Phenological and morphological adaptations to the light environment in two woody and two herbaceous plant species
Phenological and morphological adaptations to the light environment in two woody and two herbaceous plant species
复制标题
DOI：
10.1046/j.1365-2435.2003.00707.x
复制
发表时间：
2003-02
影响因子：
5.2
通讯作者：
K. Kikuzawa
中科院分区：
文献类型：
--
作者：
K. Kikuzawa
摘要1在日本人工营造的开放生境中，研究了两种草本植物(玉竹和玉竹)和两种木本植物(Fagus crenata和Alnus sieboldiana)的叶片出苗、叶片寿命、光照状况和光合作用，以阐明其对光照条件的形态和物候适应。2在生长季节开始的短时间内，水曲柳和黄精同时展开叶片(同步的叶物候)，而赤杨和何首乌则在较长的时期内逐一展开叶片(连续的叶物候)。3在单叶水平上的光条件，定义为相对于植株上方的光通量密度，对于同时存在的物种而言，在整个生长季节内基本相同。另一方面，这两个连续物种的光照条件随着时间的推移而退化。只有在连续的物种中，才有从枝条的远端到基部的光的梯度。4光合作用强度随时间的急剧下降，连续种(赤杨、何首乌)单株叶片的光合作用速率随时间迅速下降，而同时存在的种(水曲柳、黄精)的光合作用速率下降较慢。然而，在连续树种中，通过频繁更换叶片，冠层的光合作用速率作为一个整体在整个季节保持不变。两种树种的冠层光合作用随时间缓慢下降。5连续出叶适合于洪泛平原和林窗等开阔生境，而同时开叶适合于光照有限的生境，如森林林下植被。
Summary 1 Leaf emergence, leaf longevity, light regime and photosynthetic rates were investigated in order to clarify the morphological and phenological adaptations to light conditions by avoiding self-shading in two herbaceous (Polygonatum odoratum and Polygonum sachalinensis) and two woody (Fagus crenata and Alnus sieboldiana) plants in artificially created open habitats in Japan. 2 Fagus and Polygonatum open their leaves simultaneously as a flush during a short period at the start of the growing season (simultaneous foliar phenology), while Alnus and Polygonum open their leaves one by one successively for a longer period (successive foliar phenology). 3 Light conditions at the level of single leaves, defined as photon flux density relative to that above the plant, were essentially the same throughout a growing season for simultaneous species. On the other hand, light conditions for the two successive species degraded with time. There were gradients of light from the distal to basal part of a shoot only in successive species. 4 Reflecting the abrupt decrease in irradiance with time, photosynthetic rates of individual leaves decreased quickly with time in successive species (Alnus and Polygonum), while those of simultaneous species (Fagus and Polygonatum) decreased slowly. Photosynthetic rates of the canopy as a whole, however, were maintained constant over the season in successive species by replacing leaves frequently. Canopy-level photosynthesis decreased slowly with time in the two simultaneous species. 5 Successive leaf emergence is adaptive in open habitats such as flood plains and canopy gaps, while simultaneous leafing is adaptive in light-limited habitats such as the forest understorey.