Ecophysiological Investigations of Understory Eastern Redcedar in Central Missouri
Ecophysiological Investigations of Understory Eastern Redcedar in Central Missouri
复制标题
密苏里州中部林下东部红杉的生态生理学调查
DOI：
10.2307/1937490
复制
发表时间：
1983
期刊：
影响因子：
4.8
通讯作者：
S. J. Dina
中科院分区：
文献类型：
--
作者：
J. Lassoie;P. Dougherty;P. Reich;T. Hinckley;Clifford M. Metcalf;S. J. Dina
东部红雪松（Juniperus virginiana）是一种适应阳光，耐旱的先锋物种，常见于美国东部的牧场，废弃的田地，围栏行和石灰岩露头。然而，它也是密苏里州中部成熟橡树-山核桃林林下的常见组成部分，在生长季节的大部分时间里，光照水平通常<10%。这是低于东部红杉的光合作用的最佳报告。在这种环境条件下，东部红杉林下的竞争生存显然是由于它是一个万年青针叶林在落叶林。因此，它的叶子能够在一年中的大部分时间保持正的二氧化碳平衡，最大的净光合速率发生在上层无叶的时期。日平均净光合速率（Phn）最大值出现在温度适中、林下光照水平较低的地上部分出叶期。
Eastern redcedar (Juniperus virginiana) is a sun—adapted, drought—resistant pioneer species common to pastures, abandoned fields, fence rows, and calcareous rock outcrops throughout the eastern United States. However, it is also a frequent component of the understory in mature oak—hickory forests in central Missouri, where light levels are typically <10% of full sunlight during much of the growing season. This is below eastern redcedar's reported optimum for photosynthesis. The competitive survival of understory eastern redcedar under such environmental conditions was apparently due to it being an evergreen conifer in a deciduous forest. Hence, its foliage was able to maintain a positive carbon dioxide balance throughout much of the year, with maximum net photosynthetic rates occurring during periods when the overstory was leafless. The greatest daily average net photosynthetic rates (Phn) occurred during overstory leaf emergence when temperatures were moderate and light levels to the understory trees wer...