Morphophysiological aspects of <i>Erythroxylum pauferrense</i> Plowman seedlings submitted to shading

Abstract

Sunlight directly influences on the development of forest species by affecting the attributes of plant growth and physiology. Among these species, Erythroxylum pauferrense Plowman is considered a rare species, as its distribution is restricted only to the state of Paraíba. Therefore, studies are needed that seek to evaluate the adaptation, development and propagation of the species under different environmental conditions. This study aimed to evaluate morphophysiological aspects of Erythroxylum pauferrense seedlings submitted to different levels of shading. The experiment was carried out under greenhouse condition in a completely randomized design with five treatments (0, 30, 50, 70, and 90% shading) and eight replicates. Growth characteristics, morphofunctional attributes, gas exchange, chlorophyll (Chl) a fluorescence, and Chl content were evaluated. Data were submitted to analysis of variance followed by polynomial regression analysis. Results showed that plants grown under 30 to 50% shading showed higher plant height, stem diameter, absolute growth rate for plant height, leaf dry mass, stem dry mass, total dry mass, Dickson’s quality index, leaf area, and leaf area index, as well as net assimilation rate of CO₂, stomatal conductance, transpiration, instantaneous water use efficiency, and Chl a, b, and a+b contents. Therefore, levels from 30 to 50% shading are the most recommended for the production of Erythroxylum pauferrense seedlings. We recommend using Erythroxylum pauferrense to reforest the understory in disturbed areas in Brejos de Altitude and large-scale production of seedlings under intermediate levels of shading.