Ecophysiological responses of naturally regonerntod seedlings to natural and man-made disturbance and their application for silviculture

研究了不同光照条件下生长的4个连续落叶阔叶树幼苗叶片形态和解剖结构与光合能力的关系。森林中桦木（Betula schmidtir）、栎树（Quercus serrata）、栎木（Zelkova serrata）和枫木（Acer tenuifolium）幼苗的演替场所分别为阳光开阔、开阔或林隙、林隙和荫蔽环境。在萌芽之前，将幼苗从小空隙或林冠下移栽到露天苗圃中。桦树也从露天场地移植到苗圃。各树种叶片厚度与最大光合速率均呈显著正相关。对于前一年在遮荫下生长的幼苗，即使在苗圃阳光充足的情况下叶片展开，橡树、红木和枫叶的叶片也只有一个栅栏薄壁层。相比之下，除枫在光照条件下仅形成一层外，前一年充分光照条件下展开的叶片均形成两层栅栏薄壁组织。遮荫下生长的所有叶片叶绿素b含量均高于露天生长的叶片。在开放条件下，气孔密度大，而维管束鞘延伸室（维管束鞘延伸所划分的面积）小。本文讨论了几种树木幼苗叶片形态、解剖结构及其气体交换能力之间的生态关系，并特别讨论了叶片原始分化的时间。

Leaf morphology and anatomy of 4 successional dcciduous broadleaved tree seedlings grown under various light levels were examined in relation to their photosynthetic capacity. The successional growth sites of seedlings of birch (Betula schmidtir), oak (Quercus serrata), Keyaki (Zelkova serrata) and maple (Acer tenuifolium) are respectively sunny open, open or gap, gap and shade environment in a forest. Before the bud break, seedlings were transplanted from a small gap or under forest canopy to open nursery. Birch was also transplanted from open site to the nursery. A positive correlation between leaf thickness and the maximum photosynthetic rate of all species was found. For the seedlings grown under shade in the preceding year, oak, Keyaki and maple leaves bore one palisade parenchyma layr even though their leaves unfolded under full sunlight in the nursery. In contrast, leaves expanded under full sunlight in previous year had two palisade parenchyma layrs except for maple where only one layr formed irrespective of growth light environment. Chlorophyll b content of all leaves developed under shade was higher then those grown in the open. In an open, stomatal density was high while the size of bundle sheath extension compartment (area divided by the extension of vascular bundle sheathes) was small. The ecological relationship among leaf morphology, anatomy and its gas exchange capacity in seral tree seedlings is discussed with special reference to the timing of leaf primordial differentiation.