Flexible drought deciduousness in a neotropical understory herb

PREMISE OF THE STUDY: Adaptive divergence across environmental gradients is a key driver of speciation. Precipitation seasonality gradients are common in the tropics, yet drought adaptation is almost entirely unexplored in neotropical understory herbs. We examine two recently diverged neotropical spiral ginger species, one adapted to seasonal drought and one reliant on perennial water, to uncover physiological and life history traits involved in drought adaptation.
METHODS: We combine ecophysiological trait measurements in the field and greenhouse with experimental and observational assessment of real-time drought response to determine how Costus villosissimus (Costaceae) differs from C. allenii to achieve drought adaptation.
KEY RESULTS: We find that drought-adapted C. villosissimus has several characteristics indicating flexible drought avoidance via semi-drought-deciduousness and a fast economic strategy. Although the two species do not differ in water use efficiency, C. villosissimu...

研究背景：沿环境梯度的适应性分化是物种形成的核心驱动因素之一。降水季节梯度在热带地区十分常见，但目前新热带区林下草本的干旱适应研究几乎完全空白。本研究选取两个新近分化的新热带区螺旋姜（闭鞘姜属Costus）物种为研究对象，分别适应季节性干旱生境与依赖常年湿润环境，旨在揭示其干旱适应相关的生理与生活史特征。
研究方法：本研究结合野外与温室条件下的生态生理性状测定，以及针对实时干旱响应的实验与观测评估，以明确多毛闭鞘姜（Costus villosissimus，闭鞘姜科Costaceae）与艾伦闭鞘姜（C. allenii）在干旱适应策略上的差异。
主要研究结果：本研究发现，适应干旱的多毛闭鞘姜具备多项通过半旱落叶实现灵活避旱的特征，且采取快速资源经济策略。尽管两个物种在水分利用效率上并无显著差异，但多毛闭鞘姜……