辐射强迫对秃瓣杜英生长和光合生理的影响

Effect of Radiative Forcing on Growth and Photosynthetic Responses of Elaeocarpus glabripetalus Merr

[目的]通过对辐射强迫下亚热带典型树种秃瓣杜英幼苗的生长及光合生理的研究,初步探讨植物对于辐射强迫的生理响应及适应性机理,进而揭示辐射变化对亚热带森林树种的影响。[方法]试验设置3个处理水平,即对照组(100%自然光)、弱辐射强迫(39%自然光)、强辐射强迫(16%自然光),对秃瓣杜英不同时期的叶绿素相对含量、光合作用参数等进行测定,分析不同处理梯度对秃瓣杜英株高、地径、叶绿素含量、气体交换参数、光响应曲线参数的影响。[结果]不同处理下秃瓣杜英的地径生长量为:对照组>弱辐射强迫组>强辐射强迫组,株高生长量在处理前期为:强辐射强迫组>弱辐射强迫组>对照组,在处理后期无明显变化规律;叶绿素相对含量表现为:强辐射强迫>强弱辐射强迫>对照组,辐射强迫处理下,秃瓣杜英的光补偿点(LCP)、光饱和点(LSP)和最大净光合速率(Amax)均降低,强辐射强迫处理下,秃瓣杜英的气孔导度(Gs)、蒸腾速率(Tr)显著小于对照组;表观光量子效率(AQY)和暗呼吸速率(Rd)变化规律不明显。[结论]综合来说,辐射强迫引起环境因子的变化,对秃瓣杜英的地径和株高生长量、叶绿素相对含量、光合生理参数有显著影响,但随着秃瓣杜英逐渐适应了这种变化,后期其对地径和株高增量的影响不显著,表明秃瓣杜英能一定程度上适应这种辐射强迫环境,在一定时期内生长正常。

[Objective] This study aimed to reveal the impact of radiative forcing on the woody plants in subtropical regions of China through the study on the effect of radiative forcing on growth and photosynthetic responses of Elaecarpus glabripetalus Merr.seedlings.[Method] Three gradients of radiative forcing treatments were applied to the species namely,control group（100% natural light）,weak radiative forcing group（39% natural light） and strong radiative forcing group（16% natural light）.The relative contents of chlorophyll,photosynthetic parameters of E.glabripetalus in different periods were measured to analyze the effects of different gradients of radiative forcing on plant height,ground diameter,chlorophyll content,gas exchange parameters,light response cure parameters.[Result] The increased ground diameter of E.glabripetalus in different treatments was the control weak radiative forcing group strong radiative forcing group;the increased plant height in the early period was strong radiative forcing group weak radiative forcing group control,but there was no significant difference during the late period;the relative content of chlorophyll was strong radiative forcing group weak radiative forcing group control.The light compensation point（LCP）,light saturation point（LSP） and the maximum net photosynthetic rate（Amax） were reduced in radiative forcing treatments.The stomatal conductance（Gs）,transpiration rate（Tr） of E.glabripetalus in strong radiative forcing group were significantly smaller than that in the control group,while there was no significant change in dark respiration rate（Rd）and apparent quantum yield（AQY）.[Conclusion] In summary,the radiative forcing can change the environmental factors which have significant effect on the ground diameter,plant height,relative content of chlorophyll and photosynthetic physiological parameters,but with the processing of treatment the effects on ground diameter and plant height increase are not significant in the late period,indicating that E.glabripetalus seedlings have some resistance and adaptability to the radiative forcing environment.