埋藏条件下3种干旱荒漠植物的种子休眠释放和土壤种子库  

Seed dormancy release and soil seed bank of three arid desert plants under burial conditions

作　　者：王彦荣[1] 杨磊[1] 胡小文[1] 

机构地区：[1]草地农业生态系统国家重点实验室,兰州大学草地农业科技学院,兰州730020

出　　处：《植物生态学报》2012年第8期774-780,共7页Chinese Journal of Plant Ecology

基　　金：国家重点基础研究发展规划项目(2007CB-108904);国家自然科学青年基金项目(31001030)资助

摘　　要：对种子休眠的自然释放及其作用因素的研究,是了解种子休眠生态学、种群适应机制的重要途径。以内蒙古阿拉善干旱荒漠区的3种主要植物牛枝子(Lespedeza potaninii)、唐古特白刺(Nitraria tangutorum)和骆驼蒿(Peganum nigellastrum)为材料,研究了种子在野外埋藏18个月期间和4个埋深条件下的休眠释放特性和土壤种子库。3种植物种子在野外埋藏时(采收后5℃冷藏6个月)的休眠率分别为98%、95%和3%。结果显示,埋藏过程中,3种植物种子的休眠释放表现出不同的变化特性。对牛枝子而言,置于地表(0cm)的种子比埋藏于土中的种子的休眠释放快,埋藏期末,埋深0、2、5和10cm的种子的休眠率分别为64%、87%、86%和82%。唐古特白刺种子埋藏6个月后,各埋深的休眠已完全释放,释放速率随埋深增加而加快。骆驼蒿种子具有典型的季节性休眠循环特性,休眠率各年度最高点出现在10月份,释放速率随埋深增加呈减慢趋势。埋藏期末不同埋深条件下,牛枝子、唐古特白刺和骆驼蒿种子的平均田间萌发率分别为11%、12%和8%;平均室内萌发率分别为3%、74%和42%;而平均死种子率分别为3%、15%和10%。根据Thompson和Grime(1979)的土壤种子库分类体系,供试的3种植物都属于持久土壤种子库类型。Aims Our objective was to study the effects of depth and duration of seed burial in the field on seed dormancy release and soil seed bank dynamics of three desert plants. Methods The field burial experiment was conducted during an 18-month period at the site of the original seed collection at Alax Desert of Nei Mongol, China during April 2008 to October 2009. The species included Lespe- deza potaninii, Nitraria tangutorum and Peganum nigellastrum with the dormancy of 98%, 95% and 3%, respec- tively, at the beginning of burial （stored 6 months at 5 ℃ since harvested）. Four burial depths were used： 0, 2, 5 and 10 cm. Important findings Dormancy release patterns were different among the three species, The dormancy per- centage of L. potaninii seeds decreased from 98% at date of burial to 64% after 18-month burial on the soil sur- face （0 cm）; lower decreases were observed when buried at 2, 5 and 10 cm （82% to 87%）. Dormancy in N. tangutorum dropped from 95% to 1% after 6-month burial in the field. In contrast to these species, P. nigellastrum seeds exhibited seasonal pattern （dormancy cycle） during the experimental period. The maximum points of dormancy were observed in October in each of the two years, decreasing thereafter with dormancy of 3% when buried. The speed of dormancy release increased in N. tangutorum as the soil burial depth in- creased, but decreased in P. nigellastrum. At the end of 18-month burial, the field-germinated seeds on average of different buried depths were 11%, 12% and 8% for L. potaninii, N. tangutorum and P. nigellastrum, respectively; the average laboratory germinations were 3%, 74% and 42%, and dead seeds averaged 3%, 15% and 10%, respec- tively. According to the soil seed bank classification proposed by Thompson and Grime （1979）, L. potaninii, N. tangutorum and P. nigellastrum had persistent seed banks.

关 键 词：萌发 牛枝子 唐古特白刺 骆驼蒿 休眠释放 埋藏 土壤种子库 

分 类 号：S154.4[农业科学—土壤学]