为了探讨植被原生演替初期关键种的碳氮磷生态化学计量特征对冰川退缩区植被原生演替进程的影响,采用时空替代法,探讨了青藏高原东麓贡嘎山海螺沟冰川退缩迹地原生演替序列初期关键种马河山黄芪(Astragalus mahoschanicus)植株土壤碳氮磷生态化学计量特征。结果表明:马河山黄芪枯落物和不同器官有机碳变化为根系>茎>枯落物>叶片; 全氮变化为叶片>根系>枯落物>茎; 全磷变化为叶片>枯落物>根系>茎; C/N变化为茎>枯落物>根系>叶片; C/P变化为茎>根系>枯落物>叶片; N/P变化为根系>叶片>枯落物>茎。说明马河山黄芪地上部分和地下部分化学计量比变化基本同步,且马河山黄芪的生长主要是受P元素限制。土壤C/N变化为27.73～30.63,土壤N/P变化为0.42～0.49,土壤C/P变化为11.90～13.42。马河山黄芪枯落物有机碳含量与枯落物全氮、全磷含量存在显著正相关关系(p<0.05),枯落物全磷含量与枯落物C/N间存在显著负相关关系(p<0.05),枯落物N/P与枯落物C/P间存在显著正相关关系(p<0.05)。马河山黄芪植株有机碳含量与N/P间存在显著正相关关系(p<0.05),植株全氮含量与土壤C/P间存在极显著正相关关系(p<0.01); 马河山黄芪土壤有机碳含量与土壤全氮含量、土壤有机碳含量与土壤C/P间、土壤C/N与土壤N/P间存在极显著负相关关系(p<0.01)。以其低的碳素消耗及较强的固氮作用,使得马河山黄芪成为冰川退缩迹地植被原生演替初期的关键种,能更好地适应微生境,推动冰川退缩区植被原生演替的进程。
In order to clarify the relation between the characteristics of organic carbon, total nitrate, total phosphorus and its stoichiometry of the key species on primary succession stages and the process of the vegetation succession, the method of replacing time with space was used to investigate the characteristics of organic carbon, total nitrate, total phosphorus and its stoichiometry of Astragalus mahoschanicus on primary succession stages in the Hailuogou Glacier Forehead. The results showed that the organic carbon of litter, roots and different organs of Astragalus mahoschanicus decreased in the order: root>stem>litter>leaf, the total nitrogen decreased in the order: leaf>root>litter>stem, total phosphorus decreased in the order: leaf>litter>root>stem, the index of C/N decreased in the order: stem>litter>root>leaf, index of C/P decreased in the order: stem>root>litter>leaf, index of N/P decreased in the order: root>leaf>litter>stem, indicating that the stoichiometry of aboveground and underground of Astragalus mahoschanicus changed synchronized, and the growth rate of Astragalus mahoschanicus was limited by the phosphorus; the values of C/N of the soils ranged from 27.73 to 30.63, the values of N/P of the soils ranged from 0.42 to 0.49 and the values of C/P of the soils range from 11.90 to 13.42; the significant positive correlation between organic carbon and total nitrogen, organic carbon and total phosphorus, N/P and C/P of the litter of Astragalus mahoschanicus(p<0.05)was found; the significant negative correlation between total phosphorus and C/N of the litter of Astragalus mahoschanicus(p<0.05)was observed; meanwhile, the significant positive correlation between total phosphorus and C/N(p<0.05), total nitrogen and soil C/P(p<0.01)of Astragalus mahoschanicus(p<0.05)was found; the significant negative correlation between soil organic carbon and total nitrogen, soil organic carbon and soil C/P(p<0.01), soil C/N and N/P of Astragalus mahoschanicus(p<0.01)was observed, Astragalus mahoschanicus was considered as the key species on primary succession stages in the Hailuogou Glacier Forehead because of the lower carbon comsumption and higher nitrogen fixation, which could better adapt to the micro-ecological habitat and trigger the conditions of the primary succession in the Hailuogou Glacier Forehead.
