Study Of Reproductive Characteristics Of Artemisia Halodendron Population In Horqin Sandy Land

Artemisia halodendron can reproduce both asexually and sexually. Its tresses produce adventitious root to fulfill clonal growth, on the other hand Artemisia halodendron takes out sexual reproduction though blossoming and bearing fruit. Depending on the reproductive characteristics, Artemisia halodendron was used for preventing drift-sand and sand storms, generally serving as a constructive species of desert shrub vegetation communities in Horqin sandy land, China. In order to quest for reproductive strategies and regeneration strategies of Artemisia halodendron along a succession gradient, asexual characteristic included clonal plasticity and clonal growth characteristics, sexual characteristic included population quantity and reproduction dynamic change, as well as characters of soil factors in different sandy land were studied. The results are as follows:1. Ggenet densities of Artemisia halodendron population on three different types sand were very significant difference. It was 1.42genets/m² on the shifting sandy land, 0.52 genets/m² on semi-fixed sandy land and 0.09 genets/m² on fixed sandy land. Regression equation of height, size of canopy and ramet quantities was y=-3.358+0.151x₁-0.0004x₂ (R=0.857, R2=0.734, y: ramet quantities, x₁: height, x₂: size of canopy).2. Ramet quantities per genet were very significant difference on the different types land (P=0.00). The value on the shifting sandy land was 16.7, the largest. It was 10 on the semi-fixed sandy land and 0.34 on fixed sandy land, the smallest, on the shifting sandy land, semi-fixed sandy land,fixed sandy land, Spacer average lengths were in tum 144.08cm, 131.04cm, 20.33cm; asexual reproduction average diffusion area per genet were 33.24m², 15.16m², 0.77m². Asexual reproduction diffusion area showed very significantly (P=0.001) decreased trend with community environment stability increased.3. Fitness R (R=Σ1_x b_x) on the semi-fixed sandy land was far greater than on the shifting sandy and fixed sandy land. Asexual reproduction diffusion area and ramet quantity of Artemisia halodendron were the largest on the shifting sandy land, so asexual reproduction ability of Artemisia halodendron population is the strongest. Reproductive strategies including fitness, reproductive allocation, reproductive investment, reproduction Value, fecundity on semi-fixed sandy land were the most. It indicated that sexual reproduction dominate. Fruit set was lower, weight per 1000 grain seed and seed vigor were the largest of Artemisia halodendron population on the fixed sandy land. But population vigor failed on the whole so that population regenerated tardily, asexual and sexual reproduction died down, population declined.4. RAPD analyses of different Artemisia halodendron population showed percentage of polymorphic loci was 87.27% on the shifting sandy land, 67.27% on the semi-fixed sandy land and fixed sandy land. Genetic diversity estimated by Shannon index and Nei index on the shifting sandy land was higher than on the fixed sandy land. It was the smallest on the semi-fixed sandy land. Gst value revealed genetic differentiation among different populations was less than in the same population. Genetic differentiation within the population on the shifting sandy land was obvious higher than the other two populations. Genetic identity of population between the semi-fixed sandy land and the fixed sandy land was the largest.