Gas exchange in sweet pepper (Capsicum chinense Jacq) under different light conditions

Abstract

Plants in the tropics are exposed to high radiation and consequently high temperature and evaporative demands throughout the year. Under these conditions, physiological processes and final yield may negatively affect crops.Responses of C. chinense to different light conditions were evaluated in open-field conditions. Two experiments were performed: In the first trial, C. chinense plants were grown under Passiflora edulis shade and under full sunlight. In the second, three light conditions (60 %, 40% and full sunlight) were assayed employing synthetic meshes. Microclimate measurements and gas exchange characteristics were evaluated. Partial shade resulted in lower VPD. Shade plants exhibited lower mean daily and total CO2 assimilation rates compared to full sunlight plants. Partial shade induced lower stomatal aperture, regulated by light intensity; while the influence of VPD on stomata closure was less pronounced. The acclimation of sweet pepper to shade conditions was evident by lower chlorophyll Chl a/b concentrations.