Effect of Three Auxins and Sucrose on In Vitro Rooting in Soil and Acclimatization of Vitis vinifera L. 'Albariño'

Abstract In vitro studies were performed to test the effect of three different auxins and sucrose on rooting in soil and acclimatization of micropropagated plantlets of Vitis vinifera L. ‘Albarino’. These results could be used to define optimal conditions for future work focused on reaching simultaneous ex vitro rooting and acclimatization. Indole-3-acetic acid (IAA), indole-3-butyric acid (IBA) and α -naphthaleneacetic acid (NAA), and different concentrations of sucrose (0, 1.5, 3, 6 and 9%) (w/v) were tested. Microshoots from multiplication phase were used as a source of explants. Shoots longer than 2.5 cm were dipped in various concentrations (1, 15, 25 and 50 mM) of each auxin solution. Shoots were placed in a sterilized planting mixture (perlite: compost 1:1 (v:v)) supplemented with sucrose. For acclimatization, plantlets were carefully transferred to minipots and placed in a growth room under 16 h-photo-period. The initial value of relative humidity was set to 100% and decreased gradually over 21 days to 60%. Histological studies were performed to observe the anatomical changes in root formation corresponding to the beginning of root induction, the formation of a de novo meristemoid, the emergence of the root primordia and root development. Rooting and acclimatization were best when the combination of an auxin IAA (25 mM) and sucrose (3%) was applied. Histological analysis confirmed that the formed roots were well-developed and functional. INTRODUCTION