Crown Architecture of Two Understory Palm Species of the Genus Licuala in a Tropical Rain Forest
Crown Architecture of Two Understory Palm Species of the Genus Licuala in a Tropical Rain Forest
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热带雨林中两种林下棕榈树的树冠结构
DOI：
10.1111/j.1442-1984.1997.tb00154.x
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发表时间：
1997
影响因子：
1.4
通讯作者：
T. Kohyama
中科院分区：
文献类型：
--
作者：
Koichi Takahashi;T. Kohyama
本文对两种林下棕榈树，即树生利夸拉（Licualaarbuscula）和树生利夸拉（L.在印度尼西亚西加里曼丹的热带低地雨林中对bintulensis进行了研究。这两个种只有停滞的茎，并开发了一个半球形的冠形成长叶柄和扇形叶片。出叶时叶柄直立，老叶叶柄向下弯曲。叶子集中在树冠的顶部。叶片偏斜约。叶柄直立时，水平方向与树冠内侧呈40°。由于叶片与叶柄间的发散角不变，叶片的天顶角随叶柄的天顶角而变化。叶片和叶柄之间的这种发散角允许形成一个紧凑的叶丛，在树冠顶部重叠较少，在树冠中部叶片水平扩展。冠内叶片的大小和数量随着冠的发育而增加，叶柄与叶片长度的比值增加。这使两个棕榈在小尺寸阶段将其同化区扩展到非光合支持部分（叶柄）上，并避免了树冠内叶片过度拥挤。这些结果表明，两种棕榈树通过调节叶片与叶柄的发散角和叶片与叶柄之间的异速生长来形成树冠，以避免自荫。
The crown architecture of two understory palms, Licuala arbuscula and L. bintulensis, was studied in a tropical lowland rain forest in West Kalimantan, Indonesia. The two species had only stagnant stems and developed a hemispherical crown formed with long petioles and fan-shaped leaf blades. Petioles at leaf emergence stood vertically, while petioles of older leaves were bent downward. Leaves were concentrated on the top of the crown. The leaf blade deflected ca. 40° from the horizon to the inside of crown when the petiole stood vertically. Because the divergence angle between the leaf blade and its petiole did not change, the zenith angle of the leaf blade changed with that of the petiole. This divergence angle between leaf blade and petiole allowed the formation of a compact foliage clump with less overlap at the top of the crown, and the horizontal expansion of leaves at the middle of the crown. The size and number of leaves within the crown increased with crown development, and the ratio of the petiole to the leaf blade length increased. This enabled the two palms to extend their assimilative area over the non-photosyn-thetic supportive part as petioles in the small size stage and to avoid the overcrowding of leaves within a crown with crown development. These results suggest that the two understory palms develop crowns as to avoid self-shading through adjusting the divergence angle between leaf blade and petiole and through the allometry between them.