It is generally recognized that the new leaf blade of rice plant emerges from the top of the front leaf sheath with regular interval one after another. The author intended to find some rules in the leaf appearance among tillers of one plant or among plants cultivated under many different conditions. The emergence date of every leaf was calculated, observing the each plant every day. The results are summarized as follows. 1. The mean appearance interval of the two successive leaves of main stem is a little longer than that of tillers. The later the tillering, the shorter the interval in the case of tillers. The main stem which has shorter interval shoots one more leaf, and heads a little later than the one having longer interval. 2. The appearance interval at early growth stage is short and then becomes gradually longer as the plant grows up, but sometimes the interval suddenly becomes much longer when the circumstances become unfavorite, especially when the nutrients are exhausted or the roots are injured. 3. In general, the interval corresponds well with the growth rate of rice plant, whereas the weight of dry matter becomes low under very high soil temperature (35∼37°C) although the interval is shortened and one or two more leaves are produced. 4. Apparent varietal difference in the interval of leaf appearance can be seen, but the reason is not known yet.

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The procedure of the stem elongation and increasing tillers which are the important elements for determining the yield and quality of mat rush, had been investigated during the growing period from planting to harvesting in a paddy field. From the results of this studies, the growing characteristics of mat rush were cleared and the basic principles to improve the cultivation have been learned. Namely, so as to increase good mat rush, long stemmed and good quality ones have to be more harvested. The following three items should be taken: 1. From the results of this studies on the growth habits, it was ascertained that the new tillers which would grow to long good stem, had generated in the period from the last decade of May to the first decade of June. Therefore, its culture must be carried out to increase the number of new tillers growing in this period, and to accomplish the sufficient and vigorous development with them. 2. As a result of investigation on the relation of principal bud and new tillers, it was found that principal bud of new tillers which would grow to long stemmed, had already started the growth at the second decade of March. The fact suggests the new method for more yield of long rush by increasing the number of tillers on and from the second decade of March. 3. But excessive tillers grown prior to the first decade of April, namely the tendency of premature, result the development of many short stems and continuous growth of tillers. Therefore the growth advances for the earlier stage than normal, almost all the tips of long stems become rotted by over-ripening, and the yields of good long stems decrease which are to grow from late May to early June.

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Studies have been carried out intending to clarify the physiological mode of the effect of hydrogen sulphide (H₂S) on the yield of rice plants through root rot. H₂S was added for two weeks to the culture solution in which rice plants were cultured, at different period from young-ear-formation stage to maturing. 1) The plants grown under higher level of nitrogen-fertilization were more severely affected by the H₂S-treatment in their yield (weight of fully ripened grains per hill) than those grown under lower level of nitrogen. In case of the plant treated at young-ear-formation-stage, at flowering stage or at ripening stage, the low yield was attributed mainly to the lower percentage of fully ripened grains. In case of those treated at booting stage, the low yield was brought about through the decreased number of spikelets per ear instead of decreased percentage of fully ripened grains. 2) Although H₂S-treated plants showed lower physiological activity in their root during the H₂S-treatment, such as respiration rate, cytochrome oxidase activity, α-naphtylamine-oxidizing and tetrazoriumchloride-reducing activity, they recovered their activity some time after the treatment and even became more active than the control plant. 3) In case of the leaves, on the other hand, H₂S-treatment brought about a considerable decrease in the ratio of photosynthesis to respiration as a result of diminution in the former and increase in the latter. Furthermore, it would be an evidence to show the occurrence of something unusual in energy metabolism that the cytochrome oxidase activity was decreased whereas the respiration fate and peroxidase activity were increased. 4) It may be concluded from these results that an aspect of the influence of H₂S on the yield of rice plants reveals itself in the diminution of photosynthesis and increase of respiration resulting in the lowered photosynthesis/respiration ratio of leaves which means a net diminution in carbohydrate production. It is quite possible that this diminution in carbohydrate production during and even after treatment may ultimately bring about the decrease in percentage of fully ripened grains.

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Since the authors reported the favourable effects of the nitrogen top-dressing at full heading time on the rice plant in the previous paper (XL VII, Vol. 27, No. 1), they have further been examining them for those several years under the various conditions differing in the amount of basic fertilizer, time of planting, spacing and variety, and obtained the following conclusions. 1. Nitrogen top-dressing at full heading time caused the plant to increase the rate of photosynthesis and amount of dry-matter as well in the period after heading except the cases of extremly unfavourable weather conditions and extremely dense spacing. 2. When the amount of dry-matter was increased by nitrogen top-dressing at full heading time, it was generally observed that yield as well as the percentage of ripened grains were clearly increased independently of the time of planting, spacing and variety, except the case of the control (non-top-dressed) plot being high enough in its percentage of ripened grains. 3. No effect of nitrogen top-dressing at full heading time was found on the plant in the case of the translocation of carbohydrates being disturbed by cool temperature in autumn or the enough amount of nitrogen being supplied to the plant from the soil even in the period after heading.

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In the previous report, the authors pointed out that the damages of rice plants caused by high and low water-temperatures at the stage of young panicle formation were much heavier than those at the booting stage under the general water-depth (3-4 cm) and presumed that the fact could be mainly ascribed to the difference in submergence of the young panicles between the two stages. By subjecting the rice plants at different growth stages to different combinations of water-temperatures and water-depths, the authors tried to prove the above mentioned presumption and also to clarify the effects of the treatments on the growth, yield and yield-components. 1. Effects of the water-depth on the plant height and the number of tillers were clearly seen when treated at the tillering stage, showing as a rule the deeper the water-depth the higher the plant height, and the fewer the number of tillers. 2. In the periods of differentiation and development of young panicles, high (37°C) and low (15°C) water-temperatures caused the development of young panicles as well as the elongation of internodes to arrest and made the plant to produce the late emerging tillers and to kill young panicles inside the tillers (only high temperature) and furthermore to decrease the values of yield-components and yield. The effectiveness of high and low temperatures on rice plants differed with the developmental stages of young panicles as well as water-depths, and the ill-effects were quite severe in any water-depth and no relation was found between the ill-effect and the water-depth at the stage of young panicle formation, in particular under the high water-temperature, while at the booting stage only slight ill-effects were found under the shallow water-depth and as the water-depth increased the plant was more seriously damaged, i.e. a direct proportion was found between the water-depth and the ill-effect (Fig. 1, 3, 4). 3. As the result of investigating the relation between the vertical positions of the young panicles and the water-surface on the initial and final dates of the treatments, it was found that all of young panicles were always below the surface of water in any water-depth at the stage of young panicle formation, while at the booting stage most of the young panicles were above the water-surface under the shallow water-depth (2 cm) and the number of young panicles below the water-surface increased as the water-deepened (Fig 2). 4. From the relation between the vertical positions of young panicles and the water-surface the effectiveness of high and low water-temperatures on the rice plant in particular on the development of young panicle could be fully understood. It may be safely concluded, therefore, that the differences of the damages caused by high and low water-temperatures between the stage of young panicle formation and the booting stage under the general water-depth are mainly brought about by the difference of the relation between the vertical position of young panicles and the water-surface, namely, the difference in submergence of young panicles.

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1. The number of differentiated spikelets is firstly affected by the amount of nitrogen absorbed by the time of late spikelet differentiation and secondly by the amount of carbohydrates produced during the period from the neck-node differentiation stage to the late spikelet differentiation stage. 2. The number of degenerated spikelets is found to be determined by the interrelationship between the number of differentiated spikelets and the amount of carbohydrates produced during the period from the late spikelet differentiation stage to the heading stage. The amount of nitrogen in leaf-blades during the period of determining the number of degenerated spikelets has no immediate effect, but has a mediate effect on determining the number of degenerated spikelets by influencing the rate of carbon assimilation. 3. Both the number of differentiated spikelets and the number of degenerated spikelets have nothing to do with the amount of carbohydrates accumulated in the rice plant. 4. It has already been pointed out by the other research workers that the nitrogen content in leaf-blades is strongly correlated with the number of spikelets per panicle, and also the weight of leaf-blades per hill or the amount of total nitrogen in leaf-blades per hill at the heading stage is closely correlated with the number of spikelets per hill, but it has also been clarified by the present experiments that the above-mentioned facts can hardly be generalized and they hold true only in the following cases:-(1) an identical variety is used and it is sown or transplanted on an identical date, (2) the period of determining the number of panicles is not overlapping with the period of determining the number of spikelets, and (3) the amount of dry-matter increased during the period from the initial stage of reduction division to the heading stage is positively correlated with the amount of nitrogen in leaf-blades at the heading stage.

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Ladino clover, seeded June 1st, 1960, was studied at five day intervals between July 1st and August 9th, to determine the growth pattern in summer, and the following results were obtained. 1) Most of the petioles, and internodes lengthened fully in 10-15 days (Tab. 1 and 2) and 5-10 days (Tab. 4) respectively; while most of the leaflets attained full size in 5-10 days (Tab. 3). Therefore, leaflets and internodes reached maximum size and length respectively almost at the same period; whereas for petioles more days were required to get lengthened fully. Most of the leaves perished after 30-35 days. 2) Correlation coefficient between leaflet length and petiole length was +0.794.^** 3) The interval between leaflet emergence was shorter in the case of branches than that of the main stem. Thus, on the average, at five day intervals only one leaflet emerged on the main stem compared with 1.5 leaflets on the branches. 4) There is a relationship between the leaf's position (X), at which the respective branch branches off, and the number of leaves (Y), at the time of branching, on the main stem as shown below. (a) Y=1.047X+2.815: In the case of primary branching. (b) Y=0.914X+3.731: In the case of secondary branching. Therefore, when a branch emerges from a leaf's position (n) on the main stem, the latter possessed n+3∼n+4 leaves. After the 7th leaf, each leaf emergence was followed by a branch development (Fig. 1). 5) The time of floral bud emergence was almost coincided with the emergence of branch from the leaf just below.

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1. Irish potatoes were grown on the cultivated volcanic ash soil and 2 placements A₁₀ and A₇B₃ to which combinated all of 3 level of nitrogen and phosphorus to 1 level of potassium. A and B denote the depth of fertilizer applied in band, namely, 10 and 20 cm from the surface respectively. Side number shows the ratio of fertilizers applied. 2. Tuber yields of A₁₀ were the highest on second level combination of nitrogen and phosphorus respectively, and the tuber yields of A₇B₃ were the highest on the third level combination of nitrogen phosphorus respectively. A₇B₃ exceeded A₁₀ on the third level of nitrogen. 3. Differences of each character depend on greatly the effect of nitrogen, the effect of phosphorus were little comparatively, and the differences of placement significantly were the result of mutual action of placement and nitrogen. 4. On the highest nitrogen level, A₁₀ was liable to become the excessive top growth and those values were liable to become large1y than the theoritical values of each components to gain maximum yields but A₇B₃ became not so. 5. If we maintain the optimum L. A. I. 3.6 from the bud stage to top muximum stage and also the same N. A. R. and distributed rate to tuber as A₇B₃, the yields which be gain by its will be about 6, 000 kg per 10 a perhaps, on the basis of this condition.

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[in Japanese]

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Effect of atmospheric humidity and soil moisture on the translocation of foliar-applied sucrose-C¹⁴ was studied in the sweet potato plant in 1960. Sucrose-C¹⁴ was applied on a single leaf and measurements of C¹⁴ were taken after 10 hours absorption. The percentages of accumulated C¹⁴ in root were much higher at 70% air humidity than at 100% air humidity in the dark and light conditions. When roots of a sweet potato were divided into two groups and each of halves was exposed to different soil moisture for 16 hours in darkness, the translocation and storage of C¹⁴ was greater under low soil moisture (40%) than under high soil moisture (100%).

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Studies were made on the developmental responses of flue-cured tobacco, Bright Yellow and Hicks, to the various warm photoperiod of 18°C with cool dark period of 13°C or 8°C. Results obtained were as follows; 1. The developmental responses of tobacco plant is not influenced by the cool temperature during the long dark period corresponding to the short period, but is accelerated to a marked degree by that corresponding to the long photoperiod. So the cool dark period in long day seemed to have retardative effects on the photoperiodic response. 2. According to the results that the number of leaves of the plant exposed the light interruption during the cool dark periods was almost equal to that of the 12hr day-length, it may be unable to expect the long-day effect equal to the effect of illumination during all night.

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In previous papers, it was clarified that in adult plants the lamina joint participates to the bending movement of laminae to their abaxial side and that an increment of cell length of the adaxial side is induced favourably in the regions because vascular bundles are here centrally placed. In this paper the effects of gibberellin and auxin on the extension of adaxial side of lamina joint in rice seedlings were demonstrated. They were cultivated in controlled condition of temperature and moisture, in Phytotron at Nagoya University, under sunlight in summer. The effects on the angles between laminae and sheaths were observed (Table 1), indicating an increment of the angular degrees by gibberellin treatment in all of the varieties used (Table 3). Further an attention was devoted to the nature of interaction between gibberellin and auxins. The gibberellin was applied to root medium and NAA, at various concentrations, was sprayed daily to their shoots. NAA alone was effective to increase the angular degrees at higher concentrations. But in combination with gibberellin NAA did not induce any additive effect in the angles between laminae and sheaths (Table 4). These results on the interaction of gibberellin and auxins in the experiment with intact plants were contradictory with those in excised leaves. This fact would be very interesting when considered the mode of action of growth substances on the extension of the lamina joint. Some experiments were also performed on the combined action of red light and gibberellin upon the lamina-joint extension (Table 6).

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In the previous papers, the anatomical aspects of the extension of lamina joints and the accentuating actions of the extension by auxin and gibberellin were revealed. The given knowledges made it attractive to speculate that some native auxins might act in this region when the cells in adaxial side were elongated by gravity. In this paper, first, the lamina-joint test is established as an assay for evaluation of existence of auxin- and gibberellin-like substances in plant extracts. The procedure was follows: after the leaf segments having lamina joint were floated in distilled water for 24 hours, they were incubated in the test solutions of 1 ml for 48 hours at 30°C in darkness, and the angular degrees between laminae and sheaths were estimated (Tables 1, 2 and Fig. 1). Auxins were extracted by n-hexane and acetonitrile, and purified by means of chromatography with ammonium isopropanol. The auxin activity was estimated by the lamina-joint method mentioned above. It became evident that auxin activity locates in the methanol extracts of the lamina joints in adult rice as well as cabbage leaves (Fig. 3 and 4).

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It is reported in this paper that the lamina-joint test, which is a method to measure the extension of lamina joints, is available for the bioassay to estimate the actions of growth inhibitors. To explore a suitable test condition responding for IAA and IBA, the store conditions of seeds and the culture conditions of seedlings were took into consideration. But the influence of such conditions on the extension was little or no. It has been proved that the pretreatment period of 24 hours, in which the excised leaf segments were floated in deionized water, is enough for increment of the response to growth substances. The inhibitive effects of many substances on the extension induced by auxin were compared, by floating the segments for 48 hours in the combined solutions of various concentrations of the test substances and 10 mg/l of IAA after they were pretreated by deionized water for 24 hours. It is interesting that the inhibitive action shows less angles than the angular degrees of the segments which were floated in deionized water alone. It may be considered to be a phenomenon resulted from some drastic actions of those inhibitors rather than a physiological one.

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The experiment was performed to make clear the effects of stable manure and phosphorus on the growth and yield of potato plants which were planted on the virgin volcanic ash soil plowed to the depth of 30 cm. Various treatments are designated by the symbols P, P+M, 3 P and 3 P+M, where P shows phosphorus, 3 P shows heavy application of phosphorus and M shows stable manure. The results obtained are summerized as follows: 1) The elongation of stem length was more higher at 3 P and 3 P+M plots than at P and P+M plots during the early stage of growth, while after the flowering time the length of stem became higher at P+M and 3 P+M plots than at 3 P and P plots. 2) Number of leaves and branches of plants on each treatments were same in order with stem length; that is 3P+M>P+M>3P>P. Fallen leaves were counted many at P+M and 3P+M plots during early stage growth, because the increase of the leaf area was remarkable in these treatments. But after the end of flowering time, leaving leaves were counted more at P+M and 3 P+M plots than at P and 3 P plots, therefore growing period was delayed about 10 days at P+M and 3 P+M plots. 3) The leaf areas were greater at 3 P and 3 P+M plots during growing period before flowering time, and since then they became greater at P+M and 3 P+M plots. Net asssimilation rate was inversly proported to the leaf area till the end of flowering time, but after this time they become higher at P+M and 3 P+M plots than at P and 3 P plots. Total production of dry matter by plants was arranged in order P+M>3 P>3 P+M>P. 4) At P plot the tuber development of potato plant in early stage was better and starch accumulation in the stem was decreased rapidly. The translocation of nutrient from shoots to tubers at 3 P plot after the end of flowering time was very smooth. 5) The content of N, P₂O₅ and K₂O in the leaf at P+M and 3 P+M plots was higher than at P and 3 P plots after the flowering time, especially with K₂O. The plant nutrient during early stage of growth was higher at 3 P plot than the others and decreased rapidly after the flowering time above all, the decrease of K₂O was remarkable. 6) The starch value of tuber was higher at 3 P plot than the others. The yield of tuber was in the following ranking; P+M>3 P>3 P+M>P. And that of starch was 3 P>P+M>3 P+M>P.

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Some field experiments were carried out to know the effect of depth of transplantation on the growth and yield of the rice plant aiming mainly to obtain informations for experimental procedure. (1) Deep transplantation caused retardation of the maximum number of tillers stage and slight retardation of the heading and the ripening stage. (2) Deep transplantation caused the plant to decrease the height of plant and the number of tillers comparing with the case of shallow transplantation in the early stage of growth, but no difference was found between deep and shallow transplantation in the height of plant, stem length and the number of leaves on the main stem at the ripening stage. As the tillering period is limited, deeply transplanted plots, which showed a growth depression at the early stage, could not catch up with the shallowly transplanted plots in the number of tillers, resulting in small number of heads, in spite of high ratios of the effective tillers being obtainted. (3) A negative correlation was found between the number of heads and the number of spikelets per head, but the former was positively correlated with the number of spikelets per unit area. The percentage of ripened grains and the weight of 1, 000 grains decreased as the number of heads increased. No significant difference in yield was found between deep and shallow transplantation, though a slightly better yield was recognized in the latter case. (4) Therefore, the primary ill-effect of deep transplantation seemed to be the retardation of rooting caused by the abnormal elongation of tillering node, which induced the decrease of the number of tillers and consequently that of heads. The effect on the number of spikelets per head, fertility and the weight of 1, 000 grains was considered to be secondary, because clear compensatory reactions were observed between yield-components. (5) This tendency which exists between plots can also be recognized between the individual plants transplanted as a group in the field, namely, a shallowly transplanted plant always brought about a vigorous growth, high yield and a large individual variation. (6) Even when little difference in yield was found between different depths of transplanting, the growth of plant was considerably affected, which meant that the effect could hardly be neglected from the view point of growth process. (7) An optimum depth of transplantation seems to be 3 cm, though it depends on the conditions of cultivation, and ill-effects were found in the cases transplanted above 5 cm depth.

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The present report deals with the primary dormancy of seeds of barnyard grass in the soil, and the results are as follows: Under the room-temperature condition, the dormancy of the seeds were broken in a shorter period under storage in upland or submerged soil condition than on the dry or wet filter paper. The dormancy of the seeds stored in a paper bag at room temperature lasts about one year after harvest. The period of dormancy of seeds in the soil varied according to the temperature and moisture content of the soil. In the storage at lower temperature (3∼5°C) than germination temperature, process of the dormancy breaking progressed in all moisture content, and the speed of progress was faster at high moisture content. In the storage at optimum temperature for germination (20∼30°C), deep dormant seeds were awakened slowly in the air dry soil, but not awakened in submerged or upland soils untill about ten months after harvest. However, partially dormant seeds (no germination at germinator) were awakened from the dormancy rapidly by the storage in submerged soils, but were reinduced to dormancy by the storage in upland condition (soil moisture content 70 to 80 per cent of the field moisture capacity). Storage treatment in submerged soil was very effective to breaking the dormancy, if the seeds were already awakened from dormancy up to some degree by storage for 15 days or more at low temperature with wet condition. Optimum period and temperature for the storage treatment in submerged soil were varied with degree of dormancy. The shallower dormant seeds were awakened from dormancy with shorter period storage at various range of temperature (5°to 40°C), but in relatively deep dormant seeds the dormancy was broken after longer period storage at high temperature (30°C to 40°C). The cause of dormancy broken by storage treatment in submerged soil is the low oxygen content in the soil because the similar effects obtained from the storage treatment of seeds in nitrogen gas. Seeds that awakened from dormancy in the soils were reinduced to dormancy with air dry treatment. As the results of these findings, it was clarified that processes of the dormancy breaking were divided in five, and low temperature during from late autumn to early spring, alternating temperature in spring and submergence at the start of rice culture were important for breaking the primary dormancy of the seeds in paddy field.

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The mechanism of variation in nodule forming ability in some strains of Rhizobium Japonicium on host plants was studied in relation to soybean varieties. Two strains of Rhizobium Japonicium viz. TODAI No. 53 which, except on soybean var. NORIN No. 1 forms nodules on many soybean varieties with ease and strain TODAI No. 56 which forms nodules on many soybean varities including var. NORIN No. 1 were used in these experiments. (1) The inoculation tests were made using 14 soybean variteies. The results show that the strain TODAI No. 53 does not produced nodules on var. NORIN No. 1, var. ZIZUKA-IBARAKI No. 1 (one of the parent of var. NORIN No. 1) and on some other varieties genetically related to var. NORIN No. 1, but it produce nodules on other varieties, while the strain TODAI No. 56 produces nodules on all varities used in this tests. (2) The results of histological observation show that both strains of Rhizobium Japonicium produce the first infection cells in host roots of var. NORIN No. 1, but later growth of bacteria of these strains is different. The strain TODAI No. 53 does not multiply after producing the first infection cell while the strain TODAI No. 56 continuously grows in it and produces the nodules. (3) The cultural experiments of both strains of Rhizobium Japonicium were done using the rot extract-agar medium prepared from the roots of var. NORIN No. 1 and var. GOSHIYA, Strain TODAI No. 53 produces nodules on the var. GOSHIYA. The growth of both these strains is almostely same on the var. GOSHIYA's extract-agar medium and on the AO medium (RAGGIO: 1957), but their growth is different on the extract-agar medium of var. NORIN No. 1. The amount of growth of strain TODAI No. 53 on extract-agar medium of var. NORIN No. 1 containing 1, 200 mg/100 ml dry root powder was almost equal to the amount of growth of strain TODAI No. 56 on extract-agar medium containing 400 mg/100 ml dry root powder. (4) The amount of growth of both these strains was compared by growing them in different cultural mediums which were made by adding components of AO medium separately to the some concentration of extract-agar medium of var. NORIN No. 1 (dry root powder 400 mg/100 ml). The amount of growth of strain TODAI No. 53 on the culture medium containing all inorganic elements and phosphate element of AO medium was almost equal to that of strain TODAI No. 56 on the culture medium not containing the components of AO medium. The auther suggests that the phosphate requirement of strain TODAI No. 53 for its growth is much higher than that of strain TODAI No. 56 and the phosphate concentration in roots of soybean var. NORIN No. 1 and some other genetically related varities is lower than in other soybean varieties. Due to these facts Rhizobium Japonicium stain TODAI No. 53 is incapable of producing nodules on var. NORIN No. 1 and some other genetically related varieties.

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Two phases of the nodule bacteria and nodule development complex have been studied; (a) the growth and the advancement in life cycle of nodule bacterium during nodule formation, and (b)the histology of nodules. (1) The developmental process in nodule formation in leguminous plants could be divided into five stages as follows: a) The infection stage, b) the embryonic stage, c) the stage of differentiation, d) the stage of elongation, and e) the stage of maturation and the senescent stage by a conventional means. The increase in total number of bacteria in nodule was closely correlated with the increase in nodule diameter, in volume of bateroid tissue and in nodule dry weight, But it did not show any direct relation with the progress of nodule forming stages, A rapid decrease was detected with bacteria number during the senescent stage. The nodule bacteria were classified into "rod-shape bacterium" and "bacteroid-shape bacterium" according to their life cycle stage by morphological and physiological points of view. The rod-shape bacteria were observed from the infection stage to the embryonic stage and the rod-shape bacterium and the bacteroid- shape bacterium were detected in a bacteroid tissues from the stage of differentiation to the stage of maturation. At the senescent stage, however the bacteroid-shape bacterium disappeared in bacteroid tissues, and as a result, only the rod-shape bacteria were observed. (2) Leghemoglobin formation in bacteroid tissues of nodules was detected in the stage of differentiation. At first it appeared at the base of the bacteroid tissue, and then increased until the entire tissue showed the red pigment at the stage of maturation. At the senescent stage, the red pigment color changes to green pigment starting from the base of bacteroid tissue viz. ……leghemoglobin(red)→legcholeglobin (green)……. The distribution area of green pigment also enlarged in the same manner as in the red pigment. In the final stage (senescent nodule) the nodule pigment change occurred again in the same manner as before. viz.……legcholeglobin (green)→legmethemoglobin (brown). (3) The change in distribution of leghemoglobin and starch in bacteroid tissues of nodules was found to be closely synchronized with the bacteroid-shape bacteria. (4) The N₂ fixing power of nodule is dependent on the physiological conditions of the host plants such as the total nitrogen contents.

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[in Japanese]

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Sub-soiling method, breaking sub-soil and not mixing to surface soil, was tested with regard to the growth and yield of rice plant as a method of deep plowing. By sub-soiling the Eh value of tilled zone of soil was maintained higher (Fig. 1) and the distribution of NH₃-N in the soil was wider (Fig. 2) than ordinary plowing plot and consequently the root of rice plant was kept healthy and the growth was vigorous accompanied with increased number of ears and number of grains per ear (Table. 1 and 2). But the yield was unstable due to decreased percentage of ripened grains which causes higher yield in some cases or lower yield in other cases than the yield of ordinary plowing plot according to the extent of decrease of percentage of ripened grains (Table. 1 and 2). Effect of sub-soiling differed with varieties; the varieties with relatively less spikelets per ear were inclined to gain higher yield owing to less decrease in percentage of ripened grains while the varieties with relatively much spikelets per ear showed opposite tendency (Table. 2). Rice plants of sub-soiling plot had higher nitrogen and lower carbohydrate content than ordinary plot (Fig. 4 and 5). After the heading stage the ferrous iron concentration in the tilled zone of the sub-soiling plot increased markedly (Fig. 3) and the contents of FeO in rice plants also increased, resulting in the decreased P₂O₅/FeO ratio in rice plants (Fig. 5). The ratio of ear to straw in the P₂O₅ content decreased by sub-soiling, expressing an impeded phosphorus translocation to ear (Fig. 6). These ratio showed varietal differences; varieties which showed greater extent of yield decrease by sub-soiling were accompanied with greater decrease in the ratio (Fig. 4 and 5). Based on these facts, the authors propose a new hypothesis that the nutritional state of plant with regard to iron could be a cause of poor ripening of grain; the poor percentage of ripened grains of sub-soiling plot may possibly be caused by high nitrogen and high FeO content of plant resulting from marked increase of ferrous iron in soil after heading stage, and retarded phosphorus translocation to ear due to high FeO content in the plant.

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The author has reported on the differences of endosperm tissue and of specific gravity of rice kernel in relation to the grain properties and has suggested that the endosperm density is an important charactor concerned in the grain property. However, the endosperm density is indicated most precisely by the hardness of endosperm, therefore this work was made to research the point-to-point variation of hardness of a single kernel and to explore the relation between hardness distribution and property of kernel. 1) Hardness Determination. Using Shimadzu Micro-Hardness Tester, a preloaded (15 g) diamond pyramid was forced into the even plane of kernel section for 13 seconds and the diagonal of quadrate impression was measured with a microscope, then Vickers hardness was calculated from the formula. 2) Hardness Distribution on Kernel Section. Hardness measurements were made on the transection of kernal at intervals of 150 p in dorso-ventral direction and of 100 p in lateral direction. According to the results on the section from middle of kernel (Fig. 1), the central point of section is rather soft and the middle region is the hardest and outer region from the middle becomes softer and softer, moreover, the region along the dorso-ventral line is somewhat softer than the adjacent region. This inclination of hardness distribution is essentially same on the sections from apical part and from basal part of kernel, except that every point of basal part is softer to a certain extent in comparison with the corresponding point of other parts. Hardness distribution. on the longisecton is recognized as the longitudinal connection of hardness diagrams of the transections as shown in Fig. 2. According to the facts above mentioned, the hardness distribution on the transection from middle of kernel is representative of hardness distribution of whole kernel and is represented by the hardness distribution along the dorso-ventral line and the lateral line crossing at the central point of the section. 3) Varietal Differences in Hardness Distribution. Diagrams of hardness distribution indicated by hardness along the dorso-ventral line and the lateral line are classified into two types by the hardness of central region (Fig. 3). Type I. (Hard Type) As shown in Fig. 3 (1-6), the central point is the hardest and outer region becomes softer on dorso-ventral and lateral line and the distinct difference can not be found between dorso-ventral line and lateral line. Indica varieties, glutinous varieties and some of upland varieties in Japan belong to this type and kernels of these varietes are assumably the hardest of all varieties. Type II. As shown in Fig. 3 (7-18), the central point is rather soft and the hardest part is the middle between the central point and aleulon layer and the region along dorso-ventral line is more or less softer than other region. Almost all varieties of Japonica are included in this type. With respect to the difference between dorso-ventral line and lateral line, this type may be subdivided into three groups. Type IIa. (Semi-Hard Type) The difference between dorso-ventral line and lateral line is rather small (Fig. 3, 7-11). Japanese varieties so-called "Koshitsu-Mai", some varieties of upland rice and some of Japonica varieties in foreign countries belong to this type. Type IIb. (Semi-Soft Type) The hardness along dorso-ventral line is softer than type II a and the difference between dorso-ventral line and lateral line is larger compared with Type IIa (Fig. 3, 12-16). Japanese varieties so-called "Nanshitsu-Mai" and some varieties of Japonica in foreign countries are included in this type. Type IIc. (Soft Type) The central point is very soft and dorso-ventral line is markedly softer than the lateral line (Fig. 3, 17-18). The varieties used for brewing in Japan (Saka-Mai) belong to this type and these varieties produce frequently white-core kernels (Fig. 6, 3). [the rest omitted]

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Absorption of K-ion in passive and active processes were studied using maize and sorghum. The results obtained were: (1) In passive uptake: Either H- or Al-ion arrested the absorption of both crops, more badly to sorghum which is susceptible to soil acidity. By adding both ions of Al and H to the solution, absorption of K-ion was interfered still more than a single use of each ion. In the solutions with neither Ca-ion nor Mg-ion, absorption of K-ion slightly increased. (2) In active uptake: K-ion was released from root of both crops to external solution by adding NaCN; it was more significant for sorghum. Low pH-value or deficiency of Ca and Mg reduced the uptake of K-ion, being larger in sorghum. The reduction of uptake of K-ion was larger in sorghum than in maize as Al or both Al and low-pH were added in the solution. These results related with the depression of respiration. (3) In mature crops: Al- and H-ions gave smaller interference with the absorption of K-ion to mature crops than to the younger one both in passive and active processes.

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