两种不同矮蔓型西葫芦冠层光合特性的差异分析

PHOTOSYNTHETIC CHARACTERISTICS DIFFERENCE OF TWO DWARF TYPE ZUCCHINIS (Cucurbita pepo L.)

在日光温室自然光照下,对2个半矮蔓和2个矮蔓西葫芦品种的光合速率与光合参数的变化及光响应进行了研究。结果表明,西葫芦净光合速率(Pn)和蒸腾速率(Tr)的日变化皆呈单峰曲线,水分利用率(WUE)变化呈双峰曲线,其中半矮蔓品种不同生育期的Pn、午后Tr及WUE都高于矮蔓品种。不同矮蔓型西葫芦冠层的光合速率的差异可以用光合叶位差(PDLP)和光合时间差(PDDT)来表示,半矮蔓品种的PDLP和PDDT显著低于矮蔓品种(苗期除外),表明半矮蔓品种耐强光,植株碳同化能力强于矮蔓品种;结瓜期半矮蔓品种午后强光下叶温低于矮蔓品种,是其Pn较高的原因之一。半矮蔓品种C3的光饱和点为1265.0μmol·m-2·s-1,补偿点为30.4μmol·m-2·s-1,最大光合速率为31.4μmol·m-2·s-1,表观量子效率(AQY)为0.0524mol·mol-1,矮蔓品种D4的光饱和点为1162.5μmol·m-2·s-1,补偿点为44.8μmol·m-2·s-1,最大光合速率为25.6μmol·m-2·s-1,表观量子效率为(AQY)0.0457mol·mol-1。与矮蔓品种相比,半矮蔓品种冠层耐强光和弱光的能力强。

Under natural light of solar greenhouse,net photosynthetic rate（Pn）,photosynthetic parameters and light response of photosynthesis in leaves of the two semi-dwarf and two dwarf zucchini varieties were studied.The results showed that diurnal variations of Pn and transpiration rate（Tr） of zucchini exhibited single-peak curve,and the change of water use efficiency（WUE） was presented by bimodal curve.The Pn and Tr in the afternoon and WUE of semi-dwarf varieties were higher than those of the dwarf varieties in different growth stages.The differences in Pn of different dwarf zucchini types could be expressed by percentage of photosynthetic disparity in leaf position（PDLP） and photosynthetic disparity in daily time（PDDT） of photosynthetic rate.The PDLP and PDDT of semi-dwarf varieties spread were significantly lower than those of drawf varieties（excuding the seedling stage）,indicating that the semi-dwarf varieties was resistant to light because of lower leaf temperature in the afternoon and stronger carbon assimilation capacity of plants.The light saturation point（LSP）of semi-dwarf varieties spread Changqingwang 4 was 1265.0μmol·m-2·s-1,the compensation point（LCP） was 30.4μmol·m-2·s-1,the maximum rate of photosynthesis（Pmax） was 31.4μmol·m-2· s-1,the apparent quantum efficiency（AQY） was 0.0524mol·mol-1.The same indices of dwarf varieties spread D4 were LSP 1162.5μmol·m-2·s-1,LCP 44.8μmol·m-2·s-1,Pmax 25.6μmol·m-2·s-1 and AQY 0.0457mol·mol-1.Compared with dwarf varieties,semi-dwarf varieties were more resistant to glare and low light.