(1) The author recognized that borate of catalytic trace elements is produced easily by reaction of borax with each element in salt of inorganic acids, whose catalytic power proued higher than salt of other mineral acids and very stable on heating or leaving. (2) The author compared the catalytic action with the growth-promoting-power of a japanese parsley in water-culture-method and a mustard by soil cultivation. (3) The author studied on the contents of boric acid in fruits and vegetables. Then, the author compared these results with the growth-points obtained by catalytic-power-estimation. From these experimental results, the author discussed on mechanisms of catalytic action on account of the borate of trace elements in nature.
The author considers on the basis of experimental results as follows. (1) On the cultivation experiments of a potted turnip on addition of ferrous iron, manganese and copper, the author recognized that these catalytic substances play an important role on account of the sprout and glowth-promoting of plants. (2) The catalytic action of molybdenum, nickel, zinc and chromium etc. for the glowth of plants is a problem one should not ignore and it is the subject for a future study. (3) The author recognized that the growth of a turnip is disturbed by decreasing of catalytic power of ferrous iron, on addition of equal quantity of manganese or copper in ferrous iron.