兰州市典型绿化树种叶性状间的权衡关系

植物叶性状的权衡关系反映了植物对环境的高度适应性及其在复杂生境下的自我调控能力,了解半干旱区城市绿化树种叶性状间的权衡关系,比较不同生长型(针叶和阔叶)树种异速生长的差异有助于进一步认识植物的进化机制。以兰州市典型绿化树种(13种针叶树和47种阔叶树)为对象,测量部分叶性状,采用标准化主轴估计和系统独立比较分析的方法比较不同性状间的权衡关系。结果表明:不同生长型树种叶面积、叶体积与叶片干重之间均为等速生长关系,针叶和阔叶树种间并无显著差异;叶厚与叶面积间为"此消彼长"的权衡关系,但并不显著;阔叶叶长与叶宽间异速生长斜率为0.764。兰州市典型绿化树种叶性状间的权衡可能是长期适应黄土高原特殊生境的自适应过程,也说明部分性状间存在协变关系,阔叶绿化树种的权衡表明其符合"快速投资-收益"特征。

Trade-off among leaf traits of typical greening tree species in Lanzhou

The trade-off relationship among plant leaf traits reflects the high adaptability of plants and their self-regulation ability in complex habitats.Understanding the trade-offs among leaf traits of urban greening tree species in semi-arid regions,and comparing the allometric growth of tree species with different growth-forms(coniferous and broad-leaved)would help to further understand the evolutionary of plants.Here,we measured leaf traits of 13 coniferous tree species and47 broad-leaved tree species,which are typical greening tree species in Lanzhou.We compared the trade-off relationships among leaf traits by the standardized major axis estimation(SMA)and phylogenetically independent contrast analysis(PIC).The results showed that the relationship between leaf area,leaf volume and leaf dry weight of different life-form tree species was isometric,with no significant difference between coniferous and broad-leaved tree species.A weak trade-off relationship was found between leaf thickness and leaf area.The allometric coefficient between leaf length and leaf width of broad-leaved species was 0.764.The trade-off among leaf traits of typical greening tree species in Lanzhou suggested long-term adaptation of those species to the habitat of Loess Plateau and a covariant relationship among some traits.The trade-offs in broad-leaved tree species indicated that those species showed the characteristics of rapid investment-return.