Studies on the Wilting Treatment of Corn Plants : III. The influence of the artificial auxin control in nodes on the behavior of rooting

[摘要] The authors reported in previous paper that on the corn plants wilted temporarily at young stage about 6 leaves age or successively at the early stage of stem elongation about 9∼12 leaves age, the growth and fodder yield showed the tendency to increase by growing under the adequate soil moisture condition after rewatering, and that even at the stage of rapid stem elongation about 15∼18 leaves age they did so in case of a rapid drought of soil moisture. It was reported in last paper that (1) the number of roots from the nodes on which rooting occurred after rewatering increased, on the corn plants wilted successively for few days or sprayed gibberellin, (2) the rooting from the upper nodes on which it didn't take place under the normal condition was accelerated, (3) there was the regularity in the behavior of rooting on the corn plants, it was related to the closing an internodal elongation. Considering from these phenomena, it may be thought that the rooting and internodal elongation are carried away by auxin level in the neighboring nodes, and that the wiling treatment is concerned with the auxin level in the neighboring nodes. In present experiment, the auxin level in the neighboring nodes was changed artificially by using a few ways i.e. lodging, added NAA or TTP to 6th, 7th and 8th nodes and X-irradiation. Then these treatment shows the same influence as the wilting treatment on the behavior of rooting. 1. On the corn plant lodged, the lower parts of each internode which is elongating are bended and the plants pick themseves up. This phenomenon is due to undergo a change in the auxin level in the neighboring nodes, thereafter to impede the growth of internodal parenchyma in inner side of bending stem and to accelerate it in outer side. Further it is observed that the rooting from the inner side of bend is impede and the rooting from the outer side of it is accelerated and that the rooting from the upper nodes on which it doesn't take place under the normal condition is promoted, too. 2. As NAA or TTP is supplied on 6∼8th nodes, the rooting from those nodes is accelerated, thereto the rooting from the more upper nodes which it doesn't take place under the normal condition is observed, too. 3. For the investigation used drought and X-irradiation at the same time, though the development of brace roots is accelerated by drought, the number of brace roots which develop after X-irradiation decreases even if the previous treatment is drought or not. 4. These auxin variations in the neighboring nodes made the rooting and internodal elongation accelerate. It may be very interesting because it's able to consider that hydrolysis of protein is progressed under the wilted condition and then TTP or IAA increase in the corn plants. As the result of the raising of the auxin level in the neighboring nodes these morphological changes are brought on.

[学科分类] 农业科学（综合）