Seed germination inLaunaea arborescens: a continuously flowering semi-desert shrub☆
Seed germination inLaunaea arborescens: a continuously flowering semi-desert shrub☆
复制标题
Launaea arborescens 的种子发芽：连续开花的半荒漠灌木☆
DOI：
--
复制
发表时间：
1997
期刊：
影响因子：
--
通讯作者：
P. Milberg
中科院分区：
文献类型：
--
作者：
W. Schütz;P. Milberg
多年生灌木（菊科）的瘦果（种子）在多种环境条件下发芽。没有一颗种子处于休眠状态，也没有任何证据表明休眠可以被诱导。显然，这种半沙漠物种没有办法阻止它们立即发芽。瘦果一年四季都有生产和分布，我们认为发芽的时间受湿润的持续时间和程度以及土壤温度适中的影响。这种发芽行为表明，没有任何机制可以使一年形成的种子的发芽推迟到第二年。相比之下，大多数沙漠植物积累了持久的种子库。树芽草的萌发策略应被认为是机会性的，种群的生存是由其他生活史特征保证的，如持续的互操作性和有效的风传播。
Achenes (seeds) of the perennial shrub Launaea arborescens (Asteraceae) germinated under a wide range of environmental conditions. None of the seeds were dormant, nor was there any evidence that dormancy could be induced. Apparently, this semi-desert species has no means of preventing immediate germination. Achenes are produced and dispersed throughout the year, and we suggest that the timing of germination is regulated by the duration and degree of wetting and the presence of moderate soil temperatures. This germination behaviour suggests that there is no mechanism by which the germination of seeds formed one year can be delayed until subsequent years. By contrast, most desert plants accumulate persistent seed banks. The germination strategy of L. arborescens must be considered opportunistic, and we suggest that the survival of populations is ensured by other life history traits like continuous iteroparity and effective dispersal by wind.