生态因子对欧洲冬青光合特性的影响

Effects of Ecological Factors on Photosynthetic Characteristics of Ilex aquifolium

以欧洲冬青(Ilex aquifolium)‘黄果’、‘阿拉斯加’为供试材料,研究不同季节欧洲冬青叶片光合参数日变化规律,并采用直角双曲线修正模型模拟光响应曲线。结果表明:不同季节欧洲冬青‘黄果’、‘阿拉斯加’叶片均出现明显的光合“午休”现象,其中春季(3月22日)、夏季(7月28日)、秋季(11月3日)叶片出现光合“午休”现象是非气孔限制因素引起的,冬季(1月17日)出现该现象则与气孔导度下降密切相关。夏季(7月28日)‘黄果’、‘阿拉斯加’叶片日平均净光合速率(P_(n))显著高于其他季节(P<0.05)。‘黄果’、‘阿拉斯加’均属于阳生植物,其中‘阿拉斯加’叶片对强光环境的适应能力较强,‘黄果’叶片碳同化能力较高。‘黄果’、‘阿拉斯加’叶片P_(n)对大气温度(T_(a))的响应曲线均呈双峰型曲线,分别在24、25℃达到最大值。叶片P_(n)随着空气相对湿度(R_(H))的减小呈下降趋势。欧洲冬青‘黄果’、‘阿拉斯加’喜温暖湿润的环境,在亚热带地区引种时应做好夏季降温、增湿等措施,以提高其适应能力。

With Ilex aquifolium‘Bacciflava’and I.aquifolium‘Alaska’as materials,diurnal variations of photosynthetic parameters in leaves of I.aquifolium in different seasons was studied,and light-response curve was simulated by a rectangular hyperbolic correction model.There were obvious midday depression of photosynthesis in leaves of I.aquifolium‘Bacciflava’and‘Alaska’in different seasons,which was due to the stomatal limitation in winter(Jan.17)and the nonstomatal limitation in spring(Mar.22),summer(Jul.28),and autumn(Nov.3).The daily average net photosynthetic rate(P_(n))of leaves of‘Bacciflava’and‘Alaska’in summer(Jul.28)was significantly higher than that in other three seasons(P<0.05).‘Bacciflava’and‘Alaska’belonged to sun plants,among which the adaptability in leaves of‘Alaska’to strong light environment was stronger than that of‘Bacciflava’,while the capacity of carbon assimilation in leaves of‘Bacciflava’was that of stronger than‘Alaska’.The response curves of net photosynthetic rate to atmospheric temperature(T_(a))were bimodal,which reached the maximums at 24℃and 25℃,respectively.With the decrease of relative air humidity,the P_(n) in leaves showed a downward trend.Thus,I.aquifolium‘Bacciflava’and‘Alaska’liked warm and humid environment.To improve their adaptability in subtropics,cooling in summer,increasing air humidity and other protective measures should be taken.