Gas exchanges and photochemical efficiency of hydroponic bell pepper under salinity and plant density

Antônio R. Cavalcante,Guilherme de F. Furtado,Lúcia H. G. Chaves,José A. Santos Júnior

doi:10.1590/1807-1929/agriambi.v23n1p3-8

Abstract

ABSTRACT Gas exchanges and chlorophyll a fluorescence are ways to physiologically analyze the response of plants to salt stress. In this context, the present work was conducted between August and November 2016 in a greenhouse at the Federal University of Campina Grande (7°12’52” S, 35°54’24” W, mean altitude of 550 m), using bell pepper plants cv. All Big, exposed to levels of nutrient solution electrical conductivity (1.7, 3.7, 5.7, 7.7, 9.7 and 11.7 dS m-1) and cultivated in hydroponic system, spaced by 0.2 and 0.3 m, focusing on the analysis of gas exchanges and photochemical efficiency. The experimental design was completely randomized, in a 6 x 2 factorial scheme, with five replicates. Plant density influenced the sensitivity of the gas exchanges to salinity and, when reduced, mitigated its effects at higher salinity levels. Increasing plant density at high levels of electrical conductivity caused damage to the photosynthetic apparatus and even reduced the levels of efficiency of the photosystem II from 3.98 dS m-1.

Highlights

Bell pepper (Capsicum annuum L.) production in semiarid regions is challenging, especially due to the limitation of water supply and salinity of the waters available for agriculture
Gas exchanges and chlorophyll a fluorescence are ways to physiologically analyze the response of plants to salt stress
This work was conducted to analyze the gas exchanges and photochemical efficiency of bell pepper plants grown in hydroponic system, at different population densities and exposed to brackish nutrient solutions

Summary

Introduction

Bell pepper (Capsicum annuum L.) production in semiarid regions is challenging, especially due to the limitation of water supply and salinity of the waters available for agriculture. Gas exchanges and photochemical efficiency have been used as parameters for analysis of plant growth and development by several authors (Silva et al, 2010; Suassuna et al, 2011), including in the bell pepper crop (Melo et al, 2017a). One of the relevant issues regarding the use of gas exchanges is that their measurements are significant to determine the photosynthetic rates (Santos et al, 2010) In this context, about the ways to analyze physiologically bell pepper response to salt stress, Melo et al (2017a) comment that research on gas exchanges provides important information, since the absorption of carbon dioxide (CO2) is fundamental for photosynthesis to occur. This work was conducted to analyze the gas exchanges and photochemical efficiency of bell pepper plants grown in hydroponic system, at different population densities and exposed to brackish nutrient solutions

Material and Methods

Results and Discussion

Conclusions

Literature Cited