不同光强对吴茱萸生长动态和光合日变化的影响

Effects of light intensity on the growth and diurnal variation of photosynthesis in Evod iarutaecarpa seedlings

关键词:  光合特性  生长特性  吴茱萸

Key words:  photosynthetic properties  growth properties  Evod iarutaecarpa

摘要:

报道了不同生长光强（透光率分别为15%、30%、50%、100%）对吴茱萸的生长和光合日变化的影响。结果表明：生长环境光强对吴茱萸苗期株高、地径和冠面积的影响较大，100% RI下的株高、地径和冠面积明显小于各遮荫处理，其中30% RI下吴茱萸的株高、地径和冠面积最大，这表明苗期强光不利于吴茱萸的生长。随着光强的减弱，吴茱萸增大冠面积与株高有利于截获更多光能。10月下旬，100% RI下吴茱萸净光合速率（Pn）日变化曲线呈“双峰型”，11：30～14：30，吴茱萸的Pn、胞间二氧化碳浓度与气孔导度均下降，表明此时的光合午休现象是由气孔部分关闭造成的。各遮荫处理下，吴茱萸的Pn日变化均呈“单峰型”，并无第二峰的出现，可能与遮荫条件下，下午光强较弱，环境温度较高，空气相对湿度较低有关。

Abstract:

The growth and diurnal variation of photosynthesis to different shading levels(15%，30%，50%，100% relative inadianes)in Evod iarutaecarpa seedlings were examined. The results showed that，the height，diameter and crown area of E.iarutaecarpa seedlings were significantly influenced by growth light intensities. The three properties under 100% sunlight were significantly lower than which under other sunlight，and those properties under 30% sunlight were the largest. It could be seen that high light was not conducive to the growth of Evod iarutaecarpa seedlings. With the decrease of light intensity，the crown area and height of E.iarutaecarpa increased significantly，which enhanced the light interception in low light. In late October，diurnal variation in net photosynthetic rate（Pn）was two peak pattern in E.iarutaecarpa under 100% sunlight. From 11：30 to 14：30，the Pn，intercellular CO2 concerntration and stomatal conductance were all decreased，which indicated that stomatal partial closure was the main direct factors which affected the diurnal variation of Pn. The Pn did not show second peak during the afernoon in E.iarutaecarpa seedlings under three shading treatment，which was related to the low light intensities，high air temperature and low air relative humidity in the afernoon under shading treatment.