Japanese Journal of Crop Science

It may be assumed by some authors that physiological responses of seed-treatment with the growth substances display the similary phenomena to vernalization and photoperiodism. The results of these experiments in which the after-effects of seed-treatment with β-indoleacatic acid (k-salt) in soybeans were studied in the summer of 1941 showed not only the identical effectcs, but also gave the increase of amounts of yield. Seeds of soybeans (variety : Tyusei Osaya) were soaked in water (for controls) or in aqueous solutions of heteroauxin in various concentrations for 24 or 48 hours. Unwashed hormonizing seeds were then sown on fields on June 1st. Under treated conditions, the flowering began 1 to 2 days earlier and the numbers of flowers increased in proportion to the concentrations of drugs. All the plants were harvested on 13th of August aud the influence of drug upon the growth and yield was studied. The increase tendency of yield was also found proportionally to the vegetative growth in the 0.005% hours treatment at highest, so that the growth substancs would be thought to have an effects for bringing the better yield in Soybeans.

View full abstract

Show abstractHide abstract

In order to ascertain the physiological roles of the hydrogen-ion concentration of nutrient medium and the intensity of daylight upon growth, yield, and chemical composition of rice plant, these experiments were carried out under the condition of water culture. Two varieties, namely "Kameno-o" and "Husaku sirazi" were cultured with two modiffed Kasigai's solutions, which were prepared to be kept at 3.1 and 5.8 pH values respectively. The nutrient solutions were renewed every other day, so that no significant change of pH values and of the chemcal forms of compounds would occure in the experiments. The pots, in which the materials were growing, were classfied into three groups and they were placed under the different conditions of solar radiation in the following plan. Three cubical wooden frames (2X3.7X3 m, ) were set on field; and two of them were covered with one or two laycrs of white cotton cloth and the other had no cover as control. The growth of plant was markedly affected by the difference of both by the reaction of the culture solutions and the light intensities. Under the conditions of decreasing light the plants apted to grow in elongation rapidly. ln some experiments, however in the strong acidic condition the light effect was marked, since growth was lirnited by hydrogen-ion concentration. The number of tillers increased directly proportional to the light intensity in the case of pH 5.8., but such a tendency was not clear in the higher acidity. Lowering the intensity to 0.65 of day light produced rather more dry matter of plant, but a further diminishing light intensity, made it to fell off considerablly. The yield of grains increased almost proportional to the amount of solar radiation in the case of pH 5.8 but in the higher acidity a reversible relation, even a slight, was found. Muchs sugars and starch were contained in the plants cultured with strong acidic solutions when the light was insufficiemt, while, they were less in the case of pH. 5.8. The amount of chlorophyll in leaves was directly proportional to the decreasing light intensities at both reaction of culture media within the limits of these experiments. In the slightly decreasring of light, carotine and xanthophyll increased exceptionally. A partial parallelism was found between the amount of nitrogen in plants and the decreasing of light intensity. Similar results were also obtained concernning to phosphorus and potassium, while less iron, on the contrary, was found, especially in the strong scidity of medium. From the fact above mentioned, it may be concluded that rice plants grow favorablly in the lack of solar radiations under the strong acidic conditions.

View full abstract

Download PDF (1308K)

Register with J-STAGE for free!