Ethylene-induced Pea Internode Swelling

Exposure of etiolated pea (Pisum sativum L. var. Alaska) subapical sections to ethylene disrupts normal polar cell expansion, but fresh weight increase is little affected and the tissue expands radially, swelling. Ethylene has no effect on gross ribonucleic acid metabolism before or during the period when swelling occurs, but incorporation of (14)C-proline and leucine into wall-associated protein is markedly inhibited after an initial 3-hour lag period which precedes swelling. Ethylene affects the composition of this protein, altering the proline-hydroxyproline ratio. The gas also alters the optical birefringence pattern of the cell wall, indicating that the cellulose microfibrillar orientation has been changed.