. Botany, an elementary text for schools. Botany. CHAPTER XIX FERTILIZATION AND POLLINATION 259. FERTILIZATION.—aSVp(/.s result from the loiion of two elements or parts. Oue of these elements, a nucleus of a plant cell, is borne in the pollen-grain. The other element, an egg-cell, is borne in the ovary. The pollen-grain falls on the stigma (Fig. 202). It absorbs the juices exuded by the stigma and grows by sending out a tube (Fig. 203). This tube grows downward through the style, absorbing food as it goes, and finally reaches the egg-cell in the interior of an ovule in the ovary, and fertiliza
. Botany, an elementary text for schools. Botany. CHAPTER XIX FERTILIZATION AND POLLINATION 259. FERTILIZATION.—aSVp(/.s result from the loiion of two elements or parts. Oue of these elements, a nucleus of a plant cell, is borne in the pollen-grain. The other element, an egg-cell, is borne in the ovary. The pollen-grain falls on the stigma (Fig. 202). It absorbs the juices exuded by the stigma and grows by sending out a tube (Fig. 203). This tube grows downward through the style, absorbing food as it goes, and finally reaches the egg-cell in the interior of an ovule in the ovary, and fertilization, or union of the two nuclei, takes place. The ovule then ripens into a seed. The growth of the pollen-tube is often spoken of as germination of the pollen, but it is not germination in the sense in which the word is used when speaking of seeds. 260. Better seeds—that is, those which produce stronger and more fruitful plants — usuallj' result when the pollen comes from another flower. Fertilization effected be- tween different flowers is cross- fertilization ; that resulting from the application of pollen to pis- tils in the same flower is close- fertilization or self-fertilization. It will be seen that the cross-ferti- lization relationship may be of many degrees—between two flowers in the same cluster, between those in different clus- ters on the same branch, between those on different plants. (128). 202. B, pollen of plum escaping from anther. A, pollen ger- minating on the stigma. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Bailey, L. H. (Liberty Hyde), 1858-1954. New York Macmillan
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