Clinal variations in seedling traits and responses to water availability correspond to seed-source environmental gradients in a foundational dryland tree species
Clinal variations in seedling traits and responses to water availability correspond to seed-source environmental gradients in a foundational dryland tree species
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幼苗性状的临床变化和对可用水量的响应与基本旱地树种的种子源环境梯度相对应
DOI：
10.1093/aob/mcad041
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发表时间：
2023
期刊：
影响因子：
4.2
通讯作者：
Weisberg, Peter J
中科院分区：
文献类型：
--
作者：
Vasey, Georgia L;Urza, Alexandra K;Chambers, Jeanne C;Pringle, Elizabeth G;Weisberg, Peter J
在旱地生态系统中，针叶树物种受到更频繁和更严重的干旱的威胁，这可能使物种超越其生理极限。充足的幼苗培育对于未来抵御全球变化至关重要。我们使用了一个共同的花园温室实验，以确定如何幼苗功能性状的表达和可塑性不同的种子来源，响应梯度的水供应，专注于美国西部的基础旱地树种，单叶松。我们假设，生长相关的幼苗性状的表达将显示模式与当地的适应一致，鉴于种子源环境之间的倾斜变化。monophyllaseeds从23个站点分布在整个范围内的梯度干旱和季节性水分供应。共3320幼苗繁殖与四个浇水处理代表逐步减少水的可用性。第一年幼苗地上和地下生长相关性状进行了测定。性状值和性状可塑性，在这里代表浇水处理之间的变异程度，被模拟为浇水处理和种子源位置的环境条件的函数（即水的可用性，降水季节性）。关键结果我们发现，在所有处理下，来自干旱气候的幼苗比来自生长较低的地点的幼苗有更大的地上和地下生物量，即使考虑到种子大小的差异，季节水分限制也是如此。此外，性状可塑性响应浇水处理是最大的幼苗从夏季潮湿的网站经历周期性季风雨events.Conclusions我们的研究结果表明，P。monophyllaseedlings响应干旱通过可塑性在多个性状，但性状反应的变化表明，不同的人群可能会独特地响应当地气候的变化。这种特征多样性可能会影响未来在预计将经历与干旱有关的树木死亡率的林地补充幼苗的潜力。
Background and AimsIn dryland ecosystems, conifer species are threatened by more frequent and severe droughts, which can push species beyond their physiological limits. Adequate seedling establishment will be critical for future resilience to global change. We used a common garden glasshouse experiment to determine how seedling functional trait expression and plasticity varied among seed sources in response to a gradient of water availability, focusing on a foundational dryland tree species of the western USA,Pinus monophylla. We hypothesized that the expression of growth-related seedling traits would show patterns consistent with local adaptation, given clinal variation among seed source environments.MethodsWe collectedP. monophyllaseeds from 23 sites distributed across rangewide gradients of aridity and seasonal moisture availability. A total of 3320 seedlings were propagated with four watering treatments representing progressively decreasing water availability. Above- and below-ground growth-related traits of first-year seedlings were measured. Trait values and trait plasticity, here representing the degree of variation among watering treatments, were modelled as a function of watering treatment and environmental conditions at the seed source locations (i.e. water availability, precipitation seasonality).Key ResultsWe found that, under all treatments, seedlings from more arid climates had larger above- and below-ground biomass compared to seedlings from sites experiencing lower growing-season water limitation, even after accounting for differences in seed size. Additionally, trait plasticity in response to watering treatments was greatest for seedlings from summer-wet sites that experience periodic monsoonal rain events.ConclusionsOur results show thatP. monophyllaseedlings respond to drought through plasticity in multiple traits, but variation in trait responses suggests that different populations are likely to respond uniquely to changes in local climate. Such trait diversity will probably influence the potential for future seedling recruitment in woodlands that are projected to experience extensive drought-related tree mortality.