Effects of exogenous hydrogen sulphide on seed germination and seedling growth of cucumber (Cucumis sativus) under sodium bicarbonate stress

Soil salinity is a major limiting factor to agricultural land productivity worldwide, especially in arid and semiarid regions. Hydrogen sulphide (H₂S) plays an important role in a variety of responses against abiotic stresses. This study investigated the effects of exogenous NaHS, a H₂S donor, on seed germination and seedling growth of cucumber (Cucumis sativus) under sodium bicarbonate (NaHCO₃) stress. The results showed that NaHCO₃ stress inhibited seed germination, reduced hypocotyl and radicle lengths, increased malondialdehyde (MDA) content, and decreased the soluble sugar content as well as α-amylase, β-amylase, superoxide dismutase (SOD) and peroxidase (POD) activities in germinating seeds and seedlings of cucumber. On the other hand, exogenous NaHS treatment significantly increased hypocotyl and radicle lengths as well as the soluble sugar content. Moreover, exogenous NaHS treatment increased the activities of α-amylase, β-amylase, SOD and POD and decreased the accumulation of MDA. Our findings strongly suggested that exogenous H₂S effectively promotes cucumber seed germination and alleviates the toxic damage caused by NaHCO₃ stress.