Tissue culture and plant regeneration of big cordgrass,Spartina cynosuroides: implications for wetland restoration

Abstract

Big cordgrass,Spartina cynosuroides (Poaceae), grows in extensive stands in brackish marshes along the Atlantic and Gulf coasts of the United States and along the margins of tidal streams where freshwater wetland plants dominate the back marsh. Since big cordgrass is a species of ecological importance in wetland replenishment, a tissue culture and regeneration protocol was developed for it. This protocol provides a mechanism for producing improved varieties.Spartina cynosuroides callus was initiated from the mesocotyl of sterile seedlings grown on both a medium containing Murashige and Skoog salts + 3% sucrose + 0.5 mg 1⁻¹ 6-benzylaminopurine + 1 mg 1⁻¹ 1-Naphthaleneacetic acid + 0.5 mg 1⁻¹ 2,4-dichlorophenoxyacetic acid and 5% coconut water and a medium containing Murashige and Skoog salts + 3% sucrose + 1 mg 1⁻¹ Indole-3-acetic acid and 1 mg 1⁻¹ 2,4-dichlorophenoxyacetic acid, but not from seedlings germinated on the previous medium plus 5% coconut water. Shoots formed from callus after it was transferred to a shoot regeneration medium containing Murashige and Skoog salts plus 1.0 mg 1⁻¹ 6-benzylaminopurine. Roots formed from the base of these shoots after the larger shoots were transferred to root regeneration medium containing reduced-strength Murashige and Skoog medium. The mode of plant regeneration was via organogenesis, and the regenerated plants have set viable seeds in the greenhouse. This callus culture and regeneration procedure will be useful for producingS. cynosuroides somaclonal variants with superior characteristics for wetland restoration and creation in stressful habitats.