提高CO2浓度对两种亚热带树苗生物量及叶片特性的影响

 广东鼎湖山季风常绿阔叶林的主要优势乔木树种荷木和黧蒴幼苗生长于自然光照和人工调节CO2浓度为500±50μl·L-1或空气CO2(350μl·L-1)的气罩中3个月。高CO2浓度下生长的黧蒴和荷木植株总干物质量分别增加26.6％和16.6%，根部增加量最大，地上部分所占的比例降低，根冠比上升，基径增大而株高降低。高CO2浓度下生长的叶片密度及比叶重增加，叶肉细胞间隙体积减少。单位干重的黧蒴叶片可溶性糖含量、全碳、磷、钾含量在高CO2浓度下稍为下降，果糖、葡萄糖、蔗糖、全氮、镁含量及N/C比明显降低。而全钙含量无明显变化。

EFFECTS OF ELEVATED [CO_2] ON DRY MATTER AND LEAF CHARACTERS OF TWO SUBTROPICAL SEEDLINGS

The biomass and the some leaf characters in the seedlings of two dominant tree species in Dinghushan forests were studied under long-term elevated CO2] conditions. Potted seedlings of Castanopsis fissa and Schima superba were grown in semiopen top chambers with ambient (350μl·l-1) and superambient (500 μl·l-1) CO2] under natural light. With increasing CO2], the total dry matter of whole plant increased by 16.6%～26.6%,and both the ratios of underground to total weight and the root/shoot ratio increased. Whereas, the increase in stem diameter of the basic part and the decrease of plant height were also observed under CO2] enrichment. In addition, the increase of leaf density, leaf thickness and specific leaf weight were associated with the decline of internal space volume. When expressed on dry weight basis, the contents of total nitrogen, Mg, fructose, glucose and sucrose as well as the N/C ratio of leaf of C. fissa reduced obviously by elevated CO2], but no obvious change in total carbon, soluble sugar, Ca, P and K was observed.