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

Abstract

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.

Gibberellic acid improves growth and reduces heavy metal accumulation: A case study in tomato (Solanum lycopersicum L.) seedlings exposed to acid mine water

“…To stimulate plant growth and ward off the effects of stress, the common measures are the application of plant regulators [ 18 ]. In line with these findings, an increase in plant height in mung bean, lettuce, and rocket was conceivably the most widely observed effect of GA 3 [ 17 , 19 , 20 , 21 ]. GA 3 promotes plant development by promoting the degradation of DELLA proteins, a nuclear family of transcription factors that acts as repressors in GA 3 signaling pathways [ 22 , 23 ].…”

Plant hormones and neurotransmitter interactions mediate antioxidant defenses under induced oxidative stress in plants

“…In great millet (Sorghum bicolor) seedlings, salinity stress (0, 100, and 200 mM NaCl) led to oxidative stress, reducing germination percentage, biomass, growth, and photosynthetic pigment content; exogenous GA 3 treatments (0, 144.3, 288.7, and 577.5 µM) and nitrogen fertilizer (0, 90, and 135 kg N ha −1 ) reduced the oxidative stress by increasing SOD and POD activities, thus improving photosynthesis and seedling growth (Ali et al, 2021). Hakla et al (2021) reported similar results in a study on mung bean (Vigna radiata) exposed to Cd toxicity (CdCl 2 , 500 µM); GA 3 at 500 µM improved the adverse effects of Cd stress on plant growth, photosynthetic apparatus, and metabolic processes. Salinity stress (150 mM NaCl) in wheat reduced germination, biomass, and photosynthetic pigments.…”

Induction of resilience strategies against biochemical deteriorations prompted by severe cadmium stress in sunflower plant when Trichoderma and bacterial inoculation were used as biofertilizers

“…This was suspected to be further increased due to the dramatic application of ash to agricultural soils and newly reclaimed ones. Using these agricultural soil types for cultivation will exacerbate the Cd stress encountered by plants; thus, the yield of crops decreases and the quality of field products gets degraded ( Abdel Latef, 2013 ; Hakla et al., 2021 ; Yaashikaa et al., 2022 ). Acute and chronic exposure to Cd can induce more damage including severe disturbance and downregulation in the physiological processes of plants, such as increased reactive oxygen and nitrogen species in the cells, which, in turn, act as deleterious molecules mediating an oxidative/nitrosative burst that could cause growth inhibition, accelerated senescence, and mostly cause plant death ( Noor et al., 2022 ).…”