Gibberellins Target Shoot-Root Growth, Morpho-Physiological and Molecular Pathways to Induce Cadmium Tolerance in Vigna radiata L

Cadmium (Cd) inhibits plant growth, perturbs nutrient uptake, and affects chloroplast ultrastructure. The role of Cd stress in affecting growth and physiology and ameliorative effects of gibberellins (GAs) in Cd-induced toxicity in mung bean are lesser-known. This study comprehensively investigated Cd stress (CdCl2, IC50—500 µM L−1) with or without GA3 on mung bean (Vigna radiata L. Var. SML-668). In our methodology, a total of 80 mung bean plants (15 days old of uniform height) were divided into four groups, and each group (n = 20) was subjected to four different treatments (Control, CdCl2, GA3, CdCl2+GA3) twice during the entire life cycle of mung bean plants (until harvest 85–90 days). Results revealed negative impacts of Cd stress on shoot morphometry (plant height, leaf surface area, stem diameter, shoot fresh weight, number of leaves, number of pods, length, and diameter of pods), root morphometry (root length, root surface area, root dry weight, nodule number and nodule diameter), photosynthetic pigments, and agronomic traits. GA3 application ameliorated Cd stress by modulating shoot and root growth, improving overall plant metabolism, photosynthetic pigments, and shoot and root morphometry and transcript abundance of VrPCS1, VrIRT1, VrIRT2 and VrCD29. Thus, we propose GA3 application for the effective management of Cd-induced phytotoxicity in mung bean plants.