. An introduction to vegetable physiology. Plant physiology. 404 VEGETABLE PHYSIOLOGY The effects of stimulation may be seen in glandular organs in plants as well as animals. Both Drosera and Dionma are excited by contact to pour out on to the surface of their leaves acid digestive secretions, which are the result of changes in the activity of the gland-cells. The conduction of the stimuli received is due in the higher animals to the existence of differentiated nerves. The way in which it is carried out by plants has been much debated, but since the discovery of the continuity of the protoplas
. An introduction to vegetable physiology. Plant physiology. 404 VEGETABLE PHYSIOLOGY The effects of stimulation may be seen in glandular organs in plants as well as animals. Both Drosera and Dionma are excited by contact to pour out on to the surface of their leaves acid digestive secretions, which are the result of changes in the activity of the gland-cells. The conduction of the stimuli received is due in the higher animals to the existence of differentiated nerves. The way in which it is carried out by plants has been much debated, but since the discovery of the continuity of the protoplasm through the cell-walls there is little doubt that we have here a similar mechanism. There is scarcely any. Fig. 161.—Continuity of the Protoplasm of contiguous Cells of the Endospbem of a Palm Seed (Bentinckia). Highly magnified. (After Gardiner.) a, contracted protoplasm of a cell; b, a group of delicate proto- plasmic filaments passing through a pit in the cell-wall. differentiation, but the power of the protoplasm to con- duct disturbances from one part of the cell to another is a matter of common observation. The connecting strands between adjacent cells (fig. 161) will suffice to suggest how impulses from the tip of the root may reach the growing region. The co-ordination of these factors we have seen is one of the most marked features of a highly differentiated nervous system. In this respect we cannot note anything in the plant which in its elaboration or in its peculiar efficiency can be compared with the co-ordinating mechanism of animals. Certain responses to stimulation can be effected,. 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 Green, J. Reynolds (Joseph Reynolds), 1848-1914. Philadelphia, P. Blakiston
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