Studies on sandal spike. Part VIII. Polyphenolase activity and metabolism of sandal (Santalum album L.) in health and disease

Abstract

Polyphenolase catalyses the hydroxylation of phenols and their oxidation to quinones, which are involved in different biological reactions. In the case of sandal the polyphenolase activity PPA) has been found to be distinctly at a higher level in the spiked leaves than in the healthy ones at all stages of development. This naturally accounts for the recorded higher level of phenolic bodies in the spiked sandal leaves. Diseased sandal leaves show a higher rate of respiration. For this phenomenon, the higher level of quinones formed through the higher PPA appears to be partly responsible, since inhibition of the PPA using sodium diethyldithiocarbamate has definitely lowered the respiration rate. However, the residuary respiration is still higher than in the healthy tissues, thereby indicating that the PPA is only partly responsible for the increased respiration in the spiked leaves. A higher level of phenols is known to affect adversely the indoleacetic acid oxidase activity in plant tissues and this appears to be the case in sandal also. The diseased tissues, which are shown to exhibit a higher level of PPA, contain more phenolic bodies which adversely affect the IAA oxidase activity, resulting in a higher level of IAA, particularly in the young leaves, and this factor appears to be responsible for the increase in the number of vegetative buds as is noticed in the spiked plants.