Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/36752
標題: 水稻不同品系幼苗對本達隆除草劑之抗感反應
Resistance mechanism of rice seedlings to bentazon herbicide among rice lines
作者: 韓岳麒
Han, yueh-chi
關鍵字: rice
水稻
bentazon
Resistance mechanism
本達隆
反應機制
出版社: 農藝學系
摘要: 本論文試驗主要目的為探討防除水田及落花生田中雜草的本達隆除草劑,其對水稻現行栽培種TNG67幼苗生長的影響及不同類型水稻抗感品系的敏感性差異之生理原因。根據TNG67幼苗生長至V3期之株高、地上部鮮重、總葉綠素、葉綠素a及葉綠素b此五性狀對本達隆除草劑的劑量反應,選定各性狀EC50之平均值,約98.8 mM濃度,處理供試品系,並於藥劑處理後0、1、3、5及7天取樣作各項生理分析。 在水稻秈稻品系的篩選中,分別選定M202及FSK作為稻抗感品系,而以TCSW1及IR36作為秈稻抗感品系。此秈稻抗感四品系和對照之TNG67,經本達隆處理後所產生的可見性傷害、葉綠素螢光釋放量及MDA的累積有明顯差異。其中對本達隆較具有抗性之稻品系M202及TNG67在可見性傷害等級、光系統Ⅱ之活性及細胞膜受傷害之情形皆小於秈稻感性品系IR36及FSK,而本達隆對秈稻抗性品系TCSW1之各項傷害情形則介於稻抗性品系M202及秈稻感性品系IR36及FSK之間。 進一步分析不同秈稻抗感品系對本達隆敏感性差異之原因。試驗結果顯示,對本達隆較具抗性的M202、TNG67雖吸收較多14C-bentazon,但其體內之14C-同位素大部分會累積在處理葉片內或轉運至老葉中累積,同時發現其體內本達隆殘留量較少、殘留之本達隆生物毒性較低及具有較多的極性代謝物,其中M202體內更測出羥基化之本達隆(bentazon-6-OH),顯示稻抗性品系M202及TNG67對本達隆具有較高的代謝能力。在秈稻感性品系IR36及FSK方面,此二品系對14C-bentazon的吸收隨處理時間增加而增加,其吸收之14C-同位素會轉運至心葉中累積,可能因此易造成幼苗的死亡。在代謝部分則發現此二品系體內殘留之本達隆較多,生物毒性也較高,其產生之極性代謝物明顯較秈稻抗性品系M202及TCSW1低,顯示秈稻感性品系IR36及FSK對本達隆的代謝能力較弱。 綜合本論文試驗結果可知,供試五品系中稻抗性品系M202及TNG67,雖然對14C-bentazon之吸收較感性品系FSK及IR36多。但在轉運及代謝部分,發現M202及TNG67會將所吸收之14C-同位素累積在處理葉片及老葉中且其體內殘留的本達隆較少,顯示M202及TNG67主要對本達隆具有較高的代謝能力,因此才造成其對本達隆具有抗性。
Bentazon is usually used in weed control for rice and peanut crops. If the growth of rice, cv. TNG67, seedlings was affected and how the physiological response was influenced by bentazon, especially for the resistant- and the susceptible-lines among Japonica- and Indica-type rice, were investigated. According to the dose-response to bentazon of five growth characters including plant height, shoot fresh weight, total chlorophyll, chlorophyll a and chlorophyll b of TNG67 seedlings at the V3 stage, the effective concentration of leaf-applied bentazon causing 50% reduction of response (EC50) was determined. And further study on the physiological resistant mechanism existed in bentazon-resistant and -susceptible lines of rice under this concentration of bentazon was conducted. As a result of screening the bentazon-resistant and —susceptible lines of rice, lines M202 and FSK are referred to resistant- and susceptible-line, respectively, among Japonica-type rice, as well as the TCSW1 and IR36 are referred to resistant- and susceptible-line among Indica-type, respectively. The bentazon-resistant line, M202, and TNG67 were suffered from little or a slight visible injury, photosynthesis inhibition and accumulation of MDA after bentazon application compared to other lines. Further analysis of the physiological mechanism of resistance for the bentazon-resistant and -susceptible lines among Japonica- and Indica-type rice was conducted. Experimental results indicate that the resistant line of Japonica-type, M202 and TNG67, absorbed more 14C-bentazon, but most of 14C-isotopes absorbed either accumulated in bentazon-treated leaf or translocated out of the treated leaf to older leaves subsequently. It is also found that the phytotoxicity resulted from residual bentazon and its metabolite was slight in these two rice lines. The hydroxybentazon (bentazon-6-OH) could be detected in the bentazon-resistant rice lines, M202, but not in other rice lines, indicating that M202 and TNG67, especially for the former line had stronger ability to metabolite more bentazon. For the bentazon-susceptible lines, FSK and IR36, which absorbed less 14C-bentazon during treatment but most of the 14C-isotopes absorbed translocated out of treated leaf and accumulated in young leaves subsequently. More accumulation of bentazon at the younger leaf might result in death of rice seedlings. In addition, more residual bentazon and stronger phytotoxicity were also confirmed in these two bentazon-susceptible lines. And less polar metabolite was obtained. This result indicates that the bentazon-sensitivity of FSK and IR36 were due mainly to the lower ability of bentazon metabolism. Reviewing the experimental results of this study, it suggested that the bentazon-resistant mechanism existed in resistant lines, M202 and TNG67, is primarily result from the stronger metabolism of bentazon, especially the generation of bentazon-6-OH for the line M202. Besides, that the most of absorbed bentazon translocated to older leaves and/or deposited at the site of bentazon application also involved in the resistance mechanism.
URI: http://hdl.handle.net/11455/36752
Appears in Collections:農藝學系

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