Abstract
In chlorophyll-containing spores of Onoclea sensibilis, depletion of lipid reserves during germination is correlated with increases in the activity of the glyoxylate cycle enzymes isocitrate lyase and malate synthase. In Onoclea, the heterotrophic activity associated with lipid catabolism occurs at the same time that autotrophic activity is taking place. Increases in chlorophyll content and in the activity of glycolate oxidase were recorded during the earliest stages of spore germination. In this species, there is no temporal separation of heterotrophic and autotrophic reactions. Concurrent increases in glyoxylate and glycolate cycle activities appear to occur naturally.