|
|
- 2018
植物源羊脂酸除草活性及其响应机制
|
Abstract:
为研制新型植物源除草剂，需从植物中筛选具有除草活性的天然产物，本研究将椰子经物理压榨成椰子油，椰子油经皂化、酸化、蒸馏分段，再经气质联用仪鉴定其中具有除草活性的产物，并采用室内生测法和田间药效试验对该产物的除草活性进行评价，测定其在不同光照和浓度条件下对小飞蓬Conyza canadensis的3种防御酶——L-苯丙氨酸解氨酶、多酚氧化酶和过氧化物酶活性的影响。结果表明：从椰子油中筛选的具有除草活性的产物经鉴定为羊脂酸，气质色谱图中保留时间为6.20 min。羊脂酸具有较高的除草活性，EC50为14.07 mg/L，100 mL的20%羊脂酸水乳剂喷施后15 d对20 m2非耕地杂草的株防效和鲜重防效分别为90.25%和90.37%，即与对照药剂草甘膦异丙胺盐水剂除草效果相当。低浓度羊脂酸对小飞蓬的防御酶活性影响不显著，较高浓度下L-苯丙氨酸解氨酶活性显著上升，多酚氧化酶和过氧化物酶活性显著下降，当光强为100~120 μmol·m-2·s-1、温度为18~20℃时，这种变化在完全黑暗条件下较完全光照条件下更为明显。表明羊脂酸除草机理可能与其抑制杂草的光合作用有关。
In order to develop novel botanical herbicides, the natural products from plant with herbicidal activities were screened. Coconut were physically crushed to produce coconut oil, after saponification and acidification, coconut oil was distillated to several parts. The herbicidal part was identified by GSMS and evaluated by laboratory and field efficacy trials. The antioxidant enzyme (L-phenylalanin ammo-nialyase, polyphenol oxidase, peroxidase) activities of Conyza canadensis was measured after caprylic acid treatment at different concentrations and under varying light intensities. The results showed that the herbicidal part from coconut oil was identified to caprylic acid on GS-MS total ion chromatogram (6.20 min). The caprylic acid has good herbicidal activity (EC50=14.07 mg/L). The control effects on the plant number and fresh weight reached 90.25% and 90.37% in a 20 m2 field after 15 d caprylic acid EW application. Caprylic acid at low concentrations has no significant influenced on antioxidant enzyme activities in C. canadensis leaves. However, higher concentration of caprylic showed significant increasing on L-phenylalanin ammo-nialyase activity and significant decreasing on peroxidase and polyphenol oxidase activities. The effects on the three antioxidant activities in the light (24 h illuminations,100-120 μmol·m-2·s-1, 18-20℃) was more signification than in the dark. Therefore, the weed control mechanism of caprylic acid might be due to photosynthesis inhibition in weeds.
