Abstract:

To elucidate the mechanism on chloride channel inhibitor Z ${{\mathrm{n}}^2}^{+}$in ameliorating salt injury to soybean from the perspective of ion response, in this study, Glycine max cultivar Suinong 35 was used as the experimental material. The differences in physiological indexes, anatomical structure and ionomics of seedlings under different treatments were compared by the method of NaCl stress plus chloride channel inhibitors. The results showed that under NaCl stress plus additional three chloride channel inhibitors, ZnCl₂ could ameliorate salt injury in soybean to a certain extent, but nifluoric acid (NFA) and anthracene-9-carboxylic acid (9-AC) showed the reverse. Under NaCl stress plus Zn²⁺, the diameter of secondary vessel in root was markedly recovered, while cortex thickness in roots was decreased, which was helpful to reduce the metabolic cost and shorten the distance of water absorption from root to vascular cylinder. Under NaCl stress plus Zn²⁺, total chlorophyll content, F_v/F_m, N ${{\mathrm{O}}_3}^{-}$and microelement contents (Fe, Mn, Cu and Zn) rose again, while leaf Cl^- content was reduced between the control and NaCl-stressed seedlings. In summary, NaCl stress plus Zn²⁺ can effectively ameliorate salt injury to soybean seedlings by reestablishing ion homeostasis, which reduces Cl^- toxicity in leaves and improves antioxidant capacity and photosynthetic capacity.

Key words: salt stress, Glycine max, chloride channel blocker, ion homeostasis