Silicon Seed Priming Combined with Foliar Spray of Sulfur Regulates Photosynthetic and Antioxidant Systems to Confer Drought Tolerance in Maize (Zea mays L.)

Abstract

The present study evaluated the effect of silicon (Si) seed priming and sulfur (S) foliar spray on drought tolerance of two contrasting maize hybrids viz. drought tolerant Hi-Corn 11 and susceptible P-1574. The maize seeds were primed with (3 mM Na2SiO3) or without Si (hydropriming) and later sown in pots filled with sandy loam soil. Drought stress (25–30% water holding capacity or WHC) was initiated at cob development stage (V5) for two weeks, whereas the well-watered plants were grown at 65–70% WHC. On appearance of drought symptoms, foliar spray of S was done using 0.5% and 1.0% (NH4)2SO4, whereas water spray was used as a control. The drought-stressed plants were grown for further two weeks at 25–30% WHC before the final harvest. The results showed a marked effect of Si seed priming and foliar S spray on biomass, physiological and enzymatic processes as well as macronutrient concentrations of maize. In comparison to control, the highest increase in leaf relative water content (25%), chlorophyll a content (56%), carotenoids (26%), photosynthetic rate (64%), stomatal conductance (56%) and intercellular CO2 concentration (48%) was observed by Si seed priming + S foliar spray (Si + S) under water deficit conditions. Also, Si + S application stimulated the activity of catalase (45%), guaiacol peroxidase (38%) and superoxide dismutase (55%), and improved NPK concentrations (40–63%) under water limitations. Our results suggest that Si seed priming + foliar spray of S is more effective than the individual application of these nutrients to enhance drought tolerance in maize.

Evaluation of Silicon Supplementation for Drought Stress under Water-Deficit Conditions: An Application of Sustainable Agriculture

“…The enzymes are responsible for O 2 − and H 2 O 2 detoxification and assist in averting the highly poisonous HO − formation [56]. A significant increment in POX, CAT, SOD, and APX production by Si application provides an additional indication that Si controls the spontaneous dismutation of O 2 − and H 2 O 2 , or can be responsible directly for the quenching of O 2 − and OH − in cells [57]. Early reports on ornamental sunflower [56], Rosa damascena [11], and gerbera [24] also proposed a rise in antioxidant activity in plants supplemented by Si during drought stress.…”

Effect of silicon priming on germination and growth of rice (Oryza sativa L.) in drought condition

“…Regulation of cellular homeostasis by Si by maintaining plant stability and permeability as well as cell membrane integrity. Increasing plant tolerance to stress is positively correlated with the addition of Si through stimulating the accumulation of photorespiratory enzymes ( [17], [18]). The mean value with the same letter of each column indicates there is no significant difference based on Duncan test α = 0.05 n = 3.…”

“…Plants activate enzymatic and non-enzymatic antioxidant as a defense mechanism to prevent cell membrane damage due to ROS accumulation when faced with stress. Nonenzymatic compounds that can be activated are ascorbic acid, tocopherol, glutamic acid, proline, phenol, and carotenoids [17]. Drought causes an increase in ROS production which damages membrane lipids.…”

Activating stress memory: eustressors as potential tools for plant breeding

“…Between these, the reactive oxygen–nitrogen–sulphur species (RONSS) stand out as a key priming agent because of their role as a key messenger in the physiology, metabolism, and responses to stress, and the crosstalk tolerance they could induce in plants (Locato et al 2018 ). By mention, recent studies have highlighted the use of sulfur fertilization to enhance drought tolerance (Chowdhury et al 2020 ; Farman et al 2021 ; Shafiq et al 2021 ) and heavy metal exposure (Ragab and Saad-Allah 2021 ) in crops through the regulation of the enzymatic antioxidant system and photosynthetic efficiency. These suggest a degree of priming additional to the biostimulants effect in the yield.…”