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

环境变化对野生植物种群生存力的影响，必须研究植物的驯化特征以及环境变化对个体适合度和种群遗传结构的影响。本文对三叶报春花、莫德斯特报春花和纳特报春花3种报春花的种群现状、生态生理特征、地上种群遗传结构和土壤种子库进行了研究。采用室外测量和室内实验相结合的方法，分析了日本易感植物三叶草对光效变化的形态和生理适应。定量揭示了光效退化对营养生长的影响。此外，还表明了品种季节性休眠对减少呼吸物质损失的重要性。对一个麻豆居群遗传结构的分析表明，深层（持久）土壤种子库不具有显著的遗传结构，而表层（短暂）种子库具有显著的空间遗传结构。由于安全建立地点的空间分布不均匀，因此幸存的幼苗在短距离上聚集，从而使明显的精细空间结构得以发展和加强。为了研究花生这种潜在的监测全球变暖种群效应的模式物种如何在广阔的环境范围内分布，研究了其生长季节形态和物理性状对环境变量的可塑性。种群调查和室内试验结果表明，水杨虽然能适应各种水分条件，但在低温（< 10℃）和光照条件下生长速度最快。

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.