摘要
对生长在青藏高原东部隶属于23科、49属的71种高山植物(包括多年生和一年生植物)的稳定碳同位素比值、氮含量以及碳/氮比率进行了分析,并以稳定碳同位素比值及碳/氮比率来分别指示植物的水分利用效率和氮素利用效率.结果表明:(1)多年生植物稳定碳同位素比值显著高于一生年植物,而碳/氮比率显著低于一年生植物(P<0.01),氮含量两者无显著性差异.(2)多年生植物和一年生植物的稳定碳同位素比值均与碳/氮比率呈显著负相关(-0.643**和-0.707),而与氮含量均无明显相关性.研究证实,在自然条件下多年生植物的水分利用效率比一年生植物更高,而氮素利用效率却更低;高山植物水分利用效率和氮素利用效率存在明显的权衡",即植物不能同时提高水分利用效率和氮素利用效率,高水分利用效率的代价是降低氮素利用效率,青藏高原不同植物即使在相同环境条件下具有不同适应对策.
Nitrogen concentrations,C/N ratios and δ^13C values of 71 alpine plants（perennials and annuals） grown at the east of Qinghai-Tibet Plateau in natural condition were measured. δ^13C values were used to denote the long-term water use efficiency（WUE） of plants whereas long-term nitrogen use efficiency（NUE） was estimated by the ratio of C to N. The results indicated that （1） perennials had higher δ^13C values and lower C/N ratios compared with annuals （P〈0. 01）. On the contrary, the N concentrations of perennials and annuals was similar （P〉0. 05）. （2）δ^13C values were not correlated with N concentrations in perennials or annuals （P〉0.05） ,whereas significantly negative correlations between δ^13C values and C/N ratios were found for all samples （P〈0.001）,or for perennials （P〈0. 001） or annuals （P〈0.05） analyzed separately. The results revealed there was a trade-off between WUE and NUE for alpine plants in natural condition,i, e. alpine plants could not improve WUE and NUE simultaneously. The cost of a high WUE was a low NUE,and vice versa,which may be associated with the different life strategies for different species in the extremely natural condition in Qinghai-Tibet Plateau. In addition,the differences of δ^13C values or C/N ratios between perennials and annuals suggested perennials had higher WUE and lower NUE compared with annuals,re fleeting the different adaptations of alpine with different life span to environmental condition.
出处
《西北植物学报》
CAS
CSCD
北大核心
2007年第6期1216-1224,共9页
Acta Botanica Boreali-Occidentalia Sinica
基金
国家自然科学基金项目(30270217)
