Effect of gibberellic and salicylic acids pre-soaking on seed germination attributes of cucumber (Cucumis Sativus L.) under induced salt stress

Abstract

Saline stress is one of the most deleterious abiotic stress determining a considerable reduction in agricultural production. Seed germination is the primitive plant growth stage and considered as vulnerable to saline stress. However, the exogenous application of natural plant growth regulators has been reported as one of the mitigation strategies. A Petri dish experiment under controlled conditions was conducted at King Saud University. The aim was to quantify the negative impact of induced saline stress (NaCl) on seed germination attributes and role of gibberellic acid (GA3) and salicylic acid (SA) to reduce the inhibitory effect of saline stress on cucumber (Cucumis sativus L.) seeds. The treatments consist of two sets as: seed pre-soaking solution and NaCl stress. Five pre-soaking solutions were prepared as: H2O (control), GA3 (100 ppm), GA3 (200 ppm), SA (0.5 ppm) and SA (1.0 ppm). While saline stress was imposed by NaCl at three levels such as: no stress (distilled water, control), mild stress (NaCl, 50 mM) and higher stress (NaCl, 100 mM). Results depicted that NaCl induced stress has significantly affected the all studied germinations attributes. The maximum NaCl stress (100 mM) stood highest in inhibiting seed germination percentage, seedling length, and seedling fresh and dry weights, followed by mild stress and control, respectively. Seed presoaking treatments were recorded nonsignificant for seedling length, fresh and dry weights while significant for germination percentage and number of seeds germinated over period of time. The interaction between seed pre-soaking treatments and induced saline stress was recorded significant. Overall, GA3 at the rate of 100 ppm solution performed a contributory role to mitigate the negative effect of saline stress.