24-epibrassinolide triggers cadmium stress mitigation in Cucumis sativus through intonation of antioxidant system

Abstract

The core objective of current study was to find out the potential of 24-epibrassinolide (24-EBL) in alleviation of cadmium (Cd) induced stress in cucumber (Cucumis sativus L.). C. sativus seeds were primed with 5 μM 24-EBL and allowed to grow in Cd spiked petri dishes for 15 days. The Cd-driven stress exhibited noticeable injurious effects on growth parameters of C. sativus seedlings. The oxidative stress pledged due to overproduction of malondialdehyde (MDA) and reactive oxygen species (ROS) severely affected morphological features besides gas exchange parameters, leaf relative water content (LRWC) and amount of photosynthetic pigments in C. sativus seedlings under Cd stress. Nevertheless, 24-EBL reduced Cd contents in cucumber foliage and elucidated the vital role of this biomolecule in Cd translocation. The exogenous application of 24-EBL improved shoot length, root length and biomass production of Cd-stressed plants. Alternatively, 24-EBL triggered reduction in lipid peroxidation besides increased synthesis of ethylene and indole acetic acid (IAA). Furthermore, 24-EBL modulated the expression level of ethylene receptor genes including CS-ERS, 1-aminocyclopropane-1-carboxylate oxidase2 (CsAOX), 1-aminocyclopropane-1-carboxylate oxidase1 (CSACO1), 1-aminocyclopropane-1-carboxylate oxidase2 (CSACO2), and indole acetic related CS 453. Altogether, these physiological vicissitudes advocate that 24-EBL augmented antioxidative capability contributes in the advancement of Cd tolerance in cucumber seedlings.