PLANT RESPONSE TO GLYPHOSATE AND ITS 5-ENOLPYRUVYLSHIKIMATE- 3-PHOSPHATE SYNTHASE ACTIVITY

• Main Authors: Chang, Yun Ju, 張韻如
• Other Authors: Tsai, Wen Fu
• Format: Others
• Language: zh-TW
• Published: 1994
• Online Access: http://ndltd.ncl.edu.tw/handle/20297812905947526202

碩士 === 國立臺灣大學 === 農藝學系 === 82 === Glyphosate [N-(phosphonomethyl)glycine] is a nonselective, broadspectrum and postemergence herbicide with potential to control both annual and perennial weeds. It was found recently that a few plant species such as climbing vines, however, have higher tolerance to glyphosate and can not be effectively controlled by the herbicide at recommended rate. The objective of this study was to compare the response of such plants including Trachelospermum gracilipes, Lactuca indica，Taiwan tetrastigma and Commelina undulata to glyphosate. The EPSP synthase activity of these plants was also assayed to elucidate its relationship to glyphosate tolerance. Glyphosate caused significant phytotoxicity on all plant species tested. When sorghum seedlings were treated with 750ppm for 5 days,they became chlorotic and wilting.Leaves of L.indica also showed the same symptoms when treated with 750,1500 and 3000 ppm respectively for 7 days. The new leaves of T. gracilipes only showed wilt when treated with glyphosate.It required high concentration as 3000ppm to cause symptoms on Taiwan tetrastigma. When C.undulata were treated with 750ppm of glyphosate,the basal portion of new leaves was severely chlorotic, and 2000ppm treat- ment would cause the newly opened flower white in color. Different plant species showed different levels of EPSP synthase activity. Although sorghum was more sensitive to gly- phosate,its EPSP synthase activity was higher than T. gracilipes, L.indica, Taiwan tetrastigma and C. undulata. That means that the sensitivity of plant to glyphosate was not determined only by the activity of EPSP synthase. On the other hand, the growth vigor, leaf surface characteristics, and the difference in absorption and translocation of the herbicide may also play an important role in glyphosate tolerance.