COMPARISON OF “IN VITRO” RHIZOGENESIS OF WILD SPECIES OF THE GENUS PRUNUS

The present study was carried out to investigate the influence of different doses of auxinic phytohormone NAA (α-naphthaleneacetic acid) and MS nutrients on “in vitro” rhizogenesis of two species of Prunus genus: Prunus avium L. and Prunus mahaleb L. The most common use of these wild fruit trees is as rootstocks for sweet or sour cherry cultivars. Rooting induction appears very difficult, especially regarding to trees species. Three nutrient rooting media containing different concentrations of NAA and macro- and micronutrients, presented in the universal medium MS were compared: (I) - ? MS macronutrients, MS micronutrients, MS vitamins supplemented with 0.1 mg l-1 NAA; (II) - ? MS macronutrients, ? MS micronutrients, MS vitamins with 0.1 mg l-1 NAA and (III) - MS macronutrients, ? MS micronutrients, MS vitamins with 2 mg l-1 NAA. The rooting percentage changed according to the species and to the rooting media. The highest value of rooting for both species resulted in the first rooting medium. Prunus mahaleb plantlets showed higher rooting percentage in all examined media than Prunus avium. Root length was also evaluated and presented significant differences among treatments. Rooting medium III with higher dose of NAA gave rise of abnormal roots favoring the development of callus and limiting root formation for all the plantlets “in vitro”. As result, the use of the lower doses than 0.5 mg l-1 of auxin NAA is recommended. The well developed roots “in vitro” induces a better ability to face the stress during the plantlets acclimatization.