Climatic Variation on Gas Exchange and Chlorophyll a Fluorescence in Tabebuia roseoalba and Handroanthus heptaphyllus (Bignoniaceae)

Abstract

Climatic variation throughout the day influences the ecophysiological performance of plants at different growth stages and phases. Therefore, this work aimed to evaluate the effect of climatic variation on ecophysiological aspects of T. roseoalba and H. heptaphyllus at different hours of the day and indicate the ideal time for measuring ecophysiological variables in these species. The research was carried out in a greenhouse at the forest nursery of the Federal University of Paraíba, Campus II, in the municipality of Areia, Paraíba state, Northeastern Brazil. The experimental design was completely randomized, consisting of 10 evaluation times throughout the day (from 8 am to 5 pm), with 1 h hour interval between each evaluation. Temperature and air relative humidity inside and outside the greenhouse were evaluated to understand the effect on gas exchange (net assimilation rate of CO2, stomatal conductance, transpiration rate, internal concentration of CO2, and vapor-pressure deficit) and chlorophyll a fluorescence (initial, maximum, and variable fluorescence, photochemical quenching, and electron transport rate). Data were submitted to canonical correlation analysis and principal component analysis to verify the relationship between climatic HIGHLIGHTS• Climatic conditions influence the physiological mechanisms of species.• High irradiance and air temperature reduce photosynthetic performance of species.• The highest physiological performance of the species is between 8 am and 9 am.

Abiotic factors and photosynthetically active photon density affect the physiological mechanisms of jaboticaba

“…Ci is related to the supply and demand of CO 2 for photosynthesis. This factor is associated with turgor and leaf temperature, irradiance interception, and vapor pressure deficit, which modulate stomatal regulation (Griebel et al, 2020;Ribeiro et al, 2022). In the present study, we detected that the highest stomatal conductance (g s ) and net CO 2 assimilation rate (A) values allowed for the reduction of intercellular carbon.…”