Sulfur Nutrition Research Articles

Unraveling the mechanism of sulfur nutrition in pigeonpea inoculated with sulfur-oxidizing bacteria.

An investigation was carried out to understand the mechanism(s) involved in the uptake of sulfur (S) as sulfate in pigeonpea following single inoculation of two sulfur-oxidizing bacteria (SOB), Stenotrophomonas maltophilia and Stenotrophomonas pavanii in the treatments amended with either elemental sulfur (S0) or sulfate (S6). Colonization potential and biofilm formation were analyzed through confocal laser scanning microscope (CLSM) and scanning electron microscope (SEM). Furthermore, the effect of seed inoculation on root architecture, expression of genes involved in sulfur oxidation (sox) in bacterial inoculants, and genes involved in sulfate transport in pigeonpea (PpSULTR) were analyzed to correlate with the higher uptake of S in roots and shoots of pigeonpea. Both the SOB exhibited a good colonization potential and biofilm formation on the roots of pigeonpea. Among the 11 sox genes targeted in rhizosphere of pigeonpea, expression was achieved for seven genes, which showed 2-fold increase in treatments inoculated with S. maltophilia and amended with either S6 or S0. The inoculation of S. maltophilia and amendment of S0 led to increased expression of PpSULTR genes by several folds in roots. The inoculation of SOB had a significant influence on non-enzymatic (osmolytes like proline) and enzymatic (PAL, peroxidase, superoxide dismutase, and catalase) levels. The results revealed a significant increase in sulfur uptake in roots and shoots in treatment inoculated with S. maltophilia and amended with S6. The investigation showed that the SOB-mediated over-expression of PpSULTR genes in roots of pigeonpea and sox genes in the rhizosphere were acting synergistically in facilitating higher uptake and translocation of S in roots and shoots of pigeonpea plants.

Metabolite Analysis of Lettuce in Response to Sulfur Nutrition

Sulfur is an essential nutrient required for plant growth and metabolism, and plays an important role in relieving stress. Nutrient deficiency is one of the main factors that negatively affect crop growth, quality, and yield. This study aimed to evaluate the effect of sulfur nutrients on the growth and metabolites of lettuce after treatment with two different sulfur concentrations (16 μM and 2 mM) in spray hydroponics. The fresh weight, chlorophyll, and carotenoid content of lettuce leaves were analyzed. Root morphology was examined using the WinRHIZO program. Metabolites were comparatively evaluated with the help of LC-MS and GC-MS. The fresh weight, chlorophyll, and carotenoid contents of lettuce were higher in the high concentration sulfur treatment group than in the low concentration sulfur treatment group. In the characteristics analysis of the lettuce roots, treatment with a high concentration of sulfur had a more positive effect on the lettuce root development than treatment with a low concentration of sulfur. Moreover, mass-based metabolomics analysis showed that the lettuce metabolites content was significantly different according to low- and high-concentration sulfur treatments. Therefore, this study highlights the importance of sulfur nutrient content in lettuce growth and metabolites.

Effect of Soil Application and Foliar Spray of Sulphur Nutrition on Growth and Yield of Black Gram (Vigna mungo L.)

Aim: To study the effect of soil application and foliar spray of sulphur nutrient application in growth and development of black gram cultivation.
 Study Design: The Factorial Randomized Block Design (FRBD) was used. The treatments of soil application of sulphur viz., No basal, Gypsum @ 25 kg ha-1, SOB @ 2 kg ha-1 as basal and foliar spray viz., No spray, pulse wonder @ 5 kg ha-1on 30 DAS, K2SO4 @ 1% on 45 DAS, pulse wonder @ 5 kg ha-1 on 30 DAS + K2SO4 @ 1% on 45 DAS were used.
 Place and Duration of Study: This research trail was conducted during the Winter season (February – May) of 2022 at ICAR - Krishi Vigyan Kendra, Sirugamani, Trichy, Tamil Nadu, India.
 Methodology: The study consisted of 12 combination of treatments in FRBD which was replicated thrice. The black gram (Var. Vamban 8) was used for this study. The observations were recorded during the different phases of growth at regular intervals.
 Results: The experimental results revealed that the interaction effect of application of gypsum as basal along with foliar spray of pulse wonder + K2SO4 found to be superior and recorded significantly higher growth, yield and quality parameters viz., plant height, number of branches plant-1, dry matter accumulation, SPAD value at 20 DAS, 40 DAS and 60 DAS number of pods plant-1, number of seed pod-1, pod length, pod weight and sulphur content in seed. Gypsum as basal application along with foliar spray of pulse wonder + K2SO4 proved to be the best and increased the grain yield of 30% over the no basal application and no foliar spray. Thus application of gypsum @ 25 kg ha-1 as basal and foliar spray of pulse wonder @ 5 kg ha-1 on 30 DAS + K2SO4 @ 1% on 45 DAS could be recommended for improving the productivity of black gram.

Sulfur-Oxidizing Bacteria From Coal Mine Enhance Sulfur Nutrition in Pigeonpea (Cajanus cajan L.)

The present investigation was carried out to isolate, identify, and characterize sulfur-oxidizing bacteria (SOB) from coal mines and to evaluate the efficient strains for their ability to influence plant growth and S uptake in pigeonpea. Thirteen bacterial isolates belonging to Stenotrophomonas maltophilia (2), Stenotrophomonas pavanii (2), Rhizobium pusense (5), Bacillus velezensis (2), and Paenibacillus massiliensis (2) were obtained. Among these, seven strains that could reduce the pH of thiosulfate broth were further characterized for sulfur oxidation, plant growth-promoting (PGP) attributes, and in planta studies. Among the seven strains characterized, maximum sulfate ion was recorded for S. maltophilia DRC-18-7A (311.43 mg L−1) closely followed by S. pavanii DRC-18-7B (273.44 mg L−1) and S. maltophilia DRC-18-10 (265.75 mg L−1) after 21 days of inoculation. Among the PGP attributes quantified, maximum P solubilization was recorded in case of S. maltophilia DRC-18-7A (24.39 μg ml−1), while highest siderophore production and IAA production were recorded in S. maltophilia DRC-18-10 (14.25%) and R. pusense DRC-18-25 (15.21 μg ml−1), respectively. S. maltophilia DRC-18-7A closely followed by S. pavanii DRC-18-7B outperformed others in enhancing seed germination (%) and vigour indices. Results clearly indicated that microbial inoculants colonized the plant roots and developed biofilm on the root surface. It was further observed that plants treated with microbial inoculants induce an early formation of secondary and tertiary roots in the pigeonpea compared to the untreated control which was further confirmed by assessing the root architecture using the root scanner. Inoculation of these two strains to pigeonpea significantly enhanced plant growth parameters, the activity of reactive oxygen scavenging (ROS) enzymes, and accumulation of flavonoids, carotenoids, and proline both under sterilized and non-sterilized growth medium (sand and soil in 1:3 ratio). The application of microbial inoculants significantly increased the uptake of nitrogen, phosphorus, potassium, and sulfur in plant shoots. Further, transcript level of phosphate, potassium, and sulfur transporter genes significantly increases upon microbial inoculation leading to increased uptake and translocation of P, K, and S in the pigeonpea. The results indicate that S. maltophilia DRC-18-7A and S. pavanii DRC-18-7B could be recommended as inoculants for pigeonpea to improve its growth and sulfur nutrition.

Maize Growth, Fodder Yield and Nutrient Uptake in relation to Phosphorus and Sulphur Nutrition

Phosphorus (P) and Sulphur (S) are the most important plant nutrients which play significant roles in enhancing the early growth and development and increasing the fodder yield of maize. This important field study was planned to evaluate the P-S interaction effects on maize growth, fodder yield and nutrient (P and S) uptake. The soil used for study was clay loam, medium-alkaline (pH: 7.9), non-saline (EC: 0.85 dS m-1), strongly calcareous (CaCO3: 24 %), adequate in organic matter (1.6 %), low in ABDTPA-P (3.5 mg kg-1), while medium in SO4-S (21.5 mg kg-1). Eight P and S treatments were involved in this study, i.e. single application of each 90 kg P2O5 (T1) and 20 kg S ha-1 (T2); integration of 90 kg P2O5 with S @ 20, 40 and 60 kg ha-1 (T3, T4 and T5, respectively), and integration of 120 kg P2O5 with S @ 20, 40 and 60 kg ha-1 (T6, T7 and T8, respectively). The experiment followed an RCBD arrangement that was replicated thrice. Recommended seed rate of maize (95 kg ha-1) was used for sowing. The results revealed that shoot biomass production was maximum when maize plants received higher doses of P and S in an integrated manner (120-60 kg P2O5-S ha-1). At 30 DAS, shoot fresh biomass was found maximum, and statistically alike, when 90 or 120 kg P2O5 was integrated with S @ 60 kg ha-1. Shoot fresh biomass was maximum, at 40 DAS when 120-60 kg P2O5-S ha-1 was applied to maize. Shoot dry biomass after 30 days of sowing was highest when 90 kg P2O5 was applied with S @ 60 kg ha-1 or when, 120 kg P2O5 was used with S @ 40 and 60 kg ha-1. Shoot length was maximum, both at 30 and 40 DAS, in case of using 120-60 kg P2O5-S ha-1. Chlorophyll content of maize was maximum, both at 30 and 40 DAS, when 90 kg P2O5 was applied with S @ 60 kg ha-1. Maximum fodder yield of maize was noted when 120 kg P2O5 was applied with 60 kg S ha-1. Highest P-uptake, both at 30 and 40 DAS was noted when 120 kg P2O5 was applied with S @ 60 kg ha-1. At the first stage of growth, S-uptake was highest when 60 kg S was integrated with 90 kg P2O5 ha-1. The study advocated integrated application of 120-60 kg P2O5-S ha-1 for obtaining economically maximum fodder yield of maize.

Alterations of Content and Composition of Individual Sulfolipids, and Change of Fatty Acids Profile of Galactolipids in Lettuce Plants (Lactuca sativa L.) Grown under Sulfur Nutrition.

Alterations of chloroplast membrane lipids might serve as indicators of eco-physiologically induced and plant nutrition-induced changes during plant growth. The change in the degree of fatty acid saturation in the membranes is in particular a strategy of plants to adapt to abiotic stress conditions. Green multi-leaf lettuce plants (Lactuca sativa L.) were subjected to three different sulfur (S) levels. Sulfoquinovosyl diacylglycerol derivatives (SQDG) might be affected by S nutrition. Therefore, the present study was conducted to investigate the impact of S fertilization on the content and composition of individual SQDG. In addition to a change in the SQDG composition, a general change in the total lipid composition of the chloroplast membrane was observed. A significant increase in total SQDG content and doubling of the galactolipid content and significant alterations of individual SQDG were observed at elevated levels of S fertilization. High levels of S supply demonstrated a clear trend of increasing total chloroplast lipid content and concentrations of linolenic acid, in addition to a further decline in palmitic acid. The study opens perspectives on S supply and its crucial role in the build-up of photosynthetic apparatus. Moreover, it emphasizes the role of S-containing compounds, including sulfolipids, in modulating physiological adjustment mechanisms to improve tolerance ability to various abiotic stresses in plants and, consequently, plant food quality.

No-Tillage with Residue Retention and Foliar Sulphur Nutrition Enhances Productivity, Mineral Biofortification and Crude Protein in Rainfed Pearl Millet under Typic Haplustepts: Elucidating the Responses Imposed on an Eight-Year Long-Term Experiment.

Yield limitation and widespread sulphur (S) deficiency in pearl-millet-nurturing dryland soils has emerged as a serious threat to crop productivity and quality. Among diverse pathways to tackle moisture and nutrient stress in rainfed ecologies, conservation agriculture (CA) and foliar nutrition have the greatest potential due to their economic and environmentally friendly nature. Therefore, to understand ammonium thiosulphate (ATS)-mediated foliar S nutrition effects on yield, protein content, mineral biofortification, and sulphur economy of rainfed pearl millet under diverse crop establishment systems, a field study was undertaken. The results highlighted that pearl millet grain and protein yield was significantly higher under no-tillage +3 t/ha crop residue mulching (NTCRM) as compared to no-tillage without mulch (NoTill) and conventional tillage (ConvTill), whereas the stover yield under NTCRM and ConvTill remained at par. Likewise, grain and stover yield in foliar S application using ATS 10 mL/L_twice was 19.5% and 13.2% greater over no S application. The sulphur management strategy of foliar-applied ATS 10 mL/L_twice resulted in significant improvement in grain protein content, protein yield, micronutrient fortification, and net returns (₹ 54.6 × 1000) over the control. Overall, ATS-mediated foliar S nutrition can be an alternate pathway to S management in pearl millet for yield enhancement, micronutrient biofortification and grain protein content increase under ConvTill, as well as under the new NTCRM systems.

Benefits and Limitations to Plastic Mulching and Nitrogen Fertilization on Grain Yield and Sulfur Nutrition: Multi-Site Field Trials in the Semiarid Area of China.

Plastic mulching (PM) is widely used to improve crop water use efficiency and grain yield, but few studies have reported the effects of PM on cereal crop quality, especially sulfur (S) nutrition of wheat, which has significant effects on grain protein content, dough rheology, baking quality and human health. To fill this knowledge gap, we conducted a multi-site field experiment on the Loess Plateau from 2014 to 2016 to study the effects of PM combined with nitrogen (N) fertilizer on grain yield, shoot S accumulation, and grain S concentration of winter wheat in dryland. Compared with no mulching (NM), PM increased grain yield by 13.7% but decreased grain S concentration, S requirement for 1,000 kg–1 grain, soil available S concentration, and post-anthesis S uptake by 9.0, 9.7, 24.4, and 51.8%, respectively. Plastic mulching significantly increased shoot S accumulation at anthesis by 19.2%, but there was no significant difference at maturity. Additionally, grain S concentration and S requirement had a linear-plateau relationship with N fertilization amount, reaching maximum values at 110 and 127 kg N ha–1 under PM, 37.5 and 27.0% higher than those under NM. Furthermore, shoot S accumulation and N application rates well-fitted the linear-plateau model at anthesis and maturity. At maturity, straw, grain, and shoots accumulated the most S at threshold N rates of 120, 85 and 110 kg N ha–1, respectively. Crucially, stem + leaf S concentration at anthesis had a significant linear relationship with grain S concentration under PM; a 1 g kg–1 increase in stem leaf concentration corresponded with a 0.24 g kg–1 increase in grain S concentration. This study’s findings suggest that combining soil S supplementation with optimal N fertilizer under PM in northwest China and other regions with similar cropping systems increases grain S concentration and improves nutritional and processing qualities.

Evaluation of Soil S Pools under 23 Years of Maize Monoculture

Sulfur nutrition is a critical part of proper crop growth and development. In our study, biomass yields (BY) and S uptake were investigated on long-term maize monoculture on haplic luvisol soil during the 23 years of this trial, as well as changes in water extractable (Sw), adsorbed (Sads), mineral (Sav), and pseudo-total S (St) fractions. Treatments used in this study are: (1) Control (Cont); (2) ammonium sulfate (AS); (3) urea and ammonium nitrate (UAN); (4) UAN + phosphorus and potassium (UAN + PK); (5) UAN + phosphorus, magnesium, sulfur (UAN + PMgS); and (6) Fallow. Recently, the Mehlich 3 method started to be used in the Czech Republic to determine content of plant available S. Using this method, it was found that the content of S extracted by Mehlich 3 (SM3) closely correlates to Sav in both topsoil and subsoil (r = 0.958 in 1997 and 0.990 in 2019, both at p < 0.001). We also found that, on average, during the entire experiment, all treatments had increased yields over Cont (135–147%) and increased S uptake (291, 192, 180, and 246% of Cont for AS, UAN, UAN + PK, and UAN + PMgS, respectively). Examining the changes from 1997 to 2019 in topsoil (0–30 cm depth), we discovered a decrease of S content in Sw, Sads, Sav, and St fractions on all treatments to an average of 34.6%, 65.8%, 42.2%, and 78.6% of their initial values. The exception was AS treatment, which doubled its initial content in mineral fractions and maintained the same levels of St, and which we attribute to the very high dose of S on this treatment (142 kg ha−1 year−1). Using the simple balance method, AS and UAN + PMgS treatments lost 142.2 and 95.3 kg S ha−1 year−1 to other sinks, except plant uptake, from the entire soil profile (0–60 cm) during 23 years of experiment. Other treatments also show significant losses with the exception of Fallow. Given these results, it is clear that content of sulfur in soil is generally decreasing and attention should be paid mainly towards minimizing of its losses.

Sulfur deficiency exacerbates phytotoxicity and residues of imidacloprid through suppression of thiol-dependent detoxification in lettuce seedlings

Sulfur, an essential macronutrient, plays important roles in plant development and stress mitigation. Sulfur deficiency, a common problem in agricultural soils, may disturb plant stress resistance and xenobiotic detoxification. In the present study, the function and mechanism of limited sulfur nutrition on the residues and phtotoxicity of imidacloprid were investigated in lettuce plants. Sulfur deficiency significantly increased imidacloprid accumulation in lettuce tissues, exacerbated imidacloprid biological toxicity by enhancing the accumulation of toxic metabolites, like imidacloprid-olefin. Simultaneously, imidacloprid-induced detoxification enzymes including cytochromes P450, glutathione S-transferases (GSTs) and glycosyltransferases were inhibited under limited sulfur supply. On the other hand, sulfur deficiency further enhanced the generation of reactive oxygen species and exacerbated lipid peroxidation in lettuce tissues. Sulfur deficiency mainly reduced the abundance of thiol groups, which are essential redox modulators as well as xenobiotic conjugators, and significantly inhibited GSTs expression. These results clearly suggested that sulfur deficiency inhibited the synthesis of sulfur-containing compounds, leading to increased accumulation of pesticide residues and toxic metabolites as well as reduced detoxification capacity, consequently leading to oxidative damage to plants. Therefore, moderate sulfur supply in regions where neonicotinoid insecticides are intensively and indiscriminately used may be an efficient strategy to reduce pesticide residues and the potential risk to ecosystem.

Response of Groundnut (Arachis hypogaea L.) to Different Levels and Time of Phosphogypsum Nutrition

Background: Groundnut is one of the most important oilseed crops of India. Improving productivity of groundnut to meet the domestic vegetable oil demand through balanced fertilization is the prime challenge lying before the agronomists in the country. With the aim of evaluating phosphogypsum as a source of sulphur nutrition in groundnut, a field experiment entitled “Response of groundnut (Arachis hypogaea L.) to different levels and time of phosphogypsum nutrition” was conducted at Agronomy field unit, University of Agricultural Sciences Bangalore, during kharif-2019. Methods: Experiment was laid out in randomised complete block design (RCBD) with eleven treatments, of which eight have different combinations of phosphogypsum applied as basal and in split (30 DAS) and one with gypsum as basal alone. Whereas, the remaining two treatments, without any additional source of sulphur are included for comparison. Result: Among eleven treatments, application of phosphogypsum @ 125 kg S eq ha-1 in split recorded highest yield attributes, pod yield (2063 kg ha-1), kernel yield (1418 kg ha-1) and sulphur uptake (11.33 kg ha-1). Which were on par with 100 kg S eq ha-1 in split (2014, 1380 and 10.39 kg ha-1, respectively). All other treatments recorded lower values with lowest in treatments without any additional sulphur source.

Revisiting Sulphur—The Once Neglected Nutrient: It’s Roles in Plant Growth, Metabolism, Stress Tolerance and Crop Production

Sulphur plays crucial roles in plant growth and development, with its functions ranging from being a structural constituent of macro-biomolecules to modulating several physiological processes and tolerance to abiotic stresses. In spite of these numerous sulphur roles being well acknowledged, agriculture has paid scant regard for sulphur nutrition, until only recently. Serious problems related to soil sulphur deficiencies have emerged and the intensification of food, fiber, and animal production is escalating to feed the ever-increasing human population. In the wake of huge demand for high quality cereal and vegetable diets, sulphur can play a key role in augmenting the production, productivity, and quality of crops. Additionally, in light of the emerging problems of soil fertility exhaustion and climate change-exacerbated environmental stresses, sulphur assumes special importance in crop production, particularly under intensively cropped areas. Here, citing several relevant examples, we highlight, in addition to its plant biological and metabolism functions, how sulphur can significantly enhance crop productivity and quality, as well as acclimation to abiotic stresses. By this appraisal, we also aim to stimulate readers interests in crop sulphur research by providing priorities for future pursuance, including bettering our understanding of the molecular processes and dynamics of sulphur availability and utilization in plants, dissecting the role of soil rhizospherical microbes in plant sulphur transformations, enhancing plant phenotyping and diagnosis for nutrient deficiencies, and matching site-specific crop sulphur demands with fertilizer amendments in order to reduce nutrient use inefficiencies in both crop and livestock production systems. This will facilitate the proper utilization of sulphur in crop production and eventually enhance sustainable and environmentally friend food production.

The accuracy of PlanetScope imagery to nitrogen, phosphorus, potassium and sulfur nutrition estimation in terraced paddy field

This study aims to find out the accuracy of PlanetScope imagery in analyzing the total content of Nitrogen (N), Phosphorus (P), Potassium (K) and Sulfur (S) in terrace paddy field. The area for this research is terraced paddy fields in Wonosari Sub-district, Gondangrejo District, Karanganyar Regency, Central Java Province, Indonesia. Aerial photo analysis from PlanetScope (www.planet.com) was conducted at the Pedology Laboratory and Soil Survey, while soil sample analysis was carried out at the Laboratory of Chemistry and Soil Fertility, Faculty of Agriculture, Sebelas Maret University (UNS). The preparation aerial photo analysis from PlanetScope was carried out in September 2019. Soil sampling, laboratory analysis, and data analysis were carried out from September 2019 to January 2020. There are 3 Citra PlanetScope bands that have a significant effect on the elements being studied. Those three bands are band 1 (red), band 3 (blue) and band 4 (NIR). Multiple linear regression analysis obtained a regression equation model from those three bands. This model can be used as an estimator for the existence of the soil nutrient being studied. The accuracy values obtained for N, P, K and S in terraced paddy fields are 97.58%; 94.85%; 85.97%; and 97.39% and the R2 value of 0.39; 0.30; 0.30 and 0.27. The R2 value, which is still relatively small, indicates that there are many factors may affect the accuracy value.
 Int. J. Agril. Res. Innov. Tech. 11(1): 1-9, June 2021

Interactive Effects of Nitrogen and Sulfur Nutrition on Growth, Development, and Physiology of Brassica carinata A. Braun and Brassica napus L.

Brassica carinata (carinata) has emerged as a potential biofuel source due to its high erucic acid content, making it desirable for various industrial applications. Nitrogen (N) and sulfur (S) are required as primary sources of nutrition for growth and development in different oilseed crops and their utilization is interdependent. The purpose of the study was to analyze the interactive effect of N and S nutrition on the growth and other physiological activities of carinata and B. napus (napus). Four treatments, i.e., optimum NS (+N+S, 100% N and 100% S); N limited (−N+S, 0% N, 100% S); S limited (+N−S, 100% N, 0% S), and NS limited (−N−S, 0% N and 0% S) of N and S in full-strength Hoagland solution were imposed in the current study. Effect of different NS treatments was observed on vegetative traits such as number of primary and secondary branches, total leaf area, total biomass production and allocation, and physiological traits such as production of photosynthetic pigments, net photosynthesis, electron transport, and other aspects for both carinata and napus. The traits of stem elongation, number of nodes, node addition rate, internode length, number of primary and secondary branches were 60%, 36%, 50%, 35%, 56%, and 83% lower, respectively, in napus in comparison to carinata. Different NS treatments also positively influenced the production of photosynthetic pigments such as chlorophyll (Chl) a and b and carotenoids in carinata and napus. The concentration of Chla was 11% higher in napus in comparison to carinata. The rate of net photosynthesis, electron transport, and fluorescence was 12%, 8%, and 5% higher based on overall value, respectively, in napus compared to carinata. On the other hand, the overall value for stomatal conductance decreased by 5% in napus when compared to carinata. Different growth-related traits such as vegetative (plant height, node number, internode length, leaf area, number of primary and secondary branches), reproductive (pod number, pod length, seeds per pod), and photosynthetic capacity in oilseed brassicas are correlated with the final seed and oil yield and chemical composition which are of economic importance for the adoption of the crop. Thus, the analysis of these traits will help to determine the effect of NS interaction on crop productivity of carinata and napus.

Comparative Metabolite Profile, Biological Activity and Overall Quality of Three Lettuce (Lactuca sativa L., Asteraceae) Cultivars in Response to Sulfur Nutrition.

The main objective of the present study was to assess the effects of sulfur (S) nutrition on plant growth, overall quality, secondary metabolites, and antibacterial and radical scavenging activities of hydroponically grown lettuce cultivars. Three lettuce cultivars, namely, Pazmanea RZ (green butterhead, V1), Hawking RZ (green multi-leaf lettuce, V2), and Barlach RZ (red multi-leaf, V3) were subjected to two S-treatments in the form of magnesium sulfate (+S) or magnesium chloride (−S). Significant differences were observed under −S treatments, especially among V1 and V2 lettuce cultivars. These responses were reflected in the yield, levels of macro- and micro-nutrients, water-soluble sugars, and free inorganic anions. In comparison with the green cultivars (V1 and V2), the red-V3 cultivar revealed a greater acclimation to S starvation, as evidenced by relative higher plant growth. In contrast, the green cultivars showed higher capabilities in production and superior quality attributes under +S condition. As for secondary metabolites, sixteen compounds (e.g., sesquiterpene lactones, caffeoyl derivatives, caffeic acid hexose, 5-caffeoylquinic acid (5-OCQA), quercetin and luteolin glucoside derivatives) were annotated in all three cultivars with the aid of HPLC-DAD-MS-based untargeted metabolomics. Sesquiterpene lactone lactucin and anthocyanin cyanidin 3-O-galactoside were only detected in V1 and V3 cultivars, respectively. Based on the analyses, the V3 cultivar was the most potent radical scavenger, while V1 and V2 cultivars exhibited antibacterial activity against Staphylococcus aureus in response to S provision. Our study emphasizes the critical role of S nutrition in plant growth, acclimation, and nutritional quality. The judicious-S application can be adopted as a promising antimicrobial prototype for medical applications.

Crop sulfur status in relation to soil sulfur determined using anion exchange membranes and Mehlich 3

The aim of this study was to find an indicator of plant sulfur status correlating most significantly with bioavailable sulfur in soil. The indicators of plant sulfur status in shoot biomass were: sulfur concentration, mass nitrogen to sulfur (N/S) ratio, mass phosphorus to sulfur ratio and sulfur nutrition index (SNI). The bioavailable soil sulfur was determined using water extraction (S-water), Mehlich 3 extractant (S-M3) and anion exchange membranes (S-AEMs). Results cover four years (2015–2018) of on-farm trials in the Czech Republic with winter wheat, winter oilseed rape and maize, and pot experiments including spring wheat and maize. Shoot biomass of plants was sampled at the beginning of stem elongation (winter wheat, winter rape and maize in on-farm trials), during rapid growth (maize in pot experiment) and during flowering (wheat plants, winter rape). Only soils containing 0.5%–1.7% of organic carbon were studied (median 1.31%). Compared to shoot N/S ratio, sulfur concentration in shoot biomass of maize correlated stronger with bioavailable soil sulfur. However, bioavailable sulfur in soil correlated strongest and most significantly with shoot N/S ratio of winter wheat and winter rape grown in on-farm trials. Except for winter rape grown on non-calcareous soils and maize grown in pot experiment, the shoot N/S ratio correlated more significantly with S-M3 compared to S-water and S-AEM.

Sulphur nutrition and iron plaque formation on roots of rice seedlings and their consequences for immobilisation and uptake of chromium in solution culture

The contribution of sulphur (S)-induced responses to chromium (Cr) tolerance of rice plants is not yet fully elucidated. It is hypothesised that S nutrition mitigates the accumulation and toxicity of Cr through enhanced formation of iron plaque (IP) and S-containing chelators. This study aimed to investigate the responses of iron (Fe) and Cr availability and transfer in the hydroponic rice system to added S levels. We explored the influence of S nutrition on Cr accumulation in rice under a combination of Cr (VI) (+Cr, –Cr) and S (0, 1.75, 3.5, 7 mM) treatments. S additions at rates of 1.75 and 3.5 mM gave the least decline in root and shoot growth of rice seedlings under Cr stress. Fe concentration in shoots was consistent with the level of Cr uptake. The subcellular distribution of Cr in roots and shoots differed with varying S supply levels. Our results also revealed that S treatment at a moderate level (3.5 mM) was more effective in suppressing the bioavailability of Cr in rice shoots than were the other levels. S-induced reduction in shoot Cr concentration, particularly from 1.75 to 3.5 mM, was likely attributed to the enhanced biosynthesis of glutathione (GSH) and phytochelatins (PCs) in roots than the enhanced physical resistance of IP induced by S. The poor barrier capacity of IP to Cr absorption in rice plants primarily ascribed to the level of applied Cr concentration and partly to the competition between Cr and S at the absorbing sites.

Effects of nickel on morpho-physiological parameters and oxidative status in Brassica napus cultivars under different sulphur levels.

Increased levels of trace metals are an important problem of environmental pollution. Ni is one of the metals essential for normal plant development, but elevated levels usually cause deleterious effects on plant growth. The aim of the study was to evaluate the effects sulphur nutrition on growth, oxidative status, and Ni bioaccumulation of Ni-treated rape (Brassica napus L.). Two different oilseed rape cultivars (Hammer and Compass) were grown under sulphur deficiency and under optimal S availability (0 and 1mM sulphate, respectively) and exposed to 0.1, 0.3, and 0.5mM Ni concentrations for 3weeks. Exposure of plants to elevated Ni concentrations resulted in a decrease in the shoot and root biomass and chlorophyll content. The enhancement of Ni caused increased lipid peroxidation. The sulphur nutrition had an effect on the level of oxidative stress of Ni-treated plants-under the deficiency of sulphur the concentration of TBARS was significantly higher than under the optimal level of S. The beneficial effect of optimal sulphur nutrition was lower Ni accumulation in exposed plants but translocation of Ni was dependent on the cultivar.

High temperature patterns at the onset of seed maturation determine seed yield and quality in oilseed rape (Brassica napus L.) in relation to sulphur nutrition

High temperatures during the crop reproductive stage impact seed yield and quality. The changing climate will require consideration of the effects of high temperature events that differ from their intensity, their duration and their frequency over the seed quality-building stages. The impact of these features deserve to be investigated at the light of induced thermo-sensitization which can lead to alleviate expected negative impacts. In our work, maturing seeds of the sulphur-demanding crop, oilseed rape, were exposed to several temperature sequences that varied in intensity, duration and frequency at the onset of seed maturation. Results-measured in seeds that were at the onset of maturation when the temperature stress occurred-indicated that (i) the longer the cumulated duration of the temperature stress, the more negatively impacted the quality criteria with decreased fatty acids (FAs) concentration, increased ω6:ω3 ratio, lower seed membrane integrity and increased seed dormancy and (ii) a mild stress event prior to heat peaks had an alleviating effect on the negative impact of the later heat peaks (priming effect) on seed nitrogen, desiccation tolerance and the phytohormones involved in thermoinhibition. Sulphur restriction was positive on FAs, protein concentration and negative on breaking dormancy. In addition, sulphur supply interfered with temperature modality, features such that positive impact of sulphur limitation on boosting oxidative response were cancelled with intense late heat peaks. This work provides insights to define thermopriming protocols in relation to the timing of quality building processes, their respective optimal temperature and adequate sulphur supply.

Sulfur transfer from the endophytic fungus Serendipita indica improves maize growth and requires the sulfate transporter SiSulT.

A deficiency of the essential macronutrient sulfur leads to stunted plant growth and yield loss; however, an association with a symbiotic fungus can greatly improve nutrient uptake by the host plant. Here, we identified and functionally characterized a high-affinity sulfate transporter from the endophytic fungus Serendipita indica. SiSulT fulfills all the criteria expected of a functional sulfate transporter responding to sulfur limitation: SiSulT expression was induced when S. indica was grown under low-sulfate conditions, and heterologous expression of SiSulT complemented a yeast mutant lacking sulfate transport. We generated a knockdown strain of SiSulT by RNA interference to investigate the consequences of the partial loss of this transporter for the fungus and the host plant (maize, Zea mays) during colonization. Wild-type (WT) S. indica, but not the knockdown strain (kd-SiSulT), largely compensated for low-sulfate availability and supported plant growth. Colonization by WT S. indica also allowed maize roots to allocate precious resources away from sulfate assimilation under low-sulfur conditions, as evidenced by the reduction in expression of most sulfate assimilation genes. Our study illustrates the utility of the endophyte S. indica in sulfur nutrition research and offers potential avenues for agronomically sound amelioration of plant growth in low-sulfate environments.