New insights into leaf and fine-root trait relationships: implications of resource acquisition among 23 xerophytic woody species.

Functional traits of leaves and fine root vary broadly among different species, but little is known about how these interspecific variations are coordinated between the two organs. This study aims to determine the interspecific relationships between corresponding leaf and fine-root traits to better understand plant strategies of resource acquisition. SLA (Specific leaf area), SRL (specific root length), mass-based N (nitrogen) and P (phosphorus) concentrations of leaves and fine roots, root system, and plant sizes were measured in 23 woody species grown together in a common garden setting. SLA and SRL exhibited a strong negative relationship. There were no significant relationships between corresponding leaf and fine-root nutrient concentrations. The interspecific variations in plant height and biomass were tightly correlated with root system size characteristics, including root depth and total root length. These results demonstrate a coordinated plant size-dependent variation between shoots and roots, but for efficiency, plant resource acquisition appears to be uncoupled between the leaves and fine roots. The different patterns of leaf and fine-root traits suggest different strategies for resource acquisition between the two organs. This provides insights into the linkage between above- and belowground subsystems in carbon and nutrient economy.