ISHS Acta Horticulturae 215: Seed Research in Horticulture
MECHANISM OF SELECTIVE DEVELOPMENT OF OVULES IN PELARGONIUM, THROUGH THE OBSERVATION OF PISTILS IN NON-POLLINATED FLOWERS |
| Authors: | F. Kakihara, M. Kato, S. Tokumasu |
| Abstract:
Pelargonium has 5 carpels in the ovary. Each carpel has two ovules which rank vertically. Not all ovules can develop into seeds: usually only one can do in the same carpel. Which ovule, upper or lower, tends to develop, is species-specific. The rate of upper developed ovules to total developed ovules (upper ovule rate) varies with species and cultivars. There is a tendency that the upper ovule rate is high in male-fertile cultivars and comparatively low in male-sterile ones. Five-forked parts at the top of the pistil do not open on the first day of flowering (protandry) in male-fertile cultivars, but they open in male-sterile ones. Therefore, this difference in the development of flower organs may or may not related to the difference in their upper ovule rates. The present experiment was aimed to elucidate the relation between the developmental process of flower organs and the upper ovule rate, using several cultivars of Pelargonium. Anatomical observation of stigmas, papillae and ovules in non-pollinated flowers in different developmental stages was compared with the upper ovule rate of pollinated flowers in the respective corresponding stages. As a result, the upper ovule rate was found to be not related to the developmental stages of flower organs. | |
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