太白山独叶草无性系分株营养元素含量对异质环境的响应

以分布在太白山国家森林公园3个海拔高度的游击型克隆植物独叶草为研究对象，分析测定了不同分株营养器官中C、N、P、K和Mg含量.结果表明：分株年龄、海拔梯度以及分株年龄与海拔梯度的交互作用对独叶草分株各营养器官全碳含量的影响不显著(P>0.05)，对全氮、全磷、K和Mg含量的影响程度各不相同，说明独叶草无性系分株通过自身的生理代谢调整了各器官中营养元素的分配.在高海拔生境中，分株年龄显著影响独叶草无性系分株各器官的K含量、根状茎和根中的全氮含量(P<0.05).除了中海拔(2 800～2 900 m) 独叶草无性系分株的K与全氮、全磷和Mg含量相关性不明显外，其他海拔各元素两两间均呈显著相关(P<0.05).这表明高海拔生境中生理可塑性对克隆植物生长的贡献可能比低海拔更大，强的生理可塑性有助于克隆植物在高山环境中有效地利用资源,实现种群扩展、开拓新的生境.这也可能是独叶草在长期演化过程中对异质生境的一种生理响应.

Nutrient contents in Kingdonia uniflora ramet and their relations to heterogeneous environment on Taibai Mountains.

Taking the guerrilla type clonal plant Kingdonia uniflora at different altitudes in Taibai Mountain National Forest Park of Shaanxi Province, China as test material, the C, N, P, K and Mg contents in different vegetative organs of its ramet were measured. The results showed that ramet age, altitude, and their interaction had no significant effects on the total C content in ramet leaf, rhizome, and root (P>0.05), but different effects on the total N, total P, K and Mg contents in these vegetative organs, suggesting that ramet could regulate the allocation of nutritive elements in its vegetative organs through physiological metabolism. At high altitude (3 000-3 100 m), ramet age had significant effects on the K content in all vegetative organs and the N content in rhizome and root (P<0.05). All the test nutrient contents were significantly correlated with each other at all altitudes, except at middle altitude (2 800-2 900 m) where the ramet K content had no significant correlations with its N, P, and Mg contents. It was suggested that physiological plasticity contributed more to the performances of clonal plants at high altitude than at low altitude. Powerful physiological plasticity could help K. uniflora to effectively utilize heterogeneous resources, realize population expansion, and open up new habitat at high altitude. It was likely that the physiological plasticity of K. uniflora responding to heterogeneous habitats was formed in its long-term evolvement.