不同遮荫条件下罗布麻光合特性的初步研究

The Preliminary Research on Photosynthetic Characteristics of Apocynum venetum under Different Shading

用便携式光合测定仪和叶绿素荧光仪测定了不同遮荫条件下罗布麻叶片的光合参数和叶绿素荧光参数.结果显示:遮荫50%和70%处理较全光照的罗布麻叶片净光合速率(Pn)、蒸腾速率(Tr)和光饱和点(LSP)分别降低47%和65%、45%和68%、20.41%和37.45%,而表观量子效率(AQY)分别提高33%和36%;不同遮荫下罗布麻的叶绿素荧光参数PSⅡ原初光能转化效率(Fv/Fm)和PSⅡ潜在活性(Fv/Fo)均比全光照降低.研究表明,罗布麻虽对弱光有一定适应能力,但遮荫仍产生明显的弱光抑制而显著降低其光合效率,影响其正常生长.

Photosynthetic parameters and chlorophyll fluorescence index was measured with CIRAS-1 portable photosynthesis measurement system and OS1-FL chlorophyll fluorometer. The results showed that the photosynthetic rate （Pn） ,transpiration rate （Tr） and light saturation point （LSP） are all higher in full day light intensity than that in shading intensity （compared to 50% and 30% of light intensity） in leaves of Apocynum venetum. Under 50% and 30% of light intensity,Pn decreases by 47% and 65%,Tr decreases by 45% and 68%,LSP decreases by 20.41% and 37.45% ,respectively. The apparent quantum yield （AQY） of shading are higher than that of full light obviously,and increases by 33% and 36% ,respectively. Fv/Fm and Fv/Fo of full sunlight intensity are all higher than those in different shading intensity, which indicate that shading can restrain the growth of A. venetum definitely.