EFFECTS OF NITROGEN-SOURCE ON GROWTH-RATES AND LEVELS OF ENDOGENOUS CYTOKININS AND CHLOROPHYLL IN PROTOCORMS OF EPIDENDRUM-FULGENS

Effects of nitrogen source on development, endogenous cytokinin levels and chlorophyll content in protocorms of Epidendrum fulgens, as well as cytokinin content of matura seeds, were studied. A significant increase in growth rates of protocorms was observed with NH4NO3 and urea. Chlorophyll content increased with NH4NO3 and (NH4)2SO4. In seeds, levels of 2iP exceeded levels of zeatin. In protocorms, NO3- as the only nitrogen source increased 2iP activity, while NH4+ alone increased zeatin activity. This cytokinin was the only one detected in protocorms incubated with urea. The highest endogenous cytokinin levels were found in protocorms supplied with NH4NO3 and (NH4)2SO4. Correlations among cytokinin activity, development, and chlorophyll content in protocorms were described.