|Budget Amount *help
¥1,700,000 (Direct Cost : ¥1,700,000)
Fiscal Year 1999 : ¥1,700,000 (Direct Cost : ¥1,700,000)
Soil adaptability for cultivars of watermelon was described by Kumazawa and Akiya in 1956. However, there has been no further research on it but also on that in other vegetables. In order to elucidate the soil adaptability of watermelon and other vegetables, I made a primary research on the effect of oxygen concentration on the growth of young watermelon plants. Also f tried to demonstrate the soil adaptability of watermelon using cultivars obtained.
(1) Effect of solution oxygen concentration on plant growth was investigated using 4 cultivars. A solution culture system was developed as solution oxygen concentration and temperature were regulated. Solution temperatures were controlled at 20, 25 and 30 C. For the experiment for each temperature, which was carried out in a different season, solution oxygen concentration was set at 50, 100, and 150 % as the saturate concentration at each temperature was at 100 %. Room temperature was controlled at 25 in daytime under natural light and at 20 at night. Seedlings were raised to a 2 to 3-leaf stage under the same conditions and moved to solution temperature at 20 C for 1 week for acclimatization. Subsequently oxygen treatments were started.
Effect of oxygen concentration was estimated from measurements of number of developed leaves, stem length, and the fresh and dry weight of each of shoot and root parts. At 20 C these measurements were decreased at 50 % O2 and slightly decreased at 150 % O2 compared with 100 % O2. At 25 C, growth was remarkably retarded at both concentrations. At 30 C, no remarkable effect was observed.
(2) Four cultivars of watermelon were grown in clayey soil and sandy soil. However, there was not difference in flesh hardness among cultivars.