The effects of basal media, sucrose and phytohormone concentrations, and gelling agent combinations on in vitro frond proliferation of Lemna gibba G3 and 24 additional Lemna gibba strains were examined. Frond proliferation was equivalent on Schenk and Hidebrand. Murashige and Skoog. Nitsch and Nitsch, and Gamborg's B5 media and poor on murashige and Skoog medium in the absence of benzyladenine. With the addition of benzyladenine, Schenk and Hildebrand and Gamborg's B5 Were superior and equivalent. The addition of benzuyladenine increased equally frond proliferation at either 1 or 10μM, however at 10μM fronds were severely curled or fused. Benzyladenine and thidiazuron suppressed root growth but kinetin was found to greatly enhance root growth. Gibberellic acid inhibited frond proliferation. Frond proliferation was significantly different on the four sucrose concentrations of 0, 1, 3, and 5% Among them, 3% sucrose was found to be superior. The reduced frond size observed in cultures grown on 8% sucrose could be explained by showing medium osmotic potential in excess of frond water potential. Gell agents also varied significantly in their ability to promote frond proliferation with 0.25% Gelrite or a mixture of 0.15% Gelrite and 0.4% agar. Proliferation of 25 Lemna gibba strains on medium neat optimal for Lemna gibba G3 showed a six-fold variation across strains with Lemna gobba G3 placing in the top 5 fastest proliferating strains.

• H.K. Moon