To be or not to be shade tolerant: water and carbon economy in tree species of the Atlantic Forest (Misiones, Argentina)

In tropical and subtropical moist forests the most important factor limiting plant growth is solar radiation. On this basis, tree species had traditionally been classified into two functional groups based on their requirements for germination, establishment and growth. While shade-tolerant species germinate, grow  and establish in places with low solar radiation, intolerant species require high irradiances for development. However, spatio-temporal variations in solar radiation exist within forests and most species show intermediate characteristics between the two extreme categories, forming a continuous gradient of ecophysiological responses. In this work we analyze the adaptations related to water and carbon economy (e.g., wood density, water transport efficiency and photosynthetic capacity) of Atlantic Forest tree species with the assumptions that evolutionary pressures have selected species-specific characteristics which enable them to optimize and coordinate the capture of solar radiation with the water transport to the leaves. We show that wood density is a trait that can be used to predict the behavior of tree species in relation to growth rates and properties related to transport efficiency and water use. Less shade-tolerant species have low wood density and high efficiency in water transport from soil to leaves. In environments with high solar radiation and evaporative demand, plants that have a low wood density and high water transport efficiency from the soil to the leaves can maintain high levels of leaf water potential (and experience less water deficit), increased stomatal conductance and, consequently, a higher rate of assimilation and growth. Drastic changes in solar radiation produced by a gap opening in the forest can also impose drastic environmental changes for plant growth. The development of the individuals in the new conditions depends on its phenotypic plasticity, which can vary widely among different species. Saplings of less tolerant species can respond quickly to changes in solar radiation acclimating their physiology and morphology resulting in higher growth rates than saplings of tolerant species.

Bibliographic Details

Main Authors:	Campanell, Paula I., Gatti, M. Genoveva, Montti, Lia, Villagra, Mariana, Goldstein, Guillermo
Format:	Digital revista
Language:	spa
Published:	Asociación Argentina de Ecología 2011
Online Access:	https://ojs.ecologiaaustral.com.ar/index.php/Ecologia_Austral/article/view/1273
Tags:	Add Tag No Tags, Be the first to tag this record!