As is reported in the previous papers (1959 a & b), amounts of ferreous coatings in rice roots, both per plant and per unit surface area, increased up to the period of heading, having kept pace with the growth advance. In contrast to those changes, the relative growth rate of root weights dropped progressively. Amounts of ferreous coatings were also larger in those plants of which the root development was vigorous. Moreover, when roots were forced to age artificially, they produced much more coatings. In addition to these results, from the authors' determinations of the cation exchange capacity of roots of several varieties, it was made clear that the capacity was almost proportional to the amounts of ferreous coatinges. If the values of the capacity indicate the exchan geability of cations on root surface and the possibility of the absorption of those ions by roots, it may be suggested that the ferreous coating formation must be related to the nutritional uptake, including both anions and cations. In this investigation the authors tried to decide the relation mentioned above and to clarify the physiological significance for the ferreous coatings. Those varieties such as Norin 1, 41, 37 and 69 were planted without transplanting in paddy field of which soil is of sandy loam and of good drainage. Sampling was done every 15 days after planting, but at the harvest time it was conducted at the yellow meturation stage of each variety. In all samples the plant growth and contents of N, P and K were analysed and estimated in both top and underground parts. In the underground part, the ferreous coatings were quantitatively determined. Main results and some discussions concerned were as follows. 1) In each variety, ferreous coatings, total contents of the three elements and dry weights, respectively per plant, went upwards hand in hand as the growth advanced, until the period of heading (Fig. 1). Moreover throughout all stages of the growth and among all varieties used, the amounts of coatings were nearly proportional to the content of each element. These facts might be, however, interpreted as the accidental phenomena accompanying with the growth processes. Both factors such as the time and growth which affect the phenomena, must be therefore eliminated from those data obtained, inorder to make clear the relations among thern. 2) The time factor can be removed by caluculating those quantities per unit time, with such formulae as shown in Tab. 2. Fig. 2 shows the parallel relations among those per unit time. 3) This holds also for the elimination of the growth factor by calculating the relative rates of those quantities respectively. Formulae used for the calculations are also shown in Table 2. These relative rates changed quite parallely during the course of the growth (Fig. 3). Moreover the positive correlations between the rate of the coating formation and that of the absorption of each element were found (Fig. 4). Thus the anthors came to a conclusion that the ferreous coating formation was in a close connection with the nutritional uptake uptake and the plant growth. The ferreous coating formation may originate first from the oxidation of ferrous ions by roots at the interspace between roots and soils. Then the ferric ions may be exchanged and adsorbed on root surface to produce the coatings. The nutritional absorption may also be enhanced by the surface exchange and the oxidation in roots. Thus there may be some theoretical coincidence which justifies the experimental results. 4) Amounts of the ferreous coatings may be affected by the total root surface area at the time of the measurement and also by the integrated physiological activities favorable for the coating formation in roots. A formula such as Fe=A×∫f shows this connection. From this formula, 1/(Fe|A)=1/(∫f) is derived. [the rest omitted]

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The effects of soil temperature upon the rate of leaf emergence in rice plant were investigated. The results obtained were as follows : 1) From the first experiment in which rice plants were grown with 23 and 28°C soil temperature in the air temperature-controlled conditions kept at 20 and 30°C respectively, it was recognized that the rate of leaf emergence were affected by the soil temperature and not by the air temperature (Fig. 1). 2) In the second one, plants were grown with 23, 28 and 33°C soil temperature by use of the constant temperature water tanks out of doors, and it was concluded that the effect of soil temperature upon the rate of leaf emergence differed according to the growing stage. Namely, it was much significant at the first half period of the tillering stage and not at the jointing stage (Fig. 2 and 3). 3) Finally, for the purpose of investigating the reference of the rate of leaf emergence to the temperature of several parts of plant, i.e., leaf sheath (A) in irrigation water, base of seedling (B) in soil, and root (C), the part A and (B+C) or (A+B) and C were exposed to the different temperature separately. These parts were treated with temperature of 20 and 30°C respectively (Fig. 4). According to the result of this experiment, it was cleared that the temperature of leaf sheath was less influential upon the rate of leaf emergence than those of base and root (Table 2, and Fig. 5).

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Root developmental phase was investigated in connection to the growth of the aerial parts of rice plants cultured under two treatments, shading and deep placement of Nitrogen fertilizer. 1. It has been reported that crown root emerges on the (n-3) -th node at the time of emergence of the N-th leaf (the node number on which the N-th leaf emerged is expressed as n). Root emergence was delayed by shading, and the interval was prolonged to 3.5 nodes. But, when shading was stopped, this delay of emergence was restored to 3 nodes. 2. The total area of the cross section of secondary xylem per single root was measured related with the node-locus at which the root emerged. The development of secondary xylem of the root which emerged under shading treatment was inferior to that without shading treatment. But the development of secondary xylem of the root which emerged after the end of shading treatment was superior to that without shading treatment. 3. When nitrogen was applied into lower-layer, the growth af rice was inferior to that without treatment at the early growing period, but it became superior at the late growing period. Similarly, the development of secondary xylem of the root which emerged at the early growing period was inferior, while that of root which emerged at the late growing period was superior.

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An extraordinary amount of ammonium sulphate (7.56 kg. per are) was top-dressed under the field condition to the rice plant, which had been grown without nitrogenous fertilizer, at intervals of 5 days at successive growth stages during 3 seasons frorn 1957 to 1959. 1. The effects of the treatment on the yield, yield-components, morphological characters and so forth have been clarified and a part of the results is given in Fig. 1, as a result the top-dressings at various growth stages have come to be classified into the following 5 groups from the view point of their roles in determining yield: dreessing (I) transplanting stage and stage of just after transplanting, (II) at early tillering stage, (III) at late tillering stage, neck-node differentiating stage and primary branch differentiating stage, (lV) at spikelet differentiating stage and early stage of reduction division of P.M.C, (V) on and after late stage of reduction division of P.M.C. 2. The effects of the treatment (1) on the heading date and the lodging resistance (Tablel), (2) on the plant height, the length of each leaf-blade and-sheath, the length of the highest culm and that of each inter-node (Fig. 2 and 3) and (3) on the chemical composition of the plant (Fig. 4 and 5) have been brought to light. 3. The results above mentioned will also be effectively utilized in estimating or diagnosing the effectiveness of nitrogenous fertilizers applied or affected at various growth stages.

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This experiment was carried out to know what sort of factors at the time of heading show close relation to the increase of top-dry-weight, and serve as successful index to forecast the yield. The two paddy rice varieties, Asahiyori and Yutakasenbon having different vegetation form with each other, were grown in the paddy field under different conditions of nitrogen supply, and light intensities. The results obtained were as follows: 1) The amount of total nitrogen contained in leaf-blades as well as the dry weight of leaf-blades per unit area at the beginning of ripening stage were closely related to both increment of top-dry-weight per unit field area in ripening period and the ultimate yield. Therefore, it seems possible to forecast the yield by the weight of leaf-blades at the beginning of ripening stage. 2) When the weight of all grains was to be forecast, the figures showing the dry weight of leaf-blades were useful enough, irrespective of varities, but, when the brown rice yield must be forecast, the figures were insufiicient, because there was a slight difference in the trash rice amount between varieties. 3) The figures of leaf-blades weight per grain (leaf-blades dry weight/number of total grains) at the beginning of ripening stage was of much importance. It related closely to the percentage of ripening graines, the trash rice weight, the percentage of trash rice weight and also to the weight of 1000 grains. Therefore, forecasting of these seems to be possible by the figures of the dry weight of leaf-blades. 4) The leaf area index at beginning of ripenning stage was within frorn 2.5 to 3.9 scope in this experiment.

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The seasonal changes in transpiration were measured with the rice of early, ordinary, and late season culture. The t/E values (t: amount of rice transpiration, mm., E: amount of evaporation from free water surface, mm.) were used in order to eliminate climatic effects on transpiration. In spite of the difference of the time of transplantation, the t/E values changed similarly. (See Fig 2) When the plants were not yet so leafy and leaf area was small, the t/E values were parallel with growth. When the plant became highly leafy and the L.A.I. (leaf area per unit field area) was larger than 4∼5, the t/E values were constant and scarcely affected by growth. These facts may presumably be due to mutual shading, considering from the following results: the relation between t/E and leaf area (Fig 3), the change of t/E per unit leaf area (Fig 4), the relation between t/E per unit leaf area and leaf area per hill (Fig 5), and the relation between transpiration amount per unit leaf area and net assimilation rate (NAR). (See Fig 6) It was concluded that rice transpiration amounts in any cultivations could be estimated by measuring two factors, the growth magnitude of the plant and the evaporation from free water surface.

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Experimental determination of the more restricted development of specific ion effect has been cleared in understanding the nature of saline injufy to crops. In this paper, the chlorophyll content was used in giving expression to the degree of saline injury, on which observations at this laboratory had indicated the darker green color, the tip-burn, or the chlorosis on a leaf. The responses of rice plants (Norin No, 22) grown on sand medium to additions of 0.4, 0.8, and 1.2% of NaCl to a base nutrient solution were compared with that of unsalinized plants. Chlorophyll was assayed colorimetrically in the extract with 80% acetone solution from the 10 sq. cm of tissues that were randomly selected from the leaves classified by the leaf-order and the severity of injury, and also that were absolutely necessary to be externally normal. Addition of NaCl to the substrate actually tended to enhance the chlorophyll content, but with elapsed time, there was a general tendency toward an inverse relation between the chlorophyll content and the level of sodium or chloride content, though significant quantities of these ions were not determined, presumably as a result of the leachability on these ions. In observations on the components of chlorophylls, the differences were comparatively small. Marked changes in the mineral components, viz. total nitrogen, protein nitrogen, and phosphorus, took place with changing chlorophyll content, but soluble nitrogen and potassium components were found to have no relation. And also the water content or dry matter weight per unit area in these samples was not connected with changes of chlorophyll content. Coefiicients of correlation between the chlorophyll content and each component were shown in Table 1. Now, these figures emphasize that it is important for the light of saline-injury mechanism to consider the behaviour of both nitrogen compounds and phosphorus in saline crops. In interpreting the stability of chlorophyll-protein complex, the fluctuation of electrophoretic protein in saline leaves was investigated. It was found that the electrophoretic proteins were altered selectively with changing leaf-order and severity, but after dialysis against distilled water, no difference between the electrophoretic patterns from control and saline leaves which were externally normal was observed and also that the protein consistency detected by paper electrophresis reduced generally on all fractions or specific protein fraction in the saline leaves, containing so much amount of salt that had done enough of development of saline injury. Accordingly, an accentuated accumulation of these ions seems to effect on metabolic function with protein and to be the one directly associated with saline injury to crops.

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The relation between rice kernels and changes of free amino acid in them with elapsed storing-period was investigated by mean of paper partition chromatography. For paper chromatography, Toyo filter paper No. 51 and 80% phenol water solution chosen as solvent was used and also the developed spots were identified by Rf value determined previously with Azinomoto K. K.'s pure reagent. Ordinarily it was diclosed that free amino acid detected in extracts from flesh brown rice (Hervest;1960, Variety Norin No. 17.) were as follows; aspartic acid, glutamic acid, glycine, histidine, alanine and valine and that the decreases of above mentioned amino acids were generally found in older nice (Havest; 1957-1959), though both aspartrc acid and glutamic acid decreased more clearly than the others and the decrease of alanine was not shown clearly on map. In later stage of storage, however, now amino acids product by the degeneration of the proteins had been founded and presumably these amino acids were composed of asparagine, cystine and leucine. It was suggested that gradtial loss of the reserves in brown rice grain itself was caused for living such as maintenance of germinating ability, in the course of time after harvest and there was a general tendency that greater loss was observed in aspartic acid and glutamic acid included the brown rice and increase in leucine, asparagine and cystine was observed from unknown factors. It seems to be absolutely necessary to investigate glutamic acid, glycine and alanine as important amino acids included in white rice for the research and discussion on rice taste.

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In this experirnent, the authors determined the activities of phosphorylase and Q-enzyme in non-glutinous and glutinous rice varieties, in order to find the relations between the activities and the starch formation. Especially the difference of both enzyme activities was carefully tested among various organs of plants. The results were summarized as follows: 1) Changes in the phosphorylase activity which was determined by the histochemical method, did not show any difference among embryos of varietal seeds placed in bed (Fig. 1). It was also ascertained that changes of the same activity in leaves of plants under various treatments, i.e. supplied with topdressing of N., irrigated with cold water and shaded, showed the similar trend, notwithstanding non-glutinous and glutinous (Fig. 4). But at the various stages before the 12th leaf appeared, the activity in leaves was higher in glutinous plants than that of non-glutinous ones (Fig. 2). The activity shown in the daytime dropped after the same period (Fig. 3). 2) Q-enzyme activity was determined, following a method given by Gilbert, with such parts as boot leaf, endosperm and chaff of both varieties. No appreciable difference of the activities in both of endosperm and leaf existed between those varieties (Fig. 5). The activity was however higher in chaff of the glutinous grains as compared with non-glutinous ones (Fig. 6). 3) Fram these facts, it was inferred that the higher activity of phosphorylase in leaf and of Q-enzyme in chaff might be closely connected with the formation of the starch of amylopectin type in glutinous rice kernels.

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This paper reports an electron microscopy of amyloplasts of rice plant and sweet potato. Amyloplast was a simple sac-like body, having a thin membrane at its sufface. Usually several strip-like pattern and occasionally a few vesicles are observed within the amyloplast. No developed lamella or septum structure was however observed. From this respect, amyloplast differs from chloroplast, plastid, or mitochondria. A compound grain of rice plant is consisted of several amyloplasts. Consequently, it may not be appropriate to consider that compound grain itself is a single amyloplast.

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A research was made on the study of salt injury, and 8 varieties were used to determine their salt resistance. The results obtained were as follows. (1) The upper limit of NaCl concentration that permitted germination was 2.0% for the unhulled grains, while the upper limit that permitted the embryo organs to break rose to 4% for the hulled grains. (2) When the grains were kept in 3% NaCl solution for 7 days, germinated grams had the higher contents of NaCl as 1.15%, but ungerminated grains contained only 0.51% of NaCl. Salt injury was severe at the germinated grains than at the ungerminated ones. (3) Absorption of Cl by the germinated grains was traced by the microdetection of Cl. When the germinated grains grown in the distilled water were placed in 0.3 % NaCl solution, Cl entered into the coleorhiza hairs only in a minute. Cl moved into the base of coleorhiza and scutellum about 3 hours after the accumlation of Cl was found in the vasculer boundles of scutellum, plimule and radicle. After 6 hours, Cl appered in the epitherium layer and at the outside of endosperm. Coleorhiza absorbed Cl very quickly and absorbed Cl seemed to enter into embryo and endosperm from the coleorhiza by the route mentioned above. (4) The varietal differences of salt resistance were examined in the germination of grains in the high concentration of NaCl by the use of 8 varieties. The resistant varieties. Ayanishiki, Hatamurasaki (upland rice), Norin no.9 (upland rice) and Tosan no.38 germinated faster than the no resistant varieties, Norin no.1, Fujisaka no.5 and Hatsushimo. Norin no.18 which was shown to be no resistant variety by the Ota's study (1958) germinated faster than the group of no resistant varieties. The speed of germination by which the coleorhiza breaks the pericarp in the high concentration of NaCl seemed to depend mainly on the water absorption power of varieties under the high osmotic pressure.

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作物組織の細胞間隙が発達し, 生理的に通気系として作用する意義を持つことは既に報告されている. 稲の根と葉に発達する細胞間隙の定量的研究を行ない植物の発達段階と栽培条件との関係を検討した. 比較のために Zea mays と Vicia faba を用いた. 測定方法は次の通りである. 空気中の重量: G₁, 水中の重量: G₂, 空気を追い出した後の重量: G₃, 水の密度: p, V=(G₁-G₂)/p : 物体の容量, v=(G₃-G₂)/p : 細胞間隙の量, v%=v/V×100 : 細胞間隙量が全体積に占める割合 1) 根の細胞間隙の量は稲においてトーモロコシやソラマメより大きい. 根端からある部位まで次第に増加する. その部位は生育状態により異なる. 2) 水稲の根では水田状態において, 畑状態に生育したものより大きく約3倍に達する. 3) 葉においては葉位によつて違つた値を示し, 1枚の葉においても部位により異なる. 4) 幼葉では葉身において葉鞘より大きいが成葉では逆になる. 5) 若い苗令では水稲は陸稲より大きい値を示すが, その後次第にその関係は不明瞭になる. 6) 葉の細胞間隙の発達にも生育環境が影響する. 若い苗令では水田に生育したものは畑に生育したものより大きい値を示すが, 苗令が進むにつれて次第にその関係はなくなる.

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Studies were performed on the nature of the curvature of laminae to the abaxial side in rice leaves, shown when they have almost accomplished their longitudinal growth. When the excised leaves from adult rice plants, were placed in a horizontal position being floated on distilled water, the angles between the laminae and the sheaths in the excised leaves, each consisting of 1cm of lamina, a lamina joint and 2cm of sheath, increased, becoming larger than those in the terminal leaves, held in a vertical position, intact on the plants (Tables 1 and 2). Thus the fact that the lamina joint is a main region to percieve and respond to geotropic stimulus was proved (Table 2). Such an increment in the angle was derived from that in the cell size in the adaxial side of lamina joint (Table 3). Moreover, the behaviour of the vascular system and the following mechanical structure in the lamina joints of healthy leaves and of tubular leaves, the latters being induced by 2, 4-D treatment, were histologically investigated. It was observed that these regions were liable to bend because their vascular bundles were transferred inwards and lignin in their mechanical systems disappeared. The lamina joint is also a transitional region between the lamina, having no dorsiventrality, and the sheath, having dorsiventral structure with reference to the arrangement of vascular bundles and ground tissues. No essential difference in such vascular system was observed between the healthy leaves and the tubular ones (Photos. 1∼16)

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This paper reports an electron microscopy of amyloplasts of rice plant and sweet potato. Amyloplast was a simple sac-like body, having a thin membrane at its sufface. Usually several strip-like pattern and occasionally a few vesicles are observed within the amyloplast. No developed lamella or septum structure was however observed. From this respect, amyloplast differs from chloroplast, plastid, or mitochondria. A compound grain of rice plant is consisted of several amyloplasts. Consequently, it may not be appropriate to consider that compound grain itself is a single amyloplast.

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The author reported previously about the process of the damage by head blight as follows: Initial infection to a wheat epikelet usually occurs through the extruded anthers, and after the fungus has become established, it spreads in to adjacent tissues, especially those of rachis, and hindrance of water flow in the vascular bundles in the rachis results in physiological withering of the spike. The tests were made with 12 wheat varieties, including resistant and susceptible ones, in the field of the faculty of Agriculture, Okayama University in 1950. At first, the author selected many wheat spikes, each of which had 1 or 2 flowers infected by head blight throughout all varieties, and put a tag on each spike. And subsequent progress of blighting was marked on it every day until the ripening period. As the result of the test, the author found that the rate of symptom expression of head blight within the definite period in the susceptible varieties was more rapid than that in the resistant varieties. So that the author recognized that the varietal difference in this characteristics is closely relative with that in the resistance to head blight in wheat.

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18 Varieties of wheat including both types spring and winter, were used in this experiment. Plants grown outdoors were carried in the green house (20°C) 15, 45, and 60 days after sowing and received continuous illumination thereafter. The period of the completion of vernalization was judged from the point in which, in the graph plotted the number of days till heading after removing in green house against that placed out door, the latter shows no change to the former. Spring wheats seems to require about 15 to 30 days or less after sowing for the completion of vernalization, while winter wheats require about 45 to 60 days in the same way. The sensitivity to vernalizatian differs according to their growing stage. The yonger the plants, the more sensitive they are.

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In order to clear the effect of excess soil moisture in ripening stage on grain quality of wheat and barley, pot-experiments were carried out from 1957 to 1960. The results were summarized as follows: 1000-grain-weight of kernel raised from the soil with air porosity below about 20 volume-percent of soil was significantly inferior to one from the control plot with larger air porosity. The lowering in production in the plot holding higher soil moisture was due to smaller air capacity, higher acidity and lower redox-potential of soil. In consequence, the plant grew poorly and declined in respiration and water absorption activities. The excess soil moisture in the first half of ripening stage was mose injurious than that in the second half on plant growing. High temperature encouraged excess soil moisture injury to plant ripening. The conclusion above-mentioned was supported by surveying those points in some practical wheat fields around Chikugo Area.

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The early period of endosperm development in 6 wheat varieties under constant temperature conditions, at 10°, 20°, and 30°C were observed. The development began by the division of primary nucleus and passing through 2, 4, 6, 8, ·········nucleate stages the peripheral layer was formed (Figs. 1∼20) Throughout these periods the increasing nuclei were arranged regularly in the embryo sac cavity. In 12∼16 nucleate stage, 4 nuclei closely surrounded the zygote, and then cleavage of the fertilized egg was started. Cytoplasm around the endosperm nuclei increased in volume accompanying with the progress of nuclear divisions. On the other hand, antipodal cells which were contacted with the endosperm nuclei showed a remarkable degeneration. These suggest that the antipodals may give the nutritional cotribution to the early development of the endosperm, and the latter may have a influence upon the division of the zygote and subsequent development of the proembryo.

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落花生の雄ずい筒の特定位置に発生する, "sterile filaments" の形態的性状と, その発生程度の品種や開花呼期による差異をみるため, 開花始から約100日間, 千葉中粒43号, セレベスの二品種, 約23,000の花について調査を行なつた. 1雄ずい群内の, 正常雄ずい (f. st. ) と "sterile filaments" (ster. fil. ) との数的関係からみると, 両品種ともに "8 f.sf.+2 ster. fil." の花が最も優勢な出現をみたが, その頻度は, ついで多く出現する "9 f.st.+1 ster. fil." の花の頻度に支配され, 最も正常な型というべき, "1O f.st.+O ster. fil." の花はほとんど無視できる程度の出現をみたにすぎない (Tab. 2). また, それぞれの花の出現頻度間に相当顕著な品種間差異を認めたが, それらの時期的変化においても同様な品種的特性を認めた (Fig. 3). かかる本種における ster. fil. の発生は, 品種のみならず, 特に雄ずい分化期における植物の生理的, 環境的条件にも影響されることがうかがわれ, これがまた, 従来の記載における本種の雄ずい数の相違の一因となつていることが推察された.

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1. Changes of pH value and nutritional interrelationship of Ca, Mg and K in shell were investigated to study the function of Ca by using Chiba 74 (runner type) in sand culture with the root and fruit zones isolated from each other. As to the pH value at the early stage of the filling, no difference was detected between the nornral and Ca deficient shells, but the value in Ca deficient shell, especially in abortive pod (namely the one which ceases to develop at the stage of pod enlargement), was markedly lower than that of the normal one in the filling process (Fig. 1). The reciprocal relation among Ca, Mg and K was very distinct in their total amount at each stage of the filling; fractional analysis of them indicated that each amount of HAc-sol-Mg and alc-sol-K was in an inverse relation to the amount of HCl-sol-Ca, and that there was a little difference in the amount of both of HAc-Sol-K and alc-sol-Mg between the normal shell and the Ca deficient one (Fig. 2). 2. The distribution and rise or fall of the contents of sugar, starch, and activity of some enzymes (amylase, phosphorylase, invertase, hexokinase and phosphatase), which are related to the metabolism of carbohydrate, were determined with above samples. The contents of reducing sugars in normal shell increased until around the 20th day after gynophore reached fruiting zone, but decreased rapidly thereafter. The same increasing trend and a very slower decreasing trend were observed in shell of empty pod, and its contents in abortive pod scarcelly ever changed at any time. The contents of non-reducing sugars of shell of empty pod were higher than those of normal one, and those of abortive one decreased considerably during the filling process. On the contrary, the very rapid accumulation of starch took place in abortive one, and starch content in Ca deficient shell was higher than in normal one at every stage (Fig. 3). The activity of five enzymes found in shell, which ripened under the condition of Ca deficiency, was higher rather than that of the normal one, but the activity per unit protein-N was remarkably lower, excepting the activity of invertase (Fig. 4, 5).

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前報で報告した, 熱帯産大豆 (ecot. indo-chinensis) の適応性を考察するために, 限界日長および短日条件下の生育を検討した. 1. 熱帯産大豆品種の開花についての限界日長は, 13～14時間の範囲にあり, これはわが国の秋大豆型に較べて1時間ほど短かい. 2. 熱帯産大豆にもつとも多い無限伸育性品種は, 有限伸育性品種に較べて, 短日条件 (8～10時間) 下で茎長が長く, 収量が多いことが認められた. 熱帯産大豆は, 熱帯産の稲と異なつて, 短日条件下での開花までの日数すなわち基本栄養生長期間の著しく長いものがない. しだがつてこの無限伸育性の特長が, 熱帯の気候に適合するものであることが考察できる. 3. しかし, 12時間日長下では, 熱帯および亜熱帯産大豆品種に開花までの期間の長い (35日以上) の品種が認められた. また, 開花期間, 結実日数, 生育日数, 茎長等も開花までの日数と同じように長いことが認められた. これらの品種は大部分無限伸育性であるから, 12時間日長下で開花までの日数の長いことと, 無限伸育性と両特徴が相まつて一層開花後の各発育期間を延長し, 茎を伸長せしめるものと考えられる. 4. 上記12時間日長下で開花までの日数の長い品種は, 熱帯および亜熱帯の海岸部および島嶼部に多く, 大陸部に少なく, また大豆の原産地と考えられる中国本土には見られなかつた. また, この特徴は, 品種の播種期の差異と関連して分化していることが認められた. よつて, このような熱帯産大豆の特徴は, 中国本土から熱帯ヘ大豆が伝播するとともに分化したもので, 無限伸育性と相まつて, 熱帯の比較的短かい日長に適応するものであると考えられる.

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This paper gives the result of research made to find the influence of temperature on the translocation of foliar-applied P³² of sweet potatu in 1958. The absorption of P³² from one leaf of sweet potato increased progressively with succesively higher temperature when the plants were held in darkness over night (15hr) at soil temperatures of 10°, 20°, 30°, and 40°C, while the optimal air temperature for P³² absorption was 30°C when plants were held at 10°, 20°, 30°, and 40°C of air temperature. P³² was translocated mainly into the root and lower stem below the node of the P³² treated leaf. The effect of soil temperature on the P³² accumulation in root was generally stronger than that of air temperature, espesially the accumulation in root was greater at the soil temperature of 30° and 40°C which were higher than the temperature of leaves and stem. When roots of a plant were divided into two groups and each of halves was exposed to different temperature in darkness for 20 hours, the translocation and accumulation of P³² were better at 30°C than 40°C, better at 30°C than 20°C, and 20°C than 10°C root temperature.

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In order to determine the effective shoot cutting height on the high training in paper mulberry, two experiments were conducted. The results were as follows. Cutting at the height higher than 15 to 30 centimeters from ground surface in the first year, showed the merits as increased yield and yield rates and the distinguished marks of high training. The most effective shoot cutting height on and after the second year was 3 centimeters in 30 centimeter high training.

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The results of the experiment with upland cotton plant (variety Kanno 1) were as follows; 1) The wall thickness and tensile strength of fibre both tend to decrease as the sowing time becornes later, fruiting positions are higher (Fig. 1, 3), and the period from blooming to ripening becomes longer respectively (Fig. 2, 4). 2) The tensile strength (Fig. 5), average lint weight, and number of convolutions tend to increase as the wall thickens. 3) If we assume that the wall thickening occuring after fibre elongation has been completed is responsible to the changes of average temperature in field condition (X) (Tab. 1, 2), the amount of wall thickening of cotton fibre (Y) can be estimated by the following equation: Y^^^= -0.00805X₁+0.04080X₂-0.05251X₃-0.00651X₄+3.61242 It may be supposed that the rate of wall thickening obtain for the average temperature interval of 20 to 25°C is more larger than that of above 25°C, while it considerably decrease under 15 to 20°C and cease under below 15°C. 4) If we assume that the critical temperature for elongation and wall thickening of fibre is 15°C, the effective longest period from, blooming to ripening could be estimated at about 93 days (Tab. 5), the result being coincident with that already known for the effective ripening period. 5) The relative decrease in wall thickening with the increase of days from blooming to ripening under natural condition suggests that the limitation of physiological processes as photosynthesis rather than translcotion by low temperature, acts to retard the wall thickening by limiting the supply of raw materials into the cotton fibre.

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In order to make clear the effects of difference in planting time of sugar beet varieties on the bolting tirne, root weight and sucrose percentage, several experiments were carried out, the results being as follows. 1. Most of the easy-bolting varieties planted six times from August 10 to October 20 in Kagawa Prefecture, bolted in the middle of April. But non-bolting varieties as Klein-AA bolted on April 21 and Cesena NSA bolted on May 5. They were planted on September 4. The latter were they planted, the less often they bolted. When those two varieties were planted on October 20, there was found no bolter. 2. In the warm region of Japan as Kagawa Prefecture, cultivation of sugar beet in winter may be successful by using non-bolting varieties as Klein-AA and Cesena NSA and by seeding in September and harvesting before the rainny season of June. Considering from the bolting tendency of these non-bolting varieties the adequate time for harvest should be from the end of April to mid-May. It is very clear that the Italian type of sugar beet cultivation is very difficult to be practised, because of the excess rainfall in June and low temperature in winter in our country.

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In order to know the ecological characteristics of sugar beet plant sown in summer in the warmer districts of Japan, we have traced the general growing behavior and the changes of root compositions during August in 1959 to May in 1960. The varieties used were DONYU No 2 and HONIKU No 400, and both of them were sown in two times. August 1 and 21. The measurements of various plant characters and root compositions were done every 10 or 15 days, using 20 plants sampled at random. Grossly speaking, the whole cycle of growing may be distinguished into following four periods, i.e. seedling period, vigorous growing period, root ripening period and regrowing period, as seen in Fig. 1 and 7. A transition from the 2nd to the 3rd period is induced by plant physiogical states and by environmental factors, and especially, sinking of mean air temperature below about 1O°C is considered as the most effective among the latters. The brix degree and sugar content in stored roots increase gradually reaching a peak in middle or late February and after then decrease with plant regrowing as seen in Fig. 2. Purity shown in Fig. 3, however, continues to rise more rapidly after initiation of regrowing, relating to more rapid decrease in soluble substances such as soluble nitrogen and raffinose than decrease in sugar (see Fig. 4 and 5). On the other hand, the stored root continues to increase in weight more rapidly again after March; accordingly, the heaviest available sugar is found in the later season around late April (see Fig. 6). From the facts mentioned above, we could conclude that the ideal harvesting time for sugar manufacturing is in a season later than February that has hitherto been considered as the best time.

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XI. Improvement in oil extraction method. It was found that the most suitable drying period was between 10 to 14 days, in which the weight of leaves had decreased to 1/3∼1/4 of the original. On the other hand, with over 20 days of drying the yield of oil began again to decrease. If the leaves were dried in the shade 10 to 14 days, the yield of oil may be somewhat increased as compared with fresh leaves. Especially drying proceses is recommendable in a sense of avoiding undesirable fermentation of leaves in pile during the summer season. There was no significant changes in the chemical composition of the essentiai oil due to the drying of leaves. The oil extracion by means of n-Hexane would not be economical. It would be advantageous to have prolonged hours of distillation during the hot summer day as in such a season after-distillation will yield more oil, but do not fix any definite number of hours of distillation for the whole year. XII. The effects of S. G sprinkling on the yield of oil, the transpiration and the leaf-temperature. S. G sprinkling is effective in increasing the percentange of oil yield. This seems to be brought about chiefly by a large amount of solar radiation absorbed on the leaf-surface.

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I . The Process of Development and the Vicissitude of the Ingredients in Pelargonium Plant As the result of the trial examinations on the process of the development and vicissitude of thet ingredients of P. denticulatum and Bourbon species in Seto Naikai (the Inland Sea) zone, the process of development is divided into four stages, the first growing period, the standstill period, the second growing period and the third growing period. The first growing period shows extensible increase, namely, increase in the number of the first offshoots, the stalk length, the leaf weight and the essential oil content. The second growing period shows luxuliant development to increase the number of the second offshoots. The cause of the standstill, period between the first and the second growing period, depends upon the want of soil moisture due to the drought in summertime, and both in the top and underground parts of herb the physiological changes are observed. (Fig. 1) On the vicissitude of the ingredients Content in the top: (1) Nitrogen content is maximum at the begining of July when the oil content is great, low in the standstill period, and increases again in the second growing period. (2) P₂O₅ increases till the middle of August, decreses in the standstill period and increases again thereafter. (3) K₂O increases till dry season, and then decreases gradually until the third growing period, when slight increase is observed. (4) CaO shows the greatest change of all the ingredients, It decreases in dry season but increases again early in September. Concerning the change of oil content, the characteristics appeared in the vicissitude of the ingredients content of the herb is as follows: Both in the development and in the ingredients Content of geranium in Seto-Naikai zone there are two extremes: high and low, Which appeared directly in the vicissitude of CaO. This fact is considered to be very important problem for the cultural management to increase the essential oil yield. It will be necessary to examine the better growing method to prevent the defoliation and the excessive debility by reaping the herb by early or middle July when the weight of the herb shows the maximum, and to shorten the standstill period, and to lengthen the second growing period. (Fig. 2) II. On the Environmental factors and the Mechanism deciding the Development and the Percentage of Oil Yield As the result of observing the raw material composition classified by the leaf position, and the oil yield V. the percentage of oil yield in the green herb, under the different reaping time, of the raw herb, the percentage of oil yield is first decided by the raw herb composition and by the degree of drying after reaping. (Fig. 1) Moreover, as the percentage of oil yield from the prescribed materials shows a remarkable change in accordance with the reaping time in season and in day, the influence of the enviromental conditions are examined by dividing into the climatic conditions and the cultural conditions (elements of fertilizer, kinds of soil, quantity of sprinkling and the density of planting). The results are as follows: (1) Loam or Sandy loam is mosft suitable and Sand is also suitable for the cultivation of geranium, while Clayey soil of ill-drain bring poor development and low yield of oil. (2) The effect of sprinkling water in dry season is so conspicuous that the yield of oil from green herb increase despite of slightly low percentage of oil yield. (3) Close spacing bring the increase of quantity of green herb, and lower the percentage of oil yield. As compared with the described section, close spacing has lewered the first year plants by 9% in number, and the second year plants by 10%, and extreme close spacing lower the first year plants by 17%, and the second year plant by 19% (Fig. [the rest omitted]

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Researches were carried out in 1958-1959 to make clear the growth process of mint plant especially refering to its branching habit. The results obtained are summarized as follows: Japanese mint plant forms the initial lateral shoot at IV∼Vlth node (inserted up a shoot) on the main stem, while those of other mint species tested form at first or second node. Initial shoot of the latter grows into a stolon. No manuring or shading delays emergence of intial shoot and new rhizome formation. New rhizome formation is active on the plant which has both initial lateral shoot emergence and new rhizome formation at the same time. Lower the cutting height on the main stem at first harvest, earlier was sprouting of rhizome, more the number of sprouts increasing. As the main stem is cut heigher, new stems originating from lateral shoots become more numerous and they develop more dominantly. Standard branch development at every harvest time is shown in Fig. 3.

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This experiment was carried out to investigate the temperature response on the growth behaviour and chemical compositions of the warm-season forage crops, Bermuda grass and Bahia grass, and cool-season forage crops, Italian rye grass and Timothy. The results obtained are as follows; 1) Dry matter yield of each organ of cool-season grasses decreased as temperature rose with an exception of shoot of Timothy, while this temperature response was in the reverse relation with warm-season grasses, Bermuda grass and Bahia grass. 2) Crude protein contents of each organ of Italian rye grass were higher in the high temperature plot than in the low temperature one, while those of Timothy, Bermuda grass and Bahia grass decreased as temperature rose. 3) Total carbohydrate contents of each organ of Italian rye grass and Timothy were higher in the temperature plot of 15°C than in other temperature plots, 20°C and 25°C, whereas those of Bermuda grass and Bahia grass were higher in the temperature plot 20°C than in other temperature plots, 15°C and 25°C. This trend was shown also in total sugar, reducing sugar and non-reducing sugar contents of all the grasses. 4) The crude starch and hemicellusose contents of all the grasses did not showed a definite tendency. 5) Fructosan contents of each organ of all the grasses decreased as temperature rose, the concentration of fructosan in all the grasses was higher in stubble than in the other plant organs. 6) Lignin contents of each organ of all the grasses increased as temperature rose, and lignin was presented in higher concentration in the root than in the other plant organs.

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Relation between photosynthetic (leaf) and reserving (stubble and root) organ after clipping in Italian rye grass was studied. Parallel with advancing new top growth after clipping, a rapid reduction in quantity of stubble and root reserves took place, especially greater reduction occuring in the stubble. Thus 1-2 weeks elapsed before sufficient photosynthetic tissue was produced to enable carbohydrate production in excess of those required by current growth. Close correlations were found between the regrowth of photosynthetic tissue after the clipping and the accumulation of stubble, root reserves at the time of clipping. In the cooler climates stubble-root reserves at the time of clipping was more abundunt and the new shoot growth immediately after the clipping was more rapid than in the warmer climate. And the decreasing of dry weight, percentage of carbohydrate and nitrogen of root-stubble after clipping was more rapid at the higher temperature than the lower one. The nitrogen contents of stubble and root were relatively unaffected by clipping, although nitrogen level was kept always higher in the clipping plants than in the unclipping. In the new shoot growth the nitrogen level increased, and reached maximum about 1∼2 weeks after clipping.

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Surface runoff and soil erosion were measured at every rainfall on the experimental flames (2m×10m) of slope 9°∼13°, where 11 kinds of crops were contour-cultivated during April to December in 1959. Cultivating each crop on four flames, runoff and erosion were examined at the typical four rain falls and for whole seasons. Although extent of erosion varied with type of rainfalls and culural method, it was found that increased times of soil-hilling, straw-mulching and mix-cropping are effective to prevent erosion, creeping soybean and ladino clover were especially effective. In general, the covering degree of about 70% may be sufncient enough, because 90% of erosion can be prevented by this degree of covering. Because of a severe erosion on the bare land, the suitable mix-cropping or cover-cropping should be adopted during the inter-season of main crops.

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