. Elementary plant physiology. Plant physiology. 132 Elementary Plant Physiology. on its separate peduncle, which is curved in such manner that the unopened bud is held in a drooping position, or variously inclined, as in Fig. io6. As the development of the flower proceeds, and the stamens and pistils mature, the opened corollas are held in a horizontal position until fertiliz- ation is accomplished, when the apical portion of the peduncle again takes up a motion by which its curvature is straightened until the capsule is held in an approximately erect position. The signal or stimulus for each
. Elementary plant physiology. Plant physiology. 132 Elementary Plant Physiology. on its separate peduncle, which is curved in such manner that the unopened bud is held in a drooping position, or variously inclined, as in Fig. io6. As the development of the flower proceeds, and the stamens and pistils mature, the opened corollas are held in a horizontal position until fertiliz- ation is accomplished, when the apical portion of the peduncle again takes up a motion by which its curvature is straightened until the capsule is held in an approximately erect position. The signal or stimulus for each of these motions is set up by the plant itself. Thus the growth and enlargement of the flower bud stimu- lates the peduncle in such manner that it performs a straightening of the curva- ture until the corolla tube is held in a horizontal position. At this point the movement ceases, and the flower is held firmly Fig. io6.—Positions of buds, flowers, and pods jn this position until pol- of Sirefitocarpus Kexii. , , j .. j len has been deposited on the pistil, and presumably the growing tubes from the ger- mination of the pollen have reached the egg cell. The fusion of the nucleus from the pollen tube and that of the embryo sac sets up another signal or alarm, which again sets the peduncle in motion, and the pod is slowly erected into the position shown in the figure. 144. Complex movements of inflorescence of Al- lium.—The inflorescence of Allium Neapolitanum is enclosed in sheathing bracts and supported in a drooping position on. 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 MacDougal, Daniel Trembly, 1865-1958. New York, London [etc. ] Longmans, Green, and Co.
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