Local climate controls among-population variation in germination patterns in two Erica species across western Iberia
Local climate controls among-population variation in germination patterns in two Erica species across western Iberia
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DOI：
10.1017/s0960258518000041
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发表时间：
2018-06-01
影响因子：
2.1
通讯作者：
Moreno, Jose M.
中科院分区：
文献类型：
--
作者：
Chamorro, Daniel;Luna, Belen;Moreno, Jose M.
在季节性气候中，发芽时间主要受温度控制，特别是在具有生理种子休眠的物种中。然而，在物种的分布范围内，对温度的萌发反应可能在种群之间有所不同。了解沿着气候梯度的人口对温度的敏感性如何变化，对于确定他们对气候变异性和变化的脆弱性非常重要。本文研究了两种具有生理种子休眠的埃里卡（E. australis和E. umbellata）到整个季节（模拟秋季到春季）的温度变化以及伊比利亚西部纬度梯度上六个地点的当地气候。研究了在有和没有将种子暴露于热休克的情况下的效果。种子种源的当地气候是改变种子萌发对萌发温度的敏感性及其季节变化的关键因素。虽然每个物种都表现出特异质的发芽反应温度处理和整个梯度，这两个物种的发芽是敏感的温暖的温度和热休克。两者都表现出相似的季节性发芽模式：当我们从南到北移动时，种群往往在春季有一个较大的发芽高峰，在较冷的温度下更大。我们的结论是，与气候变化相关的气温上升将影响这些物种，特别是在它们的北方范围，那里的许多种子将在温暖的冬季保持休眠状态。可以说，旨在评估气候变化对这些物种影响的模型需要包括跨纬度的这种变化。
In seasonal climates, germination timing is mainly controlled by temperature, especially in species with physiological seed dormancy. The germination response to temperature may, however, vary among populations across the distribution range of species. Understanding how populations along climate gradients vary in their sensitivity to temperature is important for determining their vulnerability to climate variability and change. Here, we investigated the germination response of two Erica species with physiological seed dormancy (E. australis and E. umbellata) to changes in temperature throughout the seasons (simulated autumn through to spring) and to the local climate in six localities across a latitudinal gradient in western Iberia. Effects were studied with and without exposing the seeds to a heat shock. The local climate of seed provenance emerged as a key factor in modifying the germination sensitivity to germination temperature and their variation through the seasons. Although each species showed idiosyncratic germination responses to temperature treatments and across the gradient, germination of both species was sensitive to warmer temperatures and to a heat shock. Both showed similar seasonal germination patterns: as we moved from south to north, populations tended to have a larger germination peak in spring, which was greater at colder temperatures. We conclude that rising temperatures associated with climate change will affect these species, particularly at their northern ranges, where many seeds will remain dormant during warmer winters. Arguably, models aiming at assessing climate change impacts in these species need to include such variability across latitude.