Glucose-6-Phosphate and UDP-D-Glucose Dehydrogenases: Possible Markers of Vascular Differentiation

A quantitative cytochemical study of intact root apices and wounded roots of Pisum sativum, and of cotyledons from Solanum aviculare induced to form vessels from mesophyll cells, has demonstrated a sharp increase in glucose-6-phosphate dehydrogenase activity at a very early stage in the differentiation of the vascular tissues. However, UDP-D-glucose dehydrogenase activity appears to increase only at a time corresponding to the initiation of secondary cell wall events. Data from the callus cultures from Malus M27 and Cox endosperm indicated that glucose-6-phosphate dehydrogenase activity changes may be a possible marker for determining between the regenerability and recalcitrance of calluses.