HETEROBLASTY IN BROMELIADS: ITS FREQUENCY IN A LOCAL FLORA AND THE TIMING OF THE TRANSITION FROM ATMOSPHERIC TO TANK FORM IN THE FIELD
HETEROBLASTY IN BROMELIADS: ITS FREQUENCY IN A LOCAL FLORA AND THE TIMING OF THE TRANSITION FROM ATMOSPHERIC TO TANK FORM IN THE FIELD
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DOI：
10.1086/666665
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发表时间：
2012-09-01
影响因子：
2.3
通讯作者：
Zotz, Gerhard
中科院分区：
文献类型：
--
作者：
Meisner, Kerstin;Zotz, Gerhard
异胚性的患病率和功能相关性，即，在许多被子植物中，个体发育的突然形态变化仍然不清楚。为了获得第一次估计的数量heteroblastic凤梨，我们使用了一个简单的度量来区分明确heteroblastic从homoblastic物种。我们通过确定个体发育阶段（大气和坦克）之间的过渡时间，并通过比较不同栖息地的异胚性的患病率来解决生态相关性。在巴拿马的一个低地和山地森林中研究了附生的铁兰亚科。重复普查允许估计的相对增长率和14个物种的个体发育轨迹的建设。叶指数（叶长/宽）的数据，采取了23种。叶指数的个体发生变化可靠地区分同胚种和异胚种。异胚种的早期大气阶段平均持续3年，相当于平均世代时间的20%。异胚种在林下植被中和在裸露的生长地一样普遍。这一发现挑战了异胚性作为对干旱的适应的概念，因为在潮湿和干燥的栖息地中，异胚性物种的比例没有差异。提出了一个备择假设。
The prevalence and functional relevance of heteroblasty, i.e., abrupt morphological changes in ontogeny in many angiosperms, remain obscure. To obtain a first estimate of the number of heteroblastic bromeliads, we used a simple metric to distinguish unambiguously heteroblastic from homoblastic species. We addressed ecological relevance by determining the time for transition between ontogenetic stages (atmospheric and tank) and by comparing the prevalence of heteroblasty in different habitats. Epiphytic Tillandsioideae were studied in a lowland and a montane forest in Panama. Repeated censuses allowed estimates of relative growth rates and the construction of ontogenetic trajectories for 14 species. Data on leaf index (leaf length/width) were taken for 23 species. Ontogenetic changes in leaf index reliably separate homoblastic and heteroblastic species. The early atmospheric stage in heteroblastic species lasts, on average, 3 yr, equivalent to 20% of the average generation time. Heteroblastic species are as common in the understory as at exposed growing sites. This finding challenges the notion of heteroblasty as an adaptation to drought, because there are no differences in the proportion of heteroblastic species in wet and dry habitats. An alternative hypothesis is proposed.