Jiang Xiaoyan, Jia Xin, Gao Shengjie, Jiang Yan, Wei Ningning, Han Cong, Zha Tianshan, Liu Peng, Tian Yun, Qin Shugao
Yanchi Research Station, School of Soil and Water Conservation, Beijing Forestry University, Beijing, China.
Key Laboratory for Soil and Water Conservation, State Forestry and Grassland Administration, Beijing Forestry University, Beijing, China.
Front Plant Sci. 2021 Oct 26;12:734775. doi: 10.3389/fpls.2021.734775. eCollection 2021.
Although leaf economics spectrum (LES) has been extensively tested with regional and global datasets, the correlation among functional traits of desert plants remains largely unclear. Moreover, examinations on whether and how leaf and root traits are coordinated have yielded mixed results. We investigated variations in leaf and fine-root traits across 48 species in a desert community of northern China to test the hypotheses that (1) the leaf-trait syndrome of plant species in desert shrublands follows the predictions of the global LES, and is paralleled by a similar root-trait syndrome, (2) functional traits related to nutrient contents and resource uptake are tightly coordinated between leaves and fine roots in desert ecosystems where plant growth is limited primarily by dry and nutrient-poor conditions, and (3) traits as well as their relationships vary among functional groups. Our results partially supported the LES theory. Specific leaf area (SLA) was correlated with leaf tissue density, phosphorus content, and carbon-to-nitrogen ratio, but not with leaf nitrogen content. Specific root length (SRL) was not correlated with other fine-root traits, and fine-root traits were largely independent of each other. Therefore, fine-root traits did not mirror the leaf-trait syndrome. Fine-root nitrogen and phosphorus contents, nitrogen-to-phosphorous ratio, and carbon-to-nitrogen ratio all increased with analogous leaf traits, whereas SRL was not correlated with SLA. After phylogenetic effects were considered, nutrient contents and their ratios still displayed stronger coordination between leaves and fine roots than did SRL and SLA. The overall pattern of trait variations and relationships suggested differentiation among functional groups. Our results suggest that despite the absence of a root-trait syndrome, fine-root functions in the studied desert community were probably coordinated with leaf functions with respect to nutrient allocation and use.
尽管叶经济谱（LES）已通过区域和全球数据集进行了广泛测试，但沙漠植物功能性状之间的相关性仍 largely 不清楚。此外，关于叶和根性状是否以及如何协调的研究结果不一。我们调查了中国北方沙漠群落中 48 种植物的叶和细根性状变化，以检验以下假设：（1）沙漠灌丛植物物种的叶性状综合征遵循全球 LES 的预测，并伴有类似的根性状综合征；（2）在植物生长主要受干旱和养分贫瘠条件限制的沙漠生态系统中，与养分含量和资源吸收相关的功能性状在叶和细根之间紧密协调；（3）性状及其关系在功能组之间存在差异。我们的结果部分支持了 LES 理论。比叶面积（SLA）与叶组织密度、磷含量和碳氮比相关，但与叶氮含量无关。比根长（SRL）与其他细根性状无关，且细根性状在很大程度上相互独立。因此，细根性状并未反映叶性状综合征。细根氮和磷含量、氮磷比和碳氮比均随类似的叶性状增加，而 SRL 与 SLA 无关。在考虑系统发育效应后，养分含量及其比率在叶和细根之间仍比 SRL 和 SLA 表现出更强的协调性。性状变化和关系的总体模式表明功能组之间存在分化。我们的结果表明，尽管缺乏根性状综合征，但在所研究的沙漠群落中，细根功能在养分分配和利用方面可能与叶功能协调。
