ICOM1 Abstract

BELGRAVE, CAROL, LOUIS E. CHINNERY & SUSAN B. PERSAD- CHINNERY. Department of Biology, The University of the West Indies, P.O.B. 64, Bridgetown, Barbados. - Mycorrhizal induced changes in root morphology, nuclear diameters and mitotic indices of corn and leek. Corn (Zea mays) and leek (Allium porrum) separately colonised by two species of VA mycorrhizal fungi, Gigaspora decipiens and Scutellospora gregaria, showed decreased numbers of lateral roots and reduced lengths of primary roots but there were no significant differences in the mean numbers of these primary roots when compared to uncolonised controls. At distances 0 - 1, 1 - 2 and 2 - 3 cm behind the root meristems mean nuclear diameters were greater in cortical cells from colonised than from uncolonised corn roots. The size difference was more pronounced further from the root tip. Increased nuclear diameters were also recorded within 1 cm of the root tip of colonised leek. Necrotic meristematic apices were prevalent in both corn and leek roots colonised by both species of VA mycorrhizal fungi. The mitotic indices in healthy root meristems of mycorrhizal corn and leek were lower than those recorded for uncolonised plants.