四合木种群生殖对策的研究

 通过研究四合木(Tetraena mongolica Maxim)种群的生殖对策，发现四合木既可进行有性生殖，又可进行营养繁殖，以有性生殖为其主要的生殖方式。有性生殖过程中具以下特征：1)具有自交和异交相结合的交配系统，异交比例(50％)高于自交比例(15％)；2)具有花多果少的生殖格局，其开花率与生境、降水、植株年龄关系密切，不同种群的开花率有一定差异，种群的年龄结构对开花率有较大影响。在3～5月降水丰富的情况下，不仅开花比例高(40％～80％)，且每一植株的花量很大。不同年份种群结实率普遍偏低，3～5月降雨较少的1996年平均结实率为19.8％；3～5月降雨较多的1998年为12.2％。只是由于开花基数大，对四合木种群种子的总产量不会造成较大威胁；3)胚胎发育过程中败育比率极高，只有约10％～20％的胚能发育成熟。

REPRODUCTIVE STRATEGIES OF TETRAENA MONGOLICA MAXIM

While sexual reproduction is the major reproductive process in Tetraena mongolica Maxim vegetative propagation is also important. The following are the characteristics of sexual reproduction: 1) a mixed breeding system with self (15%) and cross breeding (50%); 2) a pattern of fruit and seed yield in which plants produce many more flowers than fruits; the flowering rate contacts with environment,amount of rainfall,age of plant, which is different in different populations; age structure has a significant effect on the flowering rate of populations; in high rainfall years, both flowering rates (40% 80%), and flowers per plant are high; population seeding rates were low in all of the three years studied (from 19.8% in 1996 to 12.2% in 1998); because of the large amount of flowers produced, the yield of populations is not greatly affected by this low seeding ratio; 3) the embryo abortion rate is very high, with only 10% 20% of embryos maturing.