Title: The Role of Cell Expansion in the Abscission of Impatiens sultani leaves
Abstract:The histological events occurring during the latter stages of abscission were followed continuously in longitudinal slices through the petiole base of Impatiens sultani Hook. It appears that the middl...The histological events occurring during the latter stages of abscission were followed continuously in longitudinal slices through the petiole base of Impatiens sultani Hook. It appears that the middle lamella of the cortical parenchyma cells is degraded first. This is followed by an expansion of these cells and a concomitant stretching and separation of the collenchyma and vascular trace. The parenchyma cells continue to enlarge until they become virtually spherical, a process which finally ruptures the last restraining xylem vessels. The increased volume of the parenchyma cells appears to be principally due to a conformational change in cell shape from a near regular hexagonal prism to a sphere of similar surface area. The dimensions of the prismatic cells are such that most of them change into spheres whose diameters are the same as the transverse distance between the opposite sides of the six axially orientated faces of the prisms. Cellular expansion is thus entirely directed along the axis of the petiole. The significance of these observations to the general anatomy and mechanism of fracture of abscission zones is discussed.Read More
Publication Year: 1981
Publication Date: 1981-11-01
Language: en
Type: article
Indexed In: ['crossref']
Access and Citation
Cited By Count: 35
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