菜種の萎縮及び不稔性障害に関する研究

抄録

In order to find out the essential causes of shrinking and failing in ripening of rape plants, the authors carried out experiments during 1951 to 1953 on the fields where such injuries prevailed. The results were as follows : 1. Some differences in resistance to the injury were found among the varieties tested. 2. It might be presumed that the nursery conditions had a great influence upon the out-break of the injury ; those factors causing the acceleration of seedling growth, the decrease in the percentage of dry weight of plant body and the rise in the top-root ratio, might have been liable to promote the injury. 3. No relation has been noticed between aphis and the injury, and the occurence of injury might be influenced rather by the seedling chracters and by the field conditions. 4. Generally, such injuries were controlled by early sowing and transplanting, while in late culture the injury was increased. But the time of transplanting had larger influences on the injury than the sowing time. 5. It might be presumed, that nitrogen, potash and phosphorus promoted the injuries, especially the failure in ripening in the respective order according to the grade of acceleration of plant growth. 6. The application of compost and wood ash was very effective to keep out the plants from the injury, especially the application of wood ash in the fields being most effective, and also the application of ash in the nursery bed being beneficial to some extent. 7. Application of boron added in the basic fertilizer, or as top-dressing or by spraying on the plant was very much effective to control the injury. 8. It may be concluded from the results above mentioned, that a greater part of the cause of the injury should be the boron-deficiency in the plant, the latter being directly or indirectly affected by growth conditions. The beneficial effects of compost and wood ash might be ascribed to the presence of boron in those fertilizers.