抄録
The author investigated the reaction of tea leaves to iodine when cultured in its aqueous solution, with particular reference to the nitrogen contents in the plant. When the young shoots cut from their mother plants have absorbed iodine for about 24 hours, a number of small redish brown spots appear on the surface of the leaves. The grade of the symptom is different according to the varieties of the plant and is found to be almost in proportion to the quantity of nitrogen contents of the leaves, the larger is the content the stronger being the symptom. Though the reaction varies, on the other hand, according to the position of insertion of leaves on shoots and also to the light intensity under which the shoots are cultured, the fact proves clearly parallel to the amounts of nitrogen when these other conditions are equal. As iodine is known to react with protein and caffeine and to occur precipitation, it must be very duely understood that the symptom, that is, the development of redish brown spots on the leaf surface, is caused by such a reaction, theses nitrogenous compounds usually being rich in the tissue. The amounts of nitrogen in the leaves is one of the characteristics of the variety in the plant and is closely related not only to the quality of green tea, but also to the resistance agaist diseases. So the determination of nitrogen in the leaves by means of the iodine reaction must be very useful for practical breeding works in the plants.
