Fine Structure Changes During Function of the Digestive Gland of Venus's- Flytrap

Abstract

Changes in the structure of the digestive gland cells of Venus's-flytrap during the digestive process have been studied with light and electron microscopy. Large vacuolar lipid-protein inclusions break up and become smaller; however, they never completely disappear during the entire 7-10-day cycle. Dictyosomes in the resting digestive gland are associated with small, inconspicuous vesicles, whereas during the digestive cycle two types of prominent vesicles are observed on the peripheral tubules. Changes in plastid fine structure are complex and involve the disappearance of lipid globules and the tubular complex, followed by the formation of microtubules on the thylakoids and cisternae on the outer plastid membrane. Mitochondrial fine structure changes from the small cristae and light matrix of the resting state to large cristae and a very dense matrix representative of a change to a state where phosphorylation is tightly coupled to electron transport. Pronounced changes which occur in the cell envelope (cell wall and membrane taken together) are apparently associated with secretion of the digestive fluid. Numerous other changes are observed such as polysome formation, multivesicular body formation, mitochondria division, and changes which can be attributed in general to elevated cell activity.