Does nitric oxide protect Eucalyptus urophylla seeds under salt stress conditions?

Thalita Maciel Pereira,Lucas Amaral De Melo,Antonio Rodrigues Da Cunha Neto,Heloisa Oliveira Dos Santos,Wilson Vicente Pereira,Fabieli Pelissari

doi:10.1590/2317-1545v42236272

Thalita Maciel Pereira, Lucas Amaral De Melo + Show 4 more

Open Access

https://doi.org/10.1590/2317-1545v42236272

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Abstract

Abstract: The germination response of seeds under artificial stress conditions is a tool for better understanding of the survival and adaptation ability of species under natural stress conditions. The aims of this study were to evaluate the protective effect of nitric oxide during germination as well as seed vigor and seedling development of Eucalyptus urophylla under salt stress conditions. The experimental design was completely randomized, with five replications, in a 3 × 3 + 1 factorial arrangement, with three priming factors [water, sodium nitroprusside (SNP), and potassium nitrate (KNO3)], three germination conditions (distilled water, and the water potentials of -0.6 and -1.2 MPa), and an additional control treatment (unprimed seeds). The following determinations were made: germination count at seven and fourteen days, germination speed index, primary root length, shoot length, and total length. SNP protects seeds, leading to a higher percentage of germination, as well as greater root growth and total seedling size, whereas KNO3 is not effective in protecting seeds that suffer from salt stress, which affects their physiological and morphological characteristics. E. urophylla seeds are sensitive to salt stress, and physiological priming with SNP leads to an increase in the percentage of germination, vigor, and seedling development under salinity conditions.

Highlights

Factors that affect germination of seeds of tree species can be controlled genetically and by the environment
Priming solutions consisted of distilled water, 0.1 mmol.L−1 potassium nitrate solution (Cardoso et al, 2014), or 0.1 mmol.L−1 sodium nitroprusside solution (Ataíde et al, 2015; Silva et al, 2015; Faraji and Sepehri, 2019)
The moisture content of the E. urophylla seeds measured before the beginning of the analyses was 6.5%

Summary

Introduction

Factors that affect germination of seeds of tree species can be controlled genetically and by the environment. Salt conditions reduce speed of emergence and seedling development and affect the number of leaves and seeds per plant and seed size and weight (Saberali and Moradi, 2019). In these cases, pre-germination seed treatments was used to increase germination and increase the uniformity of emergence (Cardoso et al, 2015; Pires et al, 2016; Silva et al, 2019). Among these treatments is osmotic priming, a technique that allows control of seed hydration to a level sufficient to allow pre-germination metabolic events, yet insufficient to allow radicle emergence (Bhanuprakash and Yogeesha, 2016; Ramalho et al, 2020)

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