IN VITRO GROWTH OF ALOE BARBADENSIS MILL.: THE EFFECT OF ACTIVATED CHARCOAL ON MEDIUM PH, NITROGEN UPTAKE AND ELEMENTS CONTENT OF SHOOTS

Activated charcoal was added to the elongation medium of Aloe barbadensis micropropagated in vitro. Its inclusion significantly increased shoot growth. In order to explain the improvement of the growth performance, the effect of activated charcoal on medium pH and elements uptake during the culture period was investigated. It was found that activated charcoal prevented the drop of the medium pH which occurred in its absence, probably because it decreased the ammonium:nitrate (NH4+ : NO3-) uptake ratio. In fact, a significant negative correlation between NH4+ : NO3- uptake ratio and medium pH occurred. Moreover, activated charcoal significantly affected the N, K, Ca, Na, Mn, Fe, B, and Zn concentration in the shoots, while days of culture influenced N, K, P, Na, Fe, Zn, and Cu presence in A. barbadensis shoots.