抄録
Most pH value of plant were measured are of the expressed sap of tissues. The expressed juice, however, consists of water which lies in the intercellular spaces or conducting tissues and cell sap with some plasm substances. It is impossible to measure the pH value of a definite part of a individual cells by such a method. Nevertheless, we might know the relation between the pH value and disease by this method, when the plant tissue set up necrosis. However, in the case of studing the mechanism of the resistance to disease, the pH values we need to know are of the earlyer or normal stage of cells rather than necrosis. In such a case, the most ideal method is vital staining one. Thus, a number of pH value by this method were obtained by others. But it is regrettable that this method is not yet popularized. Then, to tried to it, we tested about 80 kinds of dyes on the permeability, intrability, and toxic character to vegetable plasms, and tried to reform microscopic colorimeter (not microcolorimeter). In this paper, we should like to report chiefly the microscopic colorimeter with some results obtained as a sample. On the rests, we shall report in another chance. The principle of the microscopic colorimeter divised is utilized conversely the principle of Abbe's drawing apparatus as shown in figure. We made standard colour solutions by adding original dye solutions (0.1%) in buffer solutions, and then set them in apparatus. We can compare tone of colour between stained cells and standard. By using this apparatus, we may distinguish acculately to the first place of decimal in pH value. Furthermore, it has good points required when using this method as follows : (1) It is possible to change easily the concentration or components of standard solutions. (2) It is possible to use any artificial light as a light source of microscope, owing to make equal quality of light by changing filter which illuminate standard solutions. The plant cell used were the 4-5 th layer of cortex of root-tip at 8mm. from the top of Barley. Dyes solved in tap water (pH 6.8) and the concentration is 0.01%. Dyes used are neutral red, neutral violet, cresol red, bismarck brown, brom thymol blue, methyl red, congo red, alizalin red S, congo rubin, phenol red, brom cresol purple, and rosolic acid. Results obtained are as follows : vacuole pH 7.4, plasm 6.6, nucleus 7.4-7.2, and membrane 6.0. [figure] C. Standard pH solutions, c is a side view of it. P. Plisms. F1, F2, f1, f2. Glass filters. T1, T2. Electric transformers. S. Slide glass with a subject. M. Microscope.
