作 者 ：张芸香,李海波,郭晋平*
期 刊 ：生态学报 2010年 30卷 24期 页码：7064~7071
Keywords:Larix principis-rupprechtii, Picea meyeri, growth strategy, response, seedling,
摘 要 ：以华北落叶松和白杄为研究对象，通过人工控制条件下的幼苗栽培实验，设置光照、基质水分和基质氮素3个环境因子的多个水平，分析了华北落叶松和白杄苗期生长对3个环境因子变化的响应，对两个树种苗期生长策略的差异进行了综合比较分析。研究结果表明，华北落叶松的苗期生长对光照条件的变化有显著响应，而对基质水分和氮素水平变化的响应不显著，一定程度的遮荫有利于幼苗生长，该树种虽为阳性树种，但苗期具有一定耐阴性。白杄的苗期生长与华北落叶松相比较为缓慢，对光照条件的变化不敏感，但对水分条件的变化有显著响应，阴湿环境不利于白杄幼苗的生长，一定程度的干旱反而可能促进幼苗的生长，基质氮素含量过高可能还会对幼苗生长带来抑制作用。华北落叶松和白杄苗期生长对环境条件异质性的不同响应模式，必将影响两者的种间关系及其在群落中的共存机制，影响群落的动态趋势和过程。
Abstract:The mixed stand of Larix principis-rupprechtii and Picea meyeri is one of the dominate forest types in the mountain area of northern China. Many forest scientists believe that the climax vegetation community in the area was pure Picea meyeri stand, however, the existing mixed stands of the two species with larger proportion and long history must have interior mechanism of tree physiology and ecology. To study different growth responses of Larix principis-rupprechtii and Picea meyeri seedlings to light intensity, water availability and nitrogen concentrations under controlled conditions，the experiment was designed using mixed substrates (fine sands∶nursery soil∶cinnamon soil=1∶3∶5) with treatments of four light intensity levels (100%, 45%, 25% and 5%), three soil water capacity levels (100%, 70% and 40%) and four nitrogen levels (20mmol/L, 15mmol/L, 10mmol/L and 5mmol/L). The seedling root collar diameters, height and biomass components of the two species were measured at the end of the experiment. The differences between their growth responses to light intensity, water availability and nitrogen concentrations were analyzed. The results showed that the seedling growth of Larix principis-rupprechtii significantly responded to different light intensities, in which the largest root collar diameter achieved under shade condition and the largest underground biomass achieved under full light (100%). It was also found that no significant responses of Larix principis-rupprechtii seedlings to water availability and nitrogen concentration treatments. It was concluded that the seedlings of Larix principis-rupprechtii required certain shade environment for their healthy growth, although the species is intolerant to shade condition in general. Comparing with Larix principis-rupprechtii, the seedlings of Picea meyeri grew slower and were not sensitive to light intensity treatment, but responded significantly to water availability in which the root collar diameter, aboveground, underground and total biomass were all the largest in the treatment of 40% soil water capacity level. The seedling height of Picea meyeri is highest with low nitrogen level (5mmol/L). It was concluded that wet and high nitrogen conditions would not be beneficial to Picea meyeri seedlings, but low soil water contents and low soil nitrogen concentration would promote the seedling growth. The study showed different growth responses of Larix principis-rupprechtii and Picea meyeri to the conditions of light intensity, water availability and nitrogen concentrations at the seedling stage. Such differences may impact the interspecies relationship, niche differentiation and co-existence of these two species, and ultimately affect the dynamic succession of the forest community.
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