Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas, USA.
Department of Biology, Tennessee Technological University, Cookeville, Tennessee, USA.
Plant Cell Environ. 2023 Nov;46(11):3337-3352. doi: 10.1111/pce.14632. Epub 2023 May 30.
Conservative flowering behaviours, such as flowering during long days in summer or late flowering at a high leaf number, are often proposed to protect against variable winter and spring temperatures which lead to frost damage if premature flowering occurs. Yet, due the many factors in natural environments relative to the number of individuals compared, assessing which climate characteristics drive these flowering traits has been difficult. We applied a multidisciplinary approach to 10 winter-annual Arabidopsis thaliana populations from a wide climactic gradient in Norway. We used a variable reduction strategy to assess which of 100 climate descriptors from their home sites correlated most to their flowering behaviours when tested for responsiveness to photoperiod after saturation of vernalization; then, assessed sequence variation of 19 known environmental-response flowering genes. Photoperiod responsiveness inversely correlated with interannual variation in timing of growing season onset. Time to flowering appeared driven by growing season length, curtailed by cold fall temperatures. The distribution of FLM, TFL2 and HOS1 haplotypes, genes involved in ambient temperature response, correlated with growing-season climate. We show that long-day responsiveness and late flowering may be driven not by risk of spring frosts, but by growing season temperature and length, perhaps to opportunistically maximize growth.
保守的开花行为，如在夏季长日下开花或在高叶数时晚期开花，通常被认为可以防止冬季和春季温度的变化，因为如果过早开花，就会导致霜冻破坏。然而，由于自然环境中的因素相对于个体数量而言很多，因此评估哪些气候特征驱动这些开花特性一直很困难。我们对来自挪威广泛气候梯度的 10 个冬季一年生拟南芥种群应用了多学科方法。我们使用了一种变量减少策略，来评估在春化饱和后对光周期响应性进行测试时，它们来自家乡的 100 个气候描述符中哪些与开花行为相关性最高；然后，评估了 19 个已知的环境响应开花基因的序列变异。对光周期的响应性与生长季节开始时间的年际变化呈负相关。开花时间似乎由生长季节长度决定，而秋季低温会缩短生长季节。参与环境温度响应的 FLM、TFL2 和 HOS1 单倍型的分布与生长季节气候相关。我们表明，长日响应和晚期开花可能不是由春季霜害的风险驱动的，而是由生长季节温度和长度驱动的，可能是为了有机会最大化生长。
