摘要
为了探究高温胁迫对蝴蝶兰幼苗叶片光合机构的影响,将蝴蝶兰幼苗置于38℃处理4天,以25℃为对照,测定了蝴蝶兰幼苗叶绿素荧光参数的变化。结果表明:随着高温胁迫时间的延长,蝴蝶兰叶片叶绿素总含量、最大光化学效率(Fv/Fm)、有效光量子产量(ΦPSⅡ)、表观光合电子传递速率(ETR)、光化学猝灭系数(qP)持续下降,而丙二醛(MDA)含量、初始荧光(Fo)、非光化学猝灭系数(qN)不断上升。与胁迫前相比,胁迫后期的上述指标均存在显著差异。由此表明,高温胁迫下蝴蝶兰幼苗PSⅡ反应中心出现了可逆失活或损伤,使光合原初反应过程受阻,显著降低了原初光能转换效率,从而引起严重的光抑制,极大地减弱了光合电子传递活性,使反应中心积累过剩光能,对光合机构和叶绿素造成光氧化破坏,但蝴蝶兰幼苗能在一定程度上通过热耗散途径来减轻伤害。
The purpose was to determine the effect of high temperature stress on the photosynthetic apparatus, the change of chlorophyll fluorescence parameters in leaves of Phalaenopsis seedlings were measured when subjected to high temperature stress at 38℃ for 4 d, or 25℃ as a control. The results indicated that the contents of total chlorophyll, the maximal quantum yield of photosystem Ⅱ（Fv/Fm）, actual efficiency of PS Ⅱ electron transport （Фps Ⅱ）, apparent photosynthetic electron transport rates （ETR）, the photochemical quenching coefficient （qp） were continuously decreased with the increasing days of high temperature stress, while the content of malondialdehyde （MDA）, the initial fluorescence （F0） and the complete non-photochemical quenching coefficient （qN） showed a constant increase. At the late stage of high temperature stress, there are significant differences in the above indexes as compared to those before high temperature stressing. It was concluded that PS Ⅱ reaction centre in leaves of Phalaenopsis seedlings were inactivated temporarily or destroyed under high temperature stress so that primary reaction of photosynthesis was be blocked, decreased significantly the efficiency of primary light energy conversion of photosystem Ⅱ, and therefore caused acute photo-inhibition, reduced dramatically photosynthetic electron transport activity, resulted in accumulation of excess energy in PS II reaction centre to cause photo-oxidation damage of the photosynthetic apparatus and chlorophyll. However, Phalaenopsis seedlings could alleviate the photochemical damage through radiationless energy dissipation.
出处
《中国农学通报》
CSCD
2012年第19期177-183,共7页
Chinese Agricultural Science Bulletin
基金
海南省作物学重点学科资助项目"高温胁迫对蝴蝶兰幼苗非酶抗氧化系统及光合机构的影响"
关键词
蝴蝶兰
高温胁迫
叶绿素荧光
光化学损害
Phalaenopsis
high temperature stress
chlorophyll fluorescence
photochemical damage
