Gas exchange and chlorophyll fluorescence relations in bell pepper plants (Capsicum annuum L.) under water stress

Abstract

Water availability is one of the most important limitations to photosynthesis and plant productivity. An experiment was performed with bell pepper (Capsicum annuum L.) plants subjected to water stress by reducing irrigation amounts. The aim was to asses the effects of water stress in both photochemistry and CO2 assimilation rates, and to quantify if there is a relation between the measured parameters. We used non-destructive biophysical methods called chlorophyll fluorescence together with a time reflectometer, psychrometric chambers and a photosynthesis device, with which we measured soil (YS) and leaf water potential (YL), gas exchange, and chlorophyll fluorescence at different times. The chlorophyll a fluorescence parameters showed a decline in photosynthetic electron transport and energy fluxes due to water stress. Similarly, CO2 assimilation rates (A), stomatal conductance (gs), and transpiration (Tr) decreased with increasing water deficit. Fluorescence measured by PItotal shown to be an effective method for the early detection of water stress and it could be a useful guide in irrigation scheduling.