Shokubutsugaku Zasshi

Es ist mir gelungen, einen Artbastard zwischen zwei ungleich chromosomigen polyploiden Arten von Chrysanthemum, nämlich von Ch. Decaisneanum und von Ch. indicum zu erzeugen, wobei die letztere die Rolle der Vater-, die erstere die der Mutter-Pflanze libernommen hat. Der F₁-Bastard steht Aussehen mar oder weniger in der Mitte zwischen den Elterpflanzen (Abb. I).
Chrysanthemum Decaisneanum hat 36 haploide Chromosomen, während Ch. indicum nur 18 aufweist. Der Bastard hat, wie erwartet, 54 diploide Chromosomen (Abb. II). Bei der heterotypischen Metaphase in P. M. Z. des Bastardes treten 27 Gemini auf (Abb. III). Man muss daher annehmen, dass wenigstens 9 Gemini durch die Autosyndese der von Ch. Decaisneanum stammenden Chromosomen gebildet worden sind.

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In the foregoing papers concerning the self-incompatibility in Petunia violacea the author has reported that the stylar tissue-juice of the self-incompatible individuals contained a special substance, which inhibits the pollen-tube growth of their pollen-grains.
When this substance is produced in the style? The author has intended to solve this problem. Working on some self-incompatible individuals of Petunia violacea, he obtained the following results.
1. Self-incompatible flowers in buds pollinated with the pollen of the same individual (bud-pollination) bear, as a rule, a higher percentage of seed than those pollinated after their opening.
2. These results may lead us to an idea that the eggs of young flowers may be more functionable than those of the open flowers. But that this is but a mere surmise is proved by the fact that the pistils of the open flowers were more easily cross-fertilized than those of the flowers in buds.
3. The duration of an individual flower-rom its pollination to its withering-can be prolonged by bud-pollination. The author has reported that the pollen-tubes of the self-incompatible plants grew through their own stylar tissues very slowly, and that they were unable to reach the ovaries within the life time of the flower. Therefore the prolongation of the duration of the individual flower may somewhat be favourable for their self-fertilization.
4. The rate of the pollen-tube growth through the stylar tissue of the same line was slower in the case of the pollination after the floweropening than in the case of the bud-pollination. And also the growing rate of the pollen-tubes in the artificial media, water solution of cane sugar containing the stylar tissue-juice of the same line was smaller in the medium with the stylar juice of the open flowers than in the one containing the juice of the flowers in buds.
5. The tips of the self-pollinated pollen-tubes were swollen irregularly in the styles of the open flowers, but they were smooth in those of the flowers in buds.
6. The self-fertilized seeds obtained through bud-pollination germinated well.
7. These results show us that the special substance which inhabits the growth of the pollen-tubes of its own line is not yet produced when the flowers are still in buds.

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