TISSUE-CULTURE AND PLANT-REGENERATION OF BIG CORDGRASS, SPARTINA CYNOSUROIDES - IMPLICATIONS FOR WETLAND RESTORATION

Big cordgrass, Spartina cynosuroides (Poaceae), grows in extensive sta nds in brackish marshes along the Atlantic and Gulf coasts of the Unit ed States and along the margins of tidal streams where freshwater wetl and plants dominate the back marsh. Since big cordgrass is a species o f 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 call us was initiated from the mesocotyl of sterile seedlings grown on both a medium containing Murashige and Skoog salts + 3% sucrose + 0.5 mg l (-1) 6-benzylaminopurine + 1 mg l(-1) 1-Naphthaleneacetic acid + 0.5 m g l(-1) 2,4-dichlorophenoxyacetic acid and 5% coconut water and a medi um containing Murashige and Skoog salts + 3% sucrose + 1 mg l(-1) Indo le-3-acetic acid and 1 mg l(-1) 2,4-dichlorophenoxyacetic acid, but no t from seedlings germinated on the previous medium plus 5% coconut wat er. Shoots formed from callus after it was transferred to a shoot rege neration medium containing Murashige and Skoog salts plus 1.0 mg l(-1) 6-benzylaminopurine. Roots formed from the base of these shoots after the larger shoots were transferred to root regeneration medium contai ning reduced-strength Murashige and Skoog medium. The mode of plant re generation was via organogenesis, and the regenerated plants have set viable seeds in the greenhouse. This callus culture and regeneration p rocedure will be useful for producing S. cynosuroides somaclonal varia nts with superior characteristics for wetland restoration and creation in stressful habitats.