摘要
以黄瓜品种"津优35号"为试材,在温室内设置遮光20%(T1)、遮光40%(T2)和遮光60%(T3)3个处理,处理时间为5、10、15、20、25d,以自然光强为对照(CK),测定不同处理下黄瓜幼龄植株叶片光合参数和荧光参数。结果表明:遮光处理下黄瓜叶片的叶绿素a、叶绿素b和总叶绿素含量均有不同程度增加,叶绿素a/b的值减小,遮光25d后,T3、T2、T1处理的叶绿素a含量较CK分别高30.6%、16.5%、15.4%;不同遮光处理下黄瓜叶片的光饱和点(LSP)、最大光合速率(Pmax)以及表观量子效率(AQE)随着处理天数的增加而减小,光补偿点(LCP)则随处理天数的增加而升高。处理25d后,T1、T2、T3处理的黄瓜叶片气孔导度分别较CK低47.3%、57.4%、57.9%,蒸腾速率分别比CK低34.7%、34.0%和52.4%;随着处理天数的增加,黄瓜叶片的气孔限制值(Ls)和水分利用效率(WUE)均呈增加趋势;遮光处理黄瓜叶片的光系统II潜在效率(Fv/Fm)随着遮光天数的增加呈下降趋势,而光化学淬灭(q P)减小,同时非光化学淬灭(q N)增大。本研究证实遮光导致黄瓜叶片叶绿素含量增加,光合能力降低。
A cucumber cv.‘Jin You35＇was chosen as an experimental material to examine the effects of shading on the photosynthetic parameters and fluorescence parameters of the young cucumber leaves. Four levels of light intensity were set in greenhouse during 25 days which comprise full light intensity（CK）, 20% of full light intensity（T1）, 40% of full light intensity（T2） and 60% of full light intensity（T3）. The results showed that： shading make the content of chlorophyll a, chlorophyll b and total chlorophyll increased in different degrees, while the value of chlorophyll a/b decreases. After shading 25 days, the content of chlorophyll a under the block 60%, 40%, 20% of the light were 30.6%, 16.5%, 15.4% higher than the control treatment respectively. The light saturation point（LSP）, maximum photosynthetic rate（Pmax） and the apparent quantum efficiency（AQE） of young cucumber leaves which under shade processing decreased, while the light compensation point（LCP） increased with the increase of the days of treatment. Treating after 25 days, the stomatal conductance（Gs）of blocking 60%, 40%, 20% of light were 57.9%, 57.4%, 47.3% smaller than the controlled treatment respectively, and the transpiration rates（Tr） were 34.7%, 34.0% and 52.4% lower than the controlled treatment respectively. With the increase of the days of treatment, the stomatal limitation（Ls） and water use efficiency（WUE） of cucumber leaves were shown an increasing trend. The potential efficiency of photosystem II（Fv/Fm） of shading cucumber leaves shown a downtrend roughly with the increased of shading days, and the photochemical quenching（q P） decreased, while the non-photochemical quenching（q N） increased. The study confirmed that shading made the chlorophyll content of cucumber leaves increased, affected photosynthesis.
出处
《中国农业气象》
CSCD
北大核心
2016年第2期222-230,共9页
Chinese Journal of Agrometeorology
基金
国家自然科学基金面上项目(41475107)
"十二五"国家支撑计划项目(2014BAD10B07)
关键词
弱光
黄瓜
叶绿素
光合特性
荧光参数
Low light level
Cucumber
Chlorophyll
Photosynthetic characteristics
Fluorescence parameters
