Abstract
The influence of the rooting substrate on the root development of papaya in vitro was studied. The rooting of microcuttings started after the swelling of the basal ends. After 4 weeks of culture, the rooting rate was highest in the starch medium at 96%, followed by the agar, rockwool and vermiculite media. In the gellan gum medium, only 8% of the microcuttings rooted. Anatomically, hypertrophy of subepidermal cells and occurrence of cracking in the epidermis were observed in the starch, agar and gellan gum media. On the other hand, no structural abnormalities were detected in roots formed in the vermiculite and rockwool media. Although, the rooting rate was enhanced with increasing concentrations of agar and gellan gum, the abnormal structures still persisted in both media even when higher concentrations were applied.
