Experimental bisection of Aquilegia floral buds cultured in vitro: II. Cytological changes following bisection

Abstract

A previous paper in this series has reported on the effect of bisecting Aquilegia floral apices of different developmental stages by maintaining a continuous photographic record of living buds (Jensen 1971). The current paper is a preliminary light and electron microscope study of the cytological changes which occur following bisection of very young buds (sepal to petal stages). Bisected buds show a progressive increase in size of grains which are positive to periodic acid – Schiff stain up to 2 days after incision, followed by a progressive decrease in size up to 7 days after incision. These grains are probably starch as they were absent in sections treated with α-amylase and malt diastase. It is suggested that after bisection the buds are in a resting state for 1 to 2 days during which time sucrose is absorbed from the medium and stored as starch. As regeneration of a new apex proceeds, starch is digested and used by the cells of the growing bud.