遮荫对欧洲荚蒾光合特性日变化的影响

Effect of Shading on Diurnal Variation of Photosynthetic Characteristics of Vihurnum opulus L.

为了解欧洲荚蒾的耐荫特性,采用LI-6400便携式光合测定系统对不同遮荫处理欧洲荚蒾的光合生理特性日变化及其与生理生态因子的关系进行了研究。结果表明:(1)欧洲荚蒾在100%和60%光照的净光合速率(Pn)日变化都呈"双峰型"曲线,有明显的"午休"现象,20%光照的Pn日变化呈"单峰型"曲线。(2)欧洲荚蒾光合速率控制因子为非气孔限制。(3)在100%和60%光照条件下,Gs是Pn的第1影响因子,而在20%光照条件下,Tr是Pn的第1影响因子。(4)适当遮荫对欧洲荚蒾的光合作用没有太大影响,深度遮荫,其光合速率明显下降。3个处理的光合能力为100%光照>60%光照>20%光照,欧洲荚蒾可以种植在较荫暗处。

In order to understand the tolerance to shade of Viburnum opulus L, the diurnal variation of photosynthetic characteristics and its relationship to the environmental factors of Vihurnum opulus L. under different shading treatment were studied with the Licor-6400 portable photosynthetic system. The results showed as following： （1） The diurnal variation of net photosynthetic rate （Pn） of Vihurnum opulus L. showed double-peak curve under the 100% light and 60% light, and showed obviously midday depression, however, under 20% light, the diurnal variation of Pn showed single-peak curve. （2） The Viburnum opulus L＇s controlling factor of photosynthetic rate was non-stomatal limitation. （3） Under 100% light and 60% light, the first factor affecting Pn was stomatal conductance（Gs）; Under 20% light, the first factor affecting Pn was Transpiration rate（Tr）.（4） The proper shade had not strong effect on the photosynthesis of Vihurnum opulus L. To strengthen the shade, the photosynthesis rate decreased significantly. The photosynthetic characteristics＇ ability of about three treatments were 100% light〉60% light〉20% light. Vihurnum opulus L could be planted in the shadow.