| Summary: | 碩士 === 國立中興大學 === 農藝學系所 === 107 === Rice can be divided into four major ecosystems according to its growth environment including irrigated rice, lowland rice, upland rice and deep water rice ecosystem. The different water management required for rice growth in different ecosystems. Due to global climate change, the frequency of flooding of crops has increased, which affects crop production severely. To study the response of different rice ecosystems to submergence stress, the submergence experiments were carried out with two different ecosystems: irrigated rice variety Tai-keng 9 (TK9) and upland rice variety Tung-lu 3 (TL3). It is known in the literature that submergence stress enhances the ethylene signal. Under the premise, these two rice varieties were grown under auxin treatment only, or submergence condition with or without auxin and ethylene signal inhibitor. The extension of the shoot of the TK9 after submergence treatment was higher than TL3, and the shoot elongation caused by submergence treatment was caused by the extension of the second leaf sheath. The extension of TL3 was caused by the elongation of the second leaf body. Comparing the response of these two varieties to submergence, TL3 showed more inhibition of shoot elongation and lamina inclination under the submergence with auxin treatment. But the lamina inclination disappears after the addition of the ethylene signal inhibitor. The analysis of antioxidant enzyme activity showed that, besides the submergence with auxin and ethylene signal inhibitor in the catalase activity, the activity of TK9 was higher than TL3, and there was no significant difference between total peroxidase, ascorbate peroxidase and superoxide dismutase. The enzyme activity between the treatments showed that the total peroxidase activity of the submerged and submergence with auxin treatments increased, while the activities of catalase and superoxide dismutase decreased. And submergence with auxin and ethylene inhibitor showed that the total peroxidase and ascorbate peroxidase activity increased. The comprehensive results show that the low oxygen escape syndrome of the TK9 in submergence stress is stronger than TL3, and the auxin is involved in the ethylene signal pathway under submergence. The interaction between the two hormones in the submergence are significant differences between the upland rice and irrigated rice ecosystems.
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