Chondol Thinles, Klimeš Adam, Hiiesalu Inga, Altman Jan, Čapková Kateřina, Jandová Veronika, Kopecký Martin, Macek Martin, Řeháková Klára, Doležal Jiří
Institute of Botany, Czech Academy of Sciences, Dukelská 135, 379 01 Třeboň, Czech Republic.
Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic.
Ann Bot. 2025 Jan 27. doi: 10.1093/aob/mcaf014.
Understanding interspecific differences in plant growth rates and their internal and external drivers is key to predicting species responses to ongoing environmental changes. Annual growth rates vary among plants based on their ecological preferences, growth forms, ecophysiological adaptations, and evolutionary history. However, the relative importance of these factors remains unclear, particularly in high-mountain ecosystems experiencing rapid changes.
We examined how habitat associations, elevational optima, growth forms, and ecophysiological and anatomical traits influence interspecific differences in radial growth rates among 324 vascular dicot species naturally occurring in the western Himalayas. Growth rates were determined from annual ring width measurements on the oldest plant sections of over 7,800 individuals from a range of habitats (desert, steppe, wetland, alpine, subnival), growth forms (perennial tap-rooted, rhizomatous, cushiony, woody), and climatic gradients (elevations of 2,650-6,150 m).
Habitat associations accounted for 24% of the variability in interspecific growth rates. Adding growth form and height increased the explanation to 42%, and incorporating plant functional traits further improved predictions to 46%. Growth rates were higher in warmer, drier conditions and lower in cold, wet environments. Subnival cushion plants had the slowest growth, while ruderal plants grew the fastest. Desert plants showed higher growth rates, reflecting their drought adaptive strategies, while wetland forbs had lower growth rates due to increased resource competition. Growth was positively correlated with leaf nitrogen content and non-structural carbohydrates (mainly fructans), due to enhanced photosynthesis and stress tolerance, and negatively correlated with leaf carbon and root nitrogen content.
Our study of 324 dicot species in the western Himalayas suggests that plant growth in high elevations is determined by a combination of habitat conditions, morphological traits, and ecophysiological adaptations. Growth variations among the highest-growing angiosperms reflect adaptive strategies along the global 'fast-slow' and 'acquisitive-conservative' spectrums. These results underscore the importance of habitat-specific studies for predicting plant growth responses to environmental changes, emphasizing a species-specific approach for effective conservation in fragile ecosystems.
了解植物生长速率的种间差异及其内在和外在驱动因素是预测物种对当前环境变化响应的关键。植物的年生长速率因生态偏好、生长形式、生态生理适应性和进化历史而异。然而，这些因素的相对重要性仍不清楚，尤其是在经历快速变化的高山生态系统中。
我们研究了生境关联、海拔最适值、生长形式以及生态生理和解剖特征如何影响喜马拉雅山西部自然生长的324种维管束双子叶植物种间径向生长速率的差异。生长速率是通过对来自一系列生境（沙漠、草原、湿地、高山、亚高山）、生长形式（多年生直根、根茎、垫状、木质）和气候梯度（海拔2650 - 6150米）的7800多个个体最老植株部分的年轮宽度测量来确定的。
生境关联占种间生长速率变异性的24%。加入生长形式和高度后，解释率提高到42%，纳入植物功能性状进一步将预测提高到46%。生长速率在温暖、干燥条件下较高，在寒冷、潮湿环境中较低。亚高山垫状植物生长最慢，而杂草植物生长最快。沙漠植物显示出较高的生长速率，反映了它们的干旱适应策略，而湿地草本植物由于资源竞争增加生长速率较低。生长与叶片氮含量和非结构性碳水化合物（主要是果聚糖）呈正相关，这是由于光合作用增强和胁迫耐受性提高，与叶片碳和根氮含量呈负相关。
我们对喜马拉雅山西部324种双子叶植物的研究表明，高海拔地区的植物生长由生境条件、形态特征和生态生理适应性共同决定。生长最快的被子植物之间的生长差异反映了沿全球“快 - 慢”和“获取 - 保守”光谱的适应策略。这些结果强调了针对特定生境的研究对于预测植物对环境变化的生长响应的重要性，强调了在脆弱生态系统中采取特定物种方法进行有效保护的重要性。
