广西滨海植物红鳞蒲桃的生理特征分析

Study on physiological characteristic of Syzygium hancei in coastal ecotone of Guangxi

采用光合作用测定系统(CI-310)对东兴市江平镇巫头岛的滨海原生植物群落的优势树种红鳞蒲桃的净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Cs)、叶绿素含量及电解质渗透率进行测定,揭示红鳞蒲桃对滨海特殊生境的适应机理。结果表明:红鳞蒲桃的光补偿点为143μmol/(m2.s),光饱和点为600μmol/(m2.s)。在一定范围内,随着光合有效辐射(PAR)的增加,Pn、Tr、Cs也增大,当PAR达到800μmol/(m2.s)后,气孔导度减小,净光合速率和蒸腾速率均呈下降趋势。其Fv/Fm值为0.432,小于多数植物正常值0.8,说明红鳞蒲桃已受到一定程度的胁迫影响。叶绿素含量也较低,与其净光合速率较低相一致。电解质渗透率的测定结果表明,红鳞蒲桃抗高温能力相对较差。调查研究发现,主要原因是人为干扰过大造成红鳞蒲桃生理衰退,自然更新困难,种群已处于老化阶段。

The net photosynthetic rate,transpiration rate,stomatal conductance,chlorophyll content and the rate of electrolyte leakage of the coastal plant communities of dominant tree species Syzygium hancei were detemined by photosynthesis system（CI—310） at the island of Wutou in the town of Jiangping,Dongxing,in order to reveal its adaptive mechanism to the coastal special habitat.Results showed that： the light compensation point of Syzygium hancei was 143 μmol/（m^2·s）,and light increased,the Pn,Trand Csincreased.When the PAR over 800 μmol/（m^2·s）,the stomatal conductance saturation point was 600 μmol/（m^2·s）,within a certain range,as the photosynthetic active radiation（PAR） decreased,net photosynthetic rate and transpiration rate also declined;the value of Fv / Fmwas 0.432,less than 0.8 of most plants normal value,which showed that the environment had some coercive effect on Syzygium hanceito some extent;lower chlorophyll content was consistent with lower net photosynthetic rate;the leakage rate of electrolyte showed that Syzygium hanceihad poor ability to resist against the high temperature.By investigation,it had been found that man-made disturbs was one of the main reasons which caused Syzygium hanceiphysical declined and difficult natural regeneration.The Syzygium hancei population was already at a aging stage.