Acclimation of cadmium-induced genotoxicity and oxidative stress in mung bean seedlings by priming effect of phytohormones and proline

Abstract

In this research, eight local mung bean (Vigna radiata) varieties were analyzed for their performance against two levels of CdCl2 solution (0.3 and 0.5 mM) alone and priming with gibberellic acid (GA3) (100 μM), salicylic acid (SA) (50 μM) and proline (5 mM) solution prior to Cd exposure. Mung bean seedlings were analyzed for disturbance in cytological, morphological, biochemical and enzymatic parameters under cadmium stress. For cytological studies, 48 h grown mung bean seedlings root tips were used to prepare slides and studied for percent mitotic index (MI%) and to calculate percent C-mitosis, laggard, sticky and fragmented chromosomes, pictures were captured by a Nikon camera (DS-Fi 1 Japan) attached with a microscope. One-week grown mung seedlings were studied for growth traits, malondialdehyde (MDA), protein, proline and antioxidant enzymes. ANOVA and DMR test of this research revealed that all the tested mung bean varieties and treatments were significantly different regarding mitotic index and number of chromosomal aberrations. Both the Cd treatments exhibited increased total chromosomal aberrations with different types and a maximum decrease in MI%. In pretreated samples, GA3, SA and proline serve as mitigating agents that reduce mutagenic effects of Cd in mung bean by increasing MI% and decreasing chromosomal aberrations as compared to non-pretreated samples. Both the Cd treatments showed a decrease in all growth traits. Total proteins were also found to be significantly reduced in a dose-dependent manner in all genotypes. Cd treatment increased the activities of all antioxidant enzymes tested. Cd caused oxidative damage as indicated by elevated levels of MDA content in treated samples in comparison to control. Proline content levels were also high in Cd treated seedlings indicating stress. Results demonstrated that pretreatment with phytohormones and proline before Cd were found to improve all morphological parameters, by altering antioxidant enzymes activities along with a decrease in MDA and proline contents as well. It was further noticed that the performance of GA3 was better at 0.3 mM Cd treatment while SA was found to be a good mitigating agent at 0.5 mM Cd stress in all tested mung bean varieties. This research concluded less deleterious effects of Cd on AZRI-2006 while more sensitivity to NM-51 towards Cd. Priming with phytohormones and proline is a user-friendly, economical, and simple mitigation strategy to reduce Cd toxicity in plants and get better yield from contaminated lands.

Growth, metal partitioning and antioxidant enzyme activities of mung beans as influenced by zinc oxide nanoparticles under cadmium stress

“…Similar results (about 250-400 U g −1 fw) were found in mung bean leaves with an exception of a negligible decline due to Cd toxicity (Leng et al 2021). However, as compared to control, an enhanced activity of APX enzyme due to Cd toxicity was observed in mung bean seedlings which also supports our results (Hassan et al 2021). About 19% increased (41.0-67.2 U g −1 fw) CAT activity due to Cd stress was observed in this study which was about 64% higher in mung bean seedlings (Leng et al 2021) as compared to control.…”

“…As compared to the uncontaminated control about 138-139% increased SOD activity was observed in mung beans due to Cd contamination (Ramzani et al 2017). However, under Cd treatments, Hassan et al (2021) found an enhanced SOD activity while a slight decreased activity was observed by Leng et al (2021). In this study, activities of all the antioxidant enzymes were increased with ZnO NPs application under Cd stress.…”

Combined interactions of amino acids and organic acids in heavy metal binding in plants

“… 72 In addationaly, all antioxidant enzymes and MDA content were also found to have a significant positive correlation. 73 In our studied showed an increase in proline and MDA levels with an increase in the concentration of metallic ions. The fact that this increase was high in the stem portion of the plant was indicative of a correlation between free radical formation and proline accumulation ( Figure 4 ).…”

Appraisal of Functions and Role of Selenium in Heavy Metal Stress Adaptation in Plants

“…In Cd stressed Nicotiana tabacum, exogenous Se treatment increased the levels of indole acetic acid (IAA) [42]. However, seed priming with GA and SA showed stimulatory effects on growth and metabolism of mung bean under Cd stress conditions [43]. Furthermore, role of JA and GA in inducing tolerance to Cd stress is also explored in Cicer arietinum [44].…”