.93, 3.13, and 3.03, respectively. The shoots regenerated with the SS and LQ cultures demonstrated 3.33 and 4.22% hyperhydricity, whereas the shoots regenerated with the TIS were healthy even though the number of shoots regenerated was less. The plantlets regenerated with the TIS demonstrated higher values for the number of roots, root length, biomass of the plantlets, leaf length/width, and area compared to the SS and LQ cultures. When the G. jemesonii "Shy Pink" plants were regenerated using the TIS, their levels of photosynthetic pigments were highest. The number of stomata on the abaxial surface of their leaves was 11.40, and the frequency of closed stomata was 59% for the plants regenerated with the TIS. The number of stomata was 21.4 and 14.5 for the plants regenerated with the SS and LQ cultures, respectively. Meanwhile, the frequency of closed stomata was 13% and 15% for the plants regenerated with SS and LQ cultures. Furthermore, G. jemesonii "Shy Pink" showed the highest survival of plants when regenerated in the TIS compared to SS and LQ cultures. The TIS was found to be the most suitable culture system for plant regeneration of G. jemesonii "Shy Pink" compared to SS and LQ cultures. [ABSTRACT FROM AUTHOR]

Salinity is a major constraint limiting the yield of tomatoes. However, grafting strategies may help to overcome the salt toxicity of this important horticultural species if appropriate rootstocks are identified. The present study aimed to test a new rootstock, JUPAFORT1, obtained by crossing the glycophyte Solanum lycopersicum (cv. Poncho Negro) with the halophyte wild-related species Solanum chilense to improve the salinity tolerance of the Chilean tomato landrace Old Limachino Tomato (OLT). Intact OLT plants were exposed to 0, 80, or 160 mM of NaCl for 21 days at the vegetative stage and compared with self-grafted (L/L) and Limachino plants grafted on JUPAFORT1 rootstock (L/R) under a completely randomized design. JUPAFORT1 increased OLT scion vigor in the absence of salt but did not significantly increase fresh weight under stress conditions. However, JUPAFORT1 confers to the scion an anisohydric behavior contrasting with the isohydric behavior of L and L/L plants as indicated by measurements of stomatal conductance; L/R plants were able to maintain their metabolic status despite a slight decrease in the leaf's relative water content. JUPAFORT1 rootstock also enabled the maintenance of photosynthetic pigment concentrations in the scion in contrast to L and L/L plants, which exhibited a decrease in photosynthetic pigments under stress conditions. L/R plants encountered oxidative stress at the highest stress intensity (160 mM of NaCl) only, while L and L/L plants suffered from oxidative damage at a lower dose (80 mM of NaCl). L/R plants behaved as includer plants and did not sequester Na+ in the root system, in contrast to L and L/L, which behaved as excluder plants retaining Na+ in the root system to avoid its translocation to the shoots. The expression of genes coding for ion transporters (HKT1.1, HKT1.2, LKT1, SKOR, SOS2, and SOS3) in the root system was not modified by salinity in L/R. In contrast, their expression varied in response to salinity in L and L/L. Overall, L/R plants exhibited higher physiological stability than L/L or L plants in response to an increasing NaCl dose and did not require additional energy investment to trigger an adaptative response to salinity. This suggests that the constitutive salinity tolerance of the halophyte S. chilense was maintained in the interspecific rootstock. JUPAFORT1 issued from S. lycopersicum x S. chilense may thus improve salt-stress resilience in OLT tomatoes. Additional studies are required to identify the molecular components involved in the root-to-shoot signaling pathway in this promising material. [ABSTRACT FROM AUTHOR]

Moxifloxacin (MOX), a widely used novel antibiotic, may pose ecological risks at its actual environmental concentrations, as has been detected in aquatic systems. However, its ecotoxicity to aquatic organisms and regulatory mechanisms of phosphorus in eutrophic aqueous environments are still limited. This study aimed to analyze its physiological and biochemical parameters, including cellular growth, chlorophyll fluorescence, photosynthetic pigments, oxidative stress biomarkers, and metabolomics to elucidate the toxicity induced by environmental concentrations of MOX in Microcystis aeruginosa at different phosphorus levels. The results revealed that the EC50 values of MOX on M. aeruginosa at different phosphorus concentrations were 8.03, 7.84, and 6.91 μg/L, respectively, indicating MOX toxicity was exacerbated with increasing phosphorus levels. High phosphorus intensified the suppression of chlorophyll fluorescence and photosynthetic pigments, while activating the antioxidant enzyme, indicating severe peroxidation damage. Metabolomic analysis showed MOX induced different discriminating metabolites under different phosphorus levels, and perturbed more biological pathways at higher phosphorus concentrations, such as starch and sucrose metabolism, pyrimidine metabolism, and glycerolipid metabolism. This indicates that phosphorus plays an important role in regulating metabolism in M. aeruginosa exposed to MOX. The findings provide valuable information on the mechanisms involved in cyanobacteria responses to antibiotic stress, and offer a theoretical basis for accurately assessing antibiotic toxicity in eutrophic aqueous environments. [ABSTRACT FROM AUTHOR]

Featured Application: The findings from this research may have a specific and so far unique application in creating new packaged food products that are not traditionally distributed as such. The results show that the selection of proper packaging material with good thickness, transparency and permeability characteristics along with favorable storage conditions can help to preserve the antioxidant compounds of fresh-cut nettle leaves for 14 days. Green leafy vegetables are very challenging in terms of storage and preservation, while packaging in controlled conditions with the selection of appropriate polymer material is crucial for maintaining their nutritional value and quality. Various packaging materials have different gas and water vapor permeability as well as physicochemical properties that can create a specific environment inside the package, therefore affecting the chemical composition, sensory characteristics, and overall quality of packed leafy vegetables. Stinging nettle is an edible plant with a high antioxidant content, making it a valuable leafy vegetable. Therefore, this study aimed to evaluate the influence of four packaging materials (biaxially oriented polypropylene (BOPP), low-density polyethylene (LDPE), polyamide/polyethylene (PA/PE), and polylactic acid (PLA)) on the antioxidant content of packed fresh nettle leaves during 14-day storage. Ascorbic acid content was the highest after 6 days of storage, equally well preserved in all tested films, with an average of 86.74 mg/100 g fm (fresh mass). After 14 days of storage, the total phenolic content was best preserved when packed in LDPE. The content of caffeoylmalic and chlorogenic acids was the highest in LDPE after 6 days. In addition, leaves packed in LDPE after 6 days of storage had the highest content of all photosynthetic pigments. According to FRAP analysis, the antioxidant capacity was best maintained in LDPE (at the 14th day, the measured capacity was 43.61 µmol TE/g). This study shows that the type of packaging material (BOPP, LDPE, PA/PE, and PLA) and storage duration (6 and 14 days) have a great impact on the level of antioxidant compounds in the nettle leaves, where LDPE and BOPP can be highlighted as the most favorable for the preservation of total and individual phenolic compounds, photosynthetic pigments, and antioxidant capacity. [ABSTRACT FROM AUTHOR]

Plant functional traits are an important indicator for the comprehensive evaluation of community stability and resilience. Therefore, exploring the variations and relationships among leaf functional traits at different maturity levels during forest restoration can deepen the understanding of plant adaptation strategies and community assembly. In this study, we measured the leaf area (LA), specific leaf area (SLA), photosynthetic pigments, non-structural carbohydrates (NSCs), leaf nitrogen content (LNC), and leaf phosphorus content (LPC) of dominant tree species in three communities with different maturity levels (defined by species composition, biodiversity and spatial structure) in a monsoon forest located in the northern margin of the tropics in China, and explored the variation and relationships among different leaf traits at individual, species, and community scales. The results showed that maturity levels significantly affected leaf functional traits. With the increase in maturity levels, SLA increased, and leaf SS and NSCs decreased, while other leaf functional traits did not show a consistent pattern. In different communities, NSCs, Chl (a:b), SS:St or Car had a trade-off or synergistic relationship with leaf economic spectrum. Additionally, the LPC, LNC, and starch were the key traits in response to selection pressure at maturity levels, inter-specific and intra-specific scales, respectively, and the trait–trait relationships were stronger or more extreme as the scale was narrowed. Therefore, when evaluating the development and succession of tropical monsoon forest communities, the selection of leaf functional characteristics and the determination of the research scale should be comprehensively and systematically considered. [ABSTRACT FROM AUTHOR]

Glycine betaine (GB) serves as a compatible solute crucial for stress tolerance across numerous plant species. Populus trichocarpa grows along coastal regions and often suffers from salt stress. In this study, we explored the effects of foliar spraying of GB on the growth, physicochemical indexes, gene expression, and stress tolerance of poplar under salt stress. To achieve this, poplar plants (Populus deltoides × Populus euramericana "Nanlin 895") were grown under four NaCl concentrations: 0, 50, 100, and 150 mM. Additionally, they were treated with 0, 5, 15, and 25 mM GB. The degree of effect on potted poplars was observed after 8 weeks. A GB treatment of about 15 mM significantly reduced the impact of salt stress and photosynthetic pigments and caused an improvement in the activity of the antioxidant enzymes peroxidase (POD) and superoxide dismutase (SOD). Moreover, GB-treated poplars had significantly more malonaldehyde (MDA) than the control lines. This study indicated that GB treatment reduces salt stress symptoms in poplars. This research helps to develop safe levels of endogenous GB, which will make poplars more resistant to environmental stresses. [ABSTRACT FROM AUTHOR]

Paris polyphylla Smith var. Chinensis (Franch.) Hara is a medicinal plant that belongs to the Liliaceae family. Its main components are parissaponins, which have excellent medicinal effects such as anti-inflammatory, anti-tumor, etc. Improving the quality of parissaponins through artificial directional regulation has emerged as a practice to meet medical demand and is a new research hotspot. In this paper, P. polyphylla plants were treated with UVA, UVB, and UVC, and the contents of PolyPhyllin VI (PPVI) and PolyPhyllin VII (PPVII), saponin synthase (squalene synthase, SS; cycloartenol synthase, CAS; cytochrome P450, CYP450; and glycosyl transferases, GT) activity, MDA, and the photosynthetic pigment indexes were measured and analyzed. The results showed that PPVII content increased by 32.43% with UVC treatment after 4 h (3.43 mg/g), but the PPVI and PPVII contents in the other groups decreased compared with CK (control group) and they did not return to the original level after 4 h. SS, CAS, CYP450, and GT synthases were activated in varying degrees via UV treatment and increased, respectively, by 22.93%, 10.83%, 20.15%, and 25.98%. Among them, GT, as the last of the synthetases, had a shorter response time to UVB (30 min) and UVC (15 min); the difference was sensible compared with CK. Moreover, UV had a stressing effect and promoted the rapid accumulation of MDA content (increased 17.66%, 34.53%, and 9.65%) and carotenoid (increased 7.58, 5.60, and 7.76 times) within 4 h compared to CK. UVB and UVC radiation visibly improved chlorophyll a content (42.56% and 35.45%), but UVA did not, and the change in chlorophyll b content showed no overt statistical difference. In addition, PPVI and PPVII were negatively correlated with SS, CAS, carotenoids, and MDA (p < 0.05) and positively correlated with CYP450, GT, and chlorophyll a (p < 0.05). This study provides a theoretical basis for using UV light to regulate secondary metabolism in P. polyphylla, which is of great value for production management. [ABSTRACT FROM AUTHOR]

Hydrogels have shown promise in improving soil quality and alleviating plant drought stress. This study investigated the effectiveness of four hydrogel composites composed of polyvinyl alcohol, sodium alginate, and pine or olive tree biochar in improving bean (Phaseolus vulgaris) plant growth and soil microbial activities. The experiment was conducted in natural soil, where biochar–hydrogel composites were applied at a concentration of 0.75% hydrogel per soil weight (w/w) for 35 days under two different moisture conditions: adequate moisture (70% of water holding capacity (WHC)) and drought stress (40% WHC). The results showed variation between hydrogel composites and, more importantly, between water regimes. Under water deficit conditions, biochar–hydrogel composites consistently caused a decrease in plant weight and in chlorophyll (CHL) CHLa/CHLb ratio. Furthermore, antioxidant enzyme activities and malondialdehyde and protein levels generally increased in contrast to the observations at 70% WHC. Regarding microbial activities, the composites reduced soil respiration (12–38%) while promoting phosphatase activity (42–65%) under both moisture regimes. Overall, the introduction of hydrogel composites did not show consistently positive effects on either plants or soil microorganisms. To thoroughly evaluate the efficacy of these hydrogels as soil amendments, further studies are needed, considering different soil types, plant species, and hydrogel application rates. [ABSTRACT FROM AUTHOR]

The impacts of climate change are reaching unprecedented levels, heightening the risk of species loss and ecosystem service degradation. Wetlands, highly threatened ecosystems, serve vital ecological functions by capturing carbon, filtering water, and harbouring diverse wildlife. Coastal wetlands encounter many challenges, such as increased drought periods and escalating salinity levels, severely impacting plant biodiversity. Assessing how plants respond to various environmental stress factors is imperative for devising successful conservation strategies. In the present study, we examined three representative grass species found in various habitats within the Albufera Natural Park, close to the city of Valencia on the Spanish Mediterranean coast: Imperata cylindrica, Phragmites australis, and Saccharum ravennae. High salinity and water stress conditions were induced by subjecting the plants to irrigation with solutions containing 200, 400, 600, and 800 mM NaCl or withholding irrigation altogether to mimic coastal flooding and drought scenarios. The treatments were maintained until noticeable wilting of the plants occurred, at which point a range of stress biomarkers were determined, including photosynthetic pigments, ions, osmolytes, oxidative stress markers, and antioxidant metabolites, as well as antioxidant enzyme activities. Saccharum ravennae displayed the highest sensitivity to salt stress, whereas I. cylindrica appeared to be the most tolerant. The primary salinity tolerance mechanism observed in I. cylindrica and P. australis was a blockage of ion transport from the root zone to the aerial part, together with the salt-induced accumulation of proline and soluble sugars to high concentrations in the former. No significant effects of the water deficit treatment on the growth or biochemical parameters were observed for any of the analysed species. These findings offer valuable information for the effective management and conservation of coastal wetlands facing the challenges posed by climate change. [ABSTRACT FROM AUTHOR]

Currently, different strategies, including the application of bio-fertilizers, are used to ameliorate the adverse effects posed by salinity stress as the major global problem in plants. Fish waste is suggested as a novel bio-fertilizer to mitigate the effects of biotic and abiotic stresses. In this investigation, an experiment was conducted to investigate the effects by applying different concentrations (0, 5, 10, and 15% (v/v)) of fish waste bio-fertilizer on stevia plants grown under salt stress conditions (0, 20, 40, and 60 mM of NaCl). Results showed that salinity negatively affected growth parameters, the photosynthetic pigments, the relative water content, and the chlorophyll fluorescence parameters while increased the activity of antioxidant enzymes, total phenol, hydrogen peroxide (H2O2), malondialdehyde (MDA), proline, and total carbohydrates compared with control samples. On the other hand, the application of fish waste bio-fertilizer mitigated the effects of salinity stress by enhancing growth and mitigating stress-relative markers, especially at the highest salinity level (60 mM). Overall, fish waste bio-fertilizer could be considered a sustainable, innovative approach for the alleviation of salinity stress effects in plants and, in addition, fish waste bio-fertilizer did not cause more salinity issues, at least with the applied doses and experiment time, which is an imperative aspect. [ABSTRACT FROM AUTHOR]

The present study evaluates the phytotoxic effects of phloretin, a prevalent secondary metabolite of apple trees, on the broadleaf weed Capsella bursa-pastoris (L.) Medik. known for its resistant myxospermous seeds that form a long-lasting soil bank. The results indicate a significant, dose-dependent inhibitory effect of phloretin on the growth and morphological parameters of weed seedlings grown in vitro. Although the applied phloretin concentrations (250–1000 µM) were not lethal to the C. bursa-pastoris seedlings after two weeks, the metabolism of the seedlings was impaired, resulting in an accumulation of lipid droplets in the root tips and root hairs. Histochemical analysis shows deposits of phenols in the root epidermal cells, which are probably aggregates of phloretin or its metabolic derivatives. The accumulation of pectin in the cell walls of root border cells in phloretin-treated seedlings indicates an attempt to reduce the uptake of phloretin and reduce its concentration in the cells. Inhibition of shoot growth associated with chlorosis and reduced photosynthetic pigment content is a consequence of seedling exposure to phloretin. This study provides a basis for further evaluation of phloretin as a new bioherbicidal compound and for elucidating the mechanism underlying its phytotoxic activity. [ABSTRACT FROM AUTHOR]

Guava is a fruit tree with high potential in the semi-arid region of northeast Brazil. However, qualitative and quantitative water scarcity is a limiting factor for the expansion of irrigated agriculture. Thus, it is necessary to use techniques to mitigate the effects of salt stress, such as foliar application of proline. The objective of this study was to evaluate the effect of foliar application of proline as a mitigator of salt stress effects on the morphophysiology of guava cv. Paluma. The experiment was carried out under field conditions at the 'Rolando Enrique Rivas Castellón' Experimental Farm in São Domingos, PB, Brazil, using a randomized block design in a 5 × 4 factorial scheme referring to five levels of electrical conductivity of irrigation water, ECw (0.8, 1.5, 2.2, 2.9, and 3.5 dS m−1) and four concentrations of proline (0, 8, 16, and 24 mM). Salinity above 0.8 dS m−1 compromised gas exchange, photosynthetic pigment synthesis, photochemical efficiency, and growth of guava plants at 360 days after transplanting. Foliar application of proline at a concentration of 24 mM mitigated the effect of salt stress on the relative water content, stomatal conductance, and carotenoid contents in plants irrigated with 3.6 dS m−1 water. Meanwhile, a proline concentration of up to 18 mM resulted in higher transpiration, CO2 assimilation rate, instantaneous carboxylation efficiency, and absolute growth rate in stem diameter under ECw of 0.8 dS m−1. Proline concentration of up to 24 mM increased the biosynthesis of photosynthetic pigments and the relative growth rate in stem diameter of guava in the period from 190 to 360 days after transplanting. [ABSTRACT FROM AUTHOR]

Grafting high-yielding tomato varieties onto stress-tolerant rootstocks can mitigate the adverse effects of saline water irrigation on plant tomato productivity in arid regions like Saudi Arabia. This study investigates the efficacy of grafting tomatoes onto both novel and commercial rootstocks to enhance salinity tolerance and its impact on growth, physiological parameters, and yield in a soilless culture system. The experiment involved two water quality levels, 2 (S1) and 4 (S2) dS m−1, two growth media types, volcanic rock (M1) and sand (M2), and six grafting treatments: Tone Guitar F1 non-grafted (G1) (commercial scion), grafted onto itself (G2), Tone Guitar F1* Maxifort F1 (G3) (commercial rootstock), and grafting the scion onto three novel rootstocks, X-218 (G4), X-238 (G5), and Alawamiya365 (G6). Growth, physiology, photosynthetic pigments, and yield improved with lower salinity (2 dS m−1) in volcanic rock and with the grafting treatments (G2–G6) compared to the non-grafted treatment (G1). The best results were achieved with the S1M1G5 treatment, where yield increased by 53% compared to the lowest yield in non-grafted plants grown in sand under higher salinity (S2M2G1). All studied traits were adversely affected under high salinity (S2) in sandy media, with the G1 treatment resulting in the lowest values for these traits. [ABSTRACT FROM AUTHOR]