The ascent of sap to any point of plant causing there an increase of turgor in tissues is signalled by a deflection of galvanometric positivity. Two electric contacts are made on the stem. Knowing the distance d from the root to the first lower contact A, and time-interval t between the application of water and the first electric response, the velocity v may be calculated by v=d/t. If the ascendingwater then reaches the second upper contact a reversal of the previous electrical response may be caused. Taking this interval between two responses as t', and the distance between the two contacts as d', the velocity v' of transport between the two points is given by v'=d'/t' The velocity calculated by the latter formula may be more accurate, because the distance from the root to the first contact cannot be determined as accurately as the distance between the two contacts. Taking into consideration, moreover, of the results by the thermoelectric method it is concluded that the effect of probable variations in the absorption of water by roots are practically eliminated in case of the latter Di-phasic method. The ascending velocities found by two experimental methods are shown in Table 1 and 2 respectively. The present investigation was carried out in the Biological Institute of Tohoku University in Sendai during the summer in 1948 and 1949. I wish to express my sincere thanks to the leader, Prof. Dr. Y. Yamaguti for the never failing interest he has taken in my work and his most valuable help and criticism.
1. In the plant cell vacuoles, preliminarily stained in vivo with thiazine dyes (but excepting methylene blue), there appear numerous crystals of the dyestuffs, when they are treated with the solutions of thiocyanide, iodide, bromide, chloride or nitrate of alkali metals (Na, K, or Ca). These demixed crystals show various types of spiral shape. 2. This demixing reaction is accelerated with the increase of the concentration of the dye-solution used, but also related to the sort of the anion of the salt employed, giving the following anion-series, concerning the acceleration of the reaction: SCN->I->Br->NO3->Cl- 3. The same demixing reaction is proved to take place in the mere water solutions of the dyestuffs, when they are treated with solutions of the same salts through a semipermeable membrane of collodion or pig bladder. The anion-series obtained from these model experiments perfectly coincide with the one obtained from the vital stainings of cell vacuoles. 4. It may be concluded, therefore, that the demixing of the spiral formed thiazine dyes in plant vacuoles has been aroused by a simple reaction of salting-out of dyecrystals in solutions. Although their shapes were various and often curious, no parts would be played by the constituents of cell saps or cytoplasms.
A critical study of the occurence of silver nitrate reduction in plant cells was carried out with the following results. 1) Minimum amount of ascorbic acid (reduced form) clearly detectable with acidified silver nitrate solution after GIROUD is 300mg% at 25°C and 150mg% at 40°C (Table 1). At 25°C, 150mg% ascorbic acid is clearly detectable with a si1ver nitrate solution at pH6. 3 (Table 2). 2) As a rule, the more contains the tissue ascorbic acid (reduced form), the more markedly occurs the reduction of silver nitrate. But this relation does not hold good in some cases (Table 4). 3) In most cases, chloroplasts remain colourless when a tissue is treated with acidified silver nitrate solution after GIROUD in darkness. 4) When the tissue treated with the acidified silver nitrate solution is immersed in ordinary alcohol, the alcohol causes a secondary blackening of chloroplasts.
We have investigated the influence of dielectric constant on the velocities of the catalase and peroxidase-reaction, and have found that the relation between dielectric constant D and the velocity constant k of the breakdown of the treble complex of the enzyme (the complex in which one substrate and one acceptor molecule are bound with a enzyme molecule) is given by the equation ∂ln k/∂(D-1/2D+1)=constant (large positive values). Accordingly, it is concluded that at the activated state of the breakdown reaction large dipole moment is induced as a result of electron migration through the protein structure.