红■木和■木光合特性的比较

在田间条件下,对同一植株接穗红■(Loropetalum chinense var.rubrumYieh)和其砧木■(Loropetalum chinense Oliver.)上发出的叶片光合特性进行了研究。结果表明:①在8月中旬,天气晴朗的条件下,2种植物净光合速率(Pn)和蒸腾速率(Tr)均呈双峰曲线;气孔导度(Cond)均呈单峰曲线;胞间CO2浓度(Ci)均呈单谷曲线;Pn日均值■木大于红■木。②红■木的光饱和点(LSP)、光补偿点(LCP)、CO2饱和点(CSP)均低于■木,CO2补偿点(CCP)高于■木;③红■木的表观量子效率(AQY)、羧化效率(CE)均低于■木,故红■木的光合能力低于■木。④2种植物固碳释氧能力相比较,红■木低于■木,故而建议在居民小区和人群聚集地进行绿化时,宜适当减少红■木的使用。

A Comparative Study on the Photosynthetic Characteristics of Loropetalum chinense var.Rubrum and Loropetalum chinense

The leaf photosynthetic physiological characteristics of cion Loropetalum chinense var.rubrum and Loropetalum chinense which were the rootstock were studied in the field condition.The results showed that:①The diurnal process of photosynthetic rate and transpiration rate of the two plants changed in a double-peak curve;the diurnal process of stomata conductance and intercellular carbon dioxide concentration of both plants changed in a single-peak curve and a single-vale curve separately;the photosynthetic rate of Loropetalum chinense var.rubrum was lower than that of Loropetalum chinense.②The light saturation point(LSP),light compensation point(LCP),CO2 saturation point(CSP) of Loropetalum chinense var.rubrum were lower than those of Loropetalum chinense,the CO2 compensation point of Loropetalum chinense var.rubrum was higher than that of Loropetalum chinense.③The apparent quantum yield(AQY),the carboxylation efficiency(CE) of Loropetalum chinense var.rubrum were lower than those of Loropetalum chinense.The photosynthetic ability of Loropetalum chinense var.rubrum was lower than that of Loropetalum chinense.④The ability to fix carbon and release oxygen of Loropetalum chinense var.rubrum was worse than that of Loropetalum chinense,so a suggestion of reducing cultivation of Loropetalum chinense var.rubrum in the dense populated area was put forward.