Drought tolerance increases with seed size in a semiarid grassland from southern Mexico
Drought tolerance increases with seed size in a semiarid grassland from southern Mexico
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DOI：
10.1007/s11258-020-01056-7
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发表时间：
2020-07-27
期刊：
影响因子：
1.7
通讯作者：
Martorell, Carlos
中科院分区：
文献类型：
--
作者：
Martinez-Lopez, Marcela;Tinoco-Ojanguren, Clara;Martorell, Carlos
由于面对不利条件的储备增加，耐旱性应随着种子大小的增加而增加。这已在实验室中得到证实，但在田间条件下的模式尚未found.We测试是否耐旱性增加种子大小在半干旱草原田间条件下。我们记录的性能（发芽，存活和生长）的12种不同大小的种子播种条件下与水分胁迫：沿着自然应力梯度相关的土壤深度，并根据实验操作的辐照度水平，影响蒸发，从而土壤湿度。我们估计每个性能指标的耐旱性指数，以及一个多变量的容忍度指数，集成了不同的组件的性能。每个指数回归种子大小占系统发育的影响。种子大小对个体指标的影响不大，但所有测试的联合证据显示，种子大小与种子大小呈明显的正相关。多元耐受指数也随着种子大小而增加，证实了预期的关系。这表明，可能需要采取涵盖整个生命周期的综合措施，才能适当地确定耐旱性的特征，这也可以解释为什么这种模式在大多数研究中仍然难以捉摸。此外，我们使用的种子大小范围很窄，所以种子大小和耐受性之间的关系可能只适用于小种子物种。
Due to increased reserves available to face adverse conditions, drought tolerance should increase with seed size. This has been confirmed in the laboratory, but under field conditions the pattern has not yet been found. We tested whether drought tolerance increases with seed size under field conditions in a semiarid grassland. We recorded the performance (germination, survival, and growth) of 12 species with different-sized seeds sown under conditions associated with hydric stress: along a natural stress gradient related to soil depth, and under experimentally manipulated irradiance levels that affected evaporation and thus soil humidity. We estimated drought tolerance indices for each performance metric, as well as a multivariate tolerance index that integrated the different components of performance. Each index was regressed on seed size accounting for phylogenetic effects. Seed size had little effect on individual metrics, but the joint evidence from all tests revealed a clear positive correlation with seed size. The multivariate tolerance index also increased with seed size, confirming the expected relationship. This suggests that comprehensive measures encompassing the whole life cycle may be required to characterize drought tolerance properly and may explain why this pattern has remained elusive in most studies. Also, we used a narrow range of seed sizes, so there is the possibility that the relationship between seed size and tolerance holds only for small-seeded species.