Abstract
Recognition pollen grains were collected from broccoli and cabbage plants. ‘Crushed’pollen as a recognition pollen material was prepared by grinding pollen grains with an agate mortar, while‘untreated’pollon as another recognition pollen material was collected without artificial treatment from the anther after the opening of broccoli or cabbage flowers. Immediately after the application of recognition pollen materials, each radish stigma was pollinated further with self pollen grains. In addition, conventional self pollination was carried out as controls.
Growth behavior of pollen grains on the stigma was examined to estimate the degree of fertility. Detailed procedures used in this investigation are stated in the previous paper.
In the self pollination (controls), a few radish pollen grains could germinate on the stigma. Pollen germination, however, was fairly increased by the preceding application of‘crushed’or‘untreated’broccoli pollen grains. In such cases, many pollen tubes could penetrate the barrier of stigma papillae. A few emptied pollen grains that had transferred their contents into the developing pollen tubes were observed on the stigma.
The percentage germination of radish pollen grains was increased considerably by the preceding application of‘crushed’or‘untreated’cabbage pollen grains. In general, the length of developed pollen tubes that were produced by the cabbage pollen application was shorter than that of pollen tubes by the application of broccoli pollen grains. In such cases, few emptied pollen grains were recognized on the stigma.
It seems that the preceding application of recognition pollen grains collected from broccoli or cabbage plants in combination with the following self pollination partially overcomes the self-incompatibility of Japanese radish.
