Ecological and genetic responses against environmental fluctuations : model study on Primula spp.

点击翻译按钮获取中文摘要

Researches on the characteristics of acclimation and consequences of the environmental fluctuations on the fitness of individuals and genetic structure of a population are indispensable to clarify the effects of environmental changes on population viability of wild plants. In this study, current status of populations, eco-physiological characteristics, and genetic structures of above-ground populations and soil seed banks were studied in three Primula species : P sieboldii, P modesta, and P nutans.Morphological and physiological acclimations in P sieboldii, vulnerable plant in Japan, to the change in light availability were analyzed by outdoor measurements and laboratory experiments. The effects of degradation in light availability on vegetative growth were quantitatively revealed. Furthermore, the importance of seasonal dormancy of ramets to minimize the loss of matters through respiration was shown.The analyses of genetic structures of a population of P modesta showed that although the deeper (persistent) soil seed banks had no significant genetic structure, the surface (transient) seed banks had significant spatial genetic structure. Surviving seedlings were aggregated at short distances because of the patchy spatial distribution of safe sites for establishment, allowing development and strengthening of the marked fine-scale spatial structure.To address how P nutans, a potential model species to monitor the population effects of global warming, can distribute throughout wide environmental range, the plasticity of its morphology and physical traits to the environmental variables during the growing season. A population survey and laboratory experiments suggested that although P nutans could acclimate to various conditions of water availability, it showed maximum growth rate under a cool (< 10℃) and light conditions.