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研究树木光合特性对环境的适应及其影响因素对阐明森林生态系统碳循环及其对气候变化的响应和适应对策具有重要意义.兴安落叶松(Larix gmelinii)作为我国北方森林的优势树种之一,具有广阔的地理分布范围和多样的生长环境,是研究树木对环境适应及其机理的理想树种.本研究将水热条件不同的6个种源兴安落叶松种植在帽儿山森林生态系统研究站的同质园内30年后,测定其光合特性及其相关因子.结果表明:(ⅰ)单位面积最大净光合速率(Pmax-a)、表观光量子效率(AQY)、暗呼吸速率(Ra)、最大羧化速率(Vmax)、最大光电子传输速率(Jmax)、磷酸丙酮糖利用效率(TPU)、光呼吸速率(Rp)和光补偿点(LCP)均存在显著的种源差异(P<0.05).除了LCP和Rp为相反趋势外,其他参数均随着种子来源地生长季平均气温(Ts)和干燥度指数(AI=平均年蒸发量/平均年降水量)的增大而增大(P<0.05),这表明叶光合特性受树木原产地长期环境条件的影响而产生遗传适应,其中温度和降水是该变异性的主要驱动因子;(ⅱ)Pmax-a和其他光合参数AQY,Vmax,Jmax,TPU间均存在显著正相关关系,而与LCP和Rp存在显著负相关关系(P<0.05);Pmax-a和叶片氮含量也存在显著正相关关系(P<0.05);随着各相关因子的增大,来自较大Ts环境下的种源树木具有更大的Pmax-a增加/减少幅度;(ⅲ)Pmax-a和同质园内3日平均气温、月平均气温、生长季平均气温、3日平均相对湿度、月降雨量均呈线性正相关关系,而Ra则均为线性负相关关系(生长季平均气温为正相关)(P<0.05),这表明叶光合特性对同质园内的气候条件产生了一定的驯化;但随着种子来源地Ts的增大,Pmax-a和各环境因子间回归方程的截距显著减小,而Ra和各环境因子间回归方程的截距则为显著增大(生长季平均温除外)(P<0.05).本研究结果表明,不同种源兴安落叶松叶光合特性和环境间的相关性是表型驯化和遗传适应综合作用的结果.
Studying the adaptation of the tree photosynthetic characteristics to the environment and its influencing factors are of great importance to elucidate the carbon cycle of forest ecosystems and their response to climate change and adaptation measures.Larix gmelinii is one of the dominant tree species in northern China, Has a wide range of geographical distribution and a variety of growing environment, is an ideal tree species to study the adaptation of the environment and its mechanism.In this study, six species of water and heat conditions different planting Larix gmelinii at Maoershan Forest Ecosystem Research Station The photosynthetic characteristics and their related factors were determined after 30 years.The results showed that: (i) the maximum photosynthetic rate (Pmax-a), apparent light quantum efficiency (AQY), dark respiration rate (Ra) Vmax, Jmax, TPU, Rp and LCP were significantly different (P <0.05), but there was no significant difference between the two treatments (P <0.05) Except LCP and Rp, the other parameters increased with the increase of Ts (average annual growth temperature) and dryness index (AI = average annual evaporation / average annual precipitation) of seed source (P <0.05), which indicates Photosynthetic characteristics were affected by the long-term environmental conditions of tree origin, which resulted in genetic adaptation. Temperature and precipitation were the main driving forces for this variability. (Ii) There were significant differences between Pmax-a and other photosynthetic parameters AQY, Vmax, Jmax and TPU (P <0.05). There was also a significant positive correlation between Pmax-a and leaf nitrogen content (P <0.05). With the increase of all the relevant factors, there was a significant positive correlation (Iii) Pmax-a and 3-day mean temperature, monthly mean temperature, average temperature of growing season, average relative humidity of 3 days , And monthly rainfall showed a linear positive correlation, while Ra all showed a linear negative correlation (the average temperature during the growing season was positively correlated) (P <0.05), indicating that photosynthetic characteristics of the homozygous climatic conditions However, with the increase of Ts, the intercept of the regression equation between Pmax-a and each environmental factor decreased significantly, while the intercept of the regression equation between Ra and each environmental factor increased significantly Except for the average temperature in growing season) (P <0.05) .The results of this study showed that different provenances Xing’an deciduous Phenotype correlation is domestication and genetic adaptation combined result between photosynthetic characteristics of the leaves and the environment.