The Reproductive Strategies Of Heterocapic Plant Atriplex Micrantha

In this paper, taking the germination phenology, the characteristics of seedling growth and the individual size, patterns of fruit and seed production, reproductive allocation of the same population in different microhabitat and habitat of Atriplex micrantha as the starting point, we probed into the ecological adaptive strategy of A. micrantha. The main results were as follows:1.(1)The germination phenology of heterocarpic seeds are unsynchronize, with the cotyledon retaining for a long time. But the cotyledon retention time of the seedling grown of both seeds are different. The brown seeds of A. micrantha germinated on March 27 th, cotyledon lasting 39 days, while black seeds germinated on April 3rd, the cotyledon lasting 30 days.(2)Compared with black seeds, seedlings grown from brown seeds have bigger size in cotyledon, root length and biomass of above and below ground.(3)The biomass distribution of above and below ground on the sprouting seedling of both seeds is different, the biomass of above and below ground of the sprouting seedling of brown seeds was significantly bigger than that of black seeds in the four times measurement.2.(1)The total reproductive allocation and the reproductive allocation of the brown and black seed of the same population in different microhabitat(steep slope, gentle slope, gully bottom) significantly increased with the increase of plant size; the reproductive allocation of brown seeds was equal to that of black seeds.(2)Along with the increasing plant size, both the number and the ratio of black seeds that outputted by the same population in different microhabitat of A. micrantha are significantly higher than those of brown seeds, the range of the proportion of black seeds and brown seeds in different microhabitat was 2.16~7.41:1?3.(1)The plant phenotype of A. micrantha in different habitat(abandoned land, shadow, desert) was different. The diameter, first grade branch, second grade branch and third grade branch of plant in abandoned land are significantly more than those in the shadow and desert, there was no third grade branch in the desert habitat.(2)The number of the seed of A. micrantha is significantly different in different habitats, the number of the seed in different habitat were 8194, 3390 and 1854 respectively, there was no difference of the proportion between black seeds and brown seeds in different habitat, the proportion of black seeds was higher than 70%.(3) The reproductive allocation was different in different habitat, the reproductive allocation in abandoned land was 53.32%, while the reproductive allocation in desert and shadow were 35.34% and 28.72% respectively.