Abstract
The available information concerning the effects of ACh, red light and far-red light upon the protoplasts of mung bean (Phaseolus aureus) root tip may be summarized as follows.
1. By the application of a combination of Lillie's buffered neutral formalin fixing together with methyl blue staining, 1) one kind of pericyclic cells, 2) small cells outside of pith, and 3) the procambial cylinder of primary root and also 4) the primordia of the lateral root showed blue color deeply.
2. On the transverse section of the central cylinder of 1000μ from the primary root apex, there are five to eight pericyclic cells in which the protoplasts are stained deeply with methyl blue; these cells contracted with 10-5 M and/or 10-4 M ACh.
3. Atropine restrains the action of ACh on these pericyclic cells.
4. In the same part of the root, there are three to five pericyclic cells in which protoplasts are barely stained with the same dye; these cells are not contracted by the ACh solution.
5. In the same part of the root, the protoplasts of the central cylinder, especially the pericyclic cells, are contracted with the irradiation by red light for 4 min after that by far-red light for 4 min.
6. Due to the irradiation with far-red light for 4 min after irradiation with red light, the features of the protoplast in the same tissue-cells of the central cylinder appears the same as the features of the material which was kept in darkness.
7. The behaviour of the protoplasts of the procambial cylinder of the primary root and of the lateral root due to treatment with ACh and/or the irradiation with red light and with far-red light was the same as that of the protoplasts of the peri-cyclic cells which were stained with methyl blue.
