The Effect of Gibberellic Acid on Cell Width and the Cell-wall of Some Phloem Fibres

Treatment of plants of Cochorusoiltorius L., Hibiscus cannabinus L., and Cannabis sativa L. with gibberellic acid induced highly significant increases in cell diameter and wall thickness of problem fibres. This difference varies along the shoot and is maximal in the middle region, internodes 10–15. The ratio $The ratio cell wall thicknesscell breadth is higher in treated plants.$ is higher in treated plants. Gibberellic acid reduces the angle of orientation of the pits to the cell wall and also the pit frequency. Pits in treated plants are longer and narrower in surface view.