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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.

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Root system architecture (RSAch) is central to drought management in plants. In this study, the mechanism of paclobutrazol (PBZ)-mediated improvement in tolerance to water deficit using five maize varieties was investigated. Comprehensive pot experiments were conducted during 2017, 2018 and 2019 and maize plants were subjected to 60% of evapotranspiration demand both in early deficit (EDI) and terminal deficit (TDI) irrigation regimes. Findings revealed that application of PBZ decreased plant height; while traits like stem diameter, root biomass, root length and root surface area under EDI and TDI improved significantly. Structural equation modelling of root traits revealed PBZ induced increase in root surface area (RSA) and length of seminal roots in EDI. For TDI, PBZ induced changes in RSA, length of seminal and brace roots and several reproductive attributes of the plant. Altogether, these findings propose improvement of root traits as an effective strategy to increase Water Use Efficiency of maize varieties with minimal impact on agronomic traits.Abstract FigureFigure graphical AbstractLife cycle of maize plants (Zea mays L.) is sensitive towards soil water availability, in particular establishment of young maize plants (from 0 days after sowing (DAS) to 35 DAS, early deficit irrigation, EDI) and 50 DAS to 65 DAS, a phase showing transition of vegetative to reproductive stage. Maize being a rain fed crop is mainly dependent upon rainwater, thus late arrival of monsoon or shorter spell of monsoon period in Indian sub continent poses water deficit or drought like conditions, consequently affecting the establishment of young plants and successful transition of vegetative to reproductive phase. In current study, early deficit irrigation (EDI) supplied 60% of the evapotranspiration demand (EVTD) commenced with or without paclobutrazol (PBZ) on 15 DAS to 35 DAS (for a period of 20 days) young maize plants mimicked the late arrival of monsoon by a period of 10-15 days. While, terminal deficit irrigation (TDI) supplied 60% of EVTD with or without PBZ at 54 DAS to 104 DAS (for a period of 50 days) plants mimicked shorter spell of monsoon, thereby reducing the soil water availability, affecting successful transition of vegetative to reproductive phase and formation of reproductive structures. Structural equation modeling (SEM) showed improved root traits and their contribution in enhancing water use efficiency resulting in better adaptation of maize under EDI and TDI, more specifically when applied with paclobutrazol. Happy maize plants in terms of improved water use efficiency (WUE) under TDI resulted in more cob yield specifically with paclobutrazol application, leading to enhanced farmers income and economic prosperity.

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