贵州喀斯特山区植物叶片碳同位素组成研究

通过测定贵州喀斯特山区灌丛12种主要植物叶片的δ13C值,研究了该区植物叶片碳同位素组成特征,以及种间、生境差异和时空变化特征。研究结果表明:该区植物叶片的碳同位素组成的变化范围为-26.98‰--29.15‰,平均值为-28.14‰。研究区δ13C值的分布相对均匀,除高于我国热带雨林区植物外,低于其它地区。研究结果还表明,种间碳同位素组成存在较大的差异。生境的变化对蕨的碳同位素组成影响较大,而对渐尖毛蕨、盐肤木、火棘、马桑影响较小。盐肤木、渐尖毛蕨、云南鼠刺、火棘叶片的δ13C值从生长初期到末期有降低的趋势,但降低的幅度存在差异。植物的δ13C值随小尺度海拔的变化规律与随大尺度海拔变化的规律一致,都是随着海拔的增加δ13C值增大,但不同植物种间变化的幅度是不一样的。

CARBON ISOTOPE COMPOSITIONS OF PLANT LEAVES FROM KARST MOUNTAINOUS AREA,GUIZHOU,CHINA

The carbon isotope compositions of 12 plant species leaves collected from the karst Mountainous area in Guizhou were analyzed.The characteristics of foliar carbon isotope compositions,the differences of carbon isotope compositions of interspecies and different habitat conditions,the changes of carbon isotope compositions with time and space were studied.The results showed that the foliar δ13C from the study area has an average of-28.14‰ and range of-26.98‰～-29.15‰.The mean value of δ13C is lower than that from other areas except for tropical rain area in China,and the change extent is narrower than that other areas.There are greater differences between species.The δ13C in Pterdium aquilinum var.latiusculum affected by habitat conditions is greater than Cyclosorus acuminatus,Rhus chinensis,Pyracantha fortureana and Coriatia sinica.The young leaves have higher δ13C values than the mature ones,but the change extents vary among species.The δ13C values increased with elevateel altitude both in small and large scales.However,the increasing extents of the δ13C values are different among species.