Seed Viability and RNA Extraction Methods of Erythrina velutina Under Drought Stress

Juliana L Souza,Laura C D P Lima,Bruno A L De Freitas,Renata Silva-Mann,Valdinete V Nunes,Maria F O Torres

doi:10.5539/jas.v12n12p192

Abstract

Abiotic stress caused by rigorous environmental conditions, such as drought, has negative effects on seeds. The species from arid and semiarid areas have mechanisms to maintain seed viability. In this study, the analyses of physical and physiological quality of the seeds of Erythrina velutina and their response to drought stress and RNA extraction methods were carried out. The seeds were collected from mother trees in two different provenances of natural occurrences of the species. The physical quality, viability, and vigor of the seeds were evaluated by morphometric parameters, germination, and electrical conductivity tests. The seeds were submitted to drought stress conditions for 0, 24, 48, and 72 hours on -0.8 MPa polyethylene glycol solution. To evaluate the viable RNA extraction method, the seed embryos were used for the extraction of this molecule and with an assessment of quantity and quality. The seeds from Pernambuco that were harvested in 2008 were bigger and presented lower vigor when in comparison to seeds that were harvested from Sergipe in 2012. The seeds under drought stress conditions presented null germination for all the treatments. After the drought stress, they were germinated on a paper substrate moistened with water, with better responses from the Lot Sergipe, 2012. The imbibition of seeds in the solution for 24 hours provides an increase in germination for less vigorous seeds, being indicated as a pre-germinative treatment. The RNA quality obtained by using a commercial extraction kit has better results, providing materials without contaminants when compared to the TRIzol method.

Highlights

Drought is a frequent condition in tropical areas, occurring in arid and semiarid regions with high temperatures and low pluviometry
The environmental conditions during drought expose plants to abiotic stress, which is mainly caused by water deficit (Aroca et al, 2012; Claeys & Inzé, 2013)
In order to test the responses of seeds to drought stress in laboratory, germination on solutions that simulate water deficit have been performed in several studies (Ji et al, 2014; O’Donnell et al, 2013; Patanè et al, 2013)

Summary

Introduction

Drought is a frequent condition in tropical areas, occurring in arid and semiarid regions with high temperatures and low pluviometry. In addition to the natural conditions, climatic changes induced by global warming have expanded the areas affected by drought, creating new regions with shortages of available water (Dai, 2013). In Northeast Brazil, a large semiarid area constitutes the Caatinga, a savanna like biome, with high temperatures and low precipitation, composing a rigorous climatic condition (Oliveira et al, 2012). In order to test the responses of seeds to drought stress in laboratory, germination on solutions that simulate water deficit have been performed in several studies (Ji et al, 2014; O’Donnell et al, 2013; Patanè et al, 2013). The most used is an osmotic aqueous solution of polyethylene glycol (PEG), a chemically inert and non-toxic component, which efficiently simulates water restriction without entering the plant cell (Hohl & Schopfer, 1991; Pereira et al, 2014; Salah et al, 2015)

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Results