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AbstractResearch on the effects of oxygen nanobubbles (ONBs) in hydroponic cultures has focused on greenhouse crops, while their impact on ornamental plants has been less studied. This study investigated the impact of ONBs on Anthurium (Anthurium andraeanum Linden ex André) plants in hydroponic culture. Oxygen nanobubbles, generated using a specialized device, were introduced into the nutrient solution. The results revealed that injecting ONBs not only elevated the dissolved oxygen (O2) concentration (DO) but also exceeded the normal solution level by 3 mg L−1 at 21 °C after 24 h. Interestingly, the decrease in DO followed a logarithmic trend: when above 16 mg L−1, O2 depletion from the solution was faster, whereas below 16 mg L−1, the rate of O2 loss slowed, stabilizing around 8 mg L−1. The findings also demonstrated that ONBs significantly enhanced plant growth and development. Plants treated with ONBs exhibited increased leaf fresh mass (64.00 vs. 55.46 g; p < 0.01), leaf dry mass (12.58 vs. 9.92 g; p < 0.01), and leaf area (766.58 vs. 646.33 cm2; p < 0.01) compared to control plants. Furthermore, ONBs notably raised phosphorus levels in the leaves (3.51 vs. 2.93 mg g−1; p < 0.01), enhanced leaf chlorophyll content (41.83 vs. 36.00 unit; p < 0.01), and improved photosynthetic activity. The results also indicated that ONBs improved root morphology, increasing both fresh (53.25 vs. 37.03 g; p < 0.01), and dry root mass (5.65 vs. 4.51 g; p < 0.01). Overall, the study suggests that ONBs have the potential to be a beneficial tool for enhancing plant production in hydroponic setups. [ABSTRACT FROM AUTHOR]

Nowadays, hydroponics is an advanced method for plant production in agriculture. The optimal balance of nutrients in the nutrient solution is crucial to enhance plant performance in this method. To investigate the effect of potassium to calcium (K:Ca) ratio change in nutrient solution on quantitative and qualitative yield of lilies in hydroponic culture, a randomized complete block design with nine treatments and three replications was designed and carried out in 30% perlite and 70% sand. The treatments included different concentrations of calcium (Ca) at three levels of 0, 3, and 6 mM and different concentrations of potassium (K) at three levels of 0, 3, and 6 mM in the Hoagland nutrient solution, with K:Ca ratios of 0:0, 0:3, 0:6, 3:0, 3:3, 3:6, 6:0, 6:3, and 6:6. Results showed that the presence of different levels of potassium and calcium was found to enhance the quality of lilies by influencing nutrient uptake. The results indicated that nutrient solutions containing different ratios of K:Ca had a significant effect on reproductive height, the number of aborted buds, stem diameter at the 5% level and the number of flowers, the number of leaves, the fresh weight of shoots, the dry weight of shoots, and the longevity at the 1% level. The highest yield in terms of longevity (17 days), the number of flowers, the number of leaves, and absorption of potassium and calcium were observed in the nutrient solution with a 3:3 K:Ca ratio. [ABSTRACT FROM AUTHOR]

Stevia rebaudiana is a plant native to South America known for producing steviol glycosides and fructans used in low-calorie and functional foods. This study aimed to cultivate and isolate inulin from hydroponically grown S. rebaudiana roots. Seedlings were grown hydroponically for 28 days; then, roots were dried and extracted at 121 °C for 20 min. Extracts were centrifuged and lyophilized, yielding supernatant (SSR-H) and precipitate (PSR-H) fractions. Fructan yields were 21.34% (SSR-H) and 2.91% (PSR-H). HPLC, FTIR, and NMR analyses confirmed inulin-like fructans with polymerization degrees of 16 and 31, respectively. The characteristic peaks of a fructan-like-inulin were observed in the FTIR, ¹H, and ¹³C NMR spectra. These results demonstrate effective inulin extraction from hydroponically grown S. rebaudiana roots, highlighting its potential applications in the food industry. [ABSTRACT FROM AUTHOR]

In this study, we aimed to examine the growth, physiological and biochemical status, and responses to salinity stress of bok choy (Brassica rapa subsp. chinensis) cultivated in a hydroponic system with a plasma-treated solution. Plasma gas generated using a cylindrical dielectric barrier discharge or air (control) was injected into Hoagland nutrient solution once a week for different durations (0, 5, and 10 min). After 4 weeks, the length of the shoots and roots, number of leaves, and dry weight of bok choy plants significantly increased in individuals grown with Hoagland solution treated with plasma gas for 10 min. An increase in dry weight of individual plants of approximately 80.5% was observed in plants in the plasma-treated group compared to those in a control group. The levels of chlorophyll, total soluble proteins, and nitrogen uptake, and transcription of genes related to salinity stress tolerance— WRKY2 , HHP3 , and ABI1 — were also significantly elevated in bok choy grown with plasma treated Hoagland solution. Moreover, when exposed to 20 mM NaCl, plant length and leaf number were significantly increased, in the group grown with Hoagland solution treated with plasma gas for 10 min. Level of H2O2 was significantly elevated in the treated nutrient solutions. In plants grown with the treated nutrient solution, intracellular NO was highly detected in the cell division and elongation zone of roots. Our findings suggest that plasma treatment of nutrient solutions in hydroponic culture systems may improve the growth, physiological and biochemical status, and tolerance to salinity stress in plants, and a crucial role of H2O2 generated in the treated nutrient solutions may play in this improvement. [ABSTRACT FROM AUTHOR]

Leafy vegetables are widely consumed around the world for their rich nutritional qualities. To ensure a reliable and cost-effective supply of leafy vegetables in the future, advancements in their production are essential. Deficiencies of nitrogen (N), phosphorus (P), and potassium (K) impair growth of leafy vegetables and the ensuing visual symptoms make the plants unmarketable. We studied the use of non-contact large area hyperspectral imaging (HSI) for early detection of N, P and K deficiencies in the leafy vegetable, Choy Sum, before the appearance of visual symptoms. The wide spectral data of 500-900 nm extracted from the plants were subjected to advanced feature mining, facilitating the creation of novel spectral indices tailored to each vital nutrient by leveraging the Pearson's correlations of 0.85 for N, 0.64 for P, and 0.68 for K with gold standard elemental concentration data. Early detection of deficiencies and timely replenishment of macronutrient(s) can prevent the development of obvious symptoms and thus maintain the visual quality of Choy Sum. These newly created spectral indices hold the potential to provide non-destructive estimation of nutrient content in plants, offering a promising avenue for future advancements in precision agriculture and resource-efficient crop management. [ABSTRACT FROM AUTHOR]

Soil fertility is declining in low-input agriculture due to insufficient fertilizer application by small-scale farmers. On the other hand, concerns are rising regarding the environmental pollution of both air and water in high-input agriculture due to the excessive use of N fertilizers in short growing seasons for vegetable crops, which is directly linked to the health of human beings and environmental safety. This study aimed to determine genotypic differences in the Nitrogen Use Efficiency (NUE) levels of different leafy vegetable species (Arugula, Spinach, Cress, Parsley, and Dill) grown hydroponically under two different N rates, low N (0.3 mM) and high N (3.0 mM), and to identify the plant traits that are contributing to NUE. A nutrient solution experiment was conducted between March and April 2024 by using an aerated Deep-Water Culture (DWC) technique in a fully automated climate room with a completely randomized block design (CRBD) with three replications for five weeks. The results indicated that shoot growth, as well as root morphological and leaf physiological responses, was significantly (p < 0.001) affected by genotype, the N rate, and genotype–N rate interactions. Shoot growth in some vegetable species (Arugula, Spinach, and Cress) was significantly higher under a low N than a high N rate, illustrating that they have a great capability for NUE under low N stress conditions. Similar results were also recorded for the root growth of the N-efficient species under low N rates. The NUE levels of these species were closely associated with leaf physiological (leaf area, leaf chlorophyll index (SPAD), photosynthesis, and total leaf chlorophyll (a + b) and carotenoids) and root morphological (root length, root volume, and average root diameter) characteristics. These plant traits could be useful indicators for the selection and breeding of 'N-efficient' leafy vegetable species for sustainable low-input agriculture systems in the future. However, further investigation should be carried out at the field level to confirm their commercial production viability. [ABSTRACT FROM AUTHOR]

Phosphorus (P) deficiency is one of the main reasons limiting plant production of Brassica napus L. Exploring the dynamics of leaf intracellular substances and the correlations with photosynthesis and growth helps to understand the response mechanisms of B. napus L. to P deficiency. This study conducted experiments on B. napus L. plants by measuring the leaf electrophysiological parameters, leaf structure, elastic modulus (Em), photosynthesis, and growth indices under different P treatment conditions. The dynamics of leaf intracellular water and nutrients of B. napus L. were calculated and analyzed by using the electrophysiological parameters, and the plant tolerance threshold to low-P stress was discovered. The results indicated that the status of the leaf intracellular water and nutrients remained stable when the P concentration was not lower than 0.250 mmol·L−1, but maximized the photosynthesis and growth at a P level of 0.250 mmol·L−1. The 0.125 mmol·L−1 P concentration significantly decreased the mesophyll cell volume, and the palisade–sponge ratio and tightness degree of leaf tissue structure were remarkably increased. This led to an increase in cell elastic modulus, and significantly improved the water retention capacity of leaf cells. At the same time, the intracellular water use efficiency and total nutrient transport capacity of leaves remained stable. As a result, the photosynthesis and growth of plants were maintained at the same level as that of the control group. However, photosynthesis and growth were clearly inhibited with a further decrease in P concentration. Therefore, 0.125 mmol·L−1 was the tolerance threshold of B. napus L. to low P. With the help of electrophysiological information, the effects of the dynamics of intracellular substances on photosynthesis and growth of B. napus L. under low-P stress can be investigated, and the plant's adaptive response can be revealed. However, the findings of the current hydroponic study are not directly applicable to field conditions with naturally P-deficient soils. [ABSTRACT FROM AUTHOR]

Cowpea is a food crop representing an important source of proteins and income, mainly for people living in the north and northeast of Brazil. This study aimed to evaluate the growth performance of two cowpea cultivars under four different ionic concentrations of the growth solution. Thus, a pot experiment was performed using the sand culture technique and set up in a completely randomized design with a 2 x 4 factorial scheme, using four replications and one plant per plot. After the period of growth, the parameters such as length of the shoot, stem diameter, number of leaves, number of secondary branches, number of pods, fresh weight of the stem, stem dry mass, leaf dry mass, shoot dry mass, and root/shoot ratio were obtained. The results pointed out that there was a significant interaction effect on parameters like stem diameter, leaf dry mass, shoot dry mass, and number of leaves. Both cultivars were strongly responsive to changes in ionic concentration, indicating a greater biomass production at ionic concentrations of 90% and 120%. A greater growth performance for BRS Rouxinol than BRS Itaim was observed, while the second cultivar indicated a high tolerance as exposed to the highest ionic concentrations. [ABSTRACT FROM AUTHOR]

This study was conducted at the Central Laboratory for Agricultural Climate (CLAC), Agricultural Research Center, Giza, Egypt, during two winter seasons of 2022 and 2023. To investigate the efficiency of two hydroponic systems (flat nutrient film technique "F-NFT" and deep water culture "DWC") under three nutrient solution concentrations (1.2, 1.5 and 1.8 dSm-1), three number of irrigation times: (24, 36 and 48 per day) and interaction of them on growth and yield of lettuce. Treatments were arranged in a split split plot design with three replicates. Measurements were i.e., number of leaves, plant fresh weight, total yield (Kg/m2), N, P, K and nitrate contents in leaves, chlorophyll reading, water and power use efficiency/m² and economic study. The results indicated that using F-NFT, solution concentration 1.8 dSm-1 and 48 irrigation times per day provided the highest values for all tested parameters more than other treatments. While, from the economic study illustrated that the cultivation of lettuce in the F-NFT system, using a nutrient solution concentration of 1.5 dSm-1 and 48 irrigation times per day gain the highest net profit under a greenhouse covered by netting during the winter season. [ABSTRACT FROM AUTHOR]

Food security has become an increasingly pressing global challenge, especially with the continuous growth of the world population and the reduction of arable land due to urbanization. Greenhouses, as controlled environments, provide an ideal framework for improving crop production and quality. Hydroponics is an intensive method of agricultural production that offers advanced environmental protection and increased food safety control. Cucumber production is one of the most successful crops in hydroponic systems. The study was conducted in the Automated Research Greenhouse at the Research Center for Studies of Food Quality and Agricultural Products, focusing on the cultivation of the long-fruited cucumber hybrid Peloton. The crop was established in the first cycle using a soilless cultivation system with perlite-filled mats (4 mm diameter). This system serves as an alternative to greenhouse cucumber cultivation. Three fertigation rates of 4 L/day, 3.6 L/day, and 3.2 L/day were employed. The main objective of the study is to identify the most efficient variant regarding the influence of fertigation rates on the number and weight of fruits per plant and overall cucumber production. [ABSTRACT FROM AUTHOR]

Leafy vegetables are widely consumed around the world for their rich nutritional qualities. To ensure a reliable and cost-effective supply of leafy vegetables in the future, advancements in their production are essential. Deficiencies of nitrogen (N), phosphorus (P), and potassium (K) impair growth of leafy vegetables and the ensuing visual symptoms make the plants unmarketable. We studied the use of non-contact large area hyperspectral imaging (HSI) for early detection of N, P and K deficiencies in the leafy vegetable, Choy Sum, before the appearance of visual symptoms. The wide spectral data of 500–900 nm extracted from the plants were subjected to advanced feature mining, facilitating the creation of novel spectral indices tailored to each vital nutrient by leveraging the Pearson’s correlations of 0.85 for N, 0.64 for P, and 0.68 for K with gold standard elemental concentration data. Early detection of deficiencies and timely replenishment of macronutrient(s) can prevent the development of obvious symptoms and thus maintain the visual quality of Choy Sum. These newly created spectral indices hold the potential to provide non-destructive estimation of nutrient content in plants, offering a promising avenue for future advancements in precision agriculture and resource-efficient crop management.

In this study, we aimed to examine the growth, physiological and biochemical status, and responses to salinity stress of bok choy (Brassica rapa subsp. chinensis) cultivated in a hydroponic system with a plasma-treated solution. Plasma gas generated using a cylindrical dielectric barrier discharge or air (control) was injected into Hoagland nutrient solution once a week for different durations (0, 5, and 10 min). After 4 weeks, the length of the shoots and roots, number of leaves, and dry weight of bok choy plants significantly increased in individuals grown with Hoagland solution treated with plasma gas for 10 min. An increase in dry weight of individual plants of approximately 80.5% was observed in plants in the plasma-treated group compared to those in a control group. The levels of chlorophyll, total soluble proteins, and nitrogen uptake, and transcription of genes related to salinity stress tolerance—WRKY2, HHP3, and ABI1— were also significantly elevated in bok choy grown with plasma treated Hoagland solution. Moreover, when exposed to 20 mM NaCl, plant length and leaf number were significantly increased, in the group grown with Hoagland solution treated with plasma gas for 10 min. Level of H2O2 was significantly elevated in the treated nutrient solutions. In plants grown with the treated nutrient solution, intracellular NO was highly detected in the cell division and elongation zone of roots. Our findings suggest that plasma treatment of nutrient solutions in hydroponic culture systems may improve the growth, physiological and biochemical status, and tolerance to salinity stress in plants, and a crucial role of H2O2 generated in the treated nutrient solutions may play in this improvement.

Soil salinization poses a significant threat to agricultural productivity, necessitating innovative agronomic strategies to mitigate its impact. This study focuses on improving salt stress resistance in tomato plants through the application of silicon (Si) in roots. A greenhouse experiment was carried out under normal conditions (control, and 1 and 4 mM Si) and under salinity stress (salt control, and 1 and 4 mM Si). Various parameters were analyzed in leaves and roots. Under normal conditions, tomato plants grown in non-saline conditions exhibited some toxicity when exposed to Na2SiO3. As for the experiments under salt stress conditions, Si mitigated oxidative damage, preserving root cell membrane integrity. The concentration of malondialdehyde was reduced by 69.5%, that of proline was reduced by 56.4% and there was a 57.6% decrease in catalase activity for tomato plants treated with 1 mM Si under salt stress. Furthermore, Fe uptake and distribution, under salt conditions, increased from 91 to 123 mg kg−1, the same concentration as that obtained for the normal control. In all cases, the lower dose produced better results under normal conditions than the 4 mM dose. In summary, this research provides a potential application of Si in non-fertigated crop systems through a radicular pathway. [ABSTRACT FROM AUTHOR]

Nutrient availability in hydroponic solutions must be accurately monitored to maintain crop productivity; however, few cost-effective, accurate, real-time, and long-term monitoring technologies have been developed. In this study, we describe the development and application of cation-/anion-exchange chromatography with a neutral eluent (20-mmol/L sodium formate, pH 7.87) for the simultaneous separation (within 50 min) of ionic nutrients, including K+, NH4+, NO2−, NO3−, and phosphate ion, in a hydroponic fertilizer solution. Using the neutral eluent avoided degradation of the separation column during precipitation of metal ion species, such as hydroxides, with an alkaline eluent and oxidation of NO2− to NO3− with an acidic eluent. The suitability of the current method for monitoring ionic components in a hydroponic fertilizer solution was confirmed. Based on our data, we propose a controlled fertilizer strategy to optimize fertilizer consumption and reduce the chemical load of drained fertilizer solutions. [ABSTRACT FROM AUTHOR]

Soil fertility is declining in low-input agriculture due to insufficient fertilizer application by small-scale farmers. On the other hand, concerns are rising regarding the environmental pollution of both air and water in high-input agriculture due to the excessive use of N fertilizers in short growing seasons for vegetable crops, which is directly linked to the health of human beings and environmental safety. This study aimed to determine genotypic differences in the Nitrogen Use Efficiency (NUE) levels of different leafy vegetable species (Arugula, Spinach, Cress, Parsley, and Dill) grown hydroponically under two different N rates, low N (0.3 mM) and high N (3.0 mM), and to identify the plant traits that are contributing to NUE. A nutrient solution experiment was conducted between March and April 2024 by using an aerated Deep-Water Culture (DWC) technique in a fully automated climate room with a completely randomized block design (CRBD) with three replications for five weeks. The results indicated that shoot growth, as well as root morphological and leaf physiological responses, was significantly (p < 0.001) affected by genotype, the N rate, and genotype–N rate interactions. Shoot growth in some vegetable species (Arugula, Spinach, and Cress) was significantly higher under a low N than a high N rate, illustrating that they have a great capability for NUE under low N stress conditions. Similar results were also recorded for the root growth of the N-efficient species under low N rates. The NUE levels of these species were closely associated with leaf physiological (leaf area, leaf chlorophyll index (SPAD), photosynthesis, and total leaf chlorophyll (a + b) and carotenoids) and root morphological (root length, root volume, and average root diameter) characteristics. These plant traits could be useful indicators for the selection and breeding of ‘N-efficient’ leafy vegetable species for sustainable low-input agriculture systems in the future. However, further investigation should be carried out at the field level to confirm their commercial production viability.

Presently, zinc sulfate (ZnSO4) based fertilizers are reported inefficient in flooded paddy fields which necessitates to find a better alternative for sustainable rice cultivation. This study was conducted to find out the effectiveness of bacterially solubilized Zn (BSZn) on the early growth of rice plants and the concentration of Zn in the plant parts in comparison to conventional ZnSO4. BSZn preparations were obtained from culture supernatant following ZnO solubilization by bacterial isolates Burkholderia spp. and Achromobacter sp. The effectiveness of BSZn was assessed on rice seed germination on Petri plates and the growth of seedlings upon treatment in hydroponic culture under controlled conditions. In general, BSZn obtained from certain Burkholderia spp. increased seed germination percentage (SG%) (98–100%), mean germination rate (MGR), mean daily germination (MDG), decreased mean germination time (MGT) and impart stimulating effect on seed germination as indicated by increased vigor indices compared to ZnSO4 treatment regimes. The obtained data from the hydroponic culture of rice seedling growth indicated a positive influence of most of the BSZn preparation on dry and wet weight of roots and shoots, and seedling length compared to ZnSO4 at p < 0.05. Both chlorophyll and carotenoid content of the seedling increased in the presence of some BSZn preparations. In general, compared to shoot, the root of seedlings accumulated a higher amount of Zn (up to 888 µg Zn/g dry biomass). Zn concentration data indicated that BSZn16 obtained from Burkholderia sp. EIKU16 culture help to accumulate significantly higher amounts of Zn in rice seedlings under hydroponic culture than that while treated with ZnSO4. [ABSTRACT FROM AUTHOR]

Inulin has been shown to possess probiotic properties and industrial applications. Chicory (Cichorium intybus L.) is the main commercial source of inulin throughout the whole world. However, the composition of the culture medium to grow chicory has a significant effect on both quality and the quantity of this active ingredient in the plant. Here, several sets of experiments were conducted in a completely randomized design under hydroponic culture. in vitro condition, to investigate the effects of phosphorus and iron fertilizer starvation on plant growth traits and also, the amount of active ingredient in chicory. Phosphorus was used at three different levels: 0.5, 1.25 and 2.5 mM while, the effect of iron treatment was investigated by removing iron from the MS culture medium and then compared to the control. The results showed that with increasing phosphorous consumption, elevated fresh and dry root weight was observed, however, iron starvation reduced root growth. In this study, the amount of inulin was significantly affected by these treatments while, the stress of phosphorus deficiency and also the elimination of iron increased the amount of inulin. [ABSTRACT FROM AUTHOR]

In this study, ploidy levels were determined by stomatal observations and flow cytometry analysis of plants polyploidised by the application of 0.05% colchicine to seedlings at the first true leaf stage. In the study of developing polyploid watermelon rootstocks, the survival rate of the plants was 77%, and the polyploidisation rates were 11% and 3% according to stomatal observations and flow cytometry analysis, respectively. According to the results of flow cytometry, 22 polyploid genotypes were determined. Auto- (12) and allotetraploids (10) of Citrullus genotypes were developed, and their plant growth performance was determined in hydroponic culture in comparison with diploids, commercial rootstocks (RS841, ‘Argentario’) and watermelon cultivar (‘Crimson Tide’). Putative tetraploids and their diploid controls were grown in hydroponic culture for 21 days, and their vegetative growth performances were determined. The results showed that the increases in plant biomass depending on polyploidisation were 100% in autotetraploids and 156% in allotetraploids as compared to diploid controls.

Phosphorus (P) deficiency is one of the main reasons limiting plant production of Brassica napus L. Exploring the dynamics of leaf intracellular substances and the correlations with photosynthesis and growth helps to understand the response mechanisms of B. napus L. to P deficiency. This study conducted experiments on B. napus L. plants by measuring the leaf electrophysiological parameters, leaf structure, elastic modulus (Em), photosynthesis, and growth indices under different P treatment conditions. The dynamics of leaf intracellular water and nutrients of B. napus L. were calculated and analyzed by using the electrophysiological parameters, and the plant tolerance threshold to low-P stress was discovered. The results indicated that the status of the leaf intracellular water and nutrients remained stable when the P concentration was not lower than 0.250 mmol·L−1, but maximized the photosynthesis and growth at a P level of 0.250 mmol·L−1. The 0.125 mmol·L−1 P concentration significantly decreased the mesophyll cell volume, and the palisade–sponge ratio and tightness degree of leaf tissue structure were remarkably increased. This led to an increase in cell elastic modulus, and significantly improved the water retention capacity of leaf cells. At the same time, the intracellular water use efficiency and total nutrient transport capacity of leaves remained stable. As a result, the photosynthesis and growth of plants were maintained at the same level as that of the control group. However, photosynthesis and growth were clearly inhibited with a further decrease in P concentration. Therefore, 0.125 mmol·L−1 was the tolerance threshold of B. napus L. to low P. With the help of electrophysiological information, the effects of the dynamics of intracellular substances on photosynthesis and growth of B. napus L. under low-P stress can be investigated, and the plant’s adaptive response can be revealed. However, the findings of the current hydroponic study are not directly applicable to field conditions with naturally P-deficient soils.

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The effects of sulfate on the zinc (Zn) bioaccumulation characteristics and photophysiological mechanisms of the ornamental plant Hydrocotyle vulgaris were explored using a hydroponic culture under three Zn concentrations (300, 500 and 700 mg L−1) with (400 μmol L−1) or without the addition of sulfate. Results showed that: (1) tissue Zn concentrations and total Zn contents increased with increasing hydroponic culture Zn concentrations; and sulfate addition decreased Zn uptake and translocation from roots to shoots; (2) Zn exposure decreased photosynthetic pigment synthesis, while sulfate changed this phenomenon, especially for chlorophyll a under 300 mg L−1 Zn treatment; (3) Zn exposure decreased photosynthetic function, while sulfate had positive effects, especially on the photosynthetic rate (Pn) and stomatal conductance (Gs); and (4) chlorophyll fluorescence parameters related to light energy capture, transfer and assimilation were generally downregulated under Zn stress, while sulfate had a positive effect on these processes. Furthermore, compared to photosynthetic pigment synthesis and photosynthesis, chlorophyll fluorescence was more responsive, especially under 300 mg L−1 Zn treatment with sulfate addition. In general, Zn stress affected photophysiological processes at different levels, while sulfate decreased Zn uptake, translocation, and bioaccumulation and showed a positive function in alleviating Zn stress, ultimately resulting in plant growth promotion. All of these results provide a theoretical reference for combining H. vulgaris with sulfate application in the bioremediation of Zn-contaminated environments at the photophysiological level. Excessive zinc reduces the photosynthetic levels of plants. In this study, we investigated how damage caused by Zn stress may be alleviated. We found that exogenous sulfate could improve the photosynthetic levels of the ornamental plant Hydrocotyle vulgaris under Zn stressed. The results of this study provide a reference for the restoration of Zn-contaminated environments by the combining of H. vulgaris with sulfate at the photophysiological level. [ABSTRACT FROM AUTHOR]

Cultivation of salt-tolerant plants is regarded as an innovative approach for desalination and remediation of salt-impacted agricultural soils. From this point of view, the effects of increasing NaCl concentrations in the root medium on some growth traits and development of wheat, oat, emmer, and barley under hydroponic conditions were studied and the phytodesalination potential of these plants was assessed at the greenhouse facilities of the YSU, Republic of Armenia. Crops were grown at six different degrees of salinity (0, 100, 200, 300, 400, 500 mM NaCl) in a hydroponic system that was set up under greenhouse. The results show that the studied plants have different tolerance to increasing concentrations of NaCl. The negative influence of salinity on main growth parameters, relative electrolytic leakage, leaf succulence, chlorophyll content index, photosynthetic rate, and transpiration rate was expressed stronger in emmer compared with the rest of studied crops. Along with the increase in NaCl concentration in the root medium, simultaneously with the significant increase in Na+ content in the leaves of emmer, a decrease in K+ content was observed, whilst in wheat, oat, and barley, on the contrary, the increase in Na+ in the leaves was accompanied by the increase in K+ concentrations, which indicated the activation of some physiological adaptation mechanisms. Summarizing our results, we concluded that barley and oat could be suggested as promising crops for saline agriculture and soil phytodesalination, since they are survivable, productive and accumulate large amounts of ions in their above-ground parts. [ABSTRACT FROM AUTHOR]

IntroductionSalinity as one of the major abiotic stresses influences plant growth and development. Rice with a salt tolerance threshold of 3 ds/m is regarded as a very sensitive crop, especially at seedling stage. Metabolite profiling is conducted by instruments such as GC-MS (Gas chromatography–mass spectrometry) and permits the study of plant responses to environmental stresses at the molecular level. The present study assessed the primary metabolite profiles related to high salinity stress in sensitive (IR28) and tolerant (CSR28) genotypes of rice seedlings in shoots and roots after 6h and 54 h salinity exposure.Material and methodsThe seeds of two rice (Oryza sativa L. ssp. Indica) genotypes with different salinity tolerance were obtained from International Rice Research Institute (IRRI) in Philippines. The plants were grown hydroponically in the greenhouse of Heinrich-Heine-University (HHU), Düsseldorf, Germany. The two-week old seedlings were exposed to 150 mM (15 ds/m) NaCl salinity. The topmost parts of the plants were harvested (in five replications of 10 seedlings each) at 6h and 54h post-treatment. Metabolite extraction was performed by GC-MS method. The experiment was conducted as factorial in a completely randomized design (CRD) and significance level was tested using ANOVA in SAS v9.2 software. R software was used for Principal Component Analysis (PCA) using metabolite z-score data Results and discussionGC-MS analysis identified 37 primary metabolites including 18 amino acids (AAs), five sugars and sugar alcohols and 14 organic acids (OAs) in roots and shoots of the CSR28 and IR28 genotypes at 6h and 54h post-salt exposure. In response to salinity, amino acids and sugars accumulated and organic acids depleted in both genotypes. Long-term stress revealed pronounced differences between the two genotypes. The major osmolyte proline indicated maximum response to salinity in CSR28 shoots, while the stress marker GABA accumulated more in IR28 shoots. Under high salinity the osmoprotectants raffinose and myo-inositol increased in CSR28 roots. Principal Component Analysis (PCA) revealed amino acid accumulations in the long-term exposure of salt stress in roots are main contributors to differentiate the genotypes for salt tolerance.ConclusionsBased on GC-MS analysis, 83.3% increase in amino acids and 61.8% decrease in organic acids were observed in response to salinity, indicating an increase in osmotic adjustment mechanisms and a decrease in photosynthetic reactions in the genotypes, respectively. The PCA demonstrated that amino acids play the most important role in separating the samples under salinity stress and control conditions in both organs. Further, the genotypes were differentiated due to metabolic changes in roots in response to salinity particularly in the long-term stress. Proline which is one of the most important osmolytes involved in abiotic stresses was significantly higher in the shoots of CSR28 under the long-term salinity compared to that of IR28. On the other hand, GABA which is a stress marker accumulated more in the shoots of the sensitive genotype. Some metabolites such as aspartate myo-inositol, citrate, glycerate, isocitrate and shikimate were specifically accumulated in roots. Finally, proline, GABA, etc. can be used as biomarkers for selecting salt tolerant lines. The present study highlights the contribution of metabolic adaptation to salinity tolerance.AcknowledgementsWe appreciate the International Rice Research Institute (IRRI) for providing the seeds. We also acknowledge the excellent technical assistance of Gorgan University of Agricultural Sciences and Natural Resources (GAU), Gorgan, Iran and Heinrich-Heine-University (HHU), Düsseldorf, Germany.

Effective management of plant essential nutrients is necessary for hydroponically grown lettuce to achieve high yields and maintain production. This study investigated in situ hyperspectral imaging of hydroponic lettuce for predicting nutrient concentrations and identifying nutrient deficiencies for: nitrogen (N), phosphorous (P), potassium (K), calcium (Ca), magnesium (Mg), and sulphur (S). A greenhouse study was conducted using 'Salanova Green' lettuce grown with controlled solution treatments with varying macronutrient fertility rates of 0, 8, 16, 32, 64, and 100% each for N, P, K, Ca, Mg, and S. Plants were imaged using a hyperspectral line scanner at six and eight weeks after transplanting; then, plant tissues were sampled, and nutrient concentrations measured. Partial least squares regression (PLSR) models were developed to predict nutrient concentrations for each nutrient individually (PLS1) and for all six nutrient concentrations (PLS2). Several binary classification models were also developed to predict nutrient deficiencies. The PLS1 and PLS2 models predicted nutrient concentrations with Coefficient of Determination (R 2) values from 0.60 to 0.88 for N, P, K, and S, while results for Ca and Mg yielded R 2 values of 0.12–0.34, for both harvest dates. Similarly, plants deficient in N, P, K, and S were classified more accurately compared to plants deficient in Ca and Mg for both harvest dates, with F1 values (F-scores) ranging from 0.71 to 1.00, with the exception of K which had F1 scores of 0.40–0.67. Overall, results indicate that both leaf tissue nutrient concentration and nutrient deficiencies can be predicted using hyperspectral data collected for whole plants. • Collected hyperspectral data for lettuce exposed to 36 different nutrient solutions. • Developed multiple-output models for predicting foliar nutrient concentrations. • Evaluated several models for classifying nutrient deficient lettuce plants. [ABSTRACT FROM AUTHOR]

Soil salinization poses a significant threat to agricultural productivity, necessitating innovative agronomic strategies to mitigate its impact. This study focuses on improving salt stress resistance in tomato plants through the application of silicon (Si) in roots. A greenhouse experiment was carried out under normal conditions (control, and 1 and 4 mM Si) and under salinity stress (salt control, and 1 and 4 mM Si). Various parameters were analyzed in leaves and roots. Under normal conditions, tomato plants grown in non-saline conditions exhibited some toxicity when exposed to Na2SiO3. As for the experiments under salt stress conditions, Si mitigated oxidative damage, preserving root cell membrane integrity. The concentration of malondialdehyde was reduced by 69.5%, that of proline was reduced by 56.4% and there was a 57.6% decrease in catalase activity for tomato plants treated with 1 mM Si under salt stress. Furthermore, Fe uptake and distribution, under salt conditions, increased from 91 to 123 mg kg−1, the same concentration as that obtained for the normal control. In all cases, the lower dose produced better results under normal conditions than the 4 mM dose. In summary, this research provides a potential application of Si in non-fertigated crop systems through a radicular pathway.

Cadmium (Cd) and fluorine (F) often coexist in environment and are toxic to organisms; however, their combined effects on plants are still not well documented. In this study, the co-effects of Cd and F on germination, biomass, photosynthesis, and nutrients uptake of lettuce were carried out in hydroponic culture. The results showed that the seed germination and seedling biomass decreased with an increase in Cd and F supplementation. The root morphology verified these effects as excess combined Cd and F diminished the root tips and surface area of lettuce, while single Cd and F inhibited the growth by decreasing root length and average diameter, respectively. These effects were also consistence with a reduction in photosynthesis which was mainly regulated by reducing the quantum yield of PS II, electron transport activity, stomatal conductance, intercellular CO2 concentration, and transpiration rate in response to the pollutants. Moreover, when lettuce exposed to Cd and F stress, the accumulation of several essential elements in shoot decreased. In a sum, the synergistic negative effects of Cd and F on the seed germination and seedling growth of lettuce were observed, and these might be owed to nutrient absorption and translocation in the plant. These findings aid in understanding the harmful effects and specific mechanisms of action of Cd and F on plants. [ABSTRACT FROM AUTHOR]

The use of peat in traditional cultivation systems and in commercial nurseries is an environmental problem. In this work, we evaluated the partial replacement of peat with different amounts of biochar sourced from vineyard pruning as plant growing substrates. We studied its effect on the growth of lettuce plants under greenhouse and semi-hydroponic conditions. Substrate mixtures contained 30% (v/v) of vermiculite and 70% (v/v) of different biochar:peat treatments as follows: 0:70 (B0), 15:55 (B15), 30:40 (B30), 50:20 (B50), and 70:0 (B70). Higher biochar treatments increased the pH and electrical conductivity of the substrate, negatively affecting plant growth and germination (especially in B70). The partial substitution of peat by 30% biochar (B30) delayed seed germination but improved plant growth and nitrogen use efficiency (NUE), with shoots containing higher levels of organic nitrogen and nitrate. Moreover, it increased the water holding capacity (WHC) and led to an efficient use of nutrients. Our study demonstrates that biochar can successfully replace and reduce peat and N fertilizer consumption. This has the potential to promote more sustainable farming with positive impacts on both plant growth and the environment. [ABSTRACT FROM AUTHOR]

Lettuce is an important vegetable in the human diet and is commonly consumed for salad. It is a source of vitamin A, which plays a vital role in human health. Improvements in lettuce production will be needed to ensure a stable and economically available supply in the future. The influence of nitrogen (N), phosphorus (P), and potassium (K) compounds on the growth dynamics of four hydroponically grown lettuce (Lactuca sativa L.) cultivars (Black Seeded Simpson, Parris Island, Rex RZ, and Tacitus) in tubs and in a nutrient film technique (NFT) system were studied. Hyperspectral images (HSI) were captured at plant harvest. Models developed from the HSI data were used to estimate nutrient levels of leaf tissues by employing principal component analysis (PCA), partial least squares regression (PLSR), multivariate regression, and variable importance projection (VIP) methods. The optimal wavebands were found in six regions, including 390.57–438.02, 497–550, 551–600, 681.34–774, 802–821, and 822–838 nm for tub-grown lettuces and four regions, namely 390.57–438.02, 497–550, 551–600, and 681.34–774 nm for NFT-system-grown lettuces. These fitted models' levels showed high accuracy (R 2 = 0.85 − 0.99) in estimating the growth dynamics of the studied lettuce cultivars in terms of nutrient content. HSI data of the lettuce leaves and applied N solutions demonstrated a direct positive correlation with an accuracy of 0.82–0.99 for blue and green regions in 400–575 nm wavebands. The results proved that, in most of the tested multivariate regression models, HSI data of freshly cut leaves correlated well with laboratory-measured data. [ABSTRACT FROM AUTHOR]

Apple scar skin viroid (ASSVd) is a major pathogen of apples that can result in significant economic losses in the apple industry. In this study, ASSVd- and apple stem grooving virus (ASGV)-infected Maluspumila 'Spy 227' apple plants were treated with ribavirin to determine its elimination efficiency. Ribavirin at 25 and 50 μg/mL (R25 and R50) did not inhibit ASSVd in apple plants regenerated from hydroponic culture. However, the elimination rates of ASGV in R25- and R50-treated plants were 50.0% and 53.3%, respectively. The ability of different concentrations of ribavirin (10, 20, and 30 μg/mL, R10, R20, and R30) to eliminate ASSVd and ASGV from in vitro plants was also evaluated. No phytotoxicity was observed during the treatment. Ribavirin increased the growth and proliferation of in vitro apple plants. The titers of ASSVd were similar throughout the treatment period, but ASGV declined. The concentration and duration of ribavirin also affected the regeneration of in vitro plants. The average survival rate of plants (80.8%) regenerated from R30 was similar to that of CK (82.5%) and was 14.2% and 16.3% higher than that of R10 and R20, respectively. Quantitative real-time PCR was used to assess the eradication efficiency of regenerated plants. The average elimination rates of ASSVd and ASGV were 1.6% and 78.7%, respectively. A low elimination rate of ASSVd was found in R30 (2.8%) at 45 days, and it was still less than 10% at the end of the treatment. Key message: This study found that it was difficult for ribavirin to eliminate apple scar skin viroid from apple plants. [ABSTRACT FROM AUTHOR]

【Objective】 The objective of this paper is to investigate the influence of nitrogen concentration in nutrient solution on physiological traits of lettuce grown in hydroponic culture. 【Method】 The experiment was conducted in a greenhouse, with the Flandria cultivar used as the model plant. We compared five nitrogen concentrations: 12.25, 24.5, 49, 98 and 196 mg/L, each having two replicates. In the experiment, we measured the leaf area index (LAI), accumulated water consumption and the change in meteorologic factors in the greenhouse, from which we derived the relationship between water consumption of the crop and nitrogen concentrations in the solution. 【Result】 The accumulated water consumption and LAI both increased first followed by a decline as the nitrogen concentration increased. The relationships between LAI and the nitrogen concentration can be fitted to a quadratic function, and comparison with measured data showed fitting of the model was accurate. The model describing the change in water consumption with nitrogen concentrations also agreed well with experimental data. 【Conclusion】 Accumulative water consumption and LAI of the hydroponic-cultured lettuce both increased with nitrogen concentration in the nutrient solution, and the models describing their relationships agreed well with experimental data.

Salicylic acid (SA) is mainly associated with the regulation of plant growth particularly in salinity stress conditions and this signaling molecule exists in pivotal parts of plant. The objective of this research analysis was to overcome stress condition by distinct foliar treatments of Salicylic acid, for instance, 0 and 100 mM. Foliar applications of SA on maize were rendered on 10 days later than transplanting under a hydroponics experiment. Plants were grown under non-saline (S0= 0 mM NaCl) and saline (S1= 100 mM NaCl) conditions. Evaluation of biochemical, physiological and morphological attributes of maize was rendered after harvesting of plants. The experimental layout of Completely Randomized Design (CRD) under a factorial arrangement with three replications of each treatment was assigned for this study. According to our results it was confirmed that cultivation of maize under saline condition reduced the morphological, physiological and biochemical attributes of plant. However, exogenous application of SA on maize had a positive impact on the above mentioned traits under presence and absence of saline environment. Finally, it was justified that exogenous application of variable concentration of SA significantly improves whole parameters of maize cultivar.

It has been estimated that between 40 and 60 % of the assimilated carbon is diverted to the roots and released in the rhizosphere in form of root exudates. Root exudates thus define a complex mixture of low and high molecular weight compounds, including carbohydrates, amino acids, organic, and proteins, but also a broad spectrum of specialized molecules, such as flavonoids, glucosinolates, terpenoids, or alkaloids. Root exudates favour soil mineral nutrition, can bind to soil aggregate and in turn modify soil physico-chemical properties, but also mediate plant-plant, plant-microbe, and plant-animal interactions belowground. With this review, we aim to highlight how chemical ecologists have approached the study of root exudates-mediated interactions between plants and their biotic and abiotic surroundings. We do so by presenting a series of study cases for, on one hand, showcasing different methodologies that have been developed to test the activity of different root exudates, and, on the other hand, to show the broad array of interactions mediated by root exudates. Ultimately, we aim to spur further research and collaborations between chemists and ecologists studying belowground chemically-mediated interactions, so as to tackle essential challenges in terms of food security and climate change in the near future.

Medicinal plants have been used to cure human diseases since decades. Silybum marianum, a medicinal plant, is regarded as a source of secondary metabolites with therapeutic value against liver diseases and diabetes. The present study was conducted to enrich the production of secondary metabolites in the vegetative parts of Silybum marianum using elicitation strategy in hydroponic system with different elicitors. The elicitors of fungus Aspergillus niger (0.2 g/L), methyl jasmonate (MeJA) (100 µM) and silver nanoparticles (AgNPs) (1 ppm) were added in hydroponic medium, individually and in combination form to the 15 days old plant. The elicitor-treated plants were harvested at different time points (24-144 h; increment 24 h) and their biochemical parameters like phenolics, flavonoids, nitric oxide (NO), and superoxide dismutase (SOD) were analyzed. The results showed hyperaccumulation of these biochemical contents, especially in response to MeJA (100 µM), followed by AgNPs (1 ppm) and co-treatment of AgNPs (1 ppm) with other elicitors. The results revealed that the treatment with MeJA (100 µM) exhibited the highest flavonoid (304 µg g-1), phenolic (372 µg g-1), and SOD (16.2 U g-1) contents. For NO levels, the maximum value of 198.6 nmole g-1 was achieved in response to the treatment with MeJA + Green synthesized AgNPs (100 µM + 1 ppm). Our findings depicted an enhanced production of medicinally important plant secondary metabolites and antioxidants; hence, the method applied in this study can play a significant role to improve therapeutic values of the plants. [ABSTRACT FROM AUTHOR]

Medicinal plants have been used to cure human diseases since decades. Silybum marianum, a medicinal plant, is regarded as a source of secondary metabolites with therapeutic value against liver diseases and diabetes. The present study was conducted to enrich the production of secondary metabolites in the vegetative parts of Silybum marianum using elicitation strategy in hydroponic system with different elicitors. The elicitors of fungus Aspergillus niger (0.2 g/L), methyl jasmonate (MeJA) (100 μM) and silver nanoparticles (AgNPs) (1 ppm) were added in hydroponic medium, individually and in combination form to the 15 days old plant. The elicitor-treated plants were harvested at different time points (24–144 h; increment 24 h) and their biochemical parameters like phenolics, flavonoids, nitric oxide (NO), and superoxide dismutase (SOD) were analyzed. The results showed hyper-accumulation of these biochemical contents, especially in response to MeJA (100 μM), followed by AgNPs (1 ppm) and co-treatment of AgNPs (1 ppm) with other elicitors. The results revealed that the treatment with MeJA (100 μM) exhibited the highest flavonoid (304 μg g–1), phenolic (372 μg g–1), and SOD (16.2 U g–1) contents. For NO levels, the maximum value of 198.6 nmole g–1 was achieved in response to the treatment with MeJA + Green synthesized AgNPs (100 μM + 1 ppm). Our findings depicted an enhanced production of medicinally important plant secondary metabolites and antioxidants; hence, the method applied in this study can play a significant role to improve therapeutic values of the plants.

Silybum marianum (L.) Gaertn. (Asteraceae) was hydroponically cultured using a nutrient film technique system. Silibinin, isosilibinin and silychristin were detected in the fruits of the cultured plants. The effect of salicylic acid on the improvement of flavonolignans production by the fruits of the hydroponically cultured S. marianum was investigated. Salicylic acid was added to the nutrient solution at different concentrations (100, 200 and 400 µM) and the mature fruits of the plant were collected five days after elicitor addition. The fruits were then analyzed for their total flavonolignans contents and individual components using quantitative proton nuclear magnetic resonance spectroscopy (qHNMR) and high-performance liquid chromatography (HPLC). The results showed that elicitation with salicylic acid at 200 µM for five days increased production of total flavonolignans (1.7-fold by qHNMR and 1.6-fold by HPLC) higher than the control cultures and (1.4-fold by qHNMR and 1.1-fold by HPLC) higher than the cultivated plants. Silychristin was the major flavonolignan produced by the cultured plant. Elicitation by 200 µM salicylic acid increased silychristin production (1.6-fold by qHNMR and HPLC) higher than the control cultures and (1.3-fold by qHNMR and 1.0-fold by HPLC) higher than the cultivated plants. The present study provides a chance to improve secondary metabolite yield, serves as a useful tool for studying the biosynthesis of these medicinally valuable compounds and its regulation in plant and spots more light on hydroponic system as an important agricultural technique.

The recovery of nutrients from wastewater streams for their later use in agricultural fertilization is an interesting approach. Wastewater recovered magnesium phosphate (MgP) salts were used in a forward osmosis (FO) system as draw solution in order to extract water and to produce a nutrient solution to be used in a hydroponic system with lettuces (Lactuca sativa, L.). Owing to the low solubility of the MgP salts (i.e., struvite, hazenite and cattiite) in water, acid dissolution was successfully tested using citric and nitric acids to reach pH 3.0. The dilution by FO of the dissolved salts reached levels close to those needed by a hydroponic culture. Ion migration through the membrane was medium to high, and although it did not limit the dilution potential of the system, it might decrease the overall feasibility of the FO process. Functional growth of the lettuces in the hydroponic system was achieved with the three MgP salts using the recovered water as nutrient solution, once properly supplemented with nutrients with the desired concentrations. This is an innovative approach for promoting water reuse in hydroponics that benefits from the use of precipitated MgP salts as a nutrient source.

The use of peat in traditional cultivation systems and in commercial nurseries is an environmental problem. In this work, we evaluated the partial replacement of peat with different amounts of biochar sourced from vineyard pruning as plant growing substrates. We studied its effect on the growth of lettuce plants under greenhouse and semi-hydroponic conditions. Substrate mixtures contained 30% (v/v) of vermiculite and 70% (v/v) of different biochar:peat treatments as follows: 0:70 (B0), 15:55 (B15), 30:40 (B30), 50:20 (B50), and 70:0 (B70). Higher biochar treatments increased the pH and electrical conductivity of the substrate, negatively affecting plant growth and germination (especially in B70). The partial substitution of peat by 30% biochar (B30) delayed seed germination but improved plant growth and nitrogen use efficiency (NUE), with shoots containing higher levels of organic nitrogen and nitrate. Moreover, it increased the water holding capacity (WHC) and led to an efficient use of nutrients. Our study demonstrates that biochar can successfully replace and reduce peat and N fertilizer consumption. This has the potential to promote more sustainable farming with positive impacts on both plant growth and the environment.

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Objectives This study was conducted to establish a method for early, quick and cheap screening of iron excess tolerance in rice (Oryza sativa L.) cultivars. Results Based on the experiments, iron excess leads to reduction in shoot length (SL) and this can be a useful characteristic for adequate screening of tolerant genotypes. The sensitive genotypes Nipponbare and BR-IRGA 409 indicated higher accumulation of iron in their tissues while BRS-Agrisul and Epagri 108 also accumulated iron, but at lower concentrations. BR-IRGA 410 displayed an intermediate phenotype regarding iron accumulation. No changes in shoot Cu content can be observed when comparing treatments. On the other hand, an increase was seen for Zn and Mn when shoots are subjected to Fe2+ excess. Fe stress at a lower concentration than 7 mM increased Zn but decreased Mn contents in shoots of BR-IRGA 409. Strong positive correlations were found here for Fe × Zn (0.93); Fe × Mn (0.97) and Zn × Mn (0.92), probably due to the Fe-induced activation of bivalent cation transporters. Results show that genotypes scored as sensitive present higher concentration of Fe in shoots and this is an efficient method to characterize rice cultivars regarding iron response.

Common bean is one of the most important grain legumes for human diets but is produced on marginal lands with unfavorable soil conditions; among which Aluminum (Al) toxicity is a serious and widespread problem. Under low pH, stable forms of Al dissolve into the soil solution and as phytotoxic ions inhibit the growth and function of roots through injury to the root apex. This results in a smaller root system that detrimentally effects yield. The goal of this study was to evaluate 227 genotypes from an Andean diversity panel (ADP) of common bean and determine the level of Al toxicity tolerance and candidate genes for this abiotic stress tolerance through root trait analysis and marker association studies. Plants were grown as seedlings in hydroponic tanks at a pH of 4.5 with a treatment of high Al concentration (50 μM) compared to a control (0 μM). The roots were harvested and scanned to determine average root diameter, root volume, root surface area, number of root links, number of root tips, and total root length. Percent reduction or increase was calculated for each trait by comparing treatments. Genome wide association study (GWAS) was conducted by testing phenotypic data against single nucleotide polymorphism (SNP) marker genotyping data for the panel. Principal components and a kinship matrix were included in the mixed linear model to correct for population structure. Analyses of variance indicated the presence of significant difference between genotypes. The heritability of traits ranged from 0.67 to 0.92 in Al-treated and reached similar values in non-treated plants. GWAS revealed significant associations between root traits and genetic markers on chromosomes Pv01, Pv04, Pv05, Pv06, and Pv11 with some SNPs contributing to more than one trait. Candidate genes near these loci were analyzed to explain the detected association and included an Al activated malate transporter gene and a multidrug and toxic compound extrusion gene. This study showed that polygenic inheritance was critical to aluminum toxicity tolerance in common beans roots. Candidate genes found suggested that exudation of malate and citrate as organic acids would be important for Al tolerance. Possible cross-talk between mechanisms of aluminum tolerance and resistance to other abiotic stresses are discussed.

Ice plant (Mesembryanthemum crystallinum L.) is regarded as a drought and saline stress-tolerant plant with many biological properties, and especially valued in gourmet cuisine. The objective of this work was to find an optimum plant cultivation mode to produce edible parts under greenhouse conditions. Three soilless media were evaluated: peat, vermiculite and hydroponic culture. Peat pot culture yielded reduced biomass. Vermiculite and hydroponics, however, led optimum M. crystallinum growth. Plants grown in vermiculite and irrigated with nutrient solution presented a significantly higher yield. In fact, vermiculite-grown plants presented enhanced leaf area and leaf fresh weight as well as high foliar N, Mg, Mn, Fe, Na, chlorophyll and carotenoid concentrations. To conclude, greater succulence and Na concentration in edible parts of the vermiculite-grown glacier lettuce can offer consumers a more interesting taste, consistency and improved nutrient contents. [ABSTRACT FROM AUTHOR]

Common bean is one of the most important grain legumes for human diets but is produced on marginal lands with unfavorable soil conditions; among which Aluminum (Al) toxicity is a serious and widespread problem. Under low pH, stable forms of Al dissolve into the soil solution and as phytotoxic ions inhibit the growth and function of roots through injury to the root apex. This results in a smaller root system that detrimentally effects yield. The goal of this study was to evaluate 227 genotypes from an Andean diversity panel (ADP) of common bean and determine the level of Al toxicity tolerance and candidate genes for this abiotic stress tolerance through root trait analysis and marker association studies. Plants were grown as seedlings in hydroponic tanks at a pH of 4.5 with a treatment of high Al concentration (50 μM) compared to a control (0 μM). The roots were harvested and scanned to determine average root diameter, root volume, root surface area, number of root links, number of root tips, and total root length. Percent reduction or increase was calculated for each trait by comparing treatments. Genome wide association study (GWAS) was conducted by testing phenotypic data against single nucleotide polymorphism (SNP) marker genotyping data for the panel. Principal components and a kinship matrix were included in the mixed linear model to correct for population structure. Analyses of variance indicated the presence of significant difference between genotypes. The heritability of traits ranged from 0.67 to 0.92 in Al-treated and reached similar values in non-treated plants. GWAS revealed significant associations between root traits and genetic markers on chromosomes Pv01, Pv04, Pv05, Pv06, and Pv11 with some SNPs contributing to more than one trait. Candidate genes near these loci were analyzed to explain the detected association and included an Al activated malate transporter gene and a multidrug and toxic compound extrusion gene. This study showed that polygenic inheritance was critical to aluminum toxicity tolerance in common beans roots. Candidate genes found suggested that exudation of malate and citrate as organic acids would be important for Al tolerance. Possible cross-talk between mechanisms of aluminum tolerance and resistance to other abiotic stresses are discussed. [ABSTRACT FROM AUTHOR]

Transferring plants between different nutritional media is a common technique in plant nutrition research. Solidified sterile media are often used for plant culture and subsequent transfer experiments. Transplanting is generally performed one plant at a time using sterile tweezers. This method has several challenges: it is time-consuming, which makes analyzing short-term responses to nutritional changes difficult; plants can be mechanically damaged, which can confound results; transferring mature plants is accompanied by root wounding due to root penetration into the solidified medium; and root shapes are altered, which precludes a precise evaluation on nutritional responses of root system architecture. To solve these problems, this study tried to adopt a system for Arabidopsis culture using solidified media covered with cellophane disks for the transfer experiments to analyze nitrogen responses as a case study. The cellophane disk prevented the penetration of roots into the solidified medium and fixed the roots loosely; thereby, facilitating sterile, rapid and noninvasive transfer of young and mature Arabidopsis plants between media without changing root shape. The plants-on-cellophane grown on the solidified media were directly transferred onto hydroponics, where plants vegetate and propagate seeds under strict nutritional control. The root proliferation on the cellophane disk allowed direct observations of root architecture and green fluorescent protein (GFP) fluorescence in the roots. Collectively, we conclude that the introduction of a cellophane sheet to the existing culture system would accelerate experiments in plant nutritional research. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agriculture & Nature / Kahramanmaraş Sütçü İmam Üniversitesi Tarım & Doğa Dergisi is the property of Kahramanmaras Sutcu Imam Universitesi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)