Studies on the Causes Relating to the Difference of dry Matter content of Sweet-Potatoes : (4) The difference of diurnal fluctuation of water content among varieties, of high dry-matter content and of low dry-matter content

摘要

The experiments were made to know the difference of varieties, high or low dry matter content. Result: (1) As to the quantity of water per 1 gram dry matter, the varieties of low dry matter content attain to the minimum at earlier time of the day and increase more rapidly in the afternoon, than those of high day matter content. (2) It is observed that the diurnal fluctuation of water contents in the tops and in the root-tubers run parallel one another. (3) The ratio of the amount of transpiration (T) to absorption (A) T/A is higher than 1 in summer and early autumn, but later it decreases gradually, and falls lower than 1 in autumn. The ouantity of water per 1 gram dry matter decreases in the period of high T/A ratio and the percentage of dry matter content increases. These facts are recognized to be more remakable in variety of percentage of high dry matter contents.