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Nanotechnology is rapidly advancing towards the development of applications for sustainable plant growth and photosynthesis optimization. The nanomaterial/plant interaction has been intensively investigated; however, there is still a gap in knowledge regarding their effect on crop seed development and photosynthetic performance. In the present work, we apply a priming procedure with 10 and 50 mg/L Pluronic-P85-grafted single-walled carbon nanotubes (P85-SWCNT) on garden pea seeds and examine the germination, development, and photosynthetic activity of young seedlings grown on soil substrate. The applied treatments result in a distorted topology of the seed surface and suppressed (by 10–19%) shoot emergence. No priming-induced alterations in the structural and functional features of the photosynthetic apparatus in 14-day-old plants are found. However, photosynthetic gas exchange measurements reveal reduced stomatal conductance (by up to 15%) and increased intrinsic water use efficiency (by 12–15%), as compared to hydro-primed variants, suggesting the better ability of plants to cope with drought stress—an assumption that needs further verification. Our study prompts further research on the stomatal behavior and dark reactions of photosynthesis in order to gain new insights into the effect of carbon nanotubes on plant performance. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the impact of diurnal and seasonal variations in photon flux density (PPFD) and air temperature on PSII efficiency in three sweet potato leaf-color cultivars: green (G), yellow-green (Y), and purple (P). The cultivars were exposed to full sunlight and measurements were taken from November to March. The maximal quantum yield of PSII photochemistry for the dark-adapted state (Fv/Fm) indicated Y's increased sensitivity to low temperatures at predawn, followed by G and P. Both quantum yield of PSII photochemistry for the dark and light-adapted state (ΔF/Fm') depressions were correlated with increased PPFD, with regression slopes in the order of Y > G > P. On high-light and low-temperature days, Fv/Fm values deviated below regression lines, with differences ranked as Y > G > P. These findings suggest that Y exhibits the highest sensitivity to high light and low temperatures, followed by G and then P in terms of PSII efficiency.

This study aimed to investigate the impact of diurnal and seasonal variations in photon flux density (PPFD) and air temperature on PSII efficiency in three sweet potato leaf-color cultivars: green (G), yellow-green (Y), and purple (P). The cultivars were exposed to full sunlight and measurements were taken from November to March. The maximal quantum yield of PSII photochemistry for the dark-adapted state (Fv/Fm) indicated Y's increased sensitivity to low temperatures at predawn, followed by G and P. Both quantum yield of PSII photochemistry for the dark and light- adapted state (ΔF/Fm') depressions were correlated with increased PPFD, with regression slopes in the order of Y > G > P. On high-light and low-temperature days, Fv/Fm values deviated below regression lines, with differences ranked as Y > G > P. These findings suggest that Y exhibits the highest sensitivity to high light and low temperatures, followed by G and then P in terms of PSII efficiency. [ABSTRACT FROM AUTHOR]

Nanotechnology is rapidly advancing towards the development of applications for sustainable plant growth and photosynthesis optimization. The nanomaterial/plant interaction has been intensively investigated; however, there is still a gap in knowledge regarding their effect on crop seed development and photosynthetic performance. In the present work, we apply a priming procedure with 10 and 50 mg/L Pluronic-P85-grafted single-walled carbon nanotubes (P85-SWCNT) on garden pea seeds and examine the germination, development, and photosynthetic activity of young seedlings grown on soil substrate. The applied treatments result in a distorted topology of the seed surface and suppressed (by 10–19%) shoot emergence. No priming-induced alterations in the structural and functional features of the photosynthetic apparatus in 14-day-old plants are found. However, photosynthetic gas exchange measurements reveal reduced stomatal conductance (by up to 15%) and increased intrinsic water use efficiency (by 12–15%), as compared to hydro-primed variants, suggesting the better ability of plants to cope with drought stress—an assumption that needs further verification. Our study prompts further research on the stomatal behavior and dark reactions of photosynthesis in order to gain new insights into the effect of carbon nanotubes on plant performance.

Photosynthesis is the most important biochemical process that takes place in plants and chlorophyll is the main pigment involved in it. Current destructive methods for determining chlorophyll content are accurate, but time-consuming and relatively expensive. The SPAD (Soil Plant Analysis Development) is a portable chlorophyll meter that provides an instant and nondestructive reading of the green color of leaves. As an important source of vitamins and antioxidants such as vitamins C, carotenoids and fiber content, lettuce (Lactucasativa L.) plays a crucial role in human nutrition, being one of the most popular staple plant foods among the population. Considering the possibility of management based on the characteristics of photosynthetic pigments, the study aimed to relate the SPAD index values with the content of leaf pigments in lettuce. The study was conducted in the Northwest region of Paraná, Brazil. The experiment was carried out in a completely randomized design with 48 leaf samples being determined the SPAD index and the content of leaf pigments. The determination of the SPAD index was performed with the SPAD-502 equipment (Minota®) with three readings per sample. For the extraction of leaf pigments, chlorophyll (a; b), total chlorophyll (a + b) and carotenoids, acetone was used as an extractor and the reading was performed in a spectrophotometer. The SPAD index was correlated with the levels of chlorophyll a (0.93), chlorophyll b (0.89), total chlorophyll (0.93) and carotenoids (0.95) in lettuce leaves. Through the SPAD, the chlorophyll content in lettuce leaves can be determined in a representative way. [ABSTRACT FROM AUTHOR]

The content of photosynthetic pigments in silver birch leaves (Betula pendula Roth.) is studied in areas with technogenic load and in baseline conditions. The research is performed in a forb type of birch forest in the suburbs of Krasnoyarsk. The wood stands exposed to a high level of technogenic pressure are located to the east of the city in the prevailing direction of air mass movement. The reference stands are under the least technogenic pollution and grow in western and northern areas of the city. The photosynthetic pigments are determined in ethanol extracts, calculated per 1 g of absolute dry mass (a.d.m.) of the leaves. A level of dust deposition on leaf surfaces is evaluated according to the method of J. Detrie (1973). The amounts of zinc, lead, aluminum, and fluorine ions are estimated in the washed leaves. It is found that the content of chlorophyll a inside the birch leaves from a relatively clean environment is slightly lower compared to the concentration in the leaves with the technogenic load. The chlorophyll b concentration is 2.5–3 times less than chlorophyll a and is close to the amount of carotenoids. The total chlorophyll content in birch leaves from different locations ranges from 5.4 to 7.3 mg/g a.d.m., the ratio of chlorophyll forms varies from 2.5 to 3, the proportion of net chlorophyll to carotenoids is between 3.4 and 3.8. As the level of dust increases, the content of the total photosynthetic pigments also rises. The accumulation of zinc ions in the birch leaf cells has a negative effect on pigment content, especially chlorophyll a, but doesn’t correlate with the ratio of the pigments. There has not been any correlation found between the lead and the photosynthetic pigments. It is noted that the rise in the concentration of aluminum significantly affects the contents of the chlorophylls and the carotenoids, while no relationship has been discovered between the concentration of aluminum and the proportion of the pigments. The relationship between fluorine and different forms of chlorophyll is absent as well. The results indicate the adaptive response of the photosynthetic system to the presence of pollutants in concentrations below the threshold values that are indicated in the literature. For citation: Stasova V.V., Skripal’shchikova L.N., Astrakhantseva N.V., Barchenkov A.P. Photosynthetic Pigments in Silver Birch Leaves (Betula pendula Roth.) with Technogenic Load. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 3, pp. 35–47. (In Russ.). https:// doi.org/10.37482/0536-1036-2023-3-35-47

The present study focused on trees of Tuscany autochthonous plum cv. Coscia di Monaca in order to evaluate the presence of viruses and elucidate the physiological and biochemical responses to virus infections under real field conditions. Among the several investigated viruses, plums tested positive only to plum pox virus (PPV) and plum bark necrosis steam pitting associated virus (PBNSPaV), occurring as both singular and co-infections. This is the first report of PBNSPaV in a Tuscany orchard. Furthermore, the present study not only confirmed the detrimental effects of PPV on the carbon dioxide assimilation rate due to both stomatal limitations and mesophyll impairments, but also showed that although PBNSPaV did not induce such photosynthetic impairments when occurring as singular infection, it enhanced this damaging effect when present as a co-infection with PPV, as confirmed by a severe decrease in the chlorophyll content. Infection-specific responses in terms of accessory pigments (i.e., carotenoids and xanthophylls), as well as sugars and organic acids, were also reported, these being likely related to photoprotective mechanisms and osmotic regulations under virus-induced oxidative stress. Overall, the results here presented represent an important step to fill knowledge gaps about the interaction of plant viruses and autochthonous Prunus cultivars. [ABSTRACT FROM AUTHOR]

Exogenous application of zinc (Zn) and silicon (Si) might serve as potent strategy to boost productivity of oil seed crops including canola in a saline environment. A trial was conducted with an aim to determine the phenotypic divergence among canola cultivars (Sandal and Rachna) under varying doses of Zn and Si (35 ppm and 70 ppm) applied solely and in conjunction with each other under two level of salinity stress (SS). Different morphological and physiological traits of canola cultivars were taken as response variables. The results revealed that SS adversely affected the leaf pigment and shoot length along with their fresh and dry weights, while antioxidant activities were increased especially under exogenous application of Si + Zn = 70 ppm. Under salinity stress conditions the root length and their fresh as well as dry weight increase as compared to the controlled plant which are grown under normal conditions without salinity stress. Moreover, canola cv. Sandal outperformed in terms for shoot–root length and their fresh and dry weight as well as the leaf pigments contents. The co-application of Si + Zn = 70 ppm exhibited the highest shoot–root length (17.64 cm—16.47 cm) and their fresh (2.60 g—1.89 g) as well as dry weight (0.73 g—0.29 g). The same treatment combination resulted in the maximum leaf pigments such as chlorophyll a (6.63 g/mg FW), chlorophyll b (4.37 g/mg FW) and total carotenoids content (2.38 g/mg FW). [ABSTRACT FROM AUTHOR]

This work was carried at a private vegetable farm (Sand Valley Experimental Station) Ismailia Governorate, Egypt during the two successive fall seasons of 2020 and 2021 to study the effect of transplanting date on vegetative growth, leaf pigments and productivity of five cauliflower hybrids under sandy soil conditions. This experiment was include 10 treatments, which were the combinations between two transplanting dates (transplanting in 1st August and transplanting in 1st September) and five cauliflower hybrids (Barkha, Solid Snow, Mexico, Fargo and Raoul). These treatments were arranged in a split plot design with three replications. Transplanting dates were randomly distributed in the main plots, while the cauliflower hybrids were randomly arranged in the sub-plots. The most important results were summarized as follows: The interaction between transplanting date in 1st Sept. and Fargo hybrid recorded the maximum values of plant height, number of leaves lant, leaf length, leaf width and leaf area, whereas the interaction between transplanting in 1 stAugust and Barkha hybrid gave the highest concentrations of chlorophyll a, b, (a+b) and carotenoides in leaf tissues of cauliflower in both seasons. The interaction between transplanting date in 1st Sept and Mexico hybrid gave he highest values of total yield/faddan with no significant differences with the interaction between transplanting in 1st Sept. and Fargo hybrid in the 1st season. However, the interaction between transplanting in 1st Sept, and Raoul hybrid significantly increased N, P and K contents in curd in both seasons. [ABSTRACT FROM AUTHOR]

Ensuring food security with severe shortages of freshwater and drastic changes in climatic conditions in arid countries requires the urgent development of feasible and user-friendly strategies. Relatively little is known regarding the impacts of the co-application (Co-A) of salicylic acid (SA), macronutrients (Mac), and micronutrients (Mic) through foliar (F) and soil (S) application strategies on field crops under arid and semiarid climatic conditions. A two-year field experiment was designed to compare the impacts of seven (Co-A) treatments of this strategy, including a control, FSA + Mic, FSA + Mac, SSA + FMic, SSA + FSA + Mic, SSA + Mic + FSA, and SSA + Mic + FMac + Mic on the agronomic performance, physiological attributes, and water productivity (WP) of wheat under normal (NI) and limited (LMI) irrigation conditions. The results reveal that the LMI treatment caused a significant reduction in various traits related to the growth (plant height, tiller and green leaf numbers, leaf area index, and shoot dry weight), physiology (relative water content and chlorophyll pigments), and yield components (spike length, grain weight and grain numbers per spike, thousand-grain weight, and harvest index) of wheat by 11.4–47.8%, 21.8–39.8%, and 16.4–42.3%, respectively, while WP increased by 13.3% compared to the NI treatment. The different Co-A treatments have shown a 0.2–23.7%, 3.6–26.7%, 2.3–21.6%, and 12.2–25.0% increase in various traits related to growth, physiology, yield, and WP, respectively, in comparison to the control treatment. The SSA+ FSA + Mic was determined as the best treatment that achieved the best results for all studied traits under both irrigation conditions, followed by FSA + Mic and SSA + Mic + FSA under LMI in addition to FSA + Mac under NI conditions. It can be concluded that the Co-A of essential plant nutrients along with SA accomplished a feasible, profitable, and easy-to-use strategy to attenuate the negative impacts of deficit irrigation stress, along with the further improvement in the growth and production of wheat under NI conditions. [ABSTRACT FROM AUTHOR]

Nitrogen is crucial for plant growth and development, and improving nitrogen use efficiency (NUE) is a viable strategy for reducing dependence on nitrogen inputs and promoting sustainability. While the benefits of heterosis in corn are well known, the physiological mechanisms underlying this phenomenon in popcorn are less understood. We aimed to investigate the effects of heterosis on growth and physiological traits in four popcorn lines and their hybrids under two contrasting nitrogen conditions. We evaluated morpho-agronomic and physiological traits such as leaf pigments, the maximum photochemical efficiency of PSII, and leaf gas exchange. Components associated with NUE were also evaluated. N deprivation caused reductions of up to 65% in terms of plant architecture, 37% in terms of leaf pigments, and 42% in terms of photosynthesis-related traits. Heterosis had significant effects on growth traits, NUE, and foliar pigments, particularly under low soil nitrogen conditions. N-utilization efficiency was found to be the mechanism favoring superior hybrid performance for NUE. Non-additive genetic effects were predominant in controlling the studied traits, indicating that exploring heterosis is the most effective strategy for obtaining superior hybrids to promote NUE. The findings are relevant and beneficial for agro farmers seeking sustainable agricultural practices and improved crop productivity through the optimization of nitrogen utilization. [ABSTRACT FROM AUTHOR]

Early crop disease detection is one of the most important tasks in plant protection. The purpose of this work was to evaluate the early wheat leaf rust detection possibility using hyperspectral remote sensing. The first task of the study was to choose tools for processing and analyze hyperspectral remote sensing data. The second task was to analyze the wheat leaf biochemical profile by chromatographic and spectrophotometric methods. The third task was to discuss a possible relationship between hyperspectral remote sensing data and the results from the wheat leaves, biochemical profile analysis. The work used an interdisciplinary approach, including hyperspectral remote sensing and data processing methods, as well as spectrophotometric and chromatographic methods. As a result, (1) the VIS-NIR spectrometry data analysis showed a high correlation with the hyperspectral remote sensing data; (2) the most important wavebands for disease identification were revealed (502, 466, 598, 718, 534, 766, 694, 650, 866, 602, 858 nm). An early disease detection accuracy of 97–100% was achieved from fourth dai (day/s after inoculation) using SVM. [ABSTRACT FROM AUTHOR]

The foliar applied silicon (Si) has the potential to ameliorate heavy metals, especially cadmium (Cd) toxicity; however, Si dose optimization is strategically important for boosting the growth of soil microbes and Cd stress mitigation. Thus, the current research was performed to assess the Si-induced physiochemical and antioxidant trait alterations along with Vesicular Arbuscular Mycorrhiza (VAM) status in maize roots under Cd stress. The trial included foliar Si application at the rate of 0, 5, 10, 15, and 20 ppm while Cd stress (at the rate of 20 ppm) was induced after full germination of maize seed. The response variables included various physiochemical traits such as leaf pigments, protein, and sugar contents along with VAM alterations under induced Cd stress. The results revealed that exogenous application of Si in higher doses remained effective in improving the leaf pigments, proline, soluble sugar, total proteins, and all free amino acids. Additionally, the same treatment remained unmatched in terms of antioxidant activity compared to lower doses of foliar-applied Si. Moreover, VAM was recorded to be at peak under 20 ppm Si treatment. Thus, these encouraging findings may serve as a baseline to develop Si foliar application as a biologically viable mitigation strategy for maize grown in Cd toxicity soils. Overall, the exogenous application of Si helpful for reducing the uptake of Cd in maize and also improving the mycorrhizal association as well as the philological mechanism and antioxidant activities in plant under cadmium stress conditions. Also, future studies must test more doses concerning to varying Cd stress levels along with determining the most responsive crop stage for Si foliar application. [ABSTRACT FROM AUTHOR]

Climate change, global warming, stagnant productivity of wheat and food security concerns owing to frequent spells of drought stress (DS) have necessitated finding biologically viable drought-mitigation strategies. A trial was conducted to test two promising wheat cultivars (Ujala-16 and Zincol-16) that were subjected to pre-sowing priming treatments with different doses of ZnO nanoparticles (NPs = 40, 80, 120 and 160 ppm) under 50% and 100% field capacity (FC) conditions. The ZnO NPs were prepared with a co-precipitation method and characterized through X-ray diffraction (XRD) and with a scanning electron microscope (SEM). For comparison purposes, untreated seeds were sown as the control treatment. The response variables included botanical traits (lengths, fresh and dry wrights of root and shoot), chlorophyll (a, b and total) contents, antioxidant and proline contents and nutrients status of wheat cultivars. The results showed that DS significantly decreased all traits of wheat cultivars, while ZnO NPs, especially the 120 ppm dose, remained superior by increasing all botanical traits at 100% FC. In addition, ZnO NPs increased the chlorophyll a (1.73 mg/g FW in Ujala-16 and 1.75 mg/g FW in Zincole-16) b (0.70 mg/g FW in Ujala-16 and 0.71 mg/g FW in Zincole-16) and total chlorophyll content (2.43 mg/g FW in Ujala-16 and 2.46 mg/g FW in Zincole-16) by improving the activity of antioxidant and proline content. Moreover, plant nutrients such as Ca, Mg, Fe, N, P, K, and Zn contents were increased by ZnO NPs, especially in the Zincol-16 cultivar. To summarize, Zincol-16 remains superior to Ujala-16, while ZnO NPs (120 ppm dose under 100% FC) increases the growth and mineral contents of both wheat varieties. Thus, this combination might be recommended to wheat growers after testing further in-depth evaluation of more doses of ZnO NPs. [ABSTRACT FROM AUTHOR]

Heavy metals (HMs) especially cadmium (Cd) absorbed by the roots of crop plants like maize have emerged as one of the most serious threats by causing stunted plant growth along with disturbing the photosynthetic machinery and nutrient homeostasis process. A trial was conducted for inducing Cd stress tolerance in maize by exogenous application of silicon nanoparticles (SiNPs) using five doses of SiNPs (0, 100, 200, 300, and 400 ppm) and three levels of Cd (0, 15, and 30 ppm) for maize hybrid (SF-9515). The response variables included morphological traits and biochemical parameters of maize. The results indicated that Cd level of 30 ppm remained the most drastic for maize plants by recording the minimum traits such as shoot length (39.35 cm), shoot fresh weight (9.52 g) and shoot dry weight (3.20 g), leaf pigments such as chlorophyll a (0.55 mg/g FW), chlorophyll b (0.27 mg/g FW), total contents (0.84 mg/g FW), and carotenoid contents (0.19 µg/g FW). Additionally, the same Cd level disrupted biochemical traits such as TSP (4.85 mg/g FW), TP (252.94 nmol/g FW), TSAA (18.92 µmol g−1 FW), TSS (0.85 mg/g FW), and antioxidant activities such as POD (99.39 min−1 g−1 FW), CAT (81.58 min−1 g−1 FW), APX (2.04 min−1 g−1 FW), and SOD (172.79 min−1 g−1 FW). However, a higher level of Cd resulted in greater root length (87.63 cm), root fresh weight (16.43 g), and root dry weight (6.14 g) along with higher Cd concentration in the root (2.52 µg/g−1) and shoot (0.48 µg/g−1). The silicon nanoparticles (Si NPs) treatment significantly increased all measured attributes of maize. The highest value was noted of all the parameters such as chlorophyll a (0.91 mg/g FW), chlorophyll b (0.57 mg/g FW), total chlorophyll contents (1.48 mg/g FW), total carotenoid contents (0.40 µg/g FW), TSP (6.12 mg/g FW), TP (384.56 nmol/g FW), TSAA (24.64 µmol g−1 FW), TSS (1.87 mg/g FW), POD (166.10 min−1 g−1 FW), CAT (149.54 min−1 g−1 FW), APX (3.49 min−1 g−1 FW), and SOD (225.57 min−1 g−1 FW). Based on recorded findings, it might be inferred that higher levels of Cd tend to drastically reduce morpho-physiological traits of maize and foliage-applied silver nanoparticles hold the potential to ameliorate the adverse effect of Cd stress on maize. [ABSTRACT FROM AUTHOR]

Low nutrient and high pH of circulating water represent two of the main issues to overcome for a successful combination of aquaculture and hydroponics in aquaponics offering a sustainable and circular economy solution for vegetable production. The purpose of this study was to screen the tolerance of four herbs to high pH and low nutrient concentration in hydroponics, i.e., green and red basils, mint, and rocket salad, with a focus on plant yield and nutraceutical aspects. Results highlighted green basil as the most tolerant species to low nutrient and high pH conditions followed by mint. On the contrary, negative effects from high pH and low nutrient were reported on red basil and especially rocket salad, which strongly affect their marketability parameters. Rocket salad fresh biomass was more than halved under the combination of high pH and low nutrients. Results on green and red basil showed the importance of testing the tolerance to these agronomic conditions at both species and variety levels. Despite the reduction in biomass, leaf pigments were not influenced by high pH and low nutrients and therefore can be considered parameters of minor importance for the evaluation of these species. In conclusion, the tolerance of green basil and mint to high pH and low nutrients under hydroponic conditions has been highlighted. Further investigation coupled with fish farming will be able to reinforce the convenience of using these species for aquaponics. [ABSTRACT FROM AUTHOR]

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The research was carried out in 2020 at the RIMSA Troyan, in an intensive plum plantation with the cultivars Stanley, Cacanska Lepotitsa, Hanita and Jojo, grafted on 6 rootstocks: Bromptom, GF 655-2, SJ A, Wavit, Wangenheims, P. cerasifera, at scheme 4x1.7m to determine their influence on the chlorophyll content of the leaves. Based on the data, photosynthetic responses can be modeled and successfully used to predict metabolic limitations of photosynthesis. The highest content of Ʃ (Chl. A+Chl. B) was found in the variants with the rootstock GF 655-2- C. lepotica 1.978 mg/g; Jojo 2.078 mg/g; Stanley 1.828 mg/g. In the Hanita cultivar, the highest levels of chlorophylls (Ʃ A+B) are in the variant with P. cerasifera rootstock (2.421 mg/g) and ratio between pigments (A/B 2.393). [ABSTRACT FROM AUTHOR]

Leaf pigments, including chlorophylls and carotenoids, are important biochemical indicators of plant photosynthesis and photoprotection. In this study, we developed, optimized, and validated a sequential extraction and liquid chromatography-diode array detection method allowing for the simultaneous quantification of the main photosynthetic pigments, including chlorophyll a, chlorophyll b, β-carotene, lutein, neoxanthin, and the xanthophyll cycle (VAZ), as well as the characterization of plant pigment derivatives. Chromatographic separation was accomplished with the newest generation of core-shell columns revealing numerous pigment derivatives. The sequential extraction allowed for a better recovery of the main pigments (+25 % chlorophyll a, +30 % chlorophyll b, +42 % b-carotene, and 61% xanthophylls), and the characterization of ca. 5.3 times more pigment derivatives (i.e., up to 62 chlorophyll and carotenoid derivatives including isomers) than with a single-step extraction. A broad working range of concentrations (300-2,000 ng.mL-1) was achieved for most pigments and their derivatives and the limit of detection was as low as a few nanograms per milliliter. The method also showed adequate trueness (RSD < 1%) and intermediate precision (RSD < 5%). The method was developed and validated with spinach leaves and their extracts. Themethod was successfully performed on leaf pigment extracts of European deciduous tree species. Within a case study using Fagus sylvatica L. leaves, pigment derivatives revealed a high within-individual tree variability throughout the growing season that could not be detected using the main photosynthetic pigments alone, eventually showing that the method allowed for the monitoring of pigment dynamics at unprecedented detail. [ABSTRACT FROM AUTHOR]

The present study focused on trees of Tuscany autochthonous plum cv. Coscia di Monaca in order to evaluate the presence of viruses and elucidate the physiological and biochemical responses to virus infections under real field conditions. Among the several investigated viruses, plums tested positive only to plum pox virus (PPV) and plum bark necrosis steam pitting associated virus (PBNSPaV), occurring as both singular and co-infections. This is the first report of PBNSPaV in a Tuscany orchard. Furthermore, the present study not only confirmed the detrimental effects of PPV on the carbon dioxide assimilation rate due to both stomatal limitations and mesophyll impairments, but also showed that although PBNSPaV did not induce such photosynthetic impairments when occurring as singular infection, it enhanced this damaging effect when present as a co-infection with PPV, as confirmed by a severe decrease in the chlorophyll content. Infection-specific responses in terms of accessory pigments (i.e., carotenoids and xanthophylls), as well as sugars and organic acids, were also reported, these being likely related to photoprotective mechanisms and osmotic regulations under virus-induced oxidative stress. Overall, the results here presented represent an important step to fill knowledge gaps about the interaction of plant viruses and autochthonous Prunus cultivars.

Leaf pigments, including chlorophylls and carotenoids, are important biochemical indicators of plant photosynthesis and photoprotection. In this study, we developed, optimized, and validated a sequential extraction and liquid chromatography-diode array detection method allowing for the simultaneous quantification of the main photosynthetic pigments, including chlorophyll a, chlorophyll b, β-carotene, lutein, neoxanthin, and the xanthophyll cycle (VAZ), as well as the characterization of plant pigment derivatives. Chromatographic separation was accomplished with the newest generation of core–shell columns revealing numerous pigment derivatives. The sequential extraction allowed for a better recovery of the main pigments (+25 % chlorophyll a, +30 % chlorophyll b, +42 % β-carotene, and 61% xanthophylls), and the characterization of ca. 5.3 times more pigment derivatives (i.e., up to 62 chlorophyll and carotenoid derivatives including isomers) than with a single-step extraction. A broad working range of concentrations (300–2,000 ng.mL−1) was achieved for most pigments and their derivatives and the limit of detection was as low as a few nanograms per milliliter. The method also showed adequate trueness (RSD < 1%) and intermediate precision (RSD < 5%). The method was developed and validated with spinach leaves and their extracts. The method was successfully performed on leaf pigment extracts of European deciduous tree species. Within a case study using Fagus sylvatica L. leaves, pigment derivatives revealed a high within-individual tree variability throughout the growing season that could not be detected using the main photosynthetic pigments alone, eventually showing that the method allowed for the monitoring of pigment dynamics at unprecedented detail.

The study was carried out in 2018 in a fruit-bearing cherry plantation of the Fruit Growing Institute – Plovdiv. The effect of the long-term chemical weed control /carried out in the period 2001-2018/ on the physiological condition and nutritional status of six sweet cherry cultivar/rootstock combinations was studied in intensive production systems. Higher values of the chlorophyll content and carotenoids were reported in all the herbicidetreated variants: chlorophyll a was by 1.23 mg/g DW; chlorophyll b by 0.17 mg/g DW; chlorophyll a+b by 0.56 mg/g DW and carotenoids by 0.65 mg/g DW higher, compared to the There was a clear tendency to higher values of nitrogen, potassium, phosphorus and magnesium in the herbicide-treated variants compared to the control, which confirmed the importance of the efficient chemical weed control as a means of maintaining a favourable microclimate in cherry production. [ABSTRACT FROM AUTHOR]

Ensuring food security with severe shortages of freshwater and drastic changes in climatic conditions in arid countries requires the urgent development of feasible and user-friendly strategies. Relatively little is known regarding the impacts of the co-application (Co-A) of salicylic acid (SA), macronutrients (Mac), and micronutrients (Mic) through foliar (F) and soil (S) application strategies on field crops under arid and semiarid climatic conditions. A two-year field experiment was designed to compare the impacts of seven (Co-A) treatments of this strategy, including a control, FSA + Mic, FSA + Mac, SSA + FMic, SSA + FSA + Mic, SSA + Mic + FSA, and SSA + Mic + FMac + Mic on the agronomic performance, physiological attributes, and water productivity (WP) of wheat under normal (NI) and limited (LMI) irrigation conditions. The results reveal that the LMI treatment caused a significant reduction in various traits related to the growth (plant height, tiller and green leaf numbers, leaf area index, and shoot dry weight), physiology (relative water content and chlorophyll pigments), and yield components (spike length, grain weight and grain numbers per spike, thousand-grain weight, and harvest index) of wheat by 11.4–47.8%, 21.8–39.8%, and 16.4–42.3%, respectively, while WP increased by 13.3% compared to the NI treatment. The different Co-A treatments have shown a 0.2–23.7%, 3.6–26.7%, 2.3–21.6%, and 12.2–25.0% increase in various traits related to growth, physiology, yield, and WP, respectively, in comparison to the control treatment. The SSA+ FSA + Mic was determined as the best treatment that achieved the best results for all studied traits under both irrigation conditions, followed by FSA + Mic and SSA + Mic + FSA under LMI in addition to FSA + Mac under NI conditions. It can be concluded that the Co-A of essential plant nutrients along with SA accomplished a feasible, profitable, and easy-to-use strategy to attenuate the negative impacts of deficit irrigation stress, along with the further improvement in the growth and production of wheat under NI conditions.

Nitrogen is crucial for plant growth and development, and improving nitrogen use efficiency (NUE) is a viable strategy for reducing dependence on nitrogen inputs and promoting sustainability. While the benefits of heterosis in corn are well known, the physiological mechanisms underlying this phenomenon in popcorn are less understood. We aimed to investigate the effects of heterosis on growth and physiological traits in four popcorn lines and their hybrids under two contrasting nitrogen conditions. We evaluated morpho-agronomic and physiological traits such as leaf pigments, the maximum photochemical efficiency of PSII, and leaf gas exchange. Components associated with NUE were also evaluated. N deprivation caused reductions of up to 65% in terms of plant architecture, 37% in terms of leaf pigments, and 42% in terms of photosynthesis-related traits. Heterosis had significant effects on growth traits, NUE, and foliar pigments, particularly under low soil nitrogen conditions. N-utilization efficiency was found to be the mechanism favoring superior hybrid performance for NUE. Non-additive genetic effects were predominant in controlling the studied traits, indicating that exploring heterosis is the most effective strategy for obtaining superior hybrids to promote NUE. The findings are relevant and beneficial for agro farmers seeking sustainable agricultural practices and improved crop productivity through the optimization of nitrogen utilization.

Evergreen plants growing at high latitudes or high elevations may experience freezing events in their photosynthetic tissues. Freezing events can have physical and physiological effects on the leaves which alter leaf optical properties affecting remote and proximal sensing parameters. We froze leaves of six alpine plant species (Soldanella alpina, Ranunculus kuepferi, Luzula nutans, Gentiana acaulis, Geum montanum, and Centaurea uniflora) and three evergreen forest understorey species (Hepatica nobilis, Fragaria vesca and Oxalis acetosella), and assessed their spectral transmittance and optically measured pigments, as well as photochemical efficiency of photosystem II (PSII) as an indicator of freezing damage. Upon freezing, leaves of all the species transmitted more photosynthetically active radiation (PAR) and some species had increased ultraviolet-A (UV-A) transmittance. These differences were less pronounced in alpine than in understorey species, which may be related to higher chlorophyll degradation, visible as reduced leaf chlorophyll content upon freezing in the latter species. Among these understorey forbs, the thin leaves of O. acetosella displayed the largest reduction in chlorophyll (−79%). This study provides insights into how freezing changes the leaf optical properties of wild plants which could be used to set a baseline for upscaling optical reflectance data from remote sensing. Changes in leaf transmittance may also serve to indicate photosynthetic sufficiency and physiological tolerance of freezing events, but experimental research is required to establish this functional association. [ABSTRACT FROM AUTHOR]

Exopolysaccharide (EPS)-producing beneficial bacteria play a multifaceted role in improving plant growth and adaptive responses against different stressors. In this study, we isolated 25 bacterial strains from pea nodules and were further studied for their sodium chloride (NaCl) and cadmium (Cd) stress tolerance. Based on our results, Rhizobium fabae SR-22 (NCBI Accession number: MG063739.1) showed better tolerance toward salinity and Cd stress and produced a wide range of plant growth-promoting compounds. However, the amount of EPS varies during NaCl and Cd stress. It was important to note that NaCl and Cd beyond the tolerant level, affected the morphology and cellular viability of R. fabae. Interestingly, plant growth-promoting (PGP) substances (indole-3-acetic acid, ammonia, siderophore, and ACC deaminase) released by R. fabae were increased with increasing NaCl concentrations. In contrast, PGP substances were greatly decreased by increasing Cd dosages. Further, the beneficial effect of EPS-producing R. fabae in Triticum aestivum grown in soil treated with different levels of NaCl and Cd was assessed. Inoculation of R. fabae in wheat seedlings grown under higher NaCl and Cd concentrations showed improved growth compared to non-inoculated plants. R. fabae exhibited maximum effect in wheat plants grown under 2% NaCl and increased seed germination (8%), root length (13%), vigor indices (19%), root biomass (20%), chlorophyll-a (31%), total chlorophyll (27%) and carotenoid content. Additionally, R. fabae increased Cd and NaCl tolerance in wheat seedlings and improved their antioxidative responses. Conclusively, this work demonstrated that EPS-producing R. fabae showed a promising role in mitigating salinity and Cd-stress in wheat possibly by reducing salt and HM stress-induced abrasions and growth promotion via inorganic phosphate solubilization, and increased nutrient absorption. In the future, R. fabae equipped with these distinguishing characteristics may be used as effective bio-inoculants/bio-formulations in agriculture to address salinity and HM stress issues. • Exopolysaccharide (EPS)-producing R. fabae SR-22 tolerated NaCl (18%) and Cd (10 mM). • EPS synthesized by strain SR-22 increased with increasing NaCl and Cd concentrations. • NaCl and Cd variably affected the bacterially synthesized growth regulating substances. • R. fabae enhanced germination and growth attributes of stressed T. aestivum seedlings. • R. fabae inoculation increased antioxidant defense mechanisms in stressed seedlings. [ABSTRACT FROM AUTHOR]

The present study deals with phytochemical analyses in Schweinfurthia papilionacea, an important medicinal plant of the Indian Thar desert. The experiments were conducted at Plant Ecology Laboratory, Botany Department, J.N.V. University, Jodhpur during 2020 and 2021.Primary metabolites such as leaf pigments, proline, osmotic potential, total sugars, crude protein and phosphorus were estimated during different developmental stages, i.e. vegetative, flowering and fruiting. The results revealed that leaf pigments, crude protein and phosphorus were maximum during flowering stage, while proline, osmotic potential and total sugars during fruiting stage. [ABSTRACT FROM AUTHOR]

Ideotypic characteristics of durum wheat associated with higher yield under different water and temperature regimes were studied under Mediterranean conditions. The focus of this paper is to provide raw and supplemental data from the research article entitled “Durum wheat ideotypes in Mediterranean environments differing in water and temperature conditions” [1], which aims to define specific durum wheat ideotypes according to their responses to different agronomic conditions. In this context, six modern (i.e. post green revolution) genotypes with contrasting yield performance (i.e. high vs low yield) were grown during two consecutive years under different treatments: (i) winter planting under support-irrigation conditions, (ii) winter planting under rainfed conditions, (iii) late planting under support-irrigation. Trials were conducted at the INIA station of Colmenar de Oreja (Madrid). Different traits were assessed to inform about water status (canopy temperature at anthesis and stable carbon isotope composition (δ13C) of the flag leaf and mature grains), root performance (root traits and the oxygen isotope composition (δ18O) in the stem base water), phenology (days from sowing to heading), nitrogen status/photosynthetic capacity (nitrogen content and stable isotope composition (δ15N) of the flag leaf and mature grain together with the pigment contents and the nitrogen balance index (NBI) of the flag leaf), crop growth (plant height (PH) and the normalized difference vegetation index (NDVI) at anthesis), grain yield and agronomic yield components. For most of the parameters assessed, data analysis demonstrated significant differences among genotypes within each treatment. The level of significance was determined using the Tukey-b test on independent samples, and ideotypes were modelled from the results of principle component analysis. The present data shed light on traits that help to define specific ideotype characteristics that confer genotypic adaptation to a wide range of agronomic conditions produced by variations in planting date, water conditions and season.

Leaf traits are good indicators of ecosystem functioning and can affect herbivory and leaf reflectance patterns, allowing a better understanding of changes in environmental conditions, such those observed during forest natural regeneration. The aim of this study was to evaluate the intraspecific variation in leaf traits and their influence on the pattern of herbivory and leaf reflectance in three species distributed along a successional gradient (early, intermediate and late stages) in a tropical dry forest (TDF) in northern Minas Gerais, Brazil. We sampled individuals of the following abundant tree species that occurred in multiple successional stages: Cenostigma pluviosum, Handroanthus ochraceus, and Tabebuia reticulata. We collected 10 leaves from each tree to determine the contents of chlorophyll a, b, and total, carotenoids and water, as well as the percentage of leaf area removed by herbivores and leaf specific mass (LSM). We also measured five spectral reflectance indices (Normalized Difference Vegetation Index-NDVI, Simple Ratio-SR, modified Normalized Difference-nND, modified SR-mSR and Water Index-WI) using a portable spectrometer. Our results showed intraspecific differences in most leaf traits along the successional gradient, suggesting that local adaptation may play an important role in plant community assembly. However, herbivory only differed for H. ochraceus in early and intermediate stages, but it was not affected by the leaf traits considered here. Spectral reflectance indices also differed among successional stage for all species together and for each species separately, except for T. reticulata in intermediate and late stages. Thus, leaf spectral signatures may be an important tool to the remote detection of different successional stages in TDFs, with implications for forest management.

Low nutrient and high pH of circulating water represent two of the main issues to overcome for a successful combination of aquaculture and hydroponics in aquaponics offering a sustainable and circular economy solution for vegetable production. The purpose of this study was to screen the tolerance of four herbs to high pH and low nutrient concentration in hydroponics, i.e., green and red basils, mint, and rocket salad, with a focus on plant yield and nutraceutical aspects. Results highlighted green basil as the most tolerant species to low nutrient and high pH conditions followed by mint. On the contrary, negative effects from high pH and low nutrient were reported on red basil and especially rocket salad, which strongly affect their marketability parameters. Rocket salad fresh biomass was more than halved under the combination of high pH and low nutrients. Results on green and red basil showed the importance of testing the tolerance to these agronomic conditions at both species and variety levels. Despite the reduction in biomass, leaf pigments were not influenced by high pH and low nutrients and therefore can be considered parameters of minor importance for the evaluation of these species. In conclusion, the tolerance of green basil and mint to high pH and low nutrients under hydroponic conditions has been highlighted. Further investigation coupled with fish farming will be able to reinforce the convenience of using these species for aquaponics.

In the external coincidence model, internal and external molecular signals, provided by the circadian clock and sunlight, respectively, are required to induce flowering. Salicylic acid (SA) applications during floral induction have multiple effects. In the current study, Malus × domestica plants were exposed to SA during the flower-induction stage to analyze the effect on various health markers and flowering. A total of 56 equal-sized Fuji/M9 trees that were about 7 years old were randomly divided into two groups. The first group (SA-treated) was sprayed with 4 mM SA solution, while the second group was sprayed with distilled water which served as control (CK). The SA applications increased various leaf pigments. Abiotic stress markers were increased in CK during the flower-induction stage. In the SA-treated group, non-enzymatic antioxidants increased, whereas in the control group, enzymatic antioxidants increased during the flower-induction stage. Histo-morphometric properties of leaves were significantly improved in the SA-treated group. The relative expression of the mRNA levels of MdMED80 , −81 , −3 , and −41 were significantly increased in SA-treated leaves, leading to an early and increased flowering phenotype. Thus, SA increased leaf expansion and health-related marker levels, which lead to early induction of flowering in M. domestica. Overall, our work established a role for leaf health assessments in the regulation of flowering in M. domestica. [ABSTRACT FROM AUTHOR]

In the external coincidence model, internal and external molecular signals, provided by the circadian clock and sunlight, respectively, are required to induce flowering. Salicylic acid (SA) applications during floral induction have multiple effects. In the current study, Malus × domestica plants were exposed to SA during the flower-induction stage to analyze the effect on various health markers and flowering. A total of 56 equal-sized Fuji/M9 trees that were about 7 years old were randomly divided into two groups. The first group (SA-treated) was sprayed with 4 mM SA solution, while the second group was sprayed with distilled water which served as control (CK). The SA applications increased various leaf pigments. Abiotic stress markers were increased in CK during the flower-induction stage. In the SA-treated group, non-enzymatic antioxidants increased, whereas in the control group, enzymatic antioxidants increased during the flower-induction stage. Histo-morphometric properties of leaves were significantly improved in the SA-treated group. The relative expression of the mRNA levels of MdMED80, −81, −3, and −41 were significantly increased in SA-treated leaves, leading to an early and increased flowering phenotype. Thus, SA increased leaf expansion and health-related marker levels, which lead to early induction of flowering in M. domestica. Overall, our work established a role for leaf health assessments in the regulation of flowering in M. domestica.

The aim of this study was to explore the efficiency of foliar potassium fertiliser relative to morphological, physiological and biochemical properties of hybrid long pepper (Capsicum annuum). Pepper plants were grown in a greenhouse and supplied with three sources of foliar potassium fertilisers, i.e., potassium-humate (1 g/L = 1,250 g/ha), potassium sulfate (1 g/L = 1,250 g/ha), and potassium chloride (1 g/L = 1,250 g/ha). Water served as control. The impacts of these treatments on the phytosynthetic parameters (photosynthetic rate, stomatal conductance, intercellular CO2, leaf carotenoids) and chlorophyll a and b, metabolic compounds and nitrogen, phosphorus and potassium were measured. The phytosynthetic parameters significantly improved by different foliar potassium application and the highest level of photosynthetic activity was noted in plants supplied with potassium sulfate, followed by potassium-humate and potassium chloride. Plant biomass accumulation, cholorophyll (a and b), and total yield showed larger increases in plants fertilised with potassium sulfate than those fertilised with potassium-humate; smallest increases occurred with potassium chloride. Concentrations of total sugars, carotenoids, chlorophyll (a and b), and endogenous level of nitrogen, phosphorus, and potassium contents in plants and fruits were possitively influenced by varying sources of potassium. The fruit color parameters and total soluble solid were also significantly increased with all foliar potassium treatments compared with control. Foliar application of potassium sulfate recorded the highest values and significantly increase all anatomical characters for leaf, stem and fruit of pepper plant.

Peppermint (Mentha piperita L.) from Lamiaceae family is one of the most important medicinal plants, used in food, sanitary and cosmetic industries. The aim of this study was to examine the effects of Nano Zinc and Zinc-Chelate on morphophysiological traits and essential oil composition of peppermint. A factorial experiment was conducted based on Randomized Complete Block Design (RCBD) with three replications in Karaj, Iran, in 2016. Treatments were zinc micronutrient in two levels (Zinc-Chelate and zinc nanoparticles) and concentration in four levels (0, 0.5, 1 and 1.5 g/l). The zinc micronutrient was applied in foliar spraying in three times of the interval of 15 days up to flowering stages. Results showed that both of Nano zinc and Zinc-Chelate micronutrient significantly increased all of morpho-physiological traits than that for control. The higher values were obtained in Zinc-Chelate (1.5 g/l) and Nano zinc (1 g/l), respectively. The effects of treatments were significant at 21 out of 34 compounds. The higher compounds with average values of 19.7%, 7.8%, 5.9%, 5.7%, 4.9% and 4.1% were obtained in Menthol, Menthone, Menthofuran, Piperitone, Menthyl acetate and Beta-caryophyllen, respectively. Nano zinc (1.5 g/l) had increased Menthol, Menthone and Menthofuran content up to 28%, 61% and 237% higher than the control, respectively. t. It was concluded that foliar spraying of Nano zinc (1 g/l) in flowering stage had increased dry matter yield and essential oil content and spraying of Nano zinc (1.5 g/l) had increased essential oil composition of peppermint. [ABSTRACT FROM AUTHOR]

This research with a factorial arrangement was undertaken to investigate physiological responses of ajowan plants to foliar treatment of salicylic acid (1 mM) and nano-Fe2O3 (3 mM) under various salinity levels (0, 4, 8, 12 dS m−1 NaCl, respectively). Rising salinity enhanced sodium and endogenous SA contents, soluble sugars, protein, glycine betaine, proline, antioxidant enzymes activities, ROS generation, and lipid peroxidation, while reduced potassium and iron contents, membrane stability index, leaf water content, leaf pigments, root and shoot biomasses, and seed yield. Application of particularly SA and SA+nano-Fe2O3 alleviated salt toxicity via enhancing K+ uptake, K+/Na+ ratio, Fe content, endogenous level of SA, the activities of antioxidant enzymes (superoxide dismutase, catalase, peroxidase, and polyphenol oxidase), and most of the osmolytes. These changes were resulted in improving membrane stability index, leaf water content, leaf pigments, root and shoot growth, and finally seed yield of plants under moderate and severe salinities. Therefore, these treatments can additively enhance salt tolerance and physiological performance of ajowan through increasing antioxidant capacity, osmolytes, and photosynthetic pigments. [ABSTRACT FROM AUTHOR]

The importance of quinoa has been emphasized considerably in the recent decades, as a highly nutritional crop seed that is tolerant to salinity and amenable to arid agronomical conditions. The focus of this paper is to provide raw and a supplemental data of the research article entitled “Agronomic performance of irrigated quinoa in desert areas: comparing different approaches for early assessment of salinity stress” [1], aiming to compare different approaches for early detection, at the genotypic and crop levels, of the effect of salinity caused by irrigation on the agronomic performance of this crop. A set of 20 genotypes was grown under drip irrigation in sandy soil, amended with manure, at the International Center for Biosaline Agriculture (UAE) for two weeks, after which half of the trial was submitted to irrigation with saline water and this was continued until crop maturity. After eight weeks of applying the two irrigation regimes, pigment contents were evaluated in fully expanded leaves. The same leaves were then harvested, dried and the stable carbon and nitrogen isotope compositions (δ13C and δ15N) and the total nitrogen and carbon contents of the dry matter analyzed, together with ion concentrations. At maturity yield components were assessed and yield harvested. Data analysis demonstrated significant differences in genotypes response under each treatment, within all assessed parameters. The significant level was provided using the Tukey-b test on independent samples. The present dataset highlights the potential use of different approaches to crop phenotyping and monitoring decision making.

Introduction: Peppermint (Mentha piperita L.), a member of Lamiaceae family, is an important medicinal plant that has many useful properties. Copper is an essential micronutrient for normal plant growth and metabolism.

The present study aimed to investigate the potentiality of certain biocontrol agents, namely Bacillus subtilis, B. pumilus, B. megaterium, Pseudomonas fluorescens, Serratia marcescens, Trichoderma album, T. harzianum and T. viride, as well as the synthetic fungicide difenoconazole to control celery powdery mildew caused by Erysiphe heraclei DC, in vitro (against conidia germination and germ tube length of E. heraclei) and in vivo (against disease severity and AUDPC). In vitro, it was found that the antifungal activity of the tested biocontrol agents significantly reduced the germination percentage of the conidia and germ tube length of the pathogen. The reduction in conidia germination ranged between 88.2% and 59.6% as a result of the treatment with B. subtilis and T. album, respectively compared with 97.1% by the synthetic fungicide difenoconazole. Moreover, the fungicide achieved the highest reduction in germ tube length (92.5%) followed by B. megaterium (82.0%), while T. album was the least effective (62.8%). Spraying celery plants with the tested biocontrol agents in the greenhouse significantly reduced powdery mildew severity, as well as the area under the disease progress curve (AUDPC), after 7, 14, 21 and 28 days of application. In this regard, B. subtilis was the most efficient followed by B. pumilus, S. marcescens and B. megaterium, with 80.1, 74.4, 73.2 and 70.5% reductions in disease severity, respectively. In AUDPC, reductions of those microorganisms were 285.3, 380.9, 396.7 and 431.8, respectively, compared to 1539.1 in the control treatment. On the other hand, the fungicide difenoconazole achieved maximum efficacy in reducing disease severity (84.7%) and lowest AUDPC (219.3) compared to the other treatments. In the field, all the applied biocontrol agents showed high efficiency in suppressing powdery mildew on celery plants, with a significant improvement in growth and yield characteristics. In addition, they caused an increase in the concentration of leaf pigments, and the activities of defense-related enzymes such as peroxidase (PO) and polyphenol oxidase (PPO) and total phenol content (TPC). In conclusion, the results showed the possibility of using tested biocontrol agents as eco-friendly alternatives to protect celery plants against powdery mildew.

The present work was carried out at Private Farm (The Experimental Farm of Sand Valley Company) at Ismailia Governorate, Egypt during the two summer seasons of 2016 and 2017 to study the response of vegetative growth, leaf pigments, yield and fruit quality of some summer squash cultivars (Haitek, Kortoba, Otto, Rivera and Shamis) grown in sandy soil to foliar spray with some antioxidants [Salicylic acid (SA), Vitamin B1 and Vitamin C] at 100 ppm of each. The interaction between Revira cultivar and spraying with SA or with Vitamin C at 100 ppm of each increased number of leaves/ plant, leaves dry matter and leaf relative water content (%), crude protein and Vitamin C content in fruits, whereas the interaction between Revira or Shamis cultivars and spraying with SA at 100 ppm increased plant height, concentration of chlorophyll a in leaf tissues, total yield/ fad., total carbohydrates and TSS in fruits. The interaction between Shamis cultivar and spraying with Vitamin B1 or Vitamin C at 100 ppm of each increased concentration of chlorophyll b in leaf tissues, but decreased the concentration of carotenoides in leaf tissues. On the other hand, spraying Otto cultivar with tap water gave the lowest value for each of chlorophyll a, b but recorded the highest concentration of carotenoides in leaf tissues, followed by Haitek and Kortoba, while spraying Kortoba cultivar with tap water gave the lowest value of total yield. [ABSTRACT FROM AUTHOR]

Seaweed extracts as natural plant growth stimulant could be significantly used as a good agricultural practice in sustainable and organic crop production. Therefore, the current study was carried out at a private farm in Shibin El-Kom, Monufia Governorate, Egypt during winter growing seasons of 2017 and 2018. The effect of brown seaweed extract used as a pre-sowing seed soaking for 12 h at a rate of 3 ml/l, in addition as foliar spraying once at rates of 1, 2 or 3 ml/l after 20 days from sowing date on vegetative growth, yield and some nutritional values of leaves and roots of red radish plants of Celesta F1 hybrid was assessed. The experiment was set in a split plot design with three replicates. The obtained results sharply indicated that seaweed soaked seeds gave significantly the higher values of all measured characters than water soaked seeds. It was highly apparent that the foliar spraying treatment of the highest rate of seaweed extract (3 ml/l) gave significantly the best values of all studied characters compared to the other treatments. The interaction had significant effects on all studied parameters, except for leaves and roots dry weight, leaves Fe, and roots Fe and Zn contents in both seasons as well as for chlorophyll a in the first season and chlorophyll b and carotenoids in the second season. The most effective treatment was found to be seaweed soaked seeds before sowing and foliar sprayed seaweed extract at 3 ml/l once 20 days after sowing (DAS). [ABSTRACT FROM AUTHOR]

[Display omitted] • Light transmission in green leaves was modeled by an exponential relation. • Exponential relation used to find the absorption spectra responsible for blue-green emission. • Excitation and emission spectra of blue green fluorescence deconvoluted into five components. • Relative amounts of related emitters were estimated on front and rear side of leaf. • Different lignin structural units gave three fluorescence decay times. In situ fluorescence measurements have been used to investigate relative amounts of blue-green pigments and their distributions in plant leaves from Euphorbia pulcherrima. Advantage was taken from the fact that this species has white leaves on the top, with low pigment concentrations, and green leaves on the stem with ordinary pigment concentrations. Excitation- and emission spectra below 410 nm from white leaves, where pigment absorption is low, are not distorted by self-absorption. Absorption- and reflection spectra from white and green leaves were measured using a spectrophotometer equipped with an integrating sphere. The absorption spectra were used to correct recorded fluorescence spectra for self-absorption. Self-absorption corrected photosystem fluorescence from green leaves, modeling light transmission in leaf tissue exponentially, matches to the excitation/emission spectra from white leaves, apart from small differences due to the pigment concentrations and selective scattering. The introduced exponentially decaying transmission relation also predicts that the ratio of excitation spectra from a white and green leaf is in proportion to the absorption spectrum of the green leaf, which was validated for Photosystem II particle fluorescence. This relation was also used to find a scaled absorption spectrum responsible for blue-green emission, which was assumed to originate from lignin. Excitation/emission spectra of the blue-green fluorescence were decomposed into five components and their relative amounts from adaxial and abaxial sides of the leaves have been quantified. Fluorescence lifetime measurements of the leaves, upon 403 nm excitation, revealed three decay times corresponding to the lignin fluorophores emitting in blue and green spectral region, and indicated that emissions at 500 and 550 nm may originate from the same fluorophore residing in the two physically different environments. [ABSTRACT FROM AUTHOR]

• Ficus carica is the fig species of greatest commercial importance worldwide. • Fig mosaic disease represents the main threat to global fig production. • Fig mosaic virus is the only identified etiological agent of fig mosaic disease. • The disease is present also in Tuscany (Central Italy). • Fig mosaic virus impaired photosynthesis and organic acid biosynthesis in leaves. Fig mosaic disease (FMD) is a major disease affecting fig trees, for which only fig mosaic virus (FMV) has been identified as etiological agent. In the present study, trees of common fig cv. Dottato, belonging to the old Tuscan germplasm, were investigated to pioneering (i) evaluate the presence of FMV in Tuscany (Central Italy), as well as other FMD-associated viruses previously reported in Italy, (ii) type and phylogenetically characterize the reported FMV isolates, and (iii) elucidate some physiological and biochemical responses of fig trees challenged by FMV. Although many studies on FMD have been carried out in Southern Italy, the present study represents the first identification of the disease in another Italian area. This work (i) showed that FMD is present also in Central Italy, also suggesting a wider diffusion than what has been reported so far; (ii) confirmed that the disease is caused by FMV, tested positive in both symptomatic and asymptomatic leaves (100 and 27% of tested samples, respectively); and also fig fleck-associated virus (FFKaV) was reported; (iii) identified three new FMV isolates (i.e., Dot-1, Dot-2 and Dot-3, deposited in GenBank), which resulted not close to other FMV Italian isolates; and (iv) pioneering elucidated that FMV impaired photosynthesis and organic acid biosynthesis in symptomatic leaves, but negative effects occurred also in asymptomatic ones in terms of photosynthetic and accessory pigments. More research should be carried out to improve our knowledge on FMD diffusion and FMV (and FFKaV) genetic features, as well on the effects of this regulated non quarantine pest on fig trees, also investigating its fruits representing an ancient source of food and health. [ABSTRACT FROM AUTHOR]

Azospirillum spp. are plant growth-promoting rhizobacteria (PGPR) that exert beneficial effects on plant growth and yield of agronomically important plant species. The aim of this study was to investigate the effects of a root treatment with Azospirillum baldaniorum Sp245 on hormones in xylem sap and physiological performance in purple basil (Ocimum basilicum L. cv. Red Rubin) plants grown under well-watered conditions and after removing water. Treatments with A. baldaniorum Sp245 included inoculation with viable cells (1·107 CFU mL–1) and addition of two doses of filtered culture supernatants (non-diluted 1·108 CFU mL–1, and diluted 1:1). Photosynthetic activity, endogenous level of hormones in xylem sap (salicylic acid, jasmonic acid, and abscisic acid), leaf pigments, leaf water potential, water-use efficiency (WUE), and drought tolerance were determined. Fluorescence and gas exchange parameters, as well as leaf water potential, showed that the highest dose of filtered culture supernatant improved both photosynthetic performance and leaf water status during water removal, associated with an increase in total pigments. Moreover, gas exchange analysis and carbon isotope discrimination found this bacterial treatment to be the most effective in inducing an increase of intrinsic and instantaneous WUE during water stress. We hypothesize that the benefits of bacterial treatments based on A. baldaniorum Sp245 are strongly correlated with the synthesis of phytohormones and the induction of plant-stress tolerance in purple basil.

Single-walled carbon nanotubes (SWCNTs) emerge as promising novel carbon-based nanoparticles for use in biomedicine, pharmacology and precision agriculture. They were shown to penetrate cell walls and membranes and to physically interact and exchange electrons with photosynthetic complexes in vitro. Here, for the first time, we studied the concentration-dependent effect of foliar application of copolymer-grafted SWCNTs on the structural and functional characteristics of intact pea plants. The lowest used concentration of 10 mg L−1 did not cause any harmful effects on the studied leaf characteristics, while abundant epicuticular wax generation on both leaf surfaces was observed after 300 mg L−1 treatment. Swelling of both the granal and the stromal regions of thylakoid membranes was detected after application of 100 mg L−1 and was most pronounced after 300 mg L−1. Higher SWCNT doses lead to impaired photosynthesis in terms of lower proton motive force generation, slower generation of non-photochemical quenching and reduced zeaxanthin content; however, the photosystem II function was largely preserved. Our results clearly indicate that SWCNTs affect the photosynthetic apparatus in a concentration-dependent manner. Low doses (10 mg L−1) of SWCNTs appear to be a safe suitable object for future development of nanocarriers for substances that are beneficial for plant growth.

The relationship between invasive plant functional traits and their invasiveness is still the subject of scientific investigation, and the backgrounds of transition from non-native to invasive species in ecosystems are therefore poorly understood. Furthermore, our current knowledge on species invasiveness is heavily biased toward terrestrial species; we know much less about the influence of allochthonous plant traits on their invasiveness in aquatic ecosystems. In this paper, we present the results of a study on physiological and ecological traits of two introduced and three native macrophyte species in the Mantua lakes system (northern Italy). We compared their photophysiology, pigment content, leaf reflectance, and phenology in order to assess how the invasive Nelumbo nucifera and Ludwigia hexapetala perform compared to native species, Nuphar lutea, Nymphaea alba, and Trapa natans. We found L. hexapetala to have higher photosynthetic efficiency and to tolerate higher light intensities than N. nucifera and the native species especially at extreme weather conditions (prolonged exposure to high light and higher temperatures). Chlorophyll a and b, and carotenoids content of both allochthonous species were substantially higher than those of native plants, suggesting adaptive response to the ecosystem of Mantua lakes system. Higher variability of recorded data in invasive species was also observed. These observations suggest advanced photosynthetic efficiency of the invasive species, especially L. hexapetala, resulting in faster growth rates and higher productivity. This was supported by the evaluation of seasonal dynamics mapped from satellite remote sensing data. This study provides empirical evidence for the relationship between specific plant physiological traits and invasiveness of aquatic plant species, highlighting the importance of trait studies in predicting ecosystem-level impacts of invasive plant species.