Blumstein Meghan, Gersony Jessica, Martínez-Vilalta Jordi, Sala Anna
Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
Department of Natural Resources, University of New Hampshire, Durham, New Hampshire, USA.
Glob Chang Biol. 2023 Apr;29(7):1854-1869. doi: 10.1111/gcb.16573. Epub 2023 Jan 9.
Woody plant species store nonstructural carbohydrates (NSCs) for many functions. While known to buffer against fluctuations in photosynthetic supply, such as at night, NSC stores are also thought to buffer against environmental extremes, such as drought or freezing temperatures by serving as either back-up energy reserves or osmolytes. However, a clear picture of how NSCs are shaped by climate is still lacking. Here, we update and leverage a unique global database of seasonal NSC storage measurements to examine whether maximum total NSC stores and the amount of soluble sugars are associated with clinal patterns in low temperatures or aridity, indicating they may confer a benefit under freezing or drought conditions. We examine patterns using the average climate at each study site and the unique climatic conditions at the time and place in which the sample was taken. Altogether, our results support the idea that NSC stores act as critical osmolytes. Soluble Sugars increase with both colder and drier conditions in aboveground tissues, indicating they can plastically increase a plants' tolerance of cold or arid conditions. However, maximum total NSCs increased, rather than decreased, with average site temperature and had no relationship to average site aridity. This result suggests that the total amount of NSC a plant stores may be more strongly determined by its capacity to assimilate carbon than by environmental stress. Thus, NSCs are unlikely to serve as reservoir of energy. This study is the most comprehensive synthesis to date of global NSC variation in relation to climate and supports the idea that NSC stores likely serve as buffers against environmental stress. By clarifying their role in cold and drought tolerance, we improve our ability to predict plant response to environment.
木本植物物种储存非结构性碳水化合物（NSCs）用于多种功能。虽然已知NSC储存可缓冲光合供应的波动，比如在夜间，但NSC储存也被认为可通过作为备用能量储备或渗透剂来缓冲极端环境，如干旱或低温。然而，关于NSCs如何受气候影响的清晰图景仍不明确。在此，我们更新并利用一个独特的全球季节性NSC储存测量数据库，以研究最大总NSC储存量和可溶性糖含量是否与低温或干旱的渐变模式相关，这表明它们可能在冷冻或干旱条件下带来益处。我们使用每个研究地点的平均气候以及采样时和采样地点的独特气候条件来研究模式。总体而言，我们的结果支持NSC储存作为关键渗透剂的观点。地上组织中的可溶性糖随寒冷和干燥条件增加，表明它们可灵活增加植物对寒冷或干旱条件的耐受性。然而，最大总NSCs随地点平均温度升高，而非降低，且与地点平均干旱程度无关。这一结果表明，植物储存的NSC总量可能更多地由其碳同化能力决定，而非环境胁迫。因此，NSCs不太可能作为能量储备。这项研究是迄今为止关于全球NSC与气候关系变化的最全面综合研究，支持NSC储存可能作为抵御环境胁迫缓冲剂的观点。通过阐明它们在耐寒和耐旱方面的作用，我们提高了预测植物对环境反应的能力。
