Seed Germination And Seedling Establishment Of Ten Xerophytes

With the influence of climate and human activities in recent years,the degree and speed of desertification in Inner Mongolia are deepening,which leads to vegetation degradation and endangered species.Planting drought plants with wind and sand fixation has become the key measures to improve the ecological environment.This thesis takes the seeds of ten typical dry plants in desert areas,such as Ammopiptanthus mongolicus,Zygophyllum xanthoxylon,Tetraena mongolica,Reaumuria songarica,Haloxylon ammodendron,Calligonum alaschanicum,Hedysarum scoparium,Caragana korshinskii,Prunus mongolica and Peganum harmala and take them as the main research object,and studies the morphological characteristics and physiological characteristics.By contrast,the fastest and best way to break the dormancy state of seeds is selected.Based on the above,the optimum combination of germination conditions was studied by setting different temperature,light condition and germination bed treatment,and the drought resistance ability of seeds was evaluated by simulating drought stress treatment.Finally,different water conditions were set up to explore the influence of water on seedling construction and provide effective scientific basis for the construction of such plants in arid desert areas.The main findings are as follows:1.The seeds of Prunus mongolica,Ammopiptanthus mongolicus and Calligonum alaschanicum,while the seeds of Prunus mongolica existed physical dormancy and physiological dormancy.By removing the inner fruit skin of seeds,the physical dormancy can be quickly removed,and the seeds after low temperature stratification can release physiological dormancy.The seed of Ammopiptanthus mongolicus has the water absorption barrier of seed coat,and the dormancy of seeds could be broken by soaking seeds in water and grinding seeds husk.The best treatment is soaking seeds for 2 days at room temperature.Physiological dormancy existed in the seeds of Calligonum alaschanicum and the dormancy degree was large.The germination rate of the seeds of the date was the highest at low temperature of 4 ? for 30 days,and the breaking dormancy effect was the most obvious.2.The optimum germination temperature of most seeds was between 20 ? and25 ?.And the optimum germination temperature of the seeds of Haloxylon ammodendron was lower,which is 15 ? and the optimum germination temperature of the seeds of Calligonum alaschanicum was higher,which is 30 ?.The germination of seeds of Peganum harmala was promoted by light.Under the light condition,the Germination Effect of seeds of Zygophyllum xanthoxylon,Reaumuria songarica,Prunus mongolica,Ammopiptanthus mongolicus and Calligonum alaschanicum were good,and whether the light had no significant effect on the seeds of Hedysarum scoparium,Prunus mongolica,Ammopiptanthus mongolicus.Most of the seeds were the best germination bed on paper and between paper.3.The seeds of Peganum harmala,Zygophyllum xanthoxylon,Hedysarum scoparium,Tetraena mongolica and Ammopiptanthus mongolicus can resist low degree of drought stress,the seeds of Haloxylon ammodendron can resist medium degree of drought stress,and the seeds of Caragana korshinskii,Reaumuria songarica and Prunus mongolica have poor resistance to drought stress.4.The optimum water condition for seedling establishment was 80 % of soil saturated water content.Seedling of Peganum harmala and Haloxylon ammodendron had strong drought tolerance.