Shifts of Sexual Reproductive and Vegetative Growth Allocation in Stipa grandis along a Climate Gradient in Inner Mongolia Steppe
Trade-off between vegetative growth and reproduction is an important plant adaptive strategy to environmental variability. The study investigated the Stipa grandis resource allocation and the relationship between its sexual reproduction and climate factors among three sites located along a typical environmental gradient in the Inner Mongolian Plateau. The results show that different climatic characteristics among three habitats cause the growth differentiation of S. grandis. S. grandis exhibits a prominent change on the resource allocation patterns. The number of reproductive tillers and panicles biomass allocation are significantly increased along the gradient of water availability and temperature whereas the number of vegetative tillers and root biomass allocation are reduced. The rate of the percentage increase is prominently reduced although the foliage allocation increased. It suggests that under the environments with drought and high temperature, S. grandis allocates more resources to sexual reproduction but reduces the investment in vegetative growth and asexual reproduction. Moreover, the amount of precipitation in April and May are significantly correlated with the sexual reproductive allocation of S. grandis.