毛竹叶片的生理特性

Physiological Characteristics of Leaves of Bamboo Phyllostachys pubescens

对毛竹叶片的光合特性、叶绿素含量、游离氨基酸含量、β-胡萝卜素含量和硝酸还原酶活性等生理指标进行测定．结果表明：毛竹叶片光合速率日变化呈现双峰曲线．出现光合“午睡”现象．上午8：00～9：30，叶片光合速率随着光照强度的增加呈直线上升趋势，在9：30出现全天第1个高峰值，16：30出现第2个高峰值，叶绿素含量与硝酸还原酶活性、游离氨基酸含量呈显著性相关，β-胡萝卜素含量高、保护光合机构能力强，光合速率大、叶绿素含量高、净光合速率大，反映植物体内N代谢旺盛、N素利用水平高，利于植物的生长发育．

Bamboo （Phyllostachys pubescens） is one of the dominant economic trees in the southern districts of China. Naturally it is widely cultivated because of its higher livability and economic benefits. To understand the photosynthetic rate for its growth, we measured some physiological targets about its photosynthetic characteristics, its chlorophyll content, free amino acid content, beta carrot content and Nitrate-reductase （NR） activity. The results show that the diurnal variation of its photosynthetic rate in leaves presented double peak curves but there was a significant midday depression ; that the relationship between the photosynthetic rate and the light intensity is a linear one from 8 ： 30 to 9 ： 30 and the peaks occur at 9 ： 30 and 16 ： 30; that there are positive correlations, in addition, among the chlorophyll content, the free amino acid content and NR activity; and that beta carrot content increases with the increase of the photosynthesis rate. All these illustrate that Nitrogen in bamboo metabolizes in full bloom and Nitrogen is utilized with high efficiency, which ultimately benefit the growth of bamboo.