作 者：李鈞敏（通訊）
影響因子：1.42
刊物名稱：Acta Oecologica
出版年卷：2016, 71: 22-30
文章摘要：The morphological and anatomical characteristics of stems have been found to be related to drought
resistance in plants. Testing the phenotypic selection of water availability on stem anatomical traits
would be useful for exploring the evolutionary potential of the stem in response to water availability. To
test the phenotypic variation of the stem anatomical traits of an invasive plant in response to water
availability, we collected a total of 320 individuals of Alternanthera philoxeroides from 16 populations
from terrestrial and aquatic habitats in 8 plots in China and then analyzed the variation, differentiation,
plasticity and selection potential of water availability on the stem anatomical traits.We found that except
for the thickness of the cortex, all of the examined phenotypic parameters of the A. philoxeroides stem
were significantly and positively correlated with soil water availability. The phenotypic differentiation
coefficient for all of the anatomical structural parameters indicated that most of the variation existed
between habitats within the same plot, whereas there was little variation among plots or among individuals
within the same habitat except for variation in the thickness of the cortex. A significant
phenotypic plasticity response to water availability was found for all of the anatomical traits of A.
philoxeroides stem except for the thickness of the cortex. The associations between fitness and some of
the anatomical traits, such as the stem diameter, the cortex area-to-stem area ratio, the pith cavity areato-
stem area ratio and the density of vascular bundles, differed with heterogeneous water availability. In
both the aquatic and terrestrial habitats, no significant directional selection gradient was found for the
stem diameter, the cortex area-to-stem area ratio or the density of vascular bundles. These results
indicated that the anatomical structure of the A. philoxeroides stem may play an important role in the
adaptation to changes in water availability.
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