Growth and gas changes of melon seedlings submitted to water salinity

Valéria F De O Sousa,Caciana C Costa,Genilson L Diniz,Kilson P Lopes,Marinês P Bomfim,João B Dos Santos

doi:10.1590/1807-1929/agriambi.v23n2p90-96

Valéria F De O Sousa, Caciana C Costa + Show 4 more

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https://doi.org/10.1590/1807-1929/agriambi.v23n2p90-96

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Abstract

ABSTRACT The melon is an outstanding fruit crop in Brazil, mainly in the Northeast region due to favorable conditions for cultivation. Water salinity affects the growth and production of several species, but there is tolerance among cultivars of the same species. The objective of this study was to evaluate the growth and gas exchange in melon seedlings subjected to water salinity. Experiment was carried out in a greenhouse belonging to the Center of Sciences and Agri-Food Technology, Federal University of Campina Grande, Pombal, PB, Brazil, from September to October 2016. The experimental design was a randomized complete block design in a 6 x 5 factorial scheme, with four replicates, for six cultivars of melon (Natal, Solares, Goldex, Iracema, Mandacaru and Amarelo Ouro) and five irrigation water salinity levels with the following electrical conductivities: 0.3, 1.1, 1.9, 2.7 and 3.5 dS m-1. Each experimental unit consisted of a polypropylene container with a volume capacity of 0.350 dm3, which contained soil + Basaplant® commercial substrate at a ratio of 2:1. At 25 days after sowing, the plants were evaluated for growth, gas exchange and dry mass accumulation. Increased salinity of irrigation water inhibits the growth, dry mass accumulation and physiological processes of melon cultivars. The cultivar Natal showed to be more tolerant, while the cultivars Solares, Goldex, Iracema and Mandacaru were moderately sensitive and the cultivar Amarelo Ouro was more sensitive to the salinity of irrigation water.

Highlights

Melon (Cucumis melo L.) is a profitable crop with fast economic return, besides being adapted to the Northeast region
The interaction between cultivars and water salinity levels had significant effects (p > 0.05) on all variables of biometric growth, physiological aspects and biomass formation by roots and shoots in the production of melon seedlings, corroborating some authors who worked with irrigation water salinity and melon cultivars (Aragão et al, 2009; Lúcio et al, 2013; Araújo et al, 2016; Lopes et al, 2017; Pereira et al, 2017)
The data of net CO2 assimilation of the cultivars Amarelo Ouro and Solares did not fit to any mathematical model with the increase in water salinity and were represented by the mean values of 3.42 and 2.13 μmol m-2 s-1 (Figure 1A)

Summary

Introduction

Melon (Cucumis melo L.) is a profitable crop with fast economic return, besides being adapted to the Northeast region. Application of water with high contents of salts in irrigation compromises growth, development, and the production of various cucurbits, including Curcubita moscata (Carmo et al, 2011), Citrullus lanatus (Costa et al, 2013; Silva et al, 2015) and Cucumis melo (Freitas et al, 2014). Adversities occur because excess salts in the water cause negative effects on plants, such as reduction in water availability, i.e., osmotic effect, nutritional imbalance and toxicity by specific ions, especially sodium (Na+) and chlorine (Cl-) at high concentrations, which compromise morphological and physiological performances, as observed by Bosco et al (2009) and Carmo et al (2011) in eggplant (Solanum melongena) and pumpkin (Curcubita moscata) and by Araújo et al (2016) in melon cultivars

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