The effect of pretreatment of Epibracinolide and Spermine on some growth, physiological parameters and SOS1 and NHX1 gene expression in Pumpkin (Cucurbita pepo L.) under salinity stress

The positive potential of brassinosteroids and polyamines as protective agents for environmental stresses has been proven.

In this study, Cucurbita pepo was pretreated with 24-epibrasinolide (EBL) (0, 0.01 and 0.1 μM) and spermine (0, 0.1 and 1 mM) and then salinity treatment (0, 40 and 80 mM sodium chloride) was applied.

Salinity stress decreased dry weight, potassium and calcium content and increased sodium content. EBL and Spm increased potassium, calcium and decreased sodium in shoots. Salinity stress increased root SOS1 gene expression and had no effect on NHX1 gene expression. EBL and Spm decreased expression of SOS1 gene while Spm increased expression of NHX1 gene. Therefore, it seems that Spm via the over-expression of the NHX1 gene substantially increased the tolerance to stress by sequestering excess Na+ into the vacuoles and sustaining a better cellular environment for improvement of plant growth under salinity stress.