The hydrion concentration of plant tissues
In previous articles of this series we have given a general survey of the reaction of stem tissues in a number of families (5), a general survey of the tissue reactions throughout the life-periods of the sunflower (1) and of the bean (6), and also an indication of the possible importance of the carbon dioxide content as a factor governing the hydrion concentration of the cell, especially between pH 6"0 and pH 4"0 which is the usual range in plant tissues (2). In the present article we summarise the data obtained during a general survey of selected herbaceous and woody stems, examined at monthly intervals throughout the year.
THE PERMEABILITY OF LIVING CELLS TO DYES AS AFFECTED BY HYDROGEN ION CONCENTRATION
1. An accurate quantitative method of measuring the penetration of dye into the living cell is described. 2. Cresyl blue is unable to penetrate rapidly unless the pH outside the cell is decidedly greater than that inside. The rate of penetration increases with increasing pH. 3. Around pH 9 penetration of the dye is rapid while the reverse is true of exosmosis. At low pH values (5.9) exosmosis is rapid and penetration is very slow.
Report on Progress Toward Security and Stability in Afghanistan
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