【摘要】 用控制试验研究了沙米(Agriophyllum squarrosum)种子萌发对温度、水势和埋深的响应模式.结果显示,在人工模拟科尔沁沙地4月(5℃/20℃)、5月(10℃/30℃)和7月(20℃/40℃)的夜/昼土壤温度条件下,沙米种子的最终萌发率分别为86%、91%和96%,各温度处理的前3d累计萌发率分别为14%、66%和32%.在5月温度条件下,种子萌发曲线为陡直的单峰状,其他两月呈多峰状.0MPa水势下,沙米种子的总萌发率为50%,当水势低于-0.4MPa时,发芽率小于10%.当种子的埋藏深度分别为0.5、1.0、2.0和4.0cm时,出苗率分别为91%、78%、41%和22%,埋深达到8cm时,没有种子出苗.研究表明,沙米种子在不同条件下萌发率差异显著,其萌发特征有利于种子在不适环境条件下减少种子库的无效损耗,而在环境条件适宜时快速萌发,提高幼苗存活机会,从而使沙米对流沙生境表现出良好适应能力.更多还原

【Abstract】 Experiments were conducted to investigate the effects of temperature and water potential on the seed germination,and burial depth on the seedling emergence of Agriophyllum squarrosum.The results showed that:(1)about 86%,91% and 96% seeds germinated finally and about 14%,66% and 32% seeds germinated in the first 3 incubating days at 5℃/20℃,10℃/30℃ and 20℃/40℃,respectively,under an adequate water condition;(2)Below the water potential of-0.4 MPa,the seeds could hardly germinate;(3)The total emergence percentages at the burial depth of 0.5 cm,1.0 cm,2.0 cm,4.0 cm and 8 cm were 91%,78%,41%,22% and 0%,respectively.These germination characteristics might help A.squarrosum decrease the depletion of seed bank in adverse conditions,while increase the seedings survival when the suroundings are favorable,and thus improve its fitness on the moving sand dunes in the Horqin Sandy Land of Inner Mongolia,China.更多还原