Dissertation Research: Tree Size at Reproductive Onset and Leaf-level Photosynthesis in Malaysia Primary Rainforest Trees

拟议的研究项目探讨树木之间的关系， 物种大小，以繁殖开始时的高度来衡量， 和叶片水平的光合光响应。 积极的 成木大小与最大光饱和度的关系 主要雨林树木的光合速率（Pmax）是 预测了 这一预测来自一个普遍的相关性 在光照水平和最大 光合作用，以及强烈的，可预测的光的存在， 穿过雨林的树冠层。 最近的研究 对阳光和阴影条件的生理适应表明 光合适应相对有限， 热带雨林树木 如果是这样，则测量的Pmax值 幼树的Pmax值应类似于成年树的Pmax值， 并且所提出的异速生长关系应该是可检测的 光合作用的测量。 将测量最大光饱和度 光合速率（Pmax）的35个树种， 收集了大小和结构异速生长数据。 不同树种幼树与成熟树Pmax的差异 将对物种进行评估。 研究中包括的每个属都跨越了 从林下乔木层到树冠层， 树，使可能的测试系统发育差异。 这项研究代表了第一次尝试检查光合作用 热带雨林树木在异速生长环境中的生理学。

The proposed research project explores relationships between tree species size, measured as the height at onset of reproduction, and leaf-level photosynthetic light response. A positive relationship between adult tree size and maximal light-saturated photosynthetic rate (Pmax) among primary rainforest trees is predicted. This prediction derives from a general correlation across environments between light levels and maximum rate of photosynthesis, and the presence of a strong, predictable light gradient through the rainforest canopy. Recent studies of physiological acclimation to sun and shade conditions suggest that photosynthetic acclimation is relatively limited in primary tropical rainforest trees. If this is so, Pmax values measured for saplings should be similar to Pmax values for adult trees, and the proposed allometric relationship should be detectable from photosynthetic measurements on saplings. Measurement will be made of maximal light-saturated photosynthetic rate (Pmax) for saplings of 35 species for which size and structural allometric data have been gathered. Differences in Pmax between saplings and mature trees of selected species will be assessed. Each genus included in the study spans a wide size range, from understory treelets to canopy-level trees, making possible tests of phylogenetic differences. This study represents the first attempt to examine photosynthetic physiology of tropical rainforest trees in an allometric context.