南非多肉植物 Anacampseros rufescens 在逆境下葉部花青素與葉綠素濃度與光合作用生理的關係

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2013

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花青素是一種水溶性黃酮類色素,廣泛分布在許多的植物組織而表現出紅或紫等顏色。花青素曾被認為是不具功能的次級代謝物,然而近年來的研究顯示,花青素可以影響植物反應及調適環境逆境的能力。本研究檢測葉花青素濃度與南非沙漠多肉植物Anacampseros rufescens (Harv.) Sweet調適逆境的關係。實驗處理為讓植物生長在高低光及有無缺水環境,透過實驗探討以下三個問題: 1、不 同光度如何影響A. rufescens上下表皮花青素的濃度。2、花青素在光保護作用中所扮演的角色。3、缺水如何影響A. rufescens葉中花青素的濃度與其光保護作用的潛力。 研究結果顯示,生長在高光環境中的植物,花青素濃度與葉綠素螢光值有顯著正相關,但在低光環境則無顯著相關性。缺水處理後,高低光生長的植物花青素及葉綠素濃度無顯著改變。然而在低光生長的植物,最大光化學效率(Fv/Fm)下降,惟下降幅度微小。 總結來說,在高光環境生長的植物其花青素可能有光保護作用,本研究結果無法支持一些研究所指花青素在植物耐缺水所扮演的作用。本實驗結果有助於釐清沙漠多肉植物葉中的花青素所扮演的角色,且有助於了解其在南非沙漠的生物學與生態學特性。
Anthocyanins are water-soluble flavonoid pigments, often having a red or purple color, that occurs in many plant tissues. Although this pigment was originally considered a metabolic waste product, contemporary research has indicated that anthocyanins can significantly influence plant responses and adaptations to environmental stress. This study examined the relationship between leaf anthocyanin concentration and plant responses to environmental stress in the South African desert succulent Anacampseros rufescens (Harv.) Sweet. Plants were grown at high and low light levels under watered and drought treatments. Questions addressed by this study include: 1. How does light level during growth affect the anthocyanin and chlorophyll concentrations of the abaxial and adaxial halves of the leaves of A. rufescens? 2. What is the role of anthocyanin in photoprotection in the leaves of A. rufescens? 3. How does drought stress affect the anthocyanin and chlorophyll concentrations and potential photoprotection in the leaves A. rufescens? Anthocyanin concentrations positively correlated with light-adapted chlorophyll fluorescence in plants grown under high light. This, however, was not true for plants grown under low light. In the drought treatment, anthocyanin and chlorophyll concentrations in the high light and low light -treated plants were not affected by the drought treatment. In the low light treatment, however, Fv/Fm declined after drought, although the decline was small. In summary, the results of this study indicate that anthocyanin likely has a photoprotective function for plants under a high light environment. A specific role of anthocyanin in drought tolerance as reported by several studies was not supported by this study. The results of this study help to clarify a photoprotective role of anthocyanin in leaves of a desert succulent and provide ecophysiological insight into the ecology and biology of this South African desert species.

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花青素, 缺水, 光保護作用, 葉綠素螢光, anthocyanin, drought, photoprotection, chlorophyll concentration

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