杭州湾湿地不同演替阶段优势物种光合生理生态特性

采用LI-6400光合作用系统测定了杭州湾滨海湿地不同演替阶段6种优势植物-包括早期植物海三棱藨草(Scirpus mariqueter)和糙叶苔草(Carex scabrifolia)、中期植物芦苇(Phragmites communis)和柽柳(Tamarixchinensis)、后期植物白茅(Imperata cylindrica)和旱柳(Salix matsudana)的光合作用光响应曲线(LRC)和CO2响应曲线(A/Ci),并拟合得出多个光合生理指标.结果表明,6种优势植物LRC净光合速率(Pn)大小顺序为海三棱藨草>糙叶苔草>芦苇>柽柳>白茅>旱柳,且早期植物显著大于后期植物(P<0.05);光补偿点(LCP)、光饱和点(LSP)、最大净光合速率(Amax)、和暗呼吸速率(Rd)变化与Pn相同,也表现出演替早期植物>中期植物>后期植物;而表观量子效率(AQY)则表现出相反趋势.由A/Ci曲线可以发现,演替早期优势植物较后期植物具有更低的CO2羧化效率(CCE)和相对较高的CO2补偿点(CCP).可见群落演替与各阶段优势植物的光合生理特征密切相关.

Ecophysiology of Dominant Plant Species during Succession in Hangzhou Bay Wetlands

Based on the measurements of leaf photosynthesis,the light response curves(LRC) and A/Ci curves of 6 dominant species in Hangzhou Bay wetlands,including Scirpus mariqueter and Carex scabrifolia in early succession,Phragmites communis and Tamarix chinensis in mid-succession,and Imperata cylindrica and Salix matsudana in later succession,were determined with LI-6400 Photosynthesis system.The data was fitted to calculate photosynthetic physiological indices.The results from LRC were indicated that the values of net photosynthesis rate(Pn) showed sequences,Scirpus mariqueter>Carex scabrifolia>Phragmites communis> Tamarix chinensis>Imperata cylindrica>Salix matsudana,and the values of light compensation point(LCP),light saturation point(LSP),the maximum photosynthesis rate(Amax) and the dark respiration rate(Rd) showed the similar sequences to Pn,but the sequences of apparent quantum efficiency(AQY) were contrary absolutely to Pn.The results from A/Ci curve showed that the carboxylation efficiency(CCE) at early succession was lower than later succession,but the CO2 compensation point(CCP) were higher.It was suggested that there was a good correlation between photosynthetic characteristics of dominants and community succession.