Abstract
O. corniculata exhibits a wide range of variations.Some have decumbent branches, and another have ascendant ones.Also some petioles are oblique and the others arrange horizontally.
When excised leaves with oblique petioles placed horizontally in the dark, the petioles bend upward.Excised petioles set on a 1D clinostat with rotating lamp, also,bend toward to the light source.But, petioles treated with NPA, did not respond to the gravitropic stimuli or photo stimuli.These observations indicated that the gravitropic and phototropic response of the O. corniculata petioles were associated with polar auxin transport in them.
The elongation zone of the petioles shifts from the basal ends to the top ends, during the elongation period.Amyloplasts in the starch sheath disappeared as the elongation zone move toward the top ends of the petioles.The amyloplasts finally disappeared from the bending region to ca. 5mm above the abscission layers.
