阿拉伯芥 Heptahelical Protein 1參與離層酸造成之氣孔及主根反應研究

Studies on the Involvement of Arabidopsis thaliana Heptahelical Protein 1 in Stoma and Primary Root Responses to Abscisic Acid

李源芳(Yuan-Fang Li)

指導教授 ： 楊健志

國立臺灣大學/生命科學院/生化科技學系/碩士(2012年)

https://doi.org/10.6342/NTU.2012.02046

摘要

為瞭解 HHP1 在離層酸作用的影響及方式，測試突變株 hhp1-1氣孔對避光處理、離層酸及其下游訊息分子 H2O2 與一氧化氮的反應，以及離層酸處理主根生長受抑制的程度。氣孔行為實驗中，避光、離層酸、H2O2 或一氧化氮處理之下，野生株及hhp1-1的氣孔均產生反應而縮小。然而，在光照及避光的處理之下，hhp1-1 氣孔寬度都較野生株為大，顯示 hhp1-1 的氣孔可能有開口較大現象，推測 HHP1影響保衛細胞離子進出平衡。
三次獨立實驗以離層酸處理的結果再現性不佳，尚不能推測 hhp1-1 的氣孔行為對離層酸敏感性有何不同。而離層酸訊息傳遞的兩個下游訊息分子H2O2及一氧化氮造成野生株及 hhp1-1 氣孔開口縮小的現象並無顯著差異，因此推測，如果 hhp1-1 的氣孔行為對離層酸較不敏感，HHP1應是作用於H2O2 及一氧化氮上游的訊息傳遞。
主根生長實驗則發現 hhp1-1受離層酸抑制明顯小野生株，因此推測HHP1促進離層酸抑制主根生長的生理作用。
本論文的主要發現在於 HHP1 可能參與離層酸抑制主根生長調控，及在離層酸引發氣孔關閉訊息傳導路徑，HHP1 可能作用於 H2O2 和一氧化氮上游。然而離層酸處理則因實驗再現性較不穩定，無法推測 hhp1-1 氣孔是否有不同的敏感性。而 HHP1 如何調控離層酸訊息傳遞的生理作用，有待後續實驗釐清。

關鍵字

離層酸 ； 訊息傳遞 ； 氣孔 ； HHP1 ； 一氧化氮 ； 阿拉伯芥

並列摘要

To understand the involvement of HHP1 in ABA responses in this study, stomatal behavior was examined using hhp1-1 with known stomatal regulator, hydrogen peroxide and nitric oxide. The inhibition of primary root growth by ABA was also examined.
Dark-, ABA-, H2O2-, or NO-induced stomatal closure were observed in both wild-type and hhp1-1. The mutant hhp1-1 was found to have larger stomatal aperture width than wild-type in the absence of regulators, indicating the altered balance of ion strength in guard cells by the loss of HHP1.
The three independent experiments of ABA treatment didn’t show good consistency, so it would not be able to tell whether hhp1-1 stoma has different sensitivity to ABA. The induced stomatal closure by the treatment of H2O2 and NO did not show significant differences between wild-type and hhp1-1 plants. It is suggested that HHP1 acts upstream of H2O2 and NO in the signaling of ABA in guard cells, if hhp1-1 does have less sensitivity in stomatal ABA response.
It was also found that the elongation of primary roots inhibited by ABA is less severe in hhp1-1 mutants than in wild-type plants, indicating that HHP1 promotes the ABA-induced inhibition of primary root elongation.
HHP1 might be involved in ABA-inhibited primary root growth, and HHP1 might act upstream of H2O2 and NO in ABA response in guard cells. Due to the inconsistency in the results of ABA-treated stomatal behavior, the sensitivity of hhp1-1 to ABA in stomatal response was unknown. Improvement is still required to further investigate how HHP1 regulates the ABA responses in plants.

並列關鍵字

abscisic acid ； signal transduction ； stoma ； heptahelical protein 1 ； nitric oxide ； Arabidopsis thaliana

參考文獻

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