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Study On Seed Germination And Seed Dispersal Of Several Plants In Arid Area

Posted on:2005-01-02Degree:MasterType:Thesis
Country:ChinaCandidate:P HuaFull Text:PDF
GTID:2120360125959174Subject:Botany
Abstract/Summary:PDF Full Text Request
The plant which grows in arid area has peculiar structure or way to adapt to the dry environment. In seed dispersal and seed germination, it also has peculiar mechanism adapting to the dry environment. With different ways of seed dispersal and seed germination, seed bank is supplied and population expanded.The seed dispersal and seed germination is an important factor which affects extension and expansion of the plant population.With an overall consiseration of the disperasal, seed germination and environment factors, we analyse their possible function in population extension and expansion, finding out the key factor of population expansion and restriction factor of population shrinking, therefore we can estimate the different type of plants adapt to the changed environment in differern habitat.Populus euphratica, Asperugo procumbens,Seriphidium santolinum and Sophora alopecuroides are important plants in arid area of northwest China, they belong to different genus. These plants have important ecological functions in arid area,but they distribute in different area ,and the change of population are different too.The studies on germination of four plants influenced by ecological factors such as soil moisture content, light,temperature ect, at the same time, seeds dispersal are studied in open air, the result show :① the seeds of Populus euphratica are tiny, and seeds germinate in summer. The seeds germination condition are high temerapture(20-30℃) and high soil miosture content. New seeds have high germination rate on the surface of soil. A Populus euphratica tree can produce numerous seeds, and seeds can distribute long distance with the help of wind. The life-span of seeds are short(most of seeds only survive one month in open air). From 1950, human activity changed environment intensely,seedings rarely emerged on a large scale in open air because of the limition of life-span and gremination area, it is one of the reasons for Populus euphratica declined constantly. ②Asperugo procumbens belong to early spring ephmrals. It's seeds germinate in early sping with optimal temeperature of 10-15℃, the seeds are not light favored ones ,the germination take place at a narrow temeperature range and high soil miosture content. The type of seed dispersal is self dispersal,.the distance and range of seed dispersal limited by length of stem. ③Seriphidium santolinum is harb plant of active sand dune, the seeds are light favored ones,the optimal temperature for germination is 10-20℃. If the sand depth is higher than 0.5cm,seeding seldom emeraged from sand, The type of seed dispersal is self dispersal and in a very small distrabution area. Both the seeds of Asperugo procumbens and Seriphidium santolinum germinate in spring, the germination is not limited by area because sand moisture is high everywhere in North Xinjiang in spring, the germination is closly related to the change of clmite of spring. ④Sophora alopecuroides is perennial grass species of Fabaceae, the seed coat Sophora alopecuroides is thick and hard, it is difficult to absorb moisture,so the germination rate of Sophora alopecuroides seed is low. High temerapture(30℃) improve the germinatio rate.The type of seed dispersal is self despersal and seeds do not depart from their parent plant right away when seeds have matured.. The population of Sophora alopecuroides expend fastly in arid area because it has strong ability of asexual propagation.
Keywords/Search Tags:Populus euphratica, Asperugo procumbens, Seriphidium santolinum, Sophora alopecuroides, seed germination, seed disperasal
PDF Full Text Request
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