RELATIONSHIPS BETWEEN FLOWERING PHENOLOGY AND LIFE-HISTORY STRATEGIES IN TUNDRA PLANTS
RELATIONSHIPS BETWEEN FLOWERING PHENOLOGY AND LIFE-HISTORY STRATEGIES IN TUNDRA PLANTS
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DOI：
10.2307/1551922
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发表时间：
1993-11-01
期刊：
影响因子：
--
通讯作者：
MOLAU, U
中科院分区：
文献类型：
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作者：
MOLAU, U
温带植物在生活史策略（例如，沿着r-K连续体）、交配系统（花粉：胚珠、种子：胚珠和果实：花比率）和遗传群体结构。在冻土带，如果我们只使用生活史特征（寿命，资源分配模式等），几乎所有的植物都将被归类为K策略者。然而，物种之间在生殖特征方面存在巨大差异，例如种子：胚珠和果实：花的比例，因此在其他生物群中有效的关系存在脱钩。相反，北极和高山植物的繁殖策略与开花物候表现出很强的相关性，从而也与积雪覆盖时间。早开花的物种表现出高远缘繁殖率和低种子：胚珠比例，大部分的遗传变异是在当地人群中发现的;相反的情况适用于晚开花的物种。这两种情况是一个连续统的极端，但北极植物可以很容易地在这个模型中分类，就像温带植物在r-K模型中一样。雌蕊异株和雌雄异株的繁殖系统只在早开花的物种中大量存在，而无融合生殖和胎生仅限于晚开花的物种。从早开花到晚开花，物种间倍性水平的变异增加。根据花在繁殖上的资源的对冲类型，早花和晚花群体分别被认为是花粉风险和种子风险策略者。
Temperate plants show high correlations between life history strategies (e.g., along the r-K continuum), mating systems (in terms of pollen:ovule, seed: ovule, and fruit:flower ratios), and genetic population structure. In the tundra, nearly all plants would be categorized as being K-strategists if we use life history traits alone (life span, resource allocation patterns, etc.). However, there is immense variation among species with regard to reproductive traits, such as seed:ovule and fruit: flower ratios, and thus there is a decoupling of the relationships that are valid in other biota. Instead, the reproductive strategies of arctic and alpine plants show strong correlations with flowering phenology, and thereby also with snow cover duration. Early-flowering species show high outbreeding rates and low seed: ovule ratios, and most of the genetic variation is found within local populations; the opposite situation applies in late-flowering species. These two cases are the extremes of a continuum, but arctic plants can be as readily categorized in this model as temperate plants are in the r-K model. Gynodioecious and dioecious breeding systems are abundant only among early-flowering species, whereas apomixis and vivipary are restricted to the late-flowering species. The variation in ploidy levels among species increase from early- to late-flowering. According to the kind of bet-hedging with the resources spent on reproduction, the early- and late-flowering groups are recognized as pollen-risk and seed-risk strategists, respectively.