The leaf is the main plant organ to make photosynthesis, the process to use the energy from sunlight, capturing carbon dioxide and releasing oxygen to the atmosphere. Life on Earth, as we currently know it, is based on this conversion of sunlight energy and associated gas exchange. Leaf functional traits (structural and chemical characteristics) are related to photosynthetic efficiency.
Leaf mass per area (the ratio between leaf dry mass and area) is a structural trait which can be used as indicator of different plant functional strategies. This structural trait, together with other chemical traits, such as nutrient concentration, varies according to plant phylogeny, type of habitat, and leaf longevity. However, how those factors affect globally to the leaf functional traits in the mediterranean woody plants remains largely unknown.
A research team of the IRNAS, CSIC, in collaboration with the Universities of Cordoba and Wageningen, has studied the variability in leaf functional traits, for a set of 98 woody species, sampled within a broad range of environmental conditions.
The results demonstrate that phylogeny, habitat type and leaf longevity are factors determining the variability in leaf structural and nutritional traits. The concentrations of leaf nutrients are negatively related with leaf mass per area; thus supporting the “leaf economics spectrum” theory. Phylogeny and leaf longevity are relevant causes for the variation in leaf mass per area and in several leaf nutrients (C, N, Mg, S and K). In contrast, some micronutrients (such as Cu and Mn) are more dependent on the habitat type.
In summary, this study supports the existence of the leaf economics spectrum, for a large set of mediterranean woody species, and demonstrates the influence of phylogeny, leaf longevity, and the environment as main drivers of the variability in leaf structural and chemical (nutrients) traits.
The work will be published in the journal Trees. Structure and Function (on line since 6 December 2017).