夏季高光下入侵植物三裂叶蟛蜞菊叶片变红的生理功能  

Physiological functions of the red leaves of Wedelia trilobata induced by high irradiance in summer

作　　者：宋莉英[1] 孙兰兰[1] 舒展[2] 李伟华[1] 彭长连[1] 

机构地区：[1]华南师范大学生命科学学院,广东省高等学校生态与环境科学重点实验室,广州510631 [2]中国科学院上海生命科学研究院植物生理生态研究所,上海200032

出　　处：《生物多样性》2009年第2期188-194,共7页Biodiversity Science

基　　金：国家科学自然基金(30870385);广东省自然科学基金(8451063101000535);中国博士后基金(20080440766);广东省科技计划项目(2008A030203006)

摘　　要：三裂叶蟛蜞菊(Wedelia trilobata)是世界最有害的100种外来入侵种之一,现已在我国东南沿海地区广为分布,并造成危害。我们对其野外种群的观察发现,在夏季光照强烈的生境中,其叶片常常有变红的现象。本研究针对这一现象,从叶片花色素苷含量的变化入手,探讨了三裂叶蟛蜞菊叶片变色的原因及其生理功能。结果表明,红叶中的花色素苷含量显著高于绿叶(P<0.05),夏季高光照诱导的花色素苷的积累是叶片由绿色变为红色的主要原因。由于花色素苷含量较高,红叶的总抗氧化能力增强,在甲基紫精(MV)光氧化处理过程中,红叶的最大光量子产量(Fv/Fm)和实际光量子产量分别下降了28.2%和79.1%,显著低于绿叶的下降幅度(70.9%和93.8%)。这一结果表明,三裂叶蟛蜞菊在夏季遭受强光胁迫时,叶片由绿色变为红色增强了对氧化逆境的耐受能力,而相同环境下的本地蟛蜞菊(W.chinensis)并没有叶片变红的现象,暗示这可能是入侵植物三裂叶蟛蜞菊抵御和适应夏季高光的一种特殊的生理机制。Wedelia trilobata, a creeping herb native to Central and South America, is one of the world＇s 100 worst invasive alien species. It was introduced into South China and has become a noxious invasive weed in agricultural fields, plantations and natural forests. In natural communities, it is observed that the leaves of W. trilobata turn from green to red under high irradiance in summer. The aims of this study were to explore what causes the leaf color change in W. trilobata and what the physiological consequences are. Anthocyanin content was significantly higher in red than in green leaves of W. trilobata, suggesting that the accumulation of anthocyanin at high irradiance was related to the leaf color change. The increased content of anthocyanin contributed to a higher total antioxidant capability in red W. trilobata leaves. Consistent with the higher antioxidant capability, decreases in maximum quantum efficiency of photosystem II photochemistry and the effective PSII quantum yield caused by artificial photo-oxidative stress were respectively smaller in red （28.2% and 79.1%） than in green leaves of W. trilobata （70.9% and 93.8%）. Leaf color change was not observed in native W. chinemis. Our results suggest that the color change may be a physiological mechanism employed by the invasive W. trilobata to acclimate to high irradiance in summer.

关 键 词：Wedelia trilobata 花色素苷 甲基紫精 光氧化 叶绿素荧光 适应机制 

分 类 号：Q945[生物学—植物学]