Table 2.
The effect of exogenous application of abscisic acid in rice during Heavy metal stress.
| Treatment | Application | Conc. | Effects/Mechanism | References |
|---|---|---|---|---|
| CuSO4 and CdCl2 | ABA | 10 μM | Upregulation of stress membrane protein (OsSMP1), increasing tolerance to heavy metal stresses but increasing sensitivity to ABA | [36] |
| CdCl2 | Pretreatment with ABA | 10 μM | Reduced transpiration rate, decreased Cd content, and enhanced Cd tolerance of TN1 seedlings. ABA content enhanced in roots and leaves of Cd-tolerant cultivar | [37] |
| Cd | ABA | 100 μM | Stomatal closure, reduced transpiration rate, and dramatically reduced the accumulation of Cd in the leaves | [32] |
| Pb, Cd, As | ABA | - | Increase in ABA concentrations; signaling and biosynthesis genes of ABA are upregulated | [17] |
| Cd, Cu | -Si | - | Increased level of endogenous ABA in Si-plants after 10 days, triggered heavy metal transporters (OsHMA2 and OsHMA3) genes | [34] |
| Cd | ABA | - | Upregulation of ABA biosynthesis genes, positive correlation between Cd tolerance and endogenous ABA content, rapid ABA production detected in roots and leaves of Cd-tolerant rice genotypes | [37] |
| Cd (0.1 mM) or Nickel (0.5 mM) | ABA | 19 µM | Potentiate the effects of heavy metals by accumulating carbohydrates and inhibiting growth | [35] |
| As(III) (25 and 50 mM L−1) | pretreated with ABA | 10 µM | As altered phosphatase, H+/ATPase, alkaline phosphatase, ROS, antioxidative and proline biosynthesis genes and ABA regulated phosphatase, H+/ATPase and alkaline phosphatase to moderate phosphate and upregulated antioxidative biosynthesis genes and downregulated ROS biosynthesis genes | [40] |
| As(V) (25 µM) | - | - | Two ABA biosynthesis genes, OsNCED2 and OsNCED3, were strongly increased and 4 ABA signaling genes were upregulated. Expression of GARP-G2-like and C3H transcription factors was specifically modulated by As(V) stress. MAPKs activity was enhanced. |
[33] |
| Pb (0.25 mM Pb) | Pretreatment with ABA | 0.1 g m−3 | Restricted amount of Pb translocated from roots to shoots, decreased malondialdehyde and H2O2 contents in leaves, and alleviated Pb-induced decrease in plant growth and leaf chlorophyll content and improved increased ascorbate peroxidase and catalase activities | [42] |
| Vanadium (1 mM) | - | - | Expression of ABA hormone signaling pathways increased. NAC (NAM, ATAF, CUC) proved to be V-specific transcription factor | [28] |