Induction of Foliar Buds by Morphactin Treatment of Flower:Bud of Pineapple (Ananas comosus MERR.)

Abstract

n order to improve the efficiency of the asexual reproduction of pineapple plant (Ananas coleaosus MERR.), morphactins, known as plant regulator-like chemicals, were applied to the flower bud. Prior to the morphactin application, the apices of plant materials were pre-treated with ethrel to enforce the synchronous induction of compound flower buds. The flower buds thus induced were subsequently treated with various concentrations of morphactin solution, at different developmental stages, and different replications of treatment. Following the morphactin treatments, a number of foliar buds was developed from the fruitlets of a syncarp. This foliar bud development is not observed in natural pineapple plant and also had not been reported in the other plants treatecl with morphactin. These foliar buds were tentatively called "buds-from-fruit" in the present paper. When morphactin at concentrations of 80 and 100ppm was applied to the mater.ials in 6 to 12 days after ethrel pre-treatment, more than 80% of the plants produced "buds-from-fruit", and the average number of "buds-from-fruit" of single plant, i. e. single syncarp, obtained langed between 8.8 to 15.7 The maximum number of "buds from-fruit" obtained on a syncarp was 32. There was a certain stage in the development of the flower bud which was found to be critical as regards the effect of morphactin activity. This stage preceded the differentiation of the syncarp into flower primordium. In addition, morphactin treatrnent also gave rise to an increase in the number of natural foliar buds such as slips and suckers, a retardation in the emergence of the compound flower bud, and a tendency for the apical leaves of the treated plant to roll up which is a typical function of morphactin activity.