Abstract
Several varieties of tobacco plant were grown on water-logged soil and their developmental responses were compared with those of plants on soil whose underground water-level was 90 cm below the soile surface. From this experiment, it was concluded that plants grown on water-logged soil bore a smaller number of leaves and their flowering time was obviously accerelated. Thereupon, the auther conducted the following experiment in the greenhouse. Seedlings of various ages whose leaf numbers were 8, 10, 12 respectively, were transferred from the same seed bed to pots. The pots were subjected to water-logging treatment starting either at the time of transplantation or 10 days after. The remaining pots were kept without treatment. The results were as follows: In the seedlings with more than ten leaves, regardless of the time of treatment, the total leaf number per plant decreased and the flowering time was accerelated as in the previous experiment. In the seedling with 8 leaves, on the other hand, the flowering time was obviously retarded and their leaves showed frenching like symptoms of disease. From this experiment, it may be said that the change in flowering time due to water-logging seems to differ according to the growth stage of seedlings at the time of treatment.
