Immunohistochemical localization of β-glucosidases in lignin and isoflavone metabolism in Cicer arietinum L. seedlings.

Coniferin specific- and isoflavone 7-glucoside specific β-glucosidases have been localized in stem and root sections of chick pea (Cicer arietinum L.) seedlings by the indirect immunofluorometrical method. The coniferin specific β-glucosidase has been found in the cell walls of the tracheary elements and of the endo-, epi-, and exodermis. All these tissues are known to contain either lignin or polymers, like suberin and cutin, which consist partially of phenylpropanoid elements. The localization of this β-glucosidase is therefore in agreement with its postulated relationship to the phenylpropanoid metabolism. The isoflavone 7-glucoside specific β-glucosidase, on the other hand, is predominantly located in the parenchymatic cortex cells, and obviously in the cytoplasm. These cells are known to contain the isoflavone formononetin, which has been shown to undergo turnover in chick pea seedlings. We therefore have good reason to assume that this β-glucosidase is involved in the metabolism of the 7-glucoside of this isoflavone.