浑善达克沙地冰草种子萌发、出苗和幼苗生长对土壤水分的反应

研究了浑善达克沙地 4～ 10月份土壤含水量变动情况和冰草种子萌发、出苗和幼苗生长对土壤含水量的响应。结果表明 ,4月下旬至 5月上中旬的土壤含水量对冰草种子萌发、出苗和定居极为关键。控制条件下 ,冰草种子萌发和出苗的最适土壤含水量范围是 12 %～ 2 0 % ,幼苗生长的最适土壤含水量是 12 %。当土壤含水量低于 3% ,冰草种子不能萌发 ,土壤含水量低于 6 %时 ,幼苗不能出土并定居。当土壤含水量达到 16 %时 ,冰草幼苗生物量有所下降。在 6 %～ 8%的土壤含水量条件下 ,植株将更多的生物量投资于根的生长

The responses of seed germination, seedling emergence and seedling growth in Agropyron cristatum to sand water content in Otindag Sandland, China

Agropyron cristatum (L.) Gaertn is a dominant perennial grass in Otindag Sandland, China. The survival and distribution of A. cristatum mainly depends on the mechanisms ensuring germination and seedling development at the right time and in a suitable place. We investigated the sand water content from April to October in Otindag Sandland and the responses of seed germination, seedling emergence and seedling growth in A. cristatum to sand water content (1, 2, 3, 4, 6, 8, 12, 16 and 20%). Results showed that the sand water content from the last ten-day of April to the first twenty-day of May was critical to seed germination, seedling emergence and seedling settlement in A. cristatum. The optimal sand water content for seed germination and seedling emergence in A. cristatum was 12 to 20%. The optimal sand water content for A. cristatum's seedling development was 12%. When sand water content was under 3%, seed could not germinate; when sand water content was under 6%, seedling could not emerge and settle. When sand water was 16 and 20%, biomass decreased a little. At 6 to 8%, seedling allocated more biomass to root.