Location of enzymes metabolising sucrose and starch in the grasses Pennisetum purpureum and Muhlenbergia montana

Abstract

Leaf tissue of the panicoid grass Pennisetum purpureum (Schum) and of the chloridoid grass Muhlenbergia montana (Hitchcock) were fractionated to produce preparations enriched in the contents of mesophyll and bundle sheath cells. Sucrose phosphate synthetase and sucrose synthetase were found predominantly in the mesophyll tissues of both species, as was uridine-diphosphate-glucose pyrophosphorylase in Pennisetum. In Muhlenbergia this enzyme was more plentiful in the bundle sheath cell fraction. Starch synthetase and adenosine-diphosphate-glucose pyrophosphorylase were plentiful in bundle sheath extracts of both species but phosphorylase was associated with extracts of mesophyll cells. In no case was there a clear-cut compartmentation of enzymes between leaf fractions.