Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/37062
標題: 水稻幼苗對過量UV-B輻射之反應及其耐感性差異的比較
Responses of rice seedling to excess UV-B radiation and comperison between tolerance and susceptible cultiver
作者: 周昶汎
CHOU, CHANG-FAN
關鍵字: UV-B
紫外線
antioxidant
tolerance
susceptible
抗氧化系統
耐性
感性
出版社: 農藝學系
摘要: 本試驗的主要目的在於探討水稻幼苗遭受過量的UV-B照射後,其植株形態及生理反應的變化,包括植株生長高度、植株鮮重、乾重、葉綠素含量、光合作用、電解質滲漏、丙二醛含量以及抗氧化酵素活性和抗氧化物的含量。並從186個由行政院農委會農業試驗所農藝系種源庫所提供的水稻品種中,篩選出對過量UV-B輻射具有耐性及具有感性的品種,希望藉由比較耐性水稻及感性水稻之幼苗在過量UV-B照射處理下,其植株形態變化及生理反應的不同,以便於瞭解耐感性差異的原因,用以作為日後有關植物與UV-B方面之研究的參考。 試驗項目分為:一.台農67號水稻幼苗對過量UV-B照射的反應;二.耐性與感性水稻品種的選拔;三.耐、感性水稻幼苗對過量UV-B照射的反應。試驗的材料為各受試品種之三葉期幼苗。UV-B的照射處理則是以UV-B燈管做為外加的人工UV-B光源,且依處理的不同,有不同的照射時間及輻射強度。 試驗結果顯示UV-B的照射處理會抑制水稻植株株高的生長、減少水稻的鮮重、抑制水稻乾重的累積、降低葉綠素的含量、抑制光合作用進行的效率、破壞葉片上表皮氣孔、丙二醛含量及電導度的增加。在抗氧化系統方面,超氧歧化酶、抗壞血酸過氧化酶及穀胱苷還原酶的活性在處理第一天會增加,之後便開始下降增加,抗壞血酸、還原態穀胱苷及氧化態穀胱苷的含量則隨著處理時間而略有增加。 此外,發現水稻對UV-B輻射的耐感性有遺傳上的差異,因此經由選拔選出耐性水稻品種M202、Macan Binong pate及感性水稻品種Odashiroho、Dular。無論是耐、感性品種,當其遭受稻過量的UV-B照射時皆會造成傷害反應,惟感性品種的傷害程度大於耐性品種,秈稻的程度大於稉稻。耐性品種的超氧歧化酶、抗壞血酸過氧化酶及穀胱苷還原酶的活性皆較感性品種為高。穀胱苷及抗壞血酸的含量會隨UV-B照射時間而增加,耐性品種的相對增加量較感性品種大。 若將秈稉稻耐、感性品種遭受過量UV-B照射後所發生的傷害反應,與照射後產生的抗氧化系統防禦作用相比較,推測水稻幼苗對UV-B輻射的耐性機制,可能還包括其他的因素在內。
The purpose of this study is to explore the physiological and morphological responses of rice seedlings exposed to the excess UV-B irradiation. Further, to screen the UV-B tolerant and susceptible rice cultivar from 186 rice varieties and compare the physiological and morphological responses of UV-B tolerant and susceptible rice cultivars to find the possible mechanism of UV-B tolerance in rice plants. Three experiments were performed in this study, the first part was a series of morphological and physiological responses were conducted as cultivar TNG-67 V3-seedling exposed to excess UV-B irradiation. Second trial was screening the UV-B tolerant and susceptible rice cultivars. And subsequently, the last part was compared the physiological and morphological responses of tolerant and susceptible rice cultivars to excess UV-B irradiation. Plant materials were planted in growth chamber and treated at V3-seedling. The excess UV-B irradiation treatment was supplied by the UV-B lamps. Experimental results indicated that exposed to the excess UV-B irradiation affects the growth of rice plant with reduction in plant height, fresh weight, and dry weight, decreased the content of chlorophyll, decreased photosynthetic capacity, damaged stomata structure, and incresed malondialdehyde content and electrolyte conductivity. The enzymatic antioxidants ( superoxide dismutase, ascorbate peroxidase and glutathione reductase ) activity were increased at the first day of UV-B exposure, and then decreased during the treatment period. However, nonenzymatic antioxidants content of ascorbic acid, reduced form glutathione and oxidized form glutathione of rice seedling were increases of the V3-seedling after exposure of excess UV-B irradiation. As a result of screening the UV-B tolerant and susceptible cultivar of rice, cultivars M202 and Odashiroho were referred to tolerant and susceptible rice cultivar among japonica type rice, as well as the Macan Binong pate and Dular were referred to tolerant and susceptible rice cultivar among indica type. Both tolerant and susceptible rice cultivars expressed damaged under excess UV-B exposure, the tolerant rice cultivars were suffered from little damaged under excess UV-B exposure as compared to susceptible rice cultivars, and the japonica type rice were suffered a less damaged than indica type rice. The activities of enzymatic antioxidants from tolerant rice cultivars were higher than susceptible rice cultivars, and the nonenzymatic antioxidants content of tolerant rice cultivars were larger than those of susceptible rice. Finally, comparison the injury response and antioxidant activity of rice seedling exposed to excess UV-B irradiation, it is suggested that the UV-B tolerance mechanism of rice not only depend on antioxidant system, the other factors will be involved.
URI: http://hdl.handle.net/11455/37062
Appears in Collections:農藝學系

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