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

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.

The Role of Nitric Oxide in Plant Responses to Salt Stress

“…Salt inhibits seed germination, thereby causing great damage to agricultural production. Several reports have shown that the application of SNP under saline conditions increases the percent germination of various plant species, including Eucalyptus urophylla , wheat, and rice [ 30 , 31 , 32 ]. Another study found that NO alleviated the decreases in germination percentage, germination index, vigor index, and imbibition rate of wheat seeds exposed to salt stress, mainly by increasing beta-amylase activity [ 31 ].…”

Protective Effects of Sodium Nitroprusside on Photosynthetic Performance of Sorghum bicolor L. under Salt Stress

“…The information on the impact of NO on plants can sometimes be contradictory, because the effects depend on the plant species and seedling age, as well as the duration, and severity of the abiotic stress [ 31 , 33 , 44 ]. The application of the exogenous NO donor sodium nitroprusside (SNP), has been shown to cause a promising effect on crop germination under control conditions and NaCl-induced stress, as well as on fresh weight, dry weight, and shoot and root elongation [ 5 , 45 , 46 , 47 , 48 , 49 ]. It has also been shown that NO alleviates oxidative damage (i.e., decreased electrolyte leakage and lipid peroxidation) by increasing antioxidant activities [ 29 , 48 ] and preventing changes in thylakoid shape and size [ 50 ].…”

Influence of Nitric oxide donor nanoencapsulation on Dyckia excelsa Lema (Bromeliaceae) germination

“…NO has a positive effect on several plant cellular procedures, including: Breaking seed dormancy, growth and plant defense against stress. It can even has an effect on abscisic acid expression in dormancy breaking, acting positively on germination (Silva et al, 2019;Pereira et al, 2020).…”