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Title: | Tocochromanols 於水稻穀粒萌發時期之功能研究 Functional Study of Tocochromanols in Rice Grain during Seedling Emergence |
Authors: | Tsu-Chi Lin 林祖祺 |
Advisor: | 黃良得(Lean-Teik Ng) |
Keyword: | 水稻穀粒,幼苗萌發,生育醇,生育三烯醇,抗氧化系統, Rice grain,Seedling emergence,Tocopherols,Tocotrienols,Antioxidant system, |
Publication Year : | 2014 |
Degree: | 碩士 |
Abstract: | 維生素E包含生育醇 (tocopherol;Toc) 與生育三烯醇 (tocotrienol;T3),兩者亦可合稱為 tocochromanols,為脂溶性之抗氧化物,在人體中具有良好的生理活性。由於 T3 僅存在於少數植物的種子與果實中,且其在植物體中的功能與角色尚不明確,因此有必要深入了解。本研究目的為探討 Toc 及 T3 於兩水稻品種,台農71號 (TN71) 與高雄139號 (KS139) 種子中的功能及其扮演的角色。試驗於水稻穀粒浸潤前 (0 DAI) 及浸潤後的3、6、9、12、15 及 18 天 (DAI) 進行採樣,接著分析水稻之發芽與幼苗生長時期之氧化逆境指標、抗氧化化酵素活性與抗氧化物質含量,以了解 tocochromanols 於種子中之定位以及與種子抗氧化系統之關係,與 T3 存在於種子中之原因。研究結果顯示在水稻穀粒的萌發過程中,其氧化壓力指標濃度、抗氧化酵素活性及抗氧化物濃度在後期 (12 至 18 DAI) 具有較高值;以含量而言,H2O2 及 MDA 含量於穀粒萌發過程中並無明顯之變化,而 ascorbate (AsA) 含量於兩水稻品種穀粒萌發前期具有不同的變化趨勢,生育醇含量於萌發前期逐漸下降,而於中後期出現大量累積,此現象源於 alpha-Toc 於前期的大量消耗,以及 gamma-Toc 於 9 DAI 後的驟增。相較於生育醇,生育三烯醇含量在萌發過程中之變化趨勢較不明顯。然而 alpha-T3 及 gamma-T3 皆有逐漸累積而後消耗之情形,gamma-谷維素含量則於於穀粒萌發前期隨時間而上升,於中後期維持較高之含量。本研究說明,水稻穀粒於萌發過程中,由抗氧化酵素、AsA 及 tocochromanols 組成的抗氧化系統網絡能夠相互協調,維持氧化還原之恆定,而水稻穀粒於萌發之中後期可能進入不同的生長階段,需要較高的抗氧化酵素活性及抗氧化物含量,亦需產生不同型態的 tocochromanols 來滿足不同的生理需求,顯示不同型態的 tocochromanols 在植物體中可能具有不同的功能,而生育三烯醇亦有可能以抗氧化或其他功能參與種子之萌發,使其順利生長。 Tocopherols (Toc) and tocotrienols (T3), collectively known as tocochromanols, are lipid-soluble antioxidants that belong to the group of vitamin E compounds, and possess good physiological activities in human body. Because T3 only present in seeds and fruits of a limited number of plant species, and their functions in plants remain unclear, hence it is necessary to have an insight understanding of their roles. This study aimed to examine the functions of tocochromanols in two rice varieties, namely Tainung 71 (TN71) and Kaoshiung 139 (KS139). Samplings were conducted at 0, 3, 6, 9, 12, 15 and 18 days after imbibition (DAI). The rice grain samples were examined for oxidation stress markers, antioxidative enzyme activities and antioxidant contents, in view of understanding the relationship between the roles of tocochromanols and antioxidant network, and the reason for their T3 present in seeds. The results showed that during seedling emergence, the oxidative markers concentration, antioxidative enzyme activities and antioxidant concentration in late stage (12 to 18 DAI) were higher than early stage. In terms of content, H2O2 and MDA contents were not significantly change in rice seeds. The ascorbate (AsA) content changed in different trends in TN71 and KS139. The Toc content decreased in the early stage but increased significantly in mid-late stage; this situation could be resulted from the expense of alpha-Toc in the early stage and the large accumulation of gamma-Toc after 9 DAI. Unlike Toc, the change of T3 content was not obvious during the seedling emergence. Nevertheless, alpha-T3 and gamma-T3 appeared to increase in contents at 0 to 12 DAI and decrease at 15 to 18 DAI. The gamma-oryzanol content increased in the early stage and maintained of a high level in the late stage. This study indicates that the antioxidative enzymes and contents of ASA and tocochromanols play an important role in the axtioxidant system network, and coordinating with each other to maintain the redox homeostasis during seedling emergence. The rice seeds may enter a different growing phase in the mid-late stage of seedling emergence that may need potent anioxidative enzyme activities and high amount of antioxidant, as well as the different forms of tocochromanols for fulfilling the requirement of different metabolisms, suggesting that tocochromanols have different functions in plants. As for tocotrienols, they may involve in seedling emergence through functioning as antioxidants or providing other functions in assisting the growth of seedlings. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/55299 |
Fulltext Rights: | 有償授權 |
Appears in Collections: | 農業化學系 |
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