【作者】 华鹏；

【导师】 黄培祐；

【作者基本信息】 新疆大学 ， 植物学， 2004， 硕士

【摘要】 干旱区的植物，除了具有独特的结构或方式适应干旱环境外，在种子散布和种子萌发方面，也各自具有独特的机制与干旱环境相适应。植物通过不同的种子散布和萌发方式，达到了对种子库的补充和种群扩展的目的。种子萌发和种子散布是影响植物种群延续和扩展的一个重要方面。将种子散布、种子萌发和环境因素综合考虑，分析种子特性、散布特性和萌发特性对种群延续和扩展的作用，找出种群扩展的关键因素和种群萎缩的制约因素，判断在不同的生境下，不同类型的植物种子适应环境的方式。胡杨（Populus euphratica Oliv.）、糙草(Asperugo procumbens L.)、沙漠绢蒿(Seriphidium santolinum (Schrenk) Poljak.)和苦豆子(Sophora alopecuroides L.)是干旱区四种不同科属的植物，分布于不同区域环境，有着不同的适应特性，也都具有一定的生态作用，多年来，四种植物种群变化情况各不相同。对四种植物在不同因子下的种子萌发和种子散布的研究，结果表明：①胡杨种子极小；种子成熟以后立即萌发，萌发率高；种子萌发季节为夏季，种子萌发需要高温（20-30℃）、湿润环境，种子应在土壤表层萌发；胡杨种子寿命短，野外大部分种子在一个月左右就失去发芽能力；一棵胡杨树能产生数目极多的种子，种子具有远距离散布能力；近几十年来，由于人为活动造成了环境的变化，胡杨种子受到种子寿命和种子萌发区域（地点）的限制，在野外，多年未出现有效的幼苗补充，这是胡杨林萎缩的一个重要原因。②糙草是一年生短命植物，种子在早春时节萌发，种子萌发适宜温度是10-15℃，萌发需要湿润的环境，光照对种子萌发影响不大；种子散布属于独立散布；散布距离和范围受植株茎延伸长短的影响，一般散布距离不超过50cm。③沙漠绢蒿生长于流沙地，种子萌发季节为春季，适宜温度是10-20℃，种子萌发受光照影响大，野外适宜种子萌发的土壤埋深不应超过0.5cm；种子散布类型是独立散布，散布距离短，<WP=3>散布距离也在50cm。糙草和绢蒿都在春季萌发，由于北疆地区融雪水造成湿润环境范围很广，它们种子萌发受地域影响小，由于春季气温变化剧烈，气温的升降速度和幅度对湿润环境持续时间影响大，所以每年糙草和绢蒿种子萌发情况和种群的变化与春季气候息息相关。④苦豆子种子是多年生草本植物，由于种皮限制，种子萌发率比较低，种子萌发适宜温度是30℃，光照对种子萌发影响不大；种子散布是独立散布，大多数种子散布在60cm范围内，极少数种子散布可达100cm；且种子具有延迟散布的现象；由于苦豆子植株具有很强的根茎萌蘖能力，使在干旱区其它植物种群萎缩的情况下，苦豆子种群迅速扩展。更多还原

【Abstract】 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 <WP=5>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.更多还原