Examining how both climate and species distribution patterns correlate with leaf morphology can give insights into the ecological and evolutionary patterns that drive adaptive selection of leaf form and function. Drip‐tips are a common feature of leaves in rain forest tree species; they are thought to be an adaptation that aids leaf drying and maximizes photosynthesis in areas with high‐rainfall climates. We tested whether this macroecological pattern holds true across the precipitation gradients in a non‐rain forest region—the woodland savannas of Brazil known as the Cerrado—and compared our results with previous studies from Amazonia. Drip‐tips were, as expected, less common overall in the drier Cerrado than in Amazonia. In addition, within the Cerrado, drip‐tips were more prevalent in areas with higher rainfall as well as in Cerrado sites that were closer to Amazonia. Moreover, species that occurred across both the Cerrado and Amazonia had drip‐tips more often than species that were found only in the Cerrado. These findings support the hypothesis that drip‐tips are adaptive and that either the cost of retaining drip‐tips is low or that in drier regions they have other benefits.

中文翻译：

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塞拉多植物物种中的降水梯度，植物生物地理学和滴落现象的发生

研究气候和物种分布模式如何与叶片形态相关联，可以深入了解推动叶片形态和功能的自适应选择的生态和进化模式。滴头是雨林树种叶片的常见特征；它们被认为是有助于叶片干燥并在高降雨气候地区最大程度提高光合作用的一种适应方法。我们测试了这种宏观生态模式是否在非雨林地区（巴西的塞拉多森林地带热带稀树草原）的降水梯度范围内成立，并将我们的结果与亚马逊地区以前的研究进行了比较。正如预期的那样，较干燥的塞拉多地区的滴灌总体要比亚马逊地区少。此外，在塞拉多，在降雨较高的地区以及更靠近亚马逊地区的塞拉多地区，滴灌尖端更为普遍。此外，与仅在塞拉多地区发现的物种相比，塞拉多地区和亚马孙地区都存在的物种更容易出现滴水现象。这些发现支持这样的假说：滴头具有适应性，或者保持滴头的成本很低，或者在较干燥的地区它们还有其他好处。