Effectiveness of protective agents for increasing activity of five enzymes from vegetative tissues of white spruce

Abstract

Optimal conditions of pH and substrate concentration for five enzymes from crude extracts of needle and bud tissue of a white spruce (Picea glauca (Moench) Voss) tree were first investigated, and then used for subsequent experiments. With increasing age of the needles on the tree, activity of peroxidase increased, while that of 6-phosphogluconic acid dehydrogenase and ferredoxin-NADP+ reductase decreased. Polyethylene glycol increased enzyme activity from needle tissue. For isocitrate dehydrogenase and glucose-6-phosphate dehydrogenase, 2% polyethylene glycol was most effective, while for 6-phosphogluconic acid dehydrogenase, 4% was best. Enzyme activity also varied considerably with the pH of the extraction buffer. Extraction of needle and bark tissues with various combination buffers referred to in the literature clearly indicated that no one extraction buffer was optimal for all five enzymes of this study. Unlike that of needle and bark tissues, enzyme activity of bud tissues was high even in the absence of any protective agent. The effect on enzyme activity of storage of the bud extracts for 10 days at 4 °C varied with the enzyme.