精异丙甲草胺苗前封闭处理对大豆苗期生长及其生理生化指标的影响

Effects of the treatment with S-metolachlor before seedling emergence on the soybean growth and physiological and biochemical indexes

为明确精异丙甲草胺苗前封闭处理对大豆苗期生长及其生理生化指标的影响,通过室内试验,测定大豆幼苗在不同浓度精异丙甲草胺处理后28 d的相关农艺性状及各生理生化指标。结果表明,1 224 g(a.i.)/hm^2精异丙甲草胺处理对大豆生长的促进效果最好,可使植株显著增高27.06%,根显著增长10.53%,茎叶鲜重显著增加35.62%、干重显著增加33.33%,根系鲜重显著增加70.45%。大豆叶片叶绿素含量随药剂浓度的增加而降低,但在383~1 530 g(a.i.)/hm^2内与对照无显著差异;各药剂处理浓度均可增强大豆叶片过氧化物酶活性,其中3 060 g(a.i.)/hm^2处理最高,比对照显著增强32.10%;在765、1 224 g(a.i.)/hm^2浓度下均可增强过氧化氢酶和超氧化物歧化酶的活性,1 224 g(a.i.)/hm^2处理时分别比对照提高20.72%和2.88%。表明精异丙甲草胺苗前封闭处理在一定使用浓度范围内对大豆苗期植株生长有显著促进作用,对其叶绿素合成无显著影响,可有效提高抗氧化酶活性,是一种对大豆田环境友好且安全性高的除草剂。

To determine the effects of the treatment with S-metolachlor before seedling emergence on the soybean growth and biochemical mechanism, the soil was treated with S-metolachlor at seven concentrations,and the agronomic characters and physiological and biochemical indexes were measured28 days after various treatments. The results showed that 1 224 g（ a. i.） / hm^2 had the best promoting effect,which significantly increased the height of plants,length of roots,stem-leaf fresh weight,dried weight and root fresh weight by 27. 06%,10. 53%,35. 62%,33. 33% and 70. 45% compared to the CK, respectively. The leaf chlorophyll content decreased with the increase of S-metolachlor concentration,but there was no significant difference in leaf chlorophyll content between the concentration range of 383- 1 530 g（ a. i.） / hm^2 and the CK. All treatments with different concentrations could enhance the activity of peroxidase in soybean leaves. At the concentration of 3 060 g（ a. i.） / hm^2,the peroxidase activity was the highest, which increased by 32. 10% compared with the CK. At theconcentrations of 765 g（ a. i.） / hm^2 and 1 224 g（ a. i.） / hm^2,the catalase and superoxide dismutase activity significantly increased. At the concentration of 1 224 g（ a. i.） / hm^2,the catalase and superoxide dismutase activity increased by 20. 72% and 2. 88% compared with the CK,respectively. These results indicated that the treatment of S-metolachlor with a certain range of concentrations before seedling emergence significantly promoted the soybean seedling growth, and could effectively improve the antioxidant enzyme activities, but it had no significant effect on the synthesis of chlorophyll.S-metolachlor is recommended to use in the soybean fields for its environment-friendliness and high security.