Precipitation timing and soil substrate drive phenology and fitness of Arabidopsis thaliana in a Mediterranean environment
Precipitation timing and soil substrate drive phenology and fitness of Arabidopsis thaliana in a Mediterranean environment
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DOI：
10.1111/1365-2435.14391
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发表时间：
2023-07-02
影响因子：
5.2
通讯作者：
Schmitt，Johanna
中科院分区：
文献类型：
--
作者：
Martinez-Berdeja，Alejandra;Okada，Miki;Schmitt，Johanna
在地中海气候中，季节性降雨的时间决定了发芽，开花物候和健身。随着气候变化改变季节性降水模式，重要的是要问这些变化将如何影响植物种群的物候和适应性。我们用一年生植物拟南芥（Arabidopsis thaliana.In第一个实验中，我们操纵了降雨开始的日期，并记录了沙子和土壤基质上的发芽物候。在第二个实验中，我们操纵发芽日期，生长季节长度和中期干旱来测量它们对开花时间和适合度的影响。在每个实验中，我们使用分离种子休眠基因DOG 1和开花时间基因FRI的强和弱等位基因的多位点近等基因系来操纵种子休眠和开花时间。我们综合了第一个实验的发芽物候数据与第二个实验的适应度函数，以预测不同季节降雨情景下的种群适应度。发芽物候跟踪降雨开始，但在沙地上比在土壤上更慢，变化更大。许多种子在春天和夏天散布在沙子上，推迟了发芽，直到秋天温度较低。高休眠DOG1等位基因也阻止了春季和夏季的立即发芽。发芽时间强烈影响植物健身。繁殖力是最高的10月发芽队列和春季发芽下降。晚开花的FRI等位基因具有较低的繁殖力，尤其是在早秋和春季群体中。对种群适合度的预测表明：（1）秋雨的推迟会对种群适合度产生负面影响。(2)缓慢，可变的发芽沙缓冲种群对健身的影响变量春季和夏季降雨。(3)季节性选择有利于高休眠和早开花的基因型在地中海气候炎热干燥的夏天。高休眠DOG 1等位基因延迟春天分散的新鲜种子发芽，直到更有利的初秋条件，导致更高的预计人口fitness.These研究结果表明，地中海一年生植物种群容易受到季节性降水的变化，特别是在加州，降雨开始已经发生后。高度休眠、早开花基因型的适应性优势有助于解释这种策略在地中海人群中的流行。
In Mediterranean climates, the timing of seasonal rains determines germination, flowering phenology and fitness. As climate change alters seasonal precipitation patterns, it is important to ask how these changes will affect the phenology and fitness of plant populations. We addressed this question experimentally with the annual plant speciesArabidopsis thaliana.In a first experiment, we manipulated the date of rainfall onset and recorded germination phenology on sand and soil substrates. In a second experiment, we manipulated germination date, growing season length and mid‐season drought to measure their effects on flowering time and fitness. Within each experiment, we manipulated seed dormancy and flowering time using multilocus near‐isogenic lines segregating strong and weak alleles of the seed dormancy geneDOG1and the flowering time geneFRI. We synthesized germination phenology data from the first experiment with fitness functions from the second experiment to project population fitness under different seasonal rainfall scenarios.Germination phenology tracked rainfall onset but was slower and more variable on sand than on soil. Many seeds dispersed on sand in spring and summer delayed germination until the cooler temperatures of autumn. The high‐dormancyDOG1allele also prevented immediate germination in spring and summer. Germination timing strongly affected plant fitness. Fecundity was highest in the October germination cohort and declined in spring germinants. The late floweringFRIallele had lower fecundity, especially in early fall and spring cohorts. Projections of population fitness revealed that: (1) Later onset of autumn rains will negatively affect population fitness. (2) Slow, variable germination on sand buffers populations against fitness impacts of variable spring and summer rainfall. (3) Seasonal selection favours high dormancy and early flowering genotypes in a Mediterranean climate with hot dry summers. The high‐dormancyDOG1allele delayed germination of spring‐dispersed fresh seeds until more favourable early fall conditions, resulting in higher projected population fitness.These findings suggest that Mediterranean annual plant populations are vulnerable to changes in seasonal precipitation, especially in California where rainfall onset is already occurring later. The fitness advantage of highly dormant, early flowering genotypes helps explain the prevalence of this strategy in Mediterranean populations.Read the free Plain Language Summary for this article on the Journal blog.