Leymus chinensis（Trin.）Tzvel. is a fine herbage, which is a perennial rhizome grass species with high potentiality of vegetative propagation. The quantitative characters of fruit-bearing and grain weight of the population were successively investigated in three fixed stands from 1983 to 1998，analyzing the relationship between these characters and the climatic factors in different growing and developing stages. Certain degree of correlations were found between the number of seeds and grain weight of the population and different time of sunshine, temperature and rainfall accumulation before and during the growing and developing stages. From vegetative to reproductive growth of the tiller, including flowering, pollination, fertilization, and ovule development and seed formation, lower accumulated temperature and longer day light during the early growth season promoted fruit-bearing of the population, and vice versa. From turning green to fruit-ripening stage, longer sunshine duration benefited while higher accumulated temperature inhibitted nutrient deposition in the grain. Furthermore rainfall was also good to nutrient collection in the grain from turning green to milky stage，not from milky stage to mature stage. Growth and development of the winter tillers would affect the flowering, fruit-bearing, as well as the quality and quantity of seed production in the following year. Therefore, the number of fruit-bearing and the grain weight of the population could be predicted by the length of sunshine duration from August to September of the previous year and amount of rainfall in May of the present year，but the quantitative variation that estimated by simple climatic factor model was only 29.27%-35.76%.
东北草原羊草种群结实特性与气候年变化的关系
杨允菲 杨利民 张宝田 李建东
（东北师范大学草地研究所，长春130024）
摘要：对3个固定样地的羊草（Leymuschinensis(Trin.)Tzvel.）种群连续12-16年的调查和测定及其与不同生长发育阶段气候因子的相关分析，表明羊草种群结实数量和籽实重量均与形成这些性状的生育期内，及其以前各生育期不同阶段的光照时间、积温、降水量有着一定程度的相关关系。从分蘖株的营养生长到生殖生长，包括开花、授粉、受精、胚珠发育为种子形成的整个过程中，较低的温度和生长季前期较多的光照，对结实有促进作用，而较高的积温和较少的光照时间则不利于受精、结实。从返青到籽实成熟期，较多的光照时间对籽实养分积累有促进作用，较高的积温则有不利影响。从返青到乳熟期较多的降水对籽实的养分积累有促进作用，但从乳熟期到完熟期较多的降水则有不利影响。冬性枝条生长发育状况可持续影响到种群翌年的开花、结实及种子生产的数量和质量。用前一年8-9月份的光照时间和当年5 月份的降水量可提前预报羊草种群的结实数量和籽实重量。但是，由这些单项气候因子模型所估计的数量变化仅在29.27%-35.76%之间。
关键词： 羊草；结实率；千粒重；数量性状；气候因子；预报模型
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