GAS EXCHANGE, CHLOROPLAST PIGMENTS AND GROWTH OF PASSION FRUIT CULTIVATED WITH SALINE WATER AND POTASSIUM FERTILIZATION 1

Lauriane Almeida Dos Anjos Soares,Pedro Dantas Fernandes,Hans Raj Gheyi,Cosmo Gustavo Jacome Fernandes,Geovani Soares De Lima

doi:10.1590/1983-21252020v33n120rc

Lauriane Almeida Dos Anjos Soares, Pedro Dantas Fernandes + Show 3 more

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https://doi.org/10.1590/1983-21252020v33n120rc

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Abstract

ABSTRACT The objective of this study was to evaluate the gas exchange, chloroplast pigments and growth of ‘BRS Rubi do Cerrado’ passion fruit as a function of irrigation with saline water and potassium fertilization in the seedling formation stage. The experiment was conducted under greenhouse conditions in the municipality of Pombal-PB, Brazil. A randomized block design was used in 5 x 2 factorial scheme, corresponding to five levels of water electrical conductivity - ECw (0.3, 1.1, 1.9, 2.7 and 3.5 dS m-1) and two doses of potassium - KD (50 and 100% of the recommendation), with four replicates and two plants per plot. Water salinity from 0.3 dS m-1 reduced the stomatal opening, transpiration, CO2 assimilation and inhibited the growth of ‘BRS Rubi do Cerrado’ passion fruit plants, at 40 days after sowing. There was no CO2 restriction in the substomatal cavity of passion fruit plants grown under water salinity from 0.3 dS m-1. Potassium dose of 150 mg kg-1 of soil, corresponding to 100%, intensified the effect of salt stress on the assimilation rate and instantaneous carboxylation efficiency in 'BRS Rubi do Cerrado' passion fruit. There was interaction between water salinity levels and potassium doses for the chlorophyll a and b contents of 'BRS Rubi do Cerrado' passion fruit.

Highlights

Belonging to the Passifloraceae family, passion fruit stands out as one of the most cultivated species
The treatments resulted from the combination of five salt concentrations in the irrigation water expressed through the electrical conductivity - effects of irrigation with saline waters (ECw) (0.3; 1.1; 1.9; 2.7 and 3.5 dS m-1) associated with two doses of potassium fertilization - K dose (KD) (50 and 100% of the recommendation of K2O) according to Novais, Neves and Barros (1991)
Plant height was obtained by measuring the length of the aerial part, in centimeters, from the soil level to the insertion of the apical meristem

Summary

Introduction

Belonging to the Passifloraceae family, passion fruit stands out as one of the most cultivated species. In the 2018 season, Brazil stood out as the world’s largest passion fruit producer, with an area of approximately 78,502.42 hectares, resulting in the production of 602,651 tons per year. Passion fruit cultivation is carried out in almost all Brazilian states, especially in the Northeast region, which has the largest planted area, where the states of Bahia and Ceará have 15,724 and 6,862 hectares of plantations, with average yields of 10.50 and 17.25 t/ ha, respectively (IBGE, 2018). Passion fruit production in regions with low water availability, such as in the semiarid region of northeastern Brazil, causes large variations in its production cycle (ODRESCA, 2016). Soil salinization combined with inadequate irrigation management is becoming increasingly harmful to agriculture (AREF; RAD, 2012)

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