水杨酸对锌胁迫下小麦幼苗生长抑制的缓解效应

Salicylic Acid Mitigating the Inhibition of Zinc Stress to Wheat Seedling Growth

以小麦品种‘新麦18’为材料,采用室内水培实验研究了不同浓度水杨酸(SA)处理对300 mg.L-1锌胁迫下小麦种子萌发和幼苗生长的影响。结果表明:在Zn2+胁迫下,小麦种子的发芽势和发芽率、幼苗根长、芽长以及幼苗叶片的可溶性蛋白含量、根系活力显著降低,而脯氨酸和丙二醛(MDA)含量显著增加(P<0.05);外施SA显著提高了Zn2+胁迫下小麦种子的发芽势和发芽率,同时也使Zn2+胁迫7 d后的小麦幼苗的根长、芽长,幼苗叶片的脯氨酸和可溶性蛋白含量以及根系活力显著升高,膜脂过氧化产物MDA含量却显著降低(P<0.05)。由此可见,外施SA可通过提高小麦幼苗根长和芽长来增加幼苗根系活力,通过提高小麦幼苗可溶性蛋白含量、脯氨酸含量来维持细胞膜的稳定性,降低膜脂过氧化伤害程度,从而缓解了Zn2+胁迫对幼苗生长的抑制,并以14 mg.L-1外源水杨酸缓解效果最好。

Using wheat ＇Xinmai 18＇ as the material,effects of the different concentration of salicylic acid on the germination of wheat seed and the growth of wheat seedling under 300 mg·L-1 Zn2＋stress were studied by hydroponic culture.The results showed as follow：under Zn2＋stress,the germination vigor and rate,the content of soluble proteins and the root activity were significantly decreased than those of control.The contents of proline and MDA were significantly increased（P0.05）.Exogenous SA application on the root significantly increased the germination vigor and rate,while the length of root and shoot,the contents of soluble proteins and proline,and the root activity were significantly increased.The content of malonaldehyde（produce of membrane lipid peroxidation） was significantly decreased when the wheat seedlings were suffered from Zn2＋ stress for 7 d（P0.05）.The results showed that exogenous SA could effectively keep cytomembrane stabilization and reduce the damage from membrane lipid peroxidation,by which could mitigate the harmful effects from Zn2＋ stress on plants,and promote the growth of wheat,and the effect of 14 mg·L-1 SA was optimal.