控制光照下土庄绣线菊的生理生态响应和适应

Ecophysiological Responses and Acclimation of Spiraea pubescens to Different Controlled Light Treatments

本研究以一年生灌木土庄绣线菊(Spiraea pubescens Turcz.)幼苗为研究对象,人工设置相对透光率100%、50%、25%和12.5%四种控制光照水平,测量幼苗存活率以及在生理生态特征上的响应和适应性,从而加深我们对灌木幼苗的生理需求和生态特征的认识。结果表明,土庄绣线菊幼苗的存活率未受控制光照处理影响。遮阴处理导致最大净光合速率和蒸腾速率显著降低,叶绿素a和b含量显著升高,但气孔导度和类胡萝卜素含量未变化。同时,在25%和12.5%相对透光率水平下,土庄绣线菊幼苗的苗高和比叶面积显著高于100%相对透光率下幼苗,而根、茎和总生物量积累在12.5%下受到严重抑制。遮阴处理使得土庄绣线菊幼苗表现出地上生物量分配增大地下减少的一般趋势。以上结果说明土庄绣线菊幼苗对遮阴环境具有一定的生理生态响应和适应性。

One year old seedlings of Spiraea pubescens Turz.growing in four different controlled light treatments（100%,50%,25% and 12.5% transmittance levels） in an artificial environment were selected to measure their survival rates and responses and acclimation in their ecophysiological traits for better understanding of physiological and morphological characteristics of shrub species.The results showed that the survival rates of Spiraea pubescens seedlings did not change significantly by light treatments.Under shades,the Amax and E were siginificantly decreased and Chla and Chlb contents were significantly increased,while stomatal conductances and Car were not changed.At 25% and 12.5% transmittance levels,the height and SLA of Spiraea pubescens seedlings were significantly higher than that of seedlings growing at 100% transmittance level,while the root,stem and total biomass accumulation were severely inhibited at 12.5% transmittance level.Furthermore,there was a general trend of increasing aboveground biomass allocation and decreasing belowground biomass allocation as the light intensity decreased.The above results were in accordance with the field investigation results of naturally generated adult plants,which fully support and show the strong physiological and moderate morphological responses and acclimations of Spiraea pubescens seedlings to the shade.