不同种源刨花楠林下幼苗叶功能性状与地理环境的关系

研究9个种源地天然刨花楠林下幼苗主要叶功能性状差异及其与地理环境的关系,分析刨花楠林下幼苗对地理环境变化的响应与适应机制.结果表明: 不同种源间刨花楠林下幼苗主要叶功能性状种内变异系数较大(8.8%～28.2%),其中种源间比叶面积、叶相对含水率、叶组织密度和叶厚差异显著,表明刨花楠林下幼苗具有较强的叶片形态可塑性.叶组织密度与叶干物质含量、叶相对含水率均呈显著正相关,与比叶面积、叶厚则呈显著负相关;比叶面积与叶干物质含量、叶面积均呈显著负相关,反映刨花楠林下幼苗可通过叶片性状组合的调整和平衡以响应地理环境变化.影响刨花楠林下幼苗叶功能性状可塑性的主要环境因子为经度、纬度、>10 ℃年积温和年均温.叶厚随着经度的增加而降低,叶干物质含量和叶相对含水率则随着经度的增加而增加;叶组织密度与经度和年均温呈显著正相关,且经度对其影响大于年均温;叶面积与>10 ℃年积温和经度呈显著正相关,且前者对其影响大于后者.

Relationships between leaf functional traits of Machilus pauhoi understory seedlings from different provenances and geographical environmental factors.

To understand the adaptation mechanism of Machilus pauhoi seedlings to environmental changes, leaf functional traits of M. pauhoi seedlings from nine provenances, as well as relationships between leaf traits and environmental factors were analyzed. The results showed that leaf functional traits of M. pauhoi seedlings from different provenances showed significant intraspecific variations, with the coefficient of variation ranging from 8.8% to 28.2%. Specific leaf area, leaf relative water content, leaf tissue density and leaf thickness differed significantly among seedlings from different provenances, implying high leaf morphological plasticity. Moreover, leaf tissue density was positively correlated to leaf dry matter content and leaf relative water content, but negatively correlated to specific leaf area and leaf thickness. Specific leaf area showed significantly negative correlations with leaf dry matter content and leaf area. The covariation among those traits examined here indicated that M. pauhoi seedlings could adjust and balance the combination of leaf traits in response to environmental changes. Longitude, latitude, >10 ℃ annual accumulated temperature and mean annual temperature contributed largely to the variation of leaf functional traits of M. pauhoi seedlings. Leaf thickness decreased with the increase of longitude, while leaf dry matter content and leaf relative water content increased with the increase of longitude. Leaf tissue density was positively correlated with longitude and mean annual temperature, suggesting that longitude rather than mean annual temperature had greater effects on it. Leaf area was positively correlated with >10 ℃ annual accumulated temperature and longitude, indicating that annual accumulated temperature rather than longitude had greater effects on the variation of leaf area.