CELL SHAPING AND MICROTUBULES IN DEVELOPING MESOPHYLL OF WHEAT (TRITICUM-AESTIVUM L)

Differentiated mesophyll cells of Triticum aestivum (cv. Star) exhibit a lobed outline resembling tube-shaped balloons with almost regularly spaced constrictions. It was shown that these constrictions are probably the result of hoops of wall reinforcements laid down during early stages of cell expansion. It appears that these hoops prevent expansion in the corresponding regions and thus give rise to the peculiar cell shape. The comparatively thin cell walls of the bulges are uniformly reinforced after the lobed shape is established. By using immunofluorescence techniques a change in the pattern of cortical microtubule arrangement was observed which corresponded to the pattern of cell wall deposition. Discrete bands of microtubules were found beneath the sites of hoop reinforcement. These bands disintegrated during late stages of cell expansion with microtubules fanning out into the almost empty regions of the bulges. © 1990 Springer-Verlag.