This experiment was carried out to determine the effects of the soil types on the growth and chemical composition of Bahiagrass and alfalfa grown alone and in association. The seventeen soil types collected for this experiment were derived from widely different materials varying considerably in the physical and chemical properties of each soil type. The results obtained were summarized as follows: 1. The growth of Bahiagrass was scarcely affected by the soil types used in this experiment. The fact suggests that Bahiagrass is adapted to a variety of soils. 2. As increased the frequency of cutting in the mixture of Bahiagrass and alfalfa, the dry matter yield of Bahiagrass increased and that of alfalfa decreased in many cases of the soil type. 3. The harmful effect of successive cropping of alfalfa was observed in this experiment, and the extent of effect widely varied according to the soil types. 4. Soil type had a marked effect on the crude protein content in the top of Bahiagrass and alfalfa. In many types of the soil, in the first cutting of Bahiagrass and alfalfa mixture, it was observed that the higher the alfalfa content the higher the crude protein content of Bahiagrass in this grass-legume mixture, however, in the second and third cutting, this tendency could not be observed in several types of the soil within the above mentioned soil types.

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1. The result of experiment shows that the salts contained in the irrigation water, move up along the outside of the plant. 2. The salts are accumulated at the parts of ligule and auricle, and then these parts are dead. 3. The salts move up along the part at which the leaf sheaths embrace. 4. The leaf spots appear, by absorption of the salts, at the top of the leaves and afterward develope to downward.

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In Japan, the propagation of sweet potato is practiced mainly by planting sprouts, but the planting of small tubers method has been unnoticed by the majority though it seemed to be useful. The small seed tuber planted in the ground grow itself but it can not become a fleshy root of good quality. Therefore this method is not yet utilized except for forage to domestic animals and fowls in this country. The writers had improved this method by exposing setting-tuber to light immediately after its sprouting. The growth of setting-tuber which had been exposed to the light is inhibited to thicken and the new fleshy roots produced from the original setting-tuber are promoted to grown this study, the growing process of sweet potato plants grown from setting-tuber by the exposing method was traced, comparing with that of plants grown from setting-tuber which had been kept in the ground. Dry weight of setting-tubers were gradually decreased till its sprouting time and the tubers kept in the ground grew more rapidly than that of exposed tuber, but as to the growth of new fleshy roots, fleshiness was lower in the former case than the latter, and the growth of tops was almost similar in both cases. Differences in anatomical picture of setting-tubers in both cases were traced. In the light exposed plot; Cell membrane of epidermis was thicker at the harvest time than that of setting time, and there were scarcely new cells. About 30 days after setting, the appearance of chlorophyll was recognized in the epidermis and cortex cells, and the chlorophyll was observed also in parenchymatous cells diversed from cortex. And suberized cells were seen about 50 days after tuber setted. Arrangement of xylem became like a belt, and vessels were aggregated densely in this belt. Degree of lignification of the cells around vessels was remarkable, and the lignificated cells were closed together about 80 days after setting. In nonexposed plot; About 50 days after tuber setted, the surface of setting-tuber was cracked and epidermis was formed on this crack surface and new cells developed from the old tissues as chimera. Chlorophyll was not seen in the cortex and number of suberized cells were less than that in exposed plot. Layer of cortex was narrow and the size of cells was not uniform. Development of xylem was remarkable and the arrangement of xylem became as a zigzag ring. Vessels were dispersed and the degree of lignification of the cells around vessels was less than that of exposed plot. The facts that the transformation in tissues and appearance of chlorophyll in the setting tuber of sweet potato induced by exposing to light, as observed in this study, may be considered to be related to the inhibited growth of setting-tuber growing.

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This paper deals with the effects of soil and water temperatures upon the heading time and growth regulating substances in leaf sheath of rice plants. A variety named Norin No. 41 was used. The outline of each experiment and results obtained are as follows. 1) From the 6th leaf stage to the heading time, plants were placed in soil thermostats which were kept constantly at 30°, 25°, 20°and 15°C respectively. In addition to these, a plot was subjected to 30°C for the first ten days and then transferred to 15°C. Plants headed earlier as the soil temperature was held higher. A plot transferred to 15°C after ten days treatment with 30°showed a rather striking promotion of heading as compared to 15°constant. 2) Plants were treated with different soil and water temperatures for 10 days at the 3rd, 4th, 5th and 6th leaf stages. The heading promotion was most conspicuous in the plot treated with 30°C, at the 6th leaf stage. The rate of leaf emergency was promoted strikingly by the higher temperatures, so that it resulted in the decreased leaf numbers on the main stem. 3) The growth regulating substances occuring in the top of plants treated were assayed by the Avena-test at periods from 6th to 12th leaf stage. The substances occured much more in quantity as the test temperature rose. This fact might be somewhat related to the heading promotion in the high temperature plots. Moreover the substances were diminished most remarkably at the 7th leaf stage.

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The withering caused by transplanting, especially in late culture in summer season when both temperature and light intensity are high, is a serious problem because it apts ot cause delay of growth rate and decrease in yield. The degrees of withering were remarkably affected by the differences of conditions such as plant age and nutritional conditions in seedling stage. The withering is less with upland seedlings and older seedlings as compared to low land plant, and younger one respectively. The less withered plants are characterized by high percentage in dry matter and high ratio of dry weight/plant height. Next, as regards of the total nitrogen content and the respiratory rate per dry matter, the authers found the tendency that the larger these values are, the more severe the withering within either of seedlings of two types. But, in spite of the higher values of these characters of the upland seedlings, the withering of upland seedlings was less than that of low land seedlings. Because the old upland seedlings are resistant to withering, capable of producing larger amount of fresh root and of producing larger amount of fresh roots and of producing greater dry matter after transplanting, the old upland seedlings are considered to be most adaptable for the late season culture of paddy rice in Hokuriku district.

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It is a troublesome problems that the seedlings are very soft and show remarkable withering when transplanted in the late season culture of paddy rice. Besides, these seedlings have a low "dry weight/plant height" ratio and are low in the dry matter percentage as reported in the previous paper. The authers found in this study that they were characterized by the over-growth, especially by the unusual elongation and the low dry matter content in the leaf-sheath. The lowland seedlings compared with the upland seedlings, as a rule, show more severe withering and in addition over-growth of the leaf-sheath, the dry matter content of its leaf-sheath being lower than that of the upland seedlings. These phenomena are considered to be the cause of the withering. The relation between the over-growth of leaf-sheath and the withering can be attributable to the following points; firstly the decrease in the latent recovering capacity from withering owing to decreased nutrition amount in leaf-sheath caused by over-growth, secondly lowered physical resistance to withering and finally the disturbance of water balance in seedlings, because the tall seedlings resulted in the greater aerial parts of plant, above water surface in the paddy field.

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The studies were carried out to know the chemical characteristics of sugar beets sown in summer in Okayama, neighbouring district of the Inland Sea of Seto. Sugar beet of the variety Donyu No. 3 (GW 443) sown in August 4 1960 and the samples were taken from October 10 to the beginning of May. At the end of this experiment the plant have bolting. Harvested plants were seperated into blades and petioles, crowns and roots. At harvest the fresh weights of the four parts of the plants were recorded and samples for chemical analysis were taken. In this paper described the uptake of nitrogen, the changes in content of protein and soluble nitrogen, moisture and dry matter content of sugar beet plant. The results are summerized as follows: 1. The morphorogical and chemical changes in sugar beet plant sown in summer may be divided into four stages during from autum to the next spring. 2. Within the year, especially, during about 2.5∼3 months after germinated (late October or early November) nitrogen uptake, water absorption, content of protein and dry matter are increased considerably in the plant, and contributed effectively to the growth of tops and root. Following this stage, as the temperature and daylight decreased gradually, the growth of new leaves and root are retarded, but their lives are maintained. Leaves have tendency towards lowering of protein and increasing of soluble nitrogen in blades. Otherwise, root have high in soluble nitrogen in winter, and it causes to decline in quality of root for beet sugar processing. In the next early spring, the nitrogen uptake, and dry matter content in plant are increased greatly and regrowth of top and root are accelerated. 3. Sugar beet sown in summer and grown in the warmer region of Japan has remarkable weight of crown. Therefore, when we want to know the growing stage or maturity of plant sown in summer, we prefere to have the ratio in weight of leaf to root to the ratio of top to root.

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The influence of clipping on the tiller number and regrowth of shoot in Italian ryegrass was investigated under two levels of height of cilpping. In the case of removal of shoot to a 2 cm height, i.e. growing points of shoots were mostly removed, the tillers markedly decreased in number for some time after clipping and then they increased rapidly in number, and were greater in number than those of control plot. In the case of removal of shoots to a 6 cm height, i.e. growing points of shoots were mostly maintained, the tiller increased slowly in number, and they were smaller in number than those of control plot. The half emerged or pre-emerged leaf blades from sheaths at the time of clipping showed remarkable elongation after the clipping, whereas the post-emerged leaf blade did not show any marked elongation after the defoliation.

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From 1958 to 1959 the effects of low-temperature treatment in germinating seeds and young plants on the subsequent flowering of Usui peas were studied. In 1960 a further experiment was carried out to study the relation between the stage of growth in time of green-vernalization and flowering. After the treatment all materials were cultured in the greenhouse maintained above 15°C. and under the condition of 12 hours day-length. The results obtained are summarized as follows: 1. The flowering was accelerated by seed-vernalization, but not accelerated by green-vernalization. 2. Both 20 days' seed-vernalization and 30 days' green-vernalization in early stage were effective in decreasing the number of nodes to the first flower. Furthermore, it was noted that this effect increased progressively with the duration of treatment. 3. All non-vernalized plants cultured in the greenhouse maintained above 15°C flowered normally. Accordingly, there is a question whether vernalization is absolutely necessary for pea flower formation. 4. It appeared that the low-temperature treatment in the early stage of growth, such as the first leaf expanded, was most effective, but after the eighth leaf expanded green-vernalization was no longer effective.

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The experiment was made to evaluate the effect of drainage of surface water on the growth, yield and nutrient uptake of rice plant. Rice plants were grown in both submerged and drained conditions. The water level in the submerged plots was maintained at 5 cm depth through the growing season. In contrast, the drained plots were kept under wet condition (no standing water) from one week after transplanting to harvesting time. Both plots mentioned above included much and less fertilization, each with powdery, granular fertilizer and soybean cake, respectively. The results obtained were as follows. 1) The drained plots, as compared with the submerged plots, generally showed the increased number of tillers in both tillering and booting stages, and the decreased number of panicles at harvest. The weight of dry matter per hill in the drained plot became to be inferior to that in the submerged plot as the rice plant grew, especially in the case of less fertilization. 2) It was found that the amounts of N, P₂O₅, K₂O and SiO₂ absorbed by rice plant were commonly decreased by the draining, but in some cases were temporarily increased at tillering stage. The absorption rate of nutrients of rice plant in the drained plots decreased remarkably in the case of less fertilization. 3) The grain yields in the submerged plots were higher than those in the drained plots, except for the much fertilization plots with granular fertilizer. In general, the reduction of grain yield by the draining were less in the much fertilization than in the less fertilization and less in granular than in powdery and soybean cake. Thus, it is suggested that the reduction of the grain yield in the drained plots are depend chiefly on the decrease of the nutrient uptake of the rice plant at later stage of growth, because the long time drainage decreases availability of N, P₂O₅, SiO₂ etc. in soil.

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Photosynthetic ability of rice plant at ripening stage had an intimate correlation with nitrogen content in leaves. Accordingly, in general cases, it is assumed to be beneficial for the photosynthetic ability of the rice plant to maintain nitrogen content in leaf blades at a relatively higher level. During the ripening stage, the decreasing nitrogen content in leaves was mainly due to the translocation of nitrogen in leaves to the ear, associated with the carbohydrates transport from the vegetative parts to the ear. The nitrogen content in leaves could be maintained at high level during the ripening stage by the treatments, i. e., the restriction in number of glumes and the removing of the ear, but the photosynthetic ability and the net assimilation ratio of the treated plant were lower than the non-treated plants. These results suggest that the photosynthetic ability of the rice plant at the ripening stage may be materially influenced through the degree of translocation of photosyntheates from the vegetative parts.

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It has been hitherto assured by many researchers that the efficiency in utilizing sunlight in photosynthesis of plant community plays an important role in its dry matter production. The sunlight transmitting into plant community is generally reduced from its initial intensity, but there is considerable variation in its reduction rate among communities owing to their structural difference, which might cause consequently great influence on the efficiency in its utilization. In this respect, the form of plant in each stand which make up the structure of community could be of most importance as the fundamental factor affecting on the efficiency in utilizing sunlight. From this point of view, the form of plant in rice varieties has been studied since 1959. In the present report, as the first step, the significance of extinction coefficient in rice plant communities was examined in relation to the efficiency in utilizing sunlight and also to the form of plant. In rice plant community, it is well known that the form of plant shows considerable changes accompanied by variety, growth stage, cultivating condition, etc.. The experiment, therefore, was conducted at the period of heading and of about three weeks later, and the changes in growth attributes as well as light factors were measured with the communities of fourteen rice varieties. The results obtained would be described as follows: Light transmission rate (k) showed, in general, an exponential decrease with increase in leaf area index (F), but the considerable variation was found even among the communities of same F. This is considered to prove positively the influence of the form of plant on k. A very close negative correlation obtained between extinction coefficient (K) and F was clear enough to explain that the community with bigger F could be secured only in small K. More, indicating the remarkable influence of K on F when much amout of leaves are produced, the gradient of regression line which was dependent on the earliness of varieties turned steeper for late varieties. Suppose the dead leaves in lower part of community is caused by low illumination near or below the compensation point, the community of a smaller K is expected to have a smaller percent of dead leaves (D) because of its advantage in light transmissibility. This was clearly proved by a very close positive correlation between D and K. Evidence that K might account for the changes in the efficiency in uitlizing sunlight was given when daily increase in dry matter production of each community (ΔW) was plotted against F discriminated on K. Although the data obtained were not accurate enough for further discussion, there showed a tendency to increase both maximum ΔW (ΔW_max) and F (F_opt) correspondent to ΔW_max with decrease in K. This also proved that F_opt is decided dependently not only by intensity of incident sunlight but also by K. From these results mentioned above, K could be grasped as an important index deciding at one time the conditions in both side of light transmission and of light receiving in community, and through which, in due course, affecting its dry matter production. This also denotes that the form of plant must be studied in relation to K. Among the characteristics of rice plant so far investigated, the mean inclination of leaf adjusted by its thickness resulted in a fairly close negative correlation with K. This shows the advantage of community consisted with more erect and thinner leaves. A significant positive correlation of culm length to K might not be originated from its direct influence on K but be derived from its very close negative correlation (-0.739^**) to inclination of leaf.

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It was found by the authors that the elongating root hairs of rice roots contain much RNA, as compared with the epidermal cells i. e. hair-bearing short cells as well as hairless long cells, and that RNA in the mature root hairs still has existed for a long time, after RNA in the epidermal cells was extinct. On the other hand Mitsui et al reported that the process of potassium absorption in rice roots is closely related to the metabolism of RNA in them. From these findings it is assumed by the authors that the physiological longevity of the root hairs can be estimated by means of RNA detection. From this point of view the present experiments were conducted to study the physiological longevity of root hairs as well as to find the effects of vertical water percolation in paddy soils on it. The following results were obtained. Most root hairs developed in the young crown roots contained RNA, and in the mature crown roots the percentage of the root hairs containing RNA to all the root hairs per unit-root length decreased towards the base. But a small number of root hairs developed at the basal part of the crown roots as much as 18 cm in length were still found to contain RNA. In the vertically water-percolated paddy soils, the percentage of root hairs containing RNA was large, as compared with that of grown in the non-water-percolated soils. For example, in the middle part of the crown roots as much as 7 cm in length, sixty percent of root hairs formed in the former soil condition contained RNA, while in the latter one only twenty five percent of root hairs contained it. From these result it may be concluded that the root hairs of the crown roots grown in paddy soils have the physiological activity for a longer period than that suggested before, and that the physiological activity of root hairs in the non-water-percolated soils is lost at an earlier age, as compared with that in the water-percolated soils, that is to say, that the process of maturation of the epidermis of the crown roots grown in the non-water-percolated soils is accelerated.

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For the purpose to know beforehand the heading date of "early transplanted rice", we investigated the relations among the sowing date, the transplanting date, the heading date and the accumulated air temperature from 1956 to 1961. Thus we found high negative correlations between the time from sowing to heading and the sum of average temperature from the sowing date (or the transplanting date) to a certain date (Fig. 3). Therefore we can estimate exactly the heading date in every year by the sum of average temperatures from the sowing time (or the transplanting date) to a certain date (as an example to the 50th day after sowing) of that year (Fig. 4).

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結莢(莢数の増加と莢の生長)に対する開花始め後の日長処理の影響について研究した. 短日処理(8時間日長)ほ着莢率を高めるばかりでなく, 個々の莢の生長を促進する. 長日処理はこの両者を抑制する. 長夜の中央における10分間光中断は短日処理と比較して結莢を僅かに減少し, 短日効果を僅かに抑制することを示す. 30分および1時間光中断は結莢を相当強く抑制する. 日長処理の影響は処理開始頃に開花した花に最も大きく現われる. 短日処理の影響は処理開始後1週間以内に莢に現われる. これらの結実日長感応は, 本実験で見られた範囲内では花成日長感応との間に差が認められなかつた.

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1) Roots of the crop plant, either young or mature, whose requirement of lime are high, have higher concentrations of Ca, Mg and K throughout the control, additional Al and low pH plots. No such correlations are seen among those of SiO₂, Fe, Al and pH values. 2) In the roots of the crop plants, whose yields decrease on highly acidic volcanic ash soil, H-ion and Al contents readily increase under low pH and additional Al solution respectively, while, on the other hand, percentages of Ca, Mg and K are apt to decrease though not having less cation contents under the control conditions. 3) The conditons of containing Al and H-ions and those of containing Ca, Mg and K in the roots seem to be different. 4) These results obtained may due to the nature of protoplasms in the root. 5) On highly acidic volcanic ash soil, fewer exchangeable Ca and Mg, lower base saturation and higher Al-, H-ion concentrations are detrimental conditions to the plants of less tolerant to acidic soil.

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(1) In staining the protoplasms in root cells of crops which are more susceptible to soil acidity, positively charged dyes such as methylene blue and methyl violet stained more deeply, but negatively charged dyes such as eosin and bordeaux red stained in faint. In mature crops, the dyeing was influenced by the rate of content of cytoplasmic protein. Little relation was found between the degree of staining of the epidermal layer cells and the tolerance of crops to soil acidity. (2) For the estimation of the tolerance of crop plants to highly acidic soils using roots of young crops by measuring the absorbability of Al, the following technique was found to be suitable: cross sections of 0.2 mm in thickness which were obtained at about 15∼18 mm from the root tip, were pretreated with 0.03M KCN for 5 minutes after shutting up in a brass net of 80 mesh, then immersed in N/1, 000 AlCl₃ of pH 5 for one hour. The treated materials were rinsed in distilled water for 5 minutes and soaked in a mixture of equal amount of 0.1% aluminon and 3N ammonium acetate for 70 minutes, then finally immersed in Clark-Lubs (c) buffer solusion of pH 5 for 10 minutes. Before, soaking in each new solution wire gauze was wiped thoroughly with filter-paper. Observation of red staining of cytoplasms was made in a drop of the last buffer solution on a slide glass under a microscope at a magnification of 50×approximately. (3) The amount of Ca absorbed by 1g. cytoplasmic protein of the roots of crops which are tolerant to highly acidic volcanic ash soil in each medium at pH 6, pH 4 or pH 6-pH 4 was lower than that of non-tolerant one, though a little less at pH 4. The root of young crops exceeded in the amount of Ca absorbed by 1g. cytoplasmic protein to that of the matured one. (4) The proportion of cytoplasmic protein in the root cell was higher at younger stages than that of the matured, though the percentages of the protein contents at both stages were found to correlate to the lime requirement of the crops. (5) If the amount of Ca absorbed by cytoplasmic protein of the root of 100 g. in dry weight is given by the formula of (Ca uptake by 1g. cytoplasmic protein in root)×(percentage of cytoplasmic protein in root) and Ca refer to the cation examined, the amounts of Ca absorption of the root estimated by means of this formula show high correlation to lime requirement or Ca percentage in the root of water culture. In case of Al, owing to this formula, the amount of Al absorbed in the root also correlates to the yield ratio on the highly acidic volcanic ash soil.

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