1992 Volume 36 Issue 1 Pages 21-27
It was observed that the female flower clusters, which give rise to fruits at harvest time, developed according to the same arrangement as a 2/5 phyllotaxis on the inflorescence axis of castor-oil plants. The male flower clusters developed in the lower part of the axis in the same way as the female ones. In a female flower cluster, one flower (the first flower) developed terminally on the axis of the flower cluster. Two flowers (the second flowers) developed at the opposite position in the lower part of the axis of the first flower. The third and higher order flowers behaved in the same way. As a result the inflorescence of this flower cluster was considered to correspond to the dichasium. The number of fruits per dichasium was the largest in about the fifth female dichasium counted upward on the inflorescence axis. These findings suggested that the number of female dichasia on the inflorescence axis, the number of fruits per dichasium, the number of seeds per fruit, and the seed weight controlled the seed yield per inflorescence in castor-oil plants. The number of leaves and leaf area of the main stem were positively correlated with the seed yield, the number of fruits and the number of female dichasia of the primary inflorescence. The leaf area of the main stem showed a closer correlation with these yield components than the number of leaves on the main stem. The number of leaves and the leaf area were not correlated with the other yield components, i.e., the number of fruits per dichasium and the 100-seed-weight.
