In this study,a total of 73 plant samples from four natural populations,in Alihe,Huzhong,Aihui and Wuyiling of China,representing all the taxa in Larix gmelinii were used for evaluating the allozymic genetic diversity. Allozyme data for sixteen loci of ten different enzymes were obtained using a starch gel electrophoresis system. Our results revealed high levels of genetic variation in populations. The percentage of polymorphic loci (P) was 43.8%～62.5%,the average number of alleles per locus (A) was 1.8～2.0,and the mean expected heterozygosity (H_e) was 0.187～0.257. Additionally,the values of all indexes related to gene abundance were decreasing from the north to the south populations,suggesting that the species might move in the direction from north to south. The analysis on population genetic structure indicated that the variation mainly existed within a population,and the value of F_ ST is 0.111. The level of genetic differentiation was higher than that of gymnosperm on the average. The fixation index (F) of population was > 0,indicating that heterozygote was insufficient in populations. Outcrossing rate (t)(20.8%) was lower. Genetic identity(I) cluster analysis result indicated that the genetic variation in the populations was influenced by geographical isolation,and changed along with latitude.
Floral buds of Agapanthus praecox ssp. orientalis were observed under dissecting and optical microscope to characterize floral organs development and to study relationships between anther development and microsporogenesis. Floral organs differentiation was comprised of 6 distinct stages including nought differentiation, inflorescence bud differentiation, floret primordia differentiation, tepal primordia differentiation, stamen primordia differentiation, and pistil primordia differentiation. Six tepals differentiated almost simultaneously which cross arranged in space and appeared in hexagonal distribution pattern. Six stamens were differentiated inside the tepals at the same time. Finally, 3 carpel primordia differentiated and formed syncarpous pistil. The whole process of floral bud differentiation took approximately 40 d with the first 3 stages developing more slowly than the later 3 stages. Morphology and color of the anther underwent obvious changes during the period between stamen primordia differentiation and anther maturation. Microspores also underwent significant development during this same interval. The relationship between the process of microsporogenesis and anther development has already been made clear by the sauash techniaue.
