Film coating with sodium alginate improves seed germination of sweet corn (Zea mays var. Saccharata) under osmotic stress conditions

Drought stress influences seed germination and seedling growth of many plants. Seed coating is technique of covering seeds with adhesive agents to improve seed performance and plant establishment and could be used to alleviate the negative effects of osmotic stress. In order to solve the problem of low germination and poor vigor of sweet corn under osmotic stress conditions (0, -0.3, -0.6 and -0.9 MPa), film coating with different concentration of sodium alginate (NaAlg) (0, 1 and 2%) were performed. Results showed that osmotic stress reduced percentage and rate of germination, seedling length, seedling vigor index and soluble protein content and also increased the content of proline and soluble sugars. In all levels of osmotic stress, coating with NaAlg 1% improved germination and biochemical indices of sweet corn seeds compared to NaAlg 0 and 2%- and non-coated seeds. The highest percentage of germination (67 %) was related to osmotic potential of 0 MPa and the lowest germination percentage (36 %) was observed in the osmotic potential of -0.9 MPa. The highest (19.17 mg g-1 FW) and the lowest (6.68 mg g-1 FW) amount of soluble protein were obtained from NaAlg 1% at 0 MPa and NaAlg 0% at -0.9 MPa, respectively. The results suggested that seed coating with NaAlg 1% could serve as an appropriate treatment to increase the germination and early seedling growth of sweet corn under osmotic stress conditions.