关键词: 燕麦, NaCl胁迫, KCl, 活性氧代谢, 渗透溶质, Na⁺/K⁺

Abstract: We studied the effects of KCl on the plant growth, active oxygen metabolism and osmotica accumulation in Avena nude seedlings (‘Dingyou No.6’) under 120 mmol·L^-1 NaCl stress with sand cultivation in a greenhouse. Compared with 1 mmol·L^-1 KCl, 10 and 20 mmol·L^-1 KCl on A.nude seedlings, respectively, could significantly increase its weights of fresh and dry, relative water content, as well as its leaf activities of superoxide dismutase, peroxidase and ascorbate peroxidase, but decrease its the contents of O^·₂, H₂O₂, malondialdehyde and glutathione and membrane relative permeability under the NaCl stress. Moreover, the effect of 20 mmol·L^-1 KCl was higher than that of 10 mmol·L^-1, but there were no significant effects on the catalase activity and ascorbic acid content, however, the damage of salt stress was significantly increased when KCl concentration was up to 3.0 mmol·L^-1. The contents of soluble protein, soluble sugar and proline in A.nude leaves were significantly higher than that of others, when KCl concentration was 10 and 20 mmol·L^-1, but its free amino acids contents were significantly lower than that of 1 mmol·L^-1 KCl, and little variation in content of organic acids. The K⁺/Na⁺ ratio in leaves of A.nude seedlings under NaCl stress increased significantly, and the plasma membrane H⁺-ATPase activities demonstrated a hump-shaped curve with the increase of KCl. Therefore, the ratio 6∶1 of Na⁺/K⁺ could alleviate the negative impact of salt stress on A.nude seedlings through improving the ability of scavenging reactive oxygen species and osmotica accumulation.

Key words: Avena nude, NaCl stress, KCl, active oxygen metabolism, osmotica, Na⁺/K⁺