Influence of Sulfur Induced Stress on Oxidative Status and Antioxidative Machinery in Leaves of Allium cepa L.

125

Soil amendments are known to promote several plant growth parameters. In many agro-ecosystems, water scarcity and drought induced phosphorus deficiency limits crop yield significantly. Considering the climate change scenario, drought and related stress factors will be even more severe endangering the global food security. Therefore, two parallel field trials were conducted to examine at what extent soil amendment of leonardite and humic acid would affect drought and phosphorus tolerance of maize. The treatments were: control (C: 100% A pan and 125 kg P ha −1), P deficiency (phosphorus stress (PS): 62.5 kg P ha −1), water deficit stress (water stress (WS): 67% A pan), and PS + WS (67% A pan and 62.5 kg P ha −1). Three organic amendments were (i) no amendment, (ii) 625 kg S + 750 kg leonardite ha −1 and (iii) 1250 kg S + 37.5 kg humic acid ha −1) tested on stress treatments. Drought and p deficiency reduced plant biomass, grain yield, chlorophyll content, F v /F m , RWC and antioxidant activity (superoxide dismutase, peroxidase, and catalase), but increased electrolyte leakage and leaf H 2 o 2 in maize plants. The combined stress of drought and P deficiency decreased further related plant traits. Humic acid and leonardite enhanced leaf P and yield in maize plants under PS. A significant increase in related parameters was observed with humic acid and leonardite under WS. The largest increase in yield and plant traits in relation to humic acid and leonardite application was observed under combined stress situation. The use of sulfur-enriched amendments can be used effectively to maintain yield of maize crop in water limited calcareous soils. The global climate change simulations suggest fresh water availability will further deplete in many rainfed and irrigated agricultural areas 1 and thus, threatens food security 2. Although hydrological, meteorological and agricultural droughts occur simultaneously and are interrelated with each other, agricultural drought is believed to be the most common 3,4. Water stress causes a variety of responses from physiological to molecular in plants, allowing them to acclimate to harsh ecological conditions 5. Drought susceptibility of plants differs according to the plant species, stress level, and growth stages 6. Considerable yield gaps have been noticed in agricultural systems 7,8 and the availability of good quality water and mineral nutrients is critical for overcoming these yield gaps 9-11. This is principally reasonable for maize crop, one of the main cereals of the globe, covering 26% and 37% of the total cereal cultivated area and production, respectively 12. Maize is known as one of the highest water-requiring crops. Water deficiency imposed at any stage of its development can reduce grain yield significantly 13,14. As it is a fast-growing crop, its requirement for essential nutrients is also high and deficiency of any of the plant nutrients may lead to hamper growth and decrease yield 15. Maize is particularly susceptible to P deficiency, which can suppress growth and grain...

Section: Discussionmentioning

confidence: 99%

Sulfur-enriched leonardite and humic acid soil amendments enhance tolerance to drought and phosphorus deficiency stress in maize (Zea mays L.)

Kaya

Şenbayram

Akram

et al. 2020

125

“…Drought stress as well as S deprivation causes metabolic imbalance that leads to oxidative burst in plant cell 75 . S deficiency stimulates peroxidation of biomolecules due to excessive accumulation of reactive oxygen species (ROS) and reduced synthesis of S-containing compounds 76 .…”

Section: Discussionmentioning

confidence: 99%

Sulfate-mediated Drought Tolerance in Maize Involves Regulation at Physiological and Biochemical Levels

Usmani

Nawaz

Majeed³

et al. 2020

Restriction in nutrient acquisition is one of the primary causes for reduced growth and yield in water deficient soils. Sulfur (S) is an important secondary macronutrient that interacts with several stress metabolites to improve performance of food crops under various environmental stresses including drought. Increased S supply influences uptake and distribution of essential nutrients to confer nutritional homeostasis in plants exposed to limited water conditions. The regulation of S metabolism in plants, resulting in synthesis of numerous S-containing compounds, is crucial to the acclimation response to drought stress. Two different experiments were laid out in semi-controlled conditions to investigate the effects of different S sources on physiological and biochemical mechanisms of maize (Zea mays L. cv. P1574). Initially, the rate of S application in maize was optimized in terms of improved biomass and nutrient uptake. The maize seedlings were grown in sandy loam soil fertigated with various doses (0, 15, 30 and 45 kg ha −1) of different S fertilizers viz. K 2 So 4 , feSo 4 , cuSo 4 and na 2 So 4. The optimized S dose of each fertilizer was later tested in second experiment to determine its role in improving drought tolerance of maize plants. A marked effect of S fertilization was observed on biomass accumulation and nutrients uptake in maize. In addition, the optimized doses significantly increased the gas exchange characteristics and activity of antioxidant enzymes to improve yield of maize. Among various S sources, application of K 2 So 4 resulted in maximum photosynthetic rate (43%), stomatal conductance (98%), transpiration rate (61%) and sub-stomatal conductance (127%) compared to no S supply. Moreover, it also increased catalase, guaiacol peroxidase and superoxide dismutase activities by 55, 87 and 65%, respectively that ultimately improved maize yield by 33% with respect to control under water deficit conditions. These results highlight the importance of S fertilizers that would likely be helpful for farmers to get better yield in water deficient soils. Maize (Zea mays L.) is one of the major cereal crops that provide food for humans and feed for livestock. The demand for maize seed has increased significantly during past few decades due to its consumption in poultry feed and wet milling industry. The importance of maize as a food crop is well recognized and is used as a staple food in many parts of the world 1. Maize seed is an abundant source of energy as 100 g seed provides 365 kilocalories of energy 2. However, it is an extensive nutrient crop and excessive use of fertilizers to obtain high yield has resulted in the depletion of nutrients particularly sulfur (S) in soils 3. Moreover, water shortage due to climate change may induce further losses in maize production in future. Adaptation of maize to limited water conditions has received great interest from farmers, researchers and policy makers considering its importance in nutritional food security. Since maize requires large quantities of water to...

“…Previous studies also showed that low S stress decreased S-adenosyl-methionine (SAM) production leading to a reduction in chlorophyll content and an enhancement in photorespiration 19 . Moreover, S deficiency affects ribulose-1,5-bis-phosphate carboxylase/oxygenase (RuBisCO) activity and abundance of proteins involved in CO 2 assimilation, which ultimately decrease photosynthesis and biomass accumulation in plants 10 , 20 (Fig. 1 ).…”

Section: Discussionmentioning

confidence: 99%

“…The metabolic imbalance of S containing compounds generally leads to oxidative burst in plant cells 10 . The excessive accumulation of ROS due to S deficiency causes lipidperoxidation, damage to nucleic acids or proteins, and even cell death 21 (Figs 2 and 3 ) 22 .…”

Section: Discussionmentioning

confidence: 99%

“…Hence, the instant effects are noticed in metabolic profiles following exposure of plants to S-deprived conditions. S deficiency retards sulfate assimilation in plants, leading to significant increases in serine but reductions in glutathione, cysteine, O-acetylserine, tryptophan, chlorophyll, RNA, total protein and lipids contents 10 , 11 . In addition, S deficiency increases photorespiration and causes nitrogen imbalance in plants.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Melatonin alleviates low-sulfur stress by promoting sulfur homeostasis in tomato plants

Hasan

Liu

Pan

et al. 2018

Despite involvement of melatonin (MT) in plant growth and stress tolerance, its role in sulfur (S) acquisition and assimilation remains unclear. Here we report that low-S conditions cause serious growth inhibition by reducing chlorophyll content, photosynthesis and biomass accumulation. S deficiency evoked oxidative stress leading to the cell structural alterations and DNA damage. In contrast, MT supplementation to the S-deprived plants resulted in a significant diminution in reactive oxygen species (ROS) accumulation, thereby mitigating S deficiency-induced damages to cellular macromolecules and ultrastructures. Moreover, MT promoted S uptake and assimilation by regulating the expression of genes encoding enzymes involved in S transport and metabolism. MT also protected cells from ROS-induced damage by regulating 2-cysteine peroxiredoxin and biosynthesis of S-compounds. These results provide strong evidence that MT can enhance plant tolerance to low-S-induced stress by improving S uptake, metabolism and redox homeostasis, and thus advocating beneficial effects of MT on increasing the sulfur utilization efficiency.