Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/37064
標題: 玉米幼苗不同生育期對免速隆除草劑之反應及自交系之耐性研究
Tolerance mechanism of corn seedlings to bensulfuron-methyl herbicide between -tolerant and -susceptible lines of inbred corn
作者: 劉哲偉
Liu, Tse-Wei
關鍵字: bensulfuron-methyl
免速隆
corn
tolerance
herbicide
acetolactate synthase
玉米
耐性
除草劑
乙醯乳酸合成酵素
出版社: 農藝學系
摘要: 驗目的為探討免速隆(bensulfuron-methyl)對玉米現行栽培種臺農一號幼苗不同生育時期生長及其生理反應之影響,結果顯示不同生育期中以V0期之幼苗處理7天後對免速隆除草劑的抑制作用最為敏感,尤其株高反應最為敏感。不同濃度免速隆處理下,台農一號不同葉齡幼苗中以VE期(芽鞘三公分)期幼苗之乙醯乳酸合成酶活體外比活性最高,且與免速隆濃度之關係呈一典型之劑量反應曲線;隨著發育年齡ALS比活性減少,因此推測ALS酵素比活性高低以及其對免速隆之敏感度不同,可能為造成玉米不同葉齡幼苗對免速隆除草劑敏感性不同之生理機制。 玉米自交系VE期(芽鞘三公分)幼苗經免速隆處理七天後,調查株高受到抑制的程度分別選出SIW 35及SIW 60為耐性及感性之自交系,作為探討免速隆耐感性差異原因之材料。免速隆對耐性自交系(SIW 35)及感性自交系(SIW 60)株高之半抑制劑量(ED50)分別為236.7 μM及0.7 μM。由於感性自交系SIW 60對於BSM吸收量最少。轉運至地上部方面,感性自交系SIW 60與其他二耐品系並無明顯差別;另一方面,免速隆在植體內累積方面,感性自交系SIW 60幼苗根部中免速隆之累積量較其他兩品系高,而且在代謝方面,由TLC分析免速隆及其極性代謝物結果顯示,感性自交系SIW 60代謝免速隆而產生之代謝物Ι及Π的量較臺農一號及耐性自交系SIW 35低顯然代謝能力低可能影響玉米SIW60之感性。 玉米不同耐感自交系幼苗在不同濃度免速隆除草劑處理下,測定其活體外乙醯乳酸合成酶比活性,結果顯示免速隆對耐(SIW 35)、感(SIW 60)自交系VE期(芽鞘三公分)幼苗之活體外ALS比活性的半抑制劑量分別為21±12 μM及3.9±1.2 nM,由此可知,ALS酵素對於BSM之親和力及敏感度可能也是不同自交系之間免速隆耐感性差異的原因。
Bensulfuron-methyl (BSM) is usually used in weed control for rice crops. This study was conducted to investigate the dose-response to bensulfuron-methyl (BSM) for seedling growth of corn and to understand the possible mechanism of BSM tolerance occurred in inbred lines of corn. The dose-response to BSM for seven growth traits including leaf development, plant height, root length, fresh and dry weight of shoot and root, of corn seedlings at 5 early growth stage including VE(coleoptile was 1 cm), VE(coleoptile was 3 cm), V1(1-leaf), V2(2-leaf) and V3(3-leaf) stages were investigated. As a result of dose-response analysis for the growth of seedlings at the VE(coleoptile was 3 cm) stage seven days after treatment, plant height was the most susceptible growth trait to BSM. Analysis of the in vitro specific activity of acetolactate synthase (ALS) in corn, cv. TNG-1, seedlings at 4 different growth stages, showed that the highest activity expressed at VE(coleoptile was 3 cm) stage. However, ALS activity was relatively declined with the growth stage. The specific activity of ALS in seedlings at V3 stage is lesser sensitive to BSM than that at early growth stage. Thus, it is suggested that the sensitivity of ALS activity to BSM might be involved in the mechanism of BSM tolerance of the corn seedlings existed at different growth stage. According to the inhibition of plant height of corn seedlings at VE(coleoptile was 3 cm) stage by BSM, inbred line SIW 35 and SIW 60 were selected and referred as a tolerant and a susceptible line, respectively. The ED50 of plant height of SIW 35 and SIW 60 was 236.7 and 0.7 μM, respectively. Further study on the absorption, translocation and metabolism of BSM, as well as sensitivity of ALS to BSM, showed that BSM was absorbed more by seedlings of TNG-1 but less by SIW 60. In addition, there was no significant difference in partition of BSM absorbed to shoot, and also found that corn seedlings of TNG-1 and SIW 35 (T) metabolized more BSM to metabolite Ι and Π as compared to SIW 60 (S). Analysis of the in vitro specific activity of ALS, showed that the ED50 of ALS activities in seedlings of SIW 35 (T) and SIW 60 (S) at VE(coleoptile was 3 cm) stage were 21 ± 12 and 3.9 ± 1.2 μM, respectively. And the in vitro activity of ALS in seedlings of TNG-1 was higher than that of SIW 35 (T) and SIW 60 (S). Therefore, it is suggested that the sensitivity of ALS to BSM was a key factor involved in regulation of BSM tolerance between tolerant and susceptible lines of corn.
URI: http://hdl.handle.net/11455/37064
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