Drought tolerance inBrassica napusis accompanied with enhanced antioxidative protection, photosynthetic and hormonal regulation at seedling stage

Abstract

Climate change, food insecurity, water scarcity, and population growth are some of today's world's frightening problems. Drought stress exerts a constant threat to field crops and is often seen as a major constraint on global agricultural productivity; its intensity and frequency are expected to increase in the near future. The present study investigated the effects of drought stress (15% w/v polyethylene glycol PEG-6000) on physiological and biochemical changes in five Brassica napus cultivars (ZD630, ZD622, ZD619, GY605, and ZS11). For drought stress induction, 3-weekold rapeseed oil seedlings were treated with PEG-6000 in full strength Hoagland nutrient solution for 7 days. PEG treatment significantly decreased the plant growth and photosynthetic efficiency, including primary photochemistry (Fv/Fm) of PSII, intercellular CO 2 , net photosynthesis, chlorophyll contents, and water-use efficiency of all studied B. napus cultivars; however, pronounced growth retardations were observed in cultivar GY605. Drought-stressed B. napus cultivars also experienced a sharp rise in H 2 O 2 generation and malondialdehyde (MDA) content. Additionally, the accumulation of ROS was accompanied by increased activity of enzymatic antioxidants (superoxide dismutase, peroxidase, catalase, ascorbate peroxidase, glutathione reductase, and monodehydroascorbate reductase), although the increase was more obvious in ZD622 and ZS11. Drought stress also caused an increased endogenous hormonal biosynthesis (abscisic acid, jasmonic acid, salicylic acid) and accumulation of total soluble proteins and proline content, but the extent varies in B. napus cultivars.These results suggest that B. napus cultivars have an efficient drought stress tolerance mechanism, as shown by improved antioxidant enzyme activities, photosynthetic and hormonal regulation. | INTRODUCTIONWater stress is an increasingly scarce resource that decreases crop production in many parts of the world. Drought stress is one of the most severe abiotic environmental stress factors affecting crop production worldwide (Kour et al., 2020). Rapid anthropogenic climatic changes affect the annual precipitation pattern, leading to severe drought stress in many agricultural areas (Scott et al., 2014). Acquiring drought tolerance in plants probably involves molecular, cellular, physiological, and developmental adjustments enabling plants to adopt an adequate response to maintain optimal growth and development (Bergmann, 2020). In plants, drought stress adaptive strategies have been categorized as (1) drought tolerance via early flowering (Khadka et al., 2020), (2) drought escape via enhanced water uptake and reduced

Function and Mechanism of Jasmonic Acid in Plant Responses to Abiotic and Biotic Stresses

“…[116], rice (Oryza sativa) [117], pearl millet (Pennisetum glaucum L.) [118], and sugar beet (Beta vulgaris L.) [119]. The contents of total soluble proteins, proline (Pro) and malondialdehyde (MDA), and the activities of antioxidant enzymes (including superoxide dismutase, peroxidase, and catalase) all increased notably by the application of exogenous JAs, enhancing the drought tolerance of plants [115,120].…”

Genome-Wide Identification and Analysis of Ariadne Gene Family Reveal Its Genetic Effects on Agronomic Traits of Brassica napus

“…Brassica napus , an allotetraploid plant generated through hybridization between Brassica rapa and Brassica oleracea [ 30 ], is a major worldwide crop due its industrial value and oil production. Like other crops, B. napus productivity has been affected by several abiotic stresses including low temperature, drought, salinity, and so on [ 31 , 32 , 33 ]. Therefore, it is important to improve stress adaptation by identifying stress-related genes in B. napus .…”

Foliar Application of Trehalose or 5-Aminolevulinic Acid Improves Photosynthesis and Biomass Production in Drought Stressed Alpinia zerumbet

“…Its impact depends upon the severity of the stress and species of plant. The level of stress, particularly at the seedling stage, is critical to determining the severity of the impact on plant growth and productivity [34]. Thus, by adopting strategies that ameliorate the impacts of drought at the seedling stage, one can achieve a crop harvest even when plants experience stressful conditions.…”