糜子对不同除草剂的生理响应机制研究

为探明除草剂对糜子产量构成因素以及生理特性的影响,筛选适宜半干旱区糜子田使用的除草剂,以齐黍2号为试验材料,利用4种不同除草剂各设置3个浓度梯度进行糜子苗后喷施处理,研究了处理7、14和21d后糜子光合、生理特性及农艺性状的变化。结果表明,随着除草剂浓度的升高,糜子叶片的超氧化物歧化酶（SOD）活性、游离脯氨酸（Pro）和丙二醛（MDA）含量均呈上升趋势;随着除草剂胁迫时间延长,糜子叶片中SOD活性、Pro和MDA含量呈先上升后下降的变化趋势。4种供试除草剂处理后,糜子叶片的叶绿素相对含量、净光合速率、气孔导度和蒸腾速率均有不同程度降低,且都表现出一定的剂量效应。除草剂对糜子农艺性状及产量的影响不同,对主茎粗影响较小,对分蘖有促进作用,对主茎高、千粒重、主穗粒重、主穗重及产量有抑制作用。在本试验条件下,50% 2,4-D异辛酯对糜子生理及光合作用的影响较小,比较安全;苗后喷施50% 2,4-D异辛酯1000mL/hm²是糜子田除草最适剂量。

Study on the Physiological Response of Broomcorn Millet to Different Herbicides

In order to find out the effect of herbicides on yield components and physiology characteristics of broomcorn millet, and to screen out herbicides suitable for broomcorn millet fields in semi-arid areas, Qishu 2 was used as material and treated with four different herbicides. The photosynthetic indices, physiological indexes in leaves and agronomic characteristics of broomcorn millet were analyzed in 7, 14, 21 days after treatment. Results showed that with the increase of herbicide concentration, SOD activity, Pro and MDA contents in the leaves increased. With the extension of herbicide stress time, SOD activity, Pro and MDA contents in the leaves increased first and then decreased. After spraying four kinds of herbicides, chlorophyll content, net photosynthetic rate, stomatal conductance and transpiration rate were all decreased. The sensitivity of broomcorn millet to the four herbicides tested was different. Herbicides had different effects on agronomic traits and yield. Herbicides had little effect on stem diameter, but promote tillering. The main stem height, 1000-grain weight, main ear grain weight, main ear weight and yield under each treatment were lower than those of the control, which indicated that herbicides had inhibitory effect on yield components. Under the experimental conditions, spraying 50% 2,4-D isooctyl ester was safer for its the least stress on physiological and photosynthetic characteristics of broomcorn millet. Spraying 50% 2,4-D isooctyl ester at 1000mL/ha after seedling was the optimum dose in broomcorn millet field.