The experiments were carried out in 1958 to know how different soil temperatures affected the pollen germination and to clarify the relationship between the pollen germination and the grain fertility. Three constant temperature water tanks were set in the open air, of which temperatures were adjusted at 33°(Plot H), 28°(Plot M) and 23°C(Plot L) respectivly. Rice Plants (variety"Norin-29") were placed in them from Jul. 7 to Sep. 17, being irrigated with water of the same temperatures. Fresh pollen taken from strong spikelets of the plant each day were subjected to germination tests on the starch paste media. In general the Plot M tended to show high percentages and the Plot L showed low ones at each experimental date during the whole period. But in the Plot H it was nearly intermediate between them, being followed by a later drop of the percentage (Fig. 2). The average percentage of germination of strong panicles which had headed earlier was the highest in the Plot M and was the lowest in the Plot L. The Plot H was found to be ranked between them. Moreover abortive pollen were always found fewer in the Pollen which germinated with high percentages. The grain fertility was measured also with the same materials taken from all plots (Fig. 3). By observing the ears as they appeared, it was found that the grain fertility was always high in the plot M and low in the Plot H, the Plot L showing intermediate values between them. However in the Plot H a later drop of the fertility was observed as well as in the pollen germination. The Plot M showed a higher average percentage of fertile grain of strong panicles than those of the Plot H and the Plot L. These results indicate that the respective soil temperatures affected markedly the pollen germination and the grain fertility. The authors suggest that a certain relationship may exist between the pollen germination and the grain fertility, and the percentage of pollen germination may indicate the vitality of the plant

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1). Lowland rice plants grown on the soil applied with labeled Sr absorbed until their middle stage of spike differentiation 92.2 percent of the element of the total amount absorbed till the harvest time the quantities being denoted in counts per minute. The absorbed Sr-90 was distributed in the ratio of 38.4 % in the roots, 41.8 % in the culm and 19.8 % in the spike. Sr-90 adsorbed by soil colloid micelle which was extracted with 1 N-KCl solution amounted from 10 to 20 times of that free in the soil being extracted with pure water. 2). Absorptin of Sr-90 by wheat plants was also studied Sr-90 being administered into the nutrient solution was mostly absorbed by the wheat plant until its middle stage of spike dfferentiation. The absorbed ratios for root, culm and spike were similar respectively to the above mentioned absorbing ratios in lowland rice, as shown in the diagram. With a higher concentration of Sr-90 in the nutrient solution in exchange of that of calcium, an increase in the absorption of the former was observed. Frow those results, the present authors consider that Sr-90 is absorbed distinctively in the edible fraction of those crops, without regards to comparatively increased supply of calcium in the nutrient solution, and recognize that labeled strontium woulld become one of the most important contaminating isotope in soil

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1) Growth process in rice plant is closely connected with the temperature during its cultural period. Especially, with the recent spread of early-planting cultural method, the temperature environment have developed with multiple phases. The authors studied, therefore the ecological responses of rice plant to temperature during its generative growth period. 2) Increasing of the efficiency of rice grain production requires high temperature on and after the stage of young panicle formation. Namely, rice plant requires temperature higher than 20°C during that period, ideally, but the critical temperature for the stage of young panicle differentiation may be about 18°C, we presume. 3) Rice plant requires 750°C of integrated temperature from the stage of young panicle differentiation to the heading time. The stage of boot leaf emergence (the time when the tip of boot leaf protrudes from the sheath of the leaf just beneath it) lies at the middle of the period and makes a turning point on which the stage of young panicle formation changes into the booting stage. Therefore it is an indication of internal growth but it inclines before the middle point in case of late-planting rice culture. 4) In the process of the generative growth, we found that the critical temperature for the stage of young panicle formation (growth) was not equal to that for the stage of heading (elongation of internodes) and that the latter requires to be higher than the former. 5) Though late-maturing varieties are most effective in early-planting rice culture, in case of using any variety for early-planting rice culture anyhow, we must consider to adjust the generative growth period to high temperature period by integral temperature in calendar day. And when we make use of cultural period fully, with on exact knowledge of the regional adaptability of the variety, early-planting rice culture will be possible and the adjustment will effectuate the rice culture. 6) Judging from the above mentioned point of view, at Morioka, limiting times for transplanting and for ripening are the first part of May(about 10th of May) and from the end of September to the first part of October, respectively. So it may safely be said that rice variety "Sasashigure" is the most effective one in this region

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With a view to obtaining fundamental data for accomplishing the knowledges on leaf analysis of rice plant, the experiments dealt with the seasonal changes of N, P & K contents in the main culm, and the pattern of their accumulation and translocation. There was considered the physiological roles of the successive leaves in the growth process of rice plant. The experiments were carried out under a normal fertilizer condition (N, P₂ O₅ & K₂O were applied 3 Kan per Tan, respectively) on a paddy field, using var. Norin No. 37, through four crops, 1955∼58. As the results obtained from the four season crops, were similar to each other in tendency the 1958 year's results are reported here mainly as follows: 1) The N% (of dry matter) in L.B. (the leaf blade) was higher than that in L. S. (the leaf sheath) & I. N. (the internode). That % became lower in order from the lower leaves to the upper ones. But, the N% in the leaf at early dates in the field (e.g. 10th leaf) was higher than that in the leaf at a later period in the nursery (e.g. 8th leaf). In the field, the N% in lower leaves (80∼10th 1.) decreased rapidly, and they came to die, while the upper leaves (14∼16th 1.) at full expansion had lower % than the lower ones, and the N% in them decreased slowly from that time. The middle leaves (11∼13th 1.) had intermediate N%. Though L.S. had the same abovementioned trend as L.B., the N% in L.S. as well as in I.N. was lower than that in L.B. 2)N accumlation in the successive leaf blades reached their maximum 1∼2 weeks after expansion, and then the element was translocated rapidly. The higher was the position of each L.B., the more amount of the N was found in it. The amount reached a maximum in the 14th L.B., and decreased thereafter, the N amount in the terminal leaf (the 16th) being equal to that in the 11th. N amount in each successive L.S. was about 1/2∼1/3 times that in the corresponding L.B., and that behavior was similar to that in L.B.. 3) It was found that N in the upper leaves was translocated into the grain, and that in the middle leaves was assumed to play an important role in the stem and ear elongation. 4) P% in L.B. & L.S. decreased from the lower leaf to the upper one successively in the same way as N%, but was higher in L.S. & I.N., which were bothconductive tissues, than in L.B. Seasonal changes of P% was smaller in L.B. than in L.S. 5) Maximum P amounts were contained in the 13 or 14th leaf as in the case of N, but P amounts were much more in L.S. than in L.B. P amounts in L.S. decreased more greatly than that in L.B. as the grains ripened. 6) With actual values, P needed for grain formation in upper leaves was found to be approximately 3 times as much as that in middle leaves, so that P in upper ones did act a larger part in ripening. 7) The behavior of K was in the same way as that of P. But unlike the case of P, on later stage of ripening K% in L.S. increased slightly, and that in I.N. did very largely. 8) Seasonal changes of K amounts were in nearly the same manner as that of P, and its translocation in L. S. & I.N. stopped at a later stage of ripening. 9) The role of K in ripening was assumed to be smaller; it was true that the middle leaves contributed to the formation of stem and ear, and the upper ones did to the full ripe of ear, but as the K amount in the grain itself was small, much of the K amounts in upper parts might be regarded to have been utilized for maturation of vegetative tissues. 1O) With regard to the translocation quotients in successive leaves, those of N, P & K elements were low in the middle leaves, but high in the lower and upper ones. The facts were assumed to be due to some special characteristics of late maturing type of rice plant and also to different environmental conditions under which the middle leaves lived, as compared with early maturing type. [the rest omitted]

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Paddy rice plants, the variety Norin No. 29, supplied with nitrogen at various levels were grown under various light conditions, and the effects of the nutrient on the factors constituting field photosynthetic ability, respiration and dry matter productivity of the rice plants were studied. In their previous papers, the authors have postulated following farmula for the dry matter productivity of rice plants growing under community conditions. ΔW=κ·L·S·P₀·ρ-Rw In the present paper, the authors elucidated that the dry matter productivity of rice plants would be estimated more accurately by the following formula; ΔW=S·P₀·αI/1+αI·D-Rw where, ΔW denotes the dry matter produced per day, S:leaf area, P₀ : mean photosynthetic activity per unit leaf area, D: day length, α: light curve coefficient, I:mean light intensity

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Rice varieties much tolerable for heavy fertilizing with nitrogen, Fujisaka, No. 5 and Ginmasari (former early var., later medium var.), and non-tolerable varieties, 0banasawa, No.1 and Norin, No.21 (former early var., later medium var.) were grown under low, medium and high nitrogenous nutrient levels respectively, and the factors constituting field photosynthetic ability, respiration and dry matter productivity of those were studied

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The paddy rice variety used was Norin-8, which was grown in the paddy field under different levels of nitrogen supply and different density, changing the spacing at the begining of heading. The increased amount of dry matter production was measured by using growth-analysis during ripening period. Results obtained from this investigation briefly summerized as follows: 1) Relative growth rate (RGR) was completely controlled by the net assimilation rate (NAR) per unit leaf area, so far as the increment of top-dry-weight was expressed by RGR throughout ripening period. 2) The size of leaf area for maximum production of dry matter per unit field area (optimum L) was estimated nearly 2.3 m²/m² field throughout ripening period. 3) The growth rate (G=dw/dt) during ripening period was controlled by leaf area per unit field area (L) in case the leaf area was restricted below the optimum L. 4) NAR in ripening period was closely related to both the nitrogen percentage and the chlorophyll percentage in leaf-blades. The relation was shown as a curve, usually showing the maximum value of NAR at 2.3% of total nitrogen content and 1.4% of chlorophyll content as fresh matter weight in leaf-blades, and rather decling NAR values at the higher percentages. 5) Forecasting of dry matter production in ripening period seems to be possible by determining the total nitrogen content in total leaf-blades per unit field area at the begining of ripening stage

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The effect of the three major nutrient element supply upon the photosynthetic activity of rice leaves was studied by water culture experiment. From four series of experiments carried out by the authors over three years at various growing stages of the plant, the following conclusions were drawn : 1) Nitrogen supply most often gives limiting influences upon the photosynthetic activity of rice leaves within comparatively a wide range of its supply or its content in the leaves. If the other elements, however, are too short in their supply, they may become limiting to photosynthesis instead of nitrogen. 2) Phosphorus, on the other hand, may become limiting only when nitrogen supply is abundant, and potassium may become limiting only when both nitrogen and phosphorus are amply supplied. 3) When supplies of the three major elements are higher than their normal levels, the photo-synthetic activity of rice leaves can not be varied remarkably, at least in the earlier half of their growing stage, how the mutual ratios among the three may be changed

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Net assimilation ratio, nitrogen contents and photosynthetic ability of rice plants were measured, using variety Norin No. 37 grown at various planting densities and dosages of fertilizer. Dry matter production in 2 weeks was compared between the community condition and isolated condition in which mutual shading was removed by cutting leaves of the adjacent hills. The results obtained were as follows : 1) The amount of produced dry matter of rice plants under the isolated condition was larger than that under the community condition during the period from 4 to 12 weeks after transplanting. It would be ascribed to that the rice plant under the community could not get sufficient light during the period. 2) Leaf area per hill had an unfavourable effect on assimilation efficiency (ΔW/ΔW_AP0), as shown in figure 7, when the light intensity in the community decreased due to the increase of leaf area index. When the value of leaf area index was too high, the reduction of leaf area per hill or dense spacing of planting was considered to be beneficial for assimilation efficiency of the community. 3) Photosynthetic ability of the rice plant had an intimate correlation with the N content in leaf blades. Also the number of glumes per plant had a high correlation with the N content in the plant as well as that in the leaf blade. Accordingly, the number of glumes might indicate the photosynthetic ability of the rice plants at heading time in most cases (Fig. 9)

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The seedlings of lowland rice, variety. Aichi Asahi, grown under three kinds of seeding spaces, that is, 4.5cm×4cm as a thin rate, 3cm×1.5cm as an intermediate one and 1.5cm×1.5cm as a thick one were sampled at every leaf stage from 2nd to 8th, at which each leaf had completely emerged, thereafter the differentiation of primordia of leaves and tillers and the development of tillering buds were studied by using scales, calipers and microscopes. When the nth leaf has emerged, i.e. at nth stage, the (n+4)th leaf of a main stem has differentiated, simultaneously the primordia of (n+2)th and (n+1)th tillers are found as merely a swelling in appearance at the axis of(n+2)th and (n+1)th leaf, respectively. The nth tiller, which was a swelling primordium at (n-2)th and (n-1)th leaf stages, begins to develope and grow as tillering bud differentiating one or two leaf primodia at nth stage, and thereafter it continues to grow if the environmental factors are suitable. In thick rate seedlings, the growth of each tiller is supressed as compared with thin rate seedlings, the inhibiting effct of thick rate seeding, however, on the growth of nth tiller can hardly be seen before the nth leaf stage, at which the tiller beginS to differentiate leaves and to grow rapidly

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The author has studied morphological chracteristics of the 1st leaf of rice plant, which appeares above the coleptile, comparing it with the 2nd and the 3rd leaves. The main results were as follows : 1) The lst leaf consists of two parts : a blade and a sheath. And a ligule and two auricles are recognized apparently on it just as on the upper leaves. 2) The upper part of the sheath margin makes a part of the ligule, the fact being different from that in sugarcane. 3) Degrees of development of the ligule and auricles have some relation to the varietiy of the plant and soil humidity

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[in Japanese]

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Further experiments were conducted with a view of clarifyillg the developmental differences of young panicles in different maturing varieties as affected by the time of cultivation and of establishing a method for identifying the developmental stages which can hold true in any circumstances. 1) Effects of early cultivation on hastening the time of first bract differentiation (which is the initiation of ear-primordium formation) are more remarkable in early varieties than in late varieties. Therefore, the larger varietal differences are found in the date of initiation of ear-primordia when rice-plants are transplanted the earlier. 2) The number of days required from the time of transplanting to the stage of the first bract differentiation as well as that required from the first bract differentiation to the heading are small in early varieties and large in late varieties, and in any variety, moreover, both the number of days are the larger in the earlier cultivation. From this fact it is confirmed that the number of days required from the initiation of ear-primordium formation to the heading, which has been hitherto considered to be nearly constant in general, varies considerably with the variety and cultiVation time. And it has been also made clear that the differences in number of days required from the initiation of ear-primordia to the heading due to different varieties and different cultivation times can be ascribed to the differences in the total number of leaves emerging on the main culm and the varietal differences in the photoperiodic and thermic sensitivities of the plant. 3) As the results of examinig the method for identifying each developmental stage which should hold true in any circumstances, it has been proved that a corrected "foliar age index"can satisfactorily be used. (c.f. Bull. Natio. Inst. Agr. Sci. Series A 5) The corrected "foliar age index"(Y) is calculated by the following formula, taking 16 in the total number of leaves on the main culm as a standard. Y=y+(1OO-y)×16-χ/10 Where y is indicating the "foliar age index"at a given stage, χis the total number of leaves on the main culm of a given variety used, which is fairly constant as a varietal character under a given cultural condition. By the way, "the foliar age index"is represented by the percentage ratio of the number of leaves which have actually emerged on the main culm by a given time to the total number of leaves to be expected by the time of heading on the main culm

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In this paper, the tissue distribution of α-naphthylamine(α-NA)oxidizing activity in rice root is reported. The tissue slice prepared from the various part of the root were incubated in the reagent mixture, 50ppm of α-NA in 0.015% of hydrogen peroxide solution, at about 30°C for 3hours. The α-NA oxidizing activity and its tissue distribution were determined qualitatively by the grade of coloration developed. Higher activity in α-NA oxidation was seen in the tissues, root cap, epidermis, and sclerenchyma of the cortex; medium one in the tissues, meristematic region of the root tip except dermatogen, and primordia; lower one in the tissues, parenchyma and central cylinder of both the matured and elongating regions of the root. Such a distributional pattern of α-NA oxidizing activity was quite the same as that of" peroxidase", which was reported before (6), in histochemical respect. Only the different point in the detection method between them is that α-NA is used as an oxidized agent (an acceptor of oxygen) in case of α-NA test instead of benzidine in case of peroxidase. Considering from these facts, it may be supposed that the enzyme involving in α-NA oxidation should be the same as histochemically so-called "peroxidase" itself. There was, generally, recognized a tendency that α-NA oxidizing activity was greater in the aged part rather than the younger part of root. Consequently it may be reasonable that the distributional pattern of α-NA oxidizing activity in root tissues quite differs from that of TTC reducing activity, whose high activity is usually appeared in the younger part of root as has been reported before (6)

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As is reported in the previous part of this paper, all parts of root surface of rice plants can adsorbe more ferreous compounds from media, when metabolic activities of roots have dropped as the plant growth advanced. The largest amount of the coatings is therefore found about the period of heading. However it was found somewhat differently circumstanced with that per 100mg dried roots and per unit area of root surface. This fact was shown in earlier periods of growth. In the experiments of which is reported here, a positive correlation between them was proved. The amounts per unit surface area is theoretically to be called the adsorption power of ferreous compounds of roots. The adsorption power is announced in this papar as the ferreous coating formation, the amounts per unit root weight being included. In these experiments, it was first experimentally examined whether the ferreous coating formation was depended upon root activity or not. Next it was also tested whether the ferreous coating formation was related to the absorption of bases e.g. the cation-exchange capacity of roots or not. Ferric ions in media are to be exchanged by other cations on root surface and thus the adsorption of them occurs to be followed by their absorption, as well as other cations are absorbed. The absorbed ferric ions are assimilated in plant body and the surplus of them being adsorbed on the surface may be formed into ferreous coatings, accompanied with their adsorption combinations. Such adsorption may readily happen because of the lower lyotropic character of ferric ions. As far as this hypothesis may be true, the ferreous coating formation is surely related to the cation-exchange capacity of rice roots. From these experiments, the following main results were obtained. 1) Among roots which grew in all kinds of media containing ferreous compounds, it was observed that young parts of roots and young roots themselves were never stained by ferreous compounds. Moreover the parts of roots placed under oxidizing conditions such as the basal parts of roots were also scarecely stained (Tab.1). 2) Roots which emerged later were always less remarkably stained than those which appeared earlier (Tab.2 & Fig.1). 3) Plants of which the tops were untouched had roots less discoloured by ferreous compounds than those of which the aboveground parts were entirely cut off (Tab.2 & Fig.2 A & B). 4) Plants of which the underground parts were aerated during the experimental course had roots less stained, as compared with those not aerated and those of which the leaves were cut one third when each leaf emerged normally (Tab.2 & Fig.3 A & B). From these results it was assured that young roots and young parts of roots produced less ferreous coatings on their surfaces. The cation-exchange capacity of roots were estimated by the percolation method. Amounts of ferreous coatings were determined in parallel by the o-Phenanthrolin method, six varieties of different resistabilities against soil reduction being used. 5) The cation-exchange capacity per total roots weight and per 1OOg roots were rather highly correlated respectively with the amounts of ferreous coatings per total root weights (Tab.3 & Fig. 4 A, B & C). From this fact the amounts of ferreous coatings may suggest the intensity of absorption of bases from media

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Determination of leaf water content was made on the "Saline"crops, using rice, wheat, barley and naked barley, grown in sand culture. The saline cultures were done by the solution to which NaCl had been added so as to become the critical concentration for their growth. Considering data from all saline cultures with the multifarious ecotypes induced by various varieties, various nutrient deficiencies or different growing stages, the differences in leaf water content were apparent, but the average decreases of water content were as small as 0.72 to 1.50%. And also the changes of leaf water content in green part (the basal part obviously uninjured) in leaves where the burn symptom began to develop, the changes in every part on an uninjured leaf and the changes in leaves classified according to leaf-order were just the same as before. Moreover, the differences in water content at various hours in a day were also small as stated above and the hourly variations in leaf water content in the saline cultures were a little more than in the non-saline cultures. It may be said in summary that although the incipient drying resulted from salinization in rhizosphere seems to be concerned with the osmotic inhibition effect, the specific features and the details of the progressive mechanism of saline injury still remain obscure

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In our last paper, we reported that a higher soil temperature (11°C) in winter promoted the vegetative and reproductive growth of wheat varieties. In the present paper, we elucidate the fact that the grade of such promotion is correlated with the grade of winter sowing habit of the variety. In this experiment, ten wheat varieties were used as material and were seeded in the containers on Dec. 1. 1958. The soil temperatures were adjusted with constant temperature tanks at 11°C and 6°C respectively from Jan.10 to Mar. 2. The results were as follows : 1. The rate of emergence of the leaves on main axis was promoted by the higher soil temperature, and the higher the grade of winter sowing habit of the variety was, the higher this grade of promotion was (Fig. 1). 2. The total leaf number on main axis was larger at 11°C and the grade of its increase was also correlated to the variety in the same way as that of emergence of leaves (Fig. 1). 3. The initiation time of ear primordia was hastened at 11°C and that grade was lower in the higher grade varieties of winter sowing habit (Table. 3). 4. The increase of shoots in winter season was promoted by 11°C treatment, but that in spring season was promoted by 6°C treatment, and these grades of increase were also related with the grade of winter sowing habit (Fig. 2)

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In the previous papers, the authors have reported some interesting results concerning the correlation between growth of the leaves and development of the roots at the successive nodes in the rice plants and in the wheats. In this experiment with Zea mays L., the authors studied again on the correlation described in the previous papers. 1. Period of the leaf elongation in the Zea mays L. was shorter than that in the rice plants. This might possibly be due mainly to the numerous leaves of the main stem and short vegetation period. Five to six leaves were elongating together at the same time in a given period of the growth. 2. The nodal roots of a certain node shooted during the two leaves of the main stem emerged from under-nodes to upper ones in the Zea mays L.. 3. Therefore the upper the nodes and the roots were located, the more fresh, numerous and the bigger they were. 4. The authors considered that such correlation (mentioned above) between leaves and roots in the cereals may be ascribed to the development of the node

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1) The diurnal variation of the NH₄-N absorption was observed especially in relation to the sunshine. It was found that the maximum absorption occurred at the 18∼22 hour period and minimum at the 2∼6 or the 6∼10 hour period. When the time lag between the beginning of the sunshine and the beginning of the NH₄-N absorption was observed, it was found to be about 6hours. It seems that this is because it takes time before the carbohydrate produced iu the leaves begins to benefit the nourishment absorbing function of the root. A clear explanation can be obtained when the diurnal variation is considered in this light. 2) Which shading treatment af different periods of growth influenced the growth and yield of wheat and barley most was observed. It was found that shading at different periods did damage to the yield in different degrees and that the structure of decreased yield varied. The yield decreased by the shading at the period when successful panicles appeared because the number of panicles decreased and at the period of the developing and maturing of the reproductive organ because the number of the grains decreased due to the hindrance in the ripening process. It may be added that there was a certain period when no harm by shading was observed and when greater yield could be expected by checking the unsuccessful panicles

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"Benihomare" in an excellent variety for making black tea. It grows quite well during young plant, but after ten years or so when it is full grown, it is often attacked by "Edagare" disease, by which its branches are withered. On investigating the causes of this disease, the following facts have been discovered : 1) The amount of transpired water surpassing the amount of water absorbed by its rootlets. 2) This happend because of the following two facts (a) the respiratory trouble of the root and (b) the low temperature of the soil. 3) In consequence of this unbalance of water in the plant body. The tracheid turns into vessel and the transpiration from the surface of the leaves becomes so free that more supply of water is naturally required. The rootlets, being unable to meet this demand of water, the branches begin to wither. Thus "Edagare" disease appears

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A portable soft X-ray apparatus was devised for the field observation of crop plants. This apparatus can be used for the internal diagnosis of crop plants through radiographs. For instance, the successive observation can be performed on the young ears surrounded by leaves and on the grains or seeds in glumes or pods. This apparatus can be successfully used in observing the effect of day-length or temperature treatment on the growth and in inspecting the internal defects of crop plants

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The experiments on the effects of blooming and ripening states of Upland cotton (Kanno No.1) on the numbers of convolution in cotton fibre of bolls arranged at vertical position were conducted by varying the sowing dates from May 7 to July 5 at 15 days intervals. The results obtained were as follows; 1) The numbers of convolution tend to decrease as the sowing dates are later and the ripening days become longer, but at later sowing after June they become constant regardless of vertical positions or of ripening days. 2) In the cotton fibres with ripening days more than 74∼78 days, the numbers slowly decrease in May 7 sowing but take a constant value (20) in May 22 sowing. 3) In the fibre required 74∼78 days for ripening, the average accumulated temperatures per day for cell-wall thickning were calculated as about 19.5 °C, and this is minimum temperature required to the secondary thickning of cellulose of cotton fibre. 4) The changes of the numbers of convolution do not coincide with our presumption even under optimum conditions except May 7 sowing with normal chang. So, we assume that the cell-wall thickning of cotton fibres is more directly affected by vegetative growth of plant itself than temperature. Then, the early sowing is preferable for the increase of the numbers of convolution because of it will bring about the complete vegetative development of cotton plant

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This paper presents the study of the seasonal variation of percentage of oil yield of Pelargonium and the relations of its external as well as internal environments and the influential elements of the variation. The material used in the test was P. roseum "France" and the analyses of the elements was made from the data compiled during the period from 1956 to 1958. 1) In seasonal fluctuations of the percentage of oil the air temperature was the prime controlling influential factor, and the humidity and the amount of solar radiation was secondary (Fig. 1, Table 1). 2) Between seasonal and leaf age variations of the percentage of oil and the air temperature there existed a high positive correlation coefficient. To state further the characteristics : 【○!a】 The percentage of oil of the young leaf had a higher correlation coefficient than the old leaf and was more sensitive to the air temperature than the latter. 【○!b】 The percentage of oil during the period from May to August was more sensitive to the variation of the air temperature in comparison with that during the period from September to November. 【○!c】The percentage of oil during the period from 0ctober to November was somewhat higher than that during the period from May to June irrespective of generally higher temperature during the latter period. The cause of this phenomenon was presumed that the secondary influential elements aforesaid, that is humidity, rainfall, number of hours of sunshine, etc. gave favourable conditions to the secretory function of essential oil(Table 2 & 3, Fig. 2). 3) Between the rise of air temperature and the percentage of oil there existed a parabolic relation and it reached the highest limit at the temperature from 28 to 29°C (temp. at 9 a.m.) and higher temperatures caused decrease of the percentage of oil yield (Fig. 4). 4) Appropriate fertilizers, soil moisture, soil pH, etc. were effective in increasing yield of grass, but no significant effect was found for increasing the percentage oil yield. 5) The result of the study of the relations among the plant age, the duration of nursing and the percentage of oil showed that there was no difference, but about equal percentage of oil yield for the same period (Fig. 5∼8). From the foregoing analyses the important factors influencing the percentage of oil yield were to be concluded as the atmospheric elements. The biochemical mechanism relating to the fluctuation of oil yield are now under study

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With the advancement of the age potato seed tubers, the sprouting and growing processes hastens with decreasing productivity. Therefore, it is of vital importance to get high and profitable yield to plant seed tubers with suitable age. Off aged seed tubers result in the so-called runing-out which lowers the yields extraordinally. Suitable age of seed tubers is assumed to be 2∼5 months depending upon the varietal characteristics and cultural purposes. The earlier in maturity and shorter in rest the varieties were the lower in age and reverse for late varieties. For early crops high age is preferable, while for the main crops the lower age is better. Contributions from the Laboratory of Plant Breeding, Hyogo Agr. College. No. 35

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The growth and yields of upland rice and soybean plants affected by irrigation, deep plowing, heavy manuring and these assorted treatments were investigated, 1955∼1958, at the Kikyogahara Experiment farm. The results were summarized as follows: 1) The influences of these treatments, on the heading or flowering and maturity, were not so remarkable. But only the maturity of soybean plants was delayed by irrigation when heavy rainfall in the late growing season and hastened by irrigation when low rain fall in the season. 2) The roots of upland rice and soybean plants were lengthened by deep plowing and heavy manuring, and shortened by irrigation. 3) 0n the upland rice plants, genarally, each of these treatments increased length of culm and ear, number of ears, percentage of ripend grains and weight of 1OOO grains. On the soybean plants, each of these treatments increased length of stem, total number of nods, fertile pods and fertile grains per plant. Especially, the irrigation was most effective. In these treatments, the effects of a treatment were more remarkable by using together with other treatments. 4) Accordingly, it was recognized that there was interaction among these treatments on the yields of upland rice and soybean plants. The effects of irrigation and deep plowing on soybean plants were not so striking as those of upland rice plants

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After-ripened (awakend from dormancy) spikelets of D. adscdndens were placed in a germinating bed at 30°C; after five hours they absorbed an amount of water, 25 per cent of their initial weight; after 20 hours; 42 percent; and after 60 hours, 45 percent; then started to germinate. Dormant spikelets absorbed a smaller amount of water than the after-ripened ones and did not germinate. The removal of the enclosing structure (glumes and shell coat) of the after-ripened spikelets promoted their germination. The enclosing structure of the spikelets having great water holding capacity absorbed water rapidly when placed in the germinating bed, thus it inhibited the water absorption of the embryo; being closely related with the germination of the spikelets. In the methylen blue and iodine tests, these substances penetrated into the embryo end of the caryopsis via the funiculus, and spread further laterally and distally. The staining speed ofthe caryopsis of the spikelet soaked in methyen blue solution was slower than that of the caryopsis which was soaked in the solution after the removal of the enclosing structure of the spikelet (Fig. 1). In the iodine test, the inhibiting power of the enclosing structure of the spikelets on the absorption of iodine water was stronger in the dormant stage, and became weaker with the increase in the length of storage period, and at last an easy absorption was followed. As to the spikelet stored for 172days after the havest, being immersed in a iodine water and after that examined the colour of its caryopis by removing the enclosing structure, it was found that the iodine translocated mainly through the funiclus into the embryo end of the caryopsis and then moved distally (Fig. 2). However in the case of the spikelet stored for 350 days, both the distal and embryo ends of the caryopsis were stained by the iodine, especially the former was far darker. Seemingly between the palea and lemma at the distal end of the spikelet of about this age a crevice was made and through which the entry of iodine water into the caryopsis was permitted. Rice spikelets stored for 271 days were coated by paraffin, in various ways so that differnt regions of the spikelets were exposed, and were soaked in P³² solution. It was found that P³² scarcely entered through the general surface of the spikelet but entered to a small dgree through the line where the palea and lemma layers overlap. But P³² entered mainly via the rachilla and funiculus into the embryo end of the caryopsis, whence it spread laterally and distally (Table 1). But when only a very little part of the distal end of the enclosing structure was exposed, the iodine penetrated only through the exposed part and spread to the embryo end (Table 2). In the iodine test, this substance was absorbed from the embryo end or distal end of caryopsis, and first diffused to the some cell layers existing inside of the seed covering, and then spread gradually into the central part of caryopsis. And in the P³² test it seemed that P³² distributed also at outer part of caryopsis as soon as is was absorbed, because there was little difference of P³² counts among 3 parts of the caryopsis namely embryo end, distal end and remaining portion (Table 2). From the results above mentioned it will be concluded that the enclosing structure absorbes water and other water soluble substanses rapidly, preventing their penetration into the direction of the embryo by storing them. Thus the enclosing structure controls the dormancy of the embryo and the germination of the spikelets. On the other hand, besides the physical protection to the caryopsis the enclosing structure is effective to determine the passage way of the water and other substances to the embryo and thus to protect the embryo from attack by microrganisms. [the rest omitted]

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In this study about the weeds on arable lahd in Japan, the following five groups were suggested from their present geographical range, though it must be admitted that we cannot show their origin exactly. The historical consideration has also been given in this paper. 1) The recently naturalized plants have been introduced in recent year. 2) The old naturalized plants were introduced from Europe or Eurasia through China in the early stage of history. 3) Cosmopolitan. 4) The prehistoric naturalized plants were introduced from Central and South China in ancient times. 5) Native species. 1) The recently naturalized weeds on upland field : 27 species were originated from Europe, and some of the most important are as follows; Senecio vulgaris, Veronica arvensis, Cerastium visosum, Rumex Acetosella, Festuca Myuros, etc.; 5 from Eurasia, Veronica persica, etc.; 9 from Nouth America, Erigeron annuus, E. canadensis, Euphorbia supina, Oxalis Martiana, etc.; 6 from New Tropical regions or South America, Oenothera odorata, Amaranthus retroflexus, etc. 2) The old naturarized weeds: 8 species were originated from Europe. Sonchus brachyotis, Vicia sepium, V. tetrasperma, Stellaria neglecta. Polygonum nodosum, P. Persicaria, Poa annua and Polygonum lapathifolium. All these species are upland field weeds, except the latter one which is paddy field weeds. 25 species were originated from Eurasia, among them Galium spurium, Elsholtzia patrini, Lamium amplexicaule, Capsella Bursa-pastoris, Chenopodium album, etc., are in upland field, whereas the following 13 species are in paddy field, Elatine triandra, Cardamine flexuosa, Ranunculus sceleratus and the others. 3) The species of old world origin or Cosmopolitan; 27 species on upland are Stellaria aquatica, Bulbosylis barbata, Digitaris adscendens, Equisetum arvense, 0xalis corniculata, Portulaca oleracea, Amaranthus ascendens, Polygonum aviculare, etc.: 26 are found in paddy field, among them there are Bidens tripartita, MyrioPhyllum verticillatum, Nasturium palustre, Eleocharis acicularis, Hydrocharis asistica, Ceratophyllum demersum, Najas marina, etc. 4) The prehistoric naturalized species: They are originated from South eastern Asia and especially interesting because these weeds are attendant on rice plants. Among them, Eclipta alba, Dopatorium junceum, Lindernia angustifolia, L. Pyxidaria, Limnophila sesseliflora, Ludwigia prostriat, Rotala indica, Monochoria vaginalis, Eriocaulon sieboltianum, Cyperus diffomis, C. Iria, Fimbristylis miliacea, Echinochloa crus-galli var. oryzicola. etc. are most important. 5) The Japanese native species; there are endemic species and the mutual common species in Japan, Korea, China, or Siberia, etc. The former contains only two species; Pleioblastus spp. and Sagittaria Aginashi. The latter would be perhaps the native species in those days when Japanese archipelago was detached from the continent (the last part of Diluvial epoch or the early years of the Allucual epoch) The native species which can be seen in Eastern as well as Northeastern Asiatic continent are amounted about 130 species on upland field and about 90 on paddy field. The most species, however, are slightly harmuful weeds, i.e., they are grown on the bordering foot-path or in the edge of irrigation ditches. A few species are noxious. As mentioned above, most of the troublesome weeds in Japan were found among the foreign species

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The effects of irrigation, fertilization and inoculation on the nodule formation of Vigna plants in a sand dune were studied during 1955-'59. The results obtained may be summarized as follows : (1) The amount of leaves, branches and roots were increased by fertilizing, and they were also considerably enlarged by irrigation. (2) There were signifficant differences on the nodule formation between fertilized plots and non-fertilized ones as well as between heavily irrigated plots and slightly irrigated ones. (3) The effects of inoculation on the nodule formation were not recognized without applying fertilizers. (4) Fertilization, irrigation and inoculation in the sand dune not only make the plants vigorsus in growth, but also favour the nodule formation, resulting in increasing the amount of nitrogen fixed from the air. Thus, they are considered to serve to increase the soil productivity in the sand dune

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