Effects of Sulfonylurea Herbicides on the Seedling Growth of Corn (Zea mays L.)Plants

硫醯尿素類除草劑對玉米幼苗生長之影響

王慶裕(Ching-Yuh Wang)

《中華民國雜草學會會刊》 18卷1期 (1997/10) Pp. 29-39

https://doi.org/10.6274/WSSROC-1997-018(1)-029

摘要

本研究主要目的在比較台灣地區現行三種硫醯尿素類（sulfonylureas）除草劑bensulfuron-methyl, pyrazosulfuron-ethyl及imazosulfuron對於玉米幼苗生長之劑量反應，並討其差異性傷害之原因。本試驗以玉米台農一號（TN1）為材料，於四葉期分別在盆缽土中施用0、3.9、7.8、15.6、31.3、62.5、125、250及500g a.i/ha之劑量，於處理後三週利用劑量與植株反應關係之log-logistic分析模式，結果發現玉米幼苗之株高生長受到pyrazosulfuron-ethyl顯著抑制，其GR50約為4.8-7.3 g a.i/ha，對其他二種除草劑之反應較不敏感。此外，由乾重變化分析顯示，bensulfuron-methyl與pyrazosulfuron-ethyl之GR50劑量相近，分別為9.7及14.9 g a.i/ha，而imazosulfuron則為44.3 g a.i/ha，但仍以pyrazosulfuron-ethyl造成之下限（lower limit）值最低，顯示pyrazosulfuron-ethyl抑制幼苗乾重之幅度最大，bensulfuron-methyl次之，imazosulfuron最小。進一步以20 g a.i/ha之劑量處理，於處理後一週起幼苗乾物質生產開始受到抑制，至第三週時imazosulfuron、bensulfuron-methyl及pyrazosulfuron-ethyl處理者分別降為對照處理之87、83及67%。分析葉部之游離胺基酸，則顯示其在處理後一週內分別降至30、41及77%，隨後逐漸恢復，似乎游離胺基酸之含量變化無法直接反出三種除草劑抑制玉米生長的程度差異。由於硫醯尿素類除草劑主要係抑制支鏈胺基酸合成，故本試驗進一步分析，但發現valine含量並無明顯變化且略有增加，而isoleucine則在三種除草劑處理後一週內降至40-55%，其中bensulfuron-methyl處理三週後降至25%。至於leucine則以imazosulfuron處理者降低20%，而bensulfuron-methyl及pyrazosulfuron-ethyl處理者均降至40-46%。故推測三種除草劑於處理後一週內leucine與isoleucine含量下降，可能直接影響生長抑制效果。

關鍵字

硫醯尿素類除草劑 ； 玉米 ； 生長抑制 ； 支鏈胺基酸

並列摘要

Sulfony lurea herbicides are used primarily for rice weed control in Taiwan, but are seldom used on other land-crops. The study estimates the damage of seedling growth of corn plants caused by three sulfonylureas, i.e. bensulfuron-methy1, pyrazosulfuron-ethy1 and imazosulfuron. Corn, cv. Tainung No.1 (TN 1), was used as materials and various rates of the herbicides were applied into soil directly at the 4th leaf stage. The dose-response of plant height was calculated by the log-logistic function and the results indicated that plant height was significantly inhibited by pyrazosulfuron-ethy1 with 4.8-7.3 g a.i/ha of GR50 but little affected by other two sulfonylureas. In addition, the dose-response curve of plant dry matter production against three sulfonylureas showed the 9.7, 14.9 and 44.3 g a.i/ha of GR50 for bensulfuron-methy1, pyrazosulfuron-ethy1 and imazosulfuron, respectively. Also the lower limit of the response curve was largely declined for pyrazosulfuron-ethy1 by 84% of the upper limit. Furthermore, the experiment using 20g a.i/ha of sulfonylurea herbicides revealed that dry matter production started to be inhibited after one week and inhibited significantly to 87,83 and 67% for imazosulfuron, bensulfuron-methy1 and pyazosulfuron-ethy1,respectively, three weeks later. However, together with that free amino acids of leaves were declined to 30, 41 and 77% for imaosulfuron, bensulfuron-methy1 and pyrazosulfuron-ethy1 within one week, these changes of free amino acids apparently could not reflect the inhibition degree of seedling growth. In this experiment, the valine content was not influenced by sulfonylureas but bensulfuron-methy1 declined the isoleucine to 40-55% within one week and eve to 25% after three weeks. Besides, leucine was slightly decreased, ca.20%, by imazosulfuron and was decreased to 40-46% by bensulfuron-methy1 or pyazosulfuron-ethy1. The significant decreases of leucine and isoleucine within one week after treatment may possibly be related to the inhibition of seedling growth.

並列關鍵字

Sulfonylurea ； Herbicide ； Corn ； Growth inhibition ； Branched-chain amino acids