Effects of Growth-Regulating Substances on a Parthenocarpic Fruit

Abstract

1. Application of sprays of a-naphthaleneacetic acid to pineapple plants after normal differentiation of floral primordia had been completed influenced the growth of fruit, peduncle, and axillary branches. 2. Relatively high concentrations of the growth-regulating substances caused a marked increase in size and weight of ripe fruit, although the number of fruitlets was not influenced by any of the treatments. This increase in growth of the fruit was accompanied by the development of large peduncles, from which the fruit was separated with some difficulty. 3. The highest concentration of naphthaleneacetic acid also delayed ripening, and, particularly when applied in the center of the plant, partially inhibited growth of slips and suckers. 4. Relatively low concentrations applied at the same time caused some stimulation of the growth of dormant slip buds, resulting in a larger number of slips per plant.