枸骨和无刺枸骨不同光强下光合能力的比较

Comparison of Photosynthetic Capacity in Ilex cornuta and Ilex Corunta Var.fortunei under the Different Light Intensity

为了研究枸骨及其变种无刺枸骨对光强的适应能力,笔者以枸骨和无刺枸骨为材料,研究在28℃测试条件下的光强依赖的气体交换和叶绿素荧光特性。结果表明,在相同的光强下,无刺枸骨的净光合速率(Pn)始终比枸骨的大,即外在地表明前者的光合能力在该地区表现更大。但是无刺枸骨的气孔导度(Gs)、蒸腾速率(Tr)和胞间CO2浓度(Ci)均比构骨的要低,说明构骨的Pn低下不是气孔因素引起。叶绿素荧光分析表明,无刺枸骨的PSII反应中心捕获激发能效率(Fv'/Fm')和电子传递速率(ETR)反而比构骨的要低,非光化学猝灭(NPQ)则比构骨的要高,但两者的光化学猝灭(qP)无明显区别,这些结果表明无刺枸骨的CO同化能力比枸骨的要大,可能是由于CO同化阶段相关酶活性比较高。

To investigate the adaptive capacity to light irradiance,the author explored light-dependent the gas exchange and chlorophyll fluorescence properties in lex cornuta and Ilex Corunta Var.fortunei.The results showed that with increasing of light intensity under 28℃,there was a faster increase in net photosynthetic rate （Pn） in Ilex Corunta Var.fortunei,while a slower increase in lex cornuta,which indicated that the photosynthetic capacity in Ilex Corunta Var.fortunei was stronger in this region.However,the stomatal conductance （Gs）,transpiration rate （Tr） and intercellular CO 2 concentration （Ci） were higher,which indicated that the lower photosynthetic rate in Ilex Corunta was not resulted from the decrease of stomatal conductance.Further evidence by chlorophyll fluorescence showed that the efficiency of energy conversion of open PSⅡ （Fv＇/Fm＇） and its electron transport rate （ETR） was higher,while non-photochemical quenching （NPQ） was lower in Ilex Corunta,as compared to that in Ilex Corunta Var.fortunei.And there were no significance difference in photochemical quenching （qP） in two groups.The results suggested that the higher assimilation rate in Ilex Corunta Var.fortunei was probably associated with carbon assimilation.