Silicon Priming Regulates Morpho-Physiological Growth and Oxidative Metabolism in Maize under Drought Stress

Abstract

Seed priming with silicon (Si) is an efficient and easy method to regulate plant tolerance against different abiotic stresses. A pot experiment was conducted to examine the Si-mediated changes in oxidative defense and some vital physio-biochemical parameters of maize under a limited water supply. For this purpose, two maize varieties (Pearl and Malka) with different Si priming treatments (0, 4 mM, 6 mM) were grown under a control and 60% field capacity for three weeks. At 60% field capacity, significant reductions in plant growth attributes and chlorophyll contents were recorded compared with the control. The negative effects of drought stress were more severe for Malka compared with Pearl. Drought stress increased the malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents, altered the activities of antioxidant enzymes (superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT)), and triggered the accumulation of soluble sugars, glycine betaine, proline, and phenolics contents. Nevertheless, seed priming with silicon at 4 or 6 mM was effective in alleviating the detrimental effects of drought stress in both cultivars. Si priming particularly at 6 mM significantly enhanced the shoot and root lengths as well as their biomass and improved the levels of photosynthetic pigments. Moreover, Si treatments enhanced the activities of antioxidant enzymes (SOD, POD, and CAT) while it reduced the MDA and H2O2 contents in both cultivars under stress conditions. In crux, the present investigation suggests that Si priming mitigates the harmful effects of drought stress and contributes to the recovery of maize growth.

Stress Oxidative Evaluation on SiK®-Supplemented Castanea sativa Mill. Plants Growing Under High Temperature

“…4c, the exposure to B-32°C induced a more significant oxidative damage in untreated plants than in Si-fertilized plants, indicating that Si application can prevent the structural and functional deterioration of cell membranes by protecting them from ROS toxicity and reducing oxidative stress. These findings are in accordance with the studies of Rubinowska et al (2014), Shekari et al (2017), and Parveen et al (2019), who stated that the Si treatment reduced the permeability of the membranes by stimulating the synthesis of antioxidant enzymes, which deactivate the H 2 O 2 responsible for the peroxidation of cell lipids. Moreover, these authors suggested that Si can act in the stability of cell membranes through changes in the ratio of unsaturated and saturated fatty acids, maintaining the integrity and functionality of plasmatic membranes.…”

“…3b) content in plant tissues can be a precursor of a highly reactive oxygen species (Ślesak et al 2007). The accumulation of H 2 O 2 affects the structure and integrity of plasma membranes by influencing the stress-dependent peroxidation of membrane lipids (Liang et al 2006(Liang et al , 2007Parveen et al 2019). The present findings suggest that the increased CAT, POD, and APX activity in Si-treated plants (10 mM SiK®) was beneficial to the lower levels of H 2 O 2 under high temperature conditions (B-32°C), as compared to control plants (0 mM SiK®).…”

Maize Tolerance against Drought and Chilling Stresses Varied with Root Morphology and Antioxidative Defense System

“…Water deficit and suboptimal temperature are adverse environmental factors that impose drastic effects on crop plants [ 2 , 22 ]. Maize is comparatively more sensitive to water scarcity and low temperature conditions particularly at the early stages of plant growth [ 2 , 25 , 26 , 27 ]. The present study indicated that all the maize shoot growth attributes were severely hampered by drought, chilling, and combination of drought + chilling stresses ( Figure 1 and Figure 2 ).…”

“…Both chilling and drought stresses have been reported to cause the oxidative damage in plants by the overproduction of ROS in cells [ 2 , 9 , 18 , 32 , 33 ]. However, plants have developed a complex antioxidative defense system, which consists of non-enzymatic and enzymatic components to overcome the excessive production of ROS [ 19 , 26 , 34 , 35 ]. The balance between ROS generation and antioxidants (enzymatic and non-enzymatic) is critical in all plant species under stress conditions [ 12 , 29 , 33 , 34 , 36 ].…”

Is Silicon a Panacea for Alleviating Drought and Salt Stress in Crops?

“…In several species, Si appears to increase the level of soluble sugars under salt and drought stress (rice: Yang et al, 2019;wheat: Alzahrani et al, 2018;okra: Abbas et al, 2015;tobacco: Hajiboland et al, 2017), however, Kang et al (2016) reported decreased soluble sugar content in osmotically-stressed Zygophyllum xanthoxylum. Although in general Si appears to increase glycine betaine levels (Abbas et al, 2015;Saleh et al, 2017;Ahmad et al, 2019;Al-Huqail et al, 2019), decreases have been reported for drought-stressed maize (Parveen et al, 2019) and salt-stressed borage (Torabi et al, 2015). There is a trend for Si to increase polyamine levels under drought and salt-stress Yin et al, 2016;Ali et al, 2018;Yin et al, 2019).…”