Germination and biochemical changes in West Indian gherkin seeds under water stress at different temperatures

João Paulo Nobre De Almeida,Emanoela Pereira De Paiva,Salvador Barros Torres,Francisco Vanies Da Silva Sá,Moadir De Sousa Leite

doi:10.5935/1806-6690.20190049

Abstract

Information on the effects of climate conditions on the survival of species grown in semi-arid regions is essential and at the same time scarce, especially regarding rustic species such as West Indian gherkin (Cucumis anguria L.). Thus, this study aimed to evaluate germination, growth and biochemical alterations in C. anguria seeds under water stress and different temperature regimes. The experimental design was completely randomized, in 5 x 5 factorial scheme, composed of five osmotic potentials (0.0; -0.1; -0.2; -0.3 and -0.4 MPa) and four temperatures (20; 25; 30 °C and alternating temperatures of 20-30 oC), with each treatment composed of four replicates of 50 seeds. The seeds were sown on paper towel (Germitest®) and germinated in Biochemical Oxygen Demand (B.O.D.) germinators, under 8-h photoperiod. Germination percentage, germination speed index, mean time of germination, seedling length and contents of chlorophylls, carotenoids, proline, free amino acids and free sugars were determined along the experiment. Decrease in osmotic potential reduced germination, growth and contents of chloroplast pigments of C. anguria seedlings, but was more drastic at levels lower than -0.2 MPa. Low temperatures intensify the effects of water stress on the germination of C. anguria seeds. The synthesis of protecting osmolytes increased in C. anguria seedlings but these components did not promote efficient osmotic adjustment in their initial development stage.

Highlights

Cucumis anguria L., from the Cucurbitaceae family, is popularly known in Brazil as ‘maxixe’ and is an annual, rustic plant normally grown in small scale (FILGUEIRA, 2008)
As the osmotic potentials decreased, there was a drastic reduction in the germination percentage of seeds at all temperatures tested, except for those germinated at 25 oC, which maintained favorable percentages up to a osmotic potential of -0.2 MPa, evidencing that under these environmental conditions C. anguria tolerates more water stress than at other temperatures (Figure 1A)
The results found in the present study agree with those found by Alves et al (2014), who subjected C. anguria seeds to water and salt stresses

Summary

Introduction

Cucumis anguria L., from the Cucurbitaceae family, is popularly known in Brazil as ‘maxixe’ and is an annual, rustic plant normally grown in small scale (FILGUEIRA, 2008). It is extremely important to know the factors which limit the initial development of the species, especially abiotic factors such as water and thermal deficits, which affect seed germination and the initial development of plants (CARVALHO; NAKAGAWA, 2012; MARCOS-FILHO, 2015). Studies related to the germinative response of seeds to the condition of artificial stresses are important for ecophysiology and constitute tools which allow for the evaluation of limits and tolerance of survival and adaptation of these species to the conditions of natural stresses (GUEDES et al, 2013)

Objectives

Methods

Results