Data from: Demographic fate of Arabidopsis thaliana cohorts of autumn- and spring-germinated plants along an altitudinal gradient

SUMMARY: 1) Understanding how plants respond and adapt to varying environmental conditions has attracted the attention of plant ecologists for decades. To study this process, altitudinal gradients are used because of their inherent variation in environmental conditions. In the current scenario of global warming, altitudinal gradients may also represent a valuable resource to deepen our understanding about plant adaptive responses to predicted changes in environmental conditions. 2) Nowadays, the study of adaptive variation demands equal contributions from ecology and genetics. We need to assess the effects of selective pressures on phenotypic variation but also the genetic and molecular basis of phenotypic traits. The annual plant Arabidopsis thaliana represents a useful model system for investigating adaptive variation. Here, I characterized patterns of life cycle variation in natural A. thaliana populations along an altitudinal gradient to unravel how the species copes with different environmental conditions. 3) I periodically monitored thousands of plants from eight populations in NE Spain over five years (2007–2011) to estimate survival and fecundity schedules for autumn- and spring-germinated plants. Data were used to estimate net reproductive rate for each life cycle type. Data were regressed against altitude to detect altitudinal climatic clines for life cycle variation. 4) Survival of spring-germinated A. thaliana plants was significantly higher than that of winter-germinated plants. Plants from both cohorts exhibited similar fecundity values. The net reproductive rate of spring-germinated plants was four-fold higher than that of autumn-germinated plants. The proportion of spring-germinated plants increased significantly with altitude. 5) Synthesis. Arabidopsis thaliana can behave as a winter or spring annual plant. Nevertheless, the spring annual life cycle is clearly relevant to maintain A. thaliana populations, particularly at high-elevation locations. It is suggested that germination timing represents one of the most relevant traits to focus our efforts to understand adaptive variation in A. thaliana. The results illustrate the potential of annual plants to adjust their life cycles to varying environmental conditions encountered along a climatic gradient, which could mitigate the effects of global warming on annual plant populations.

摘要：1) 数十年来，解析植物响应并适应多变环境条件的机制，始终是植物生态学界的研究热点。为探究该过程，研究者常借助海拔梯度开展研究，因其本身即存在环境条件的固有差异。在当前全球变暖的背景下，海拔梯度还可作为宝贵的研究资源，助力我们深入理解植物对预测性环境变化的适应性响应。2) 如今，适应性变异研究需要生态学与遗传学的协同贡献：既要评估选择压力对表型变异的影响，也要阐明表型性状的遗传与分子基础。一年生植物拟南芥（Arabidopsis thaliana）是探究适应性变异的理想模式系统。本研究针对沿海拔梯度分布的自然拟南芥种群，解析其生活周期变异模式，以揭示该物种应对不同环境条件的策略。3) 本研究于2007至2011年的五年间，定期监测西班牙东北部8个种群的数千株植株，以此估算秋萌与春萌植株的存活动态与繁殖力格局；利用所得数据估算不同生活周期类型的净繁殖率，并将数据与海拔进行回归分析，以检测生活周期变异沿海拔的气候梯度特征。4) 春萌拟南芥植株的存活率显著高于冬萌植株；两个萌发群的繁殖力值相近，但春萌植株的净繁殖率是秋萌植株的四倍。春萌植株的占比随海拔升高显著增加。5) 综合讨论：拟南芥可表现为冬性或春性一年生植物，但春性一年生生活周期对维持拟南芥种群至关重要，尤其在高海拔区域。研究表明，萌发时机是解析拟南芥适应性变异的核心性状之一。本研究结果阐明了一年生植物如何沿气候梯度调整生活周期以适应多变环境，这或可缓解全球变暖对一年生植物种群的负面影响。