Effects of salicylic acid, zinc and glycine betaine on morpho-physiological growth and yield of maize under drought stress

Abstract

Drought is one of the major environmental stresses that negatively affect the maize (Zea mays L.) growth and production throughout the world. Foliar applications of plant growth regulators, micronutrients or osmoprotectants for stimulating drought-tolerance in plants have been intensively reported. A controlled pot experiment was conducted to study the relative efficacy of salicylic acid (SA), zinc (Zn), and glycine betaine (GB) foliar applications on morphology, chlorophyll contents, relative water content (RWC), gas-exchange attributes, activities of antioxidant enzymes, accumulations of reactive oxygen species (ROS) and osmolytes, and yield attributes of maize plants exposed to two soil water conditions (85% field capacity: well-watered, 50% field capacity: drought stress) during critical growth stages. Drought stress significantly reduced the morphological parameters, yield and its components, RWC, chlorophyll contents, and gas-exchange parameters except for intercellular CO2 concentration, compared with well water conditions. However, the foliar applications considerably enhanced all the above parameters under drought. Drought stress significantly (p < 0.05) increased the hydrogen peroxide and superoxide anion contents, and enhanced the lipid peroxidation rate measured in terms of malonaldehyde (MDA) content. However, ROS and MDA contents were substantially decreased by foliar applications under drought stress. Antioxidant enzymes activity, proline content, and the soluble sugar were increased by foliar treatments under both well-watered and drought-stressed conditions. Overall, the application of GB was the most effective among all compounds to enhance the drought tolerance in maize through reduced levels of ROS, increased activities of antioxidant enzymes and higher accumulation of osmolytes contents.

Combined application of zinc and silicon alleviates terminal drought stress in wheat by triggering morpho-physiological and antioxidants defense mechanisms

“…Furthermore, both Zn [ 18 , 28 ] and Si [ 6 , 23 ] can improve anti-oxidative defense mechanisms (both enzymatic and non-enzymatic); thus, avoid damage from ROS produced by various abiotic stresses. Although individual effect of Zn or Si to alleviate abiotic stresses are well reported [ 18 , 27 , 29 ], there is lack of knowledge on the combined effect of Zn and Si to regulate physiological and biochemical mechanisms to improve grain yield of wheat under stress conditions.…”

Foliar Potassium Sulfate Application Improved Photosynthetic Characteristics, Water Relations and Seedling Growth of Drought-Stressed Maize

“…Moreover, K regulates photosynthetic efficiency by increasing sunlight interception [57]. In our study, increased proline contents under SD in drought-tolerant cultivars ameliorated drought effects through improved osmoregulation [58,59]. It was also inferred that proline act as a signaling molecule to influence cell proliferation or cell death, and it triggered specific gene expression for plant recovery from stress [60].…”

“…Drought levels, maize cultivars and foliar application had a significant effect on relative water contents; however, drought-tolerant cultivars exhibited higher RWC, as they preserved more water under drought by virtue of osmotic adjustment and stomatal regulation [59]. Moreover, foliar application of K improved RWC (Figure 3), which might be due to the role of K in stomatal regulation and osmotic adjustment [25].…”

Application of Trehalose and Salicylic Acid Mitigates Drought Stress in Sweet Basil and Improves Plant Growth

“…Plants have natural defense systems comprising non-enzymatic and enzymatic antioxidants that efficiently ameliorate the negative impacts of excessive ROS [9]. Additionally, plants acclimate to ROS-induced stress by producing various beneficial compatible solutes, such as proline and glycine betaine [10,11].…”

“…Osmoprotectants synthesized by plants play an important role in regulating defense responses to various abiotic stresses, including drought stress [12,13]. Recently, exogenous application of osmoprotectants has been widely adopted as an effective, economical, and eco-friendly strategy to manage various environmental extremes [10,14,15]. Trehalose (α-D-glucopyranosyl-[1,1]-α-D-glucopyranoside (Tre)) is a crucial non-reducing disaccharide, composed of two glucose units attached through their 1-carbons [16].…”