烟草叶片CO_2传导与碳同化参数的研究

On the parameters of the conduction of CO_2 and carbon assimilation in tobacco leaves

研究了不同部位烟草 (N icotiana tabacum L.)叶片光合作用 CO2 传导与碳同化酶的变化。结果表明 ,随着叶位降低 ,光合速率、叶肉导度 (gm)、碳酸酐酶 (CA)活性和核酮糖 -1,5 -二磷酸羧化酶 (Ru BPCase)初始活性快速下降 ,气孔导度(gs)先保持相对稳定后迅速下降 ,胞间 CO2 浓度 (ci)呈现升高、降低、再升高的变化趋势。光合速率与叶肉导度显著正相关 ,非气孔因素是烟叶光合功能衰退的主要原因。

Changes of the conduction of CO 2 and the enzyme of carbon assimilation in tobacco (Nicotiana tabacum L.) leaves on different positions were studied. The results suggested that the photosynthetic rate, mesophyll conductance (g m ), carbonic anhydrase (CA) activity and ribulose-1,5-bisphosphate carboxylase (RuBPCase) initial activity decreased quickly, while stomatal conductance (g s ) maintained relatively stable at first and then fell sharply, and intercellular CO 2 concentration (c i ) changed from increase to decrease and increased again along with the decline of leaf position. It was concluded that the photosynthetic rate was significantly positively correlated with mesophyll conductance and non stomatal limitation factors were the main causes of the decline of photosynthetic function in tobacco leaves.