REDUCED GLUTATHIONE PROMOTES CALLUS GROWTH AND SHOOT DEVELOPMENT IN ASHOOT-TIP CULTURE OF APPLE ROOT STOCK M26

Reduced glutathione (GSH) was applied to prevent browning in shoot tip explants of apple (Malus pumila Mill). Development was compared betwe en shoot tips treated either by (a) dipping into 0.1 mM GSH solution p rior to culture (dip treatment), (b) dipping into the GSH solution and transferring to a medium containing 0.1 mM GSH (dip-and-add treatment ), or (c) without dipping or culturing with GSH (control). In the dip treatment, 100% of shoot tips developed into normal shoots after 120 d ays, while the results with the dip-and-add treatment and control were 50 and 40%, respectively. The results show that application of antiox idant GSH in the initial phase of culture promoted the normal developm ent of shoot tips.