Allocation to clonal and sexual reproduction and its plasticity in Vallisneria spinulosa along a water-depth gradient
Allocation to clonal and sexual reproduction and its plasticity in Vallisneria spinulosa along a water-depth gradient
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苦草克隆繁殖和有性繁殖的分配及其沿水深梯度的可塑性
DOI：
10.1002/ecs2.2070
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发表时间：
2018-01-01
期刊：
影响因子：
2.7
通讯作者：
Song, Zhiping
中科院分区：
文献类型：
--
作者：
Li, Lei;Lan, Zhichun;Song, Zhiping
水位的变化深刻地影响着淡水生态系统的功能稳定性，以及水生植物的生长和繁殖。尽管克隆植物的无性繁殖和有性繁殖分配之间的权衡会受到各种环境因素的影响，但生殖分配（RA）对不同环境的响应变化是否仅由大小依赖效应（表观可塑性）驱动，或者RA是否也可以独立于植物大小而变化（真正的可塑性）尚不确定。在9个6400 L的室外中型生态系统中，研究了多年生沉水植物刺苦草（Vallisneria spinulosa）在50、100和150 cm水深下的无性繁殖、有性繁殖和营养生长的响应。我们评估了大小依赖和大小无关的影响水深性和克隆RA。深水减少营养体大小和性产量（产生的果实质量），但增加块茎产量。在生物量投资方面，生殖模式之间存在明显的权衡;与浅水或中水中的植物相比，深水中的植物将更多的资源分配到克隆繁殖中，并减少对有性生殖的投资。坡度的异速生长关系（性与营养生物量和克隆与营养生物量）的水深显着影响。性RA在不同水深的变化在很大程度上是大小依赖性的，但也有大小独立的影响。与此相反，在确定克隆RA的大小变化的影响，大小无关的影响更重要。我们认为刺沙芥通过克隆繁殖和有性繁殖的可塑性平衡来适应水深梯度。此外，RA的大小独立的影响表明一个灵活的生殖策略，可能是植物在不断变化的水生环境中的性能至关重要。
Variations in water level profoundly affect functional stability of freshwater ecosystems, as well as macrophyte growth and reproduction. Although the trade-off between allocation to clonal and sexual reproduction in clonal plants can be influenced by a variety of environmental factors, whether variations of reproductive allocation (RA) in response to different environments are driven only by a size-dependent effect (apparent plasticity) or whether RA can also change independently of plant size (true plasticity) is uncertain. We conducted an experiment in nine outdoor mesocosms (6400L) to investigate the response of clonal and sexual reproduction and vegetative growth of a perennial submerged macrophyte Vallisneria spinulosa at water depths of 50, 100, or 150cm. We evaluated size-dependent and size-independent effects of water depth on sexual and clonal RA. Deep water reduced vegetative size and sexual output (mass of fruits produced), but increased tuber production of V. spinulosa. There was an apparent trade-off between reproductive modes in terms of biomass investment; plants in deep water allocated more resources into clonal propagation and reduced investment in sexual reproduction compared to plants in shallow or intermediate water. Slopes of allometric relationships (sexual vs. vegetative biomass and clonal vs. vegetative biomass) were significantly affected by water depth. Shifts in sexual RA in response to varying water depths were largely size-dependent, but there were also size-independent effects. In contrast, size-independent effects were more important than effects of size changes in determining clonal RA. We concluded that V.spinulosa adapted to a water-depth gradient by plastic trade-offs between clonal propagation and sexual reproduction. Furthermore, a size-independent effect on RA suggests a flexible reproductive strategy that could be critical for plant performance in changing aquatic environments.