This study is one of the serial experiments for practical use conducted based upon the characters of rice yield-components per panicle within a hill arranged in the order of culm length for the purpose to estimate the paddy rice yields and the yield-components per hill through the simplified survey method by using a few samples. This test was attempted in order to bring about the results more accurately than ever before and in order to devise a practical and simplified survey method which may serve well in the rice yield forecast before ripening period. Test samples were arranged in order of culm length per hill, and the yield-components, i. e., the total number of spikelets, percentage of ripe grains and 1, 000 ripe grains weight were measured according to the panicles. The test results obtained are summarized as follows: The total number of spikelets, percentage of ripe grains and 1, 000 ripe grains weight per panicle in the same order of culm length are represented in the form of a monomial distribution. Relation between the total number of spikelets per panicle and the order of culm length is represented in the form of the primary or secondary orthogonal regression. Relation of the percentage of ripe grains and 1, 000 ripe grains weight to the order of culm length can be represented in the form of a zero-order regression as a rule, but the zero-order regression seems to be subjected to change into the form of other regressions by the effect of environmental conditions.

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In the previous paper (report 15), it was reported that the rice yield-components per hill in the order of culm length could be represented in the from of a zero-order, primary or curvilinear regression. The present report refers to the fact that the positions of the selected panicles in the order of culm length which may serve as a basis for estimating the rice yield-components per hill can be calculated by using the above-mentioned regression equation. The results of our calculation are as follows; [table] The positions of the selected panicles in the order of culm length vary according to the number of panicles per hill. Relation between the rank of the selected panicles in culm length and the rice yield-components per panicle arouses the greatest interest in our serial experiments. No significant difference was found in the mean value between the hill and the selected panicles in pairs surveyed through the simplified method. Based upon the results of present experiment, it can be concluded that the rice yield-components per hill can be estimated well using the simplified survey of the selected panicles in pairs.

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Nagato And Kono have experimented the Changes in the distribution of hardness of rice of various types (Type Ia, Type IIc, Type IId, and Type IIe) according to starch cellular tissues. We also attempted, by using the samples cited below, to clarify the differences in the process of cooking the brown and white rice of Types I and II by heating over hot water of by heating with ordinary cooking methods. In order to find out the changes of sample rice into cooked rice, authors took microphotographs of 28 magnifications by employing the so-called "Sump" printing method. Test samples: Type Ia: Foreign rice variety (Denurado) Type IIc: Domestic semi-soft rice varieties (Norin No. 22, Honen-wase) Type IId: Domestic soft rice variety (Otsune-bozu, a scented rice) Type IIe: Domestic ultra-soft rice varieties (Karasu and Hieri) Test results: (1) In both cases of brown rice and white rice, Type Ia rice was slowest in cooking when cooked by heating, and Type II group rice were quick in cooking in the order of Type IIc, Type IId and Type IIe. When cooked in an electric rice cooker prevailing now widely in the country, the standard time for cooking regular white rice showed somewhat shorter for cooking Type Ia rice, while too longer for cooking Type IIe rice. (2) Even in the cases of rice of rice of the same type, the changes of brown rice into cooked rice by heating over hot water were not always coincident with the changes of white rice by heating with ordinary cooking methods. Particularly great disparity in the changes was found in the case of Type IIe white rice. Namely, by 20 minutes' heating, the changes in Type IIe white rice took place more slowly or as quickly as the changes in Type Ia or Type IIc rice, but by 30 minutes' heating-immediately before completion of cooking-the changes of white rice to become pasty and swollen took place quickly in particular, while in the case of brown rice, the aforesaid distinction could not be found clearly. (3) Type Ia foreign rice variety began to become pasty and swollen from the peripheral part of grains, but in the case of cell groups which have developed fully in ever part. most of them remained still unswollen. (4) Grains of Types IIc and IId rice began to become pasty and swollen from their peripheral parts followed by these parts in the order: starch cells along the longitudinal line (running through the back and abdominal parts), the central parts of grains, and the middle parts of grains making a right angle with the longitudinal line; thus, completing the cooking process. (5) In the case of Type IIe ultra-soft rice varieties, particularly some scented rice, at the beginning of cooking process by heating, the changes took place as quickly as or rather little more slowly than the changes in Type Ia and Type IIc rice, but after that the former changed into cooked rice very quickly, and that the grains of the former burst open in every direction just like a popcorn, though those of the latter stretched out only. From the above test results, it can be concluded that the changes in the distribution of hardness of each type of rice according to starch cellular tissues found by Nagato and Kono coincided well with the differences in the process of cooking white rice we found out.

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1. A field test was carried out to clarify the effects of cutting intervals on the regrowing ability of Ladino clover after cutting in the warm area. Two treatments of cutting intervals, cuttings at 15-day intervals and at 30-day intervals, were given from April, and Ladino clover growing in community was tested on dry matter basis about three seasons; June, August and October. 2. Both plant height and dry matter production of Ladino clover were affected by cutting intervals, being higher at the 30-day intervals plot than at the 15-day intervals plot, arid at every seasonal investigation such effects on the regrowth could be recognized from about ten days after cutting. A ratio of leaves to total plant on dry matter weight was always higher at the 15-day intervals plot and the difference between the two plots became larger as cutting treatments were repeated showing to be the largest in October. As to an increasing rate of green leaf number, it wad higher at the 30-day intervals plot in case of October and folioles were longer as well. 3. At every seasonal investigation the 30-day intervals plot was superior to the 15-day intervals plot in an increasing rate of LAI after cutting and in its maximum value. Therefore, a decreasing rate of relative luminous intensity on the soil surface under Ladino clover community after cutting was larger in the 30-day intervals plot. In the correlation between LAI and relative luminous intensity, slopes of the regression lines differed according to cutting intervals, and from this fact it was inferred that some changes in the form of Ladino clover community might have been brought by varying its cutting intervals. 4. In each season a significant negative correlation was found at the level of 1 % between NAR and LAI and the regression. coefficient was varied according to cumulative frequency of cutting. In June when Ladino clover grew vigorously and had, not been subjected to cuttings so often, the 15-day intervals was superior to the 30-day intervals in an increasing rate of CGR and in its absolute value. On the contrary, in August and in October when the plant had suffered from repeated cutting treatments and its growth was not so vigorous under unfavorable surrounding conditions, the 30-day intervals was superior. 5. Carbohydrate contents in the tip of runners. (part between first node and third one) decreased rapidly immediately after cutting, but regained in about 25 days after cutting. In this case, Ladino clover in the 30-day intervals plot showed more rapid regaining and it accumulated more amount of carbohydrate in runners, compared with that of the 15-day intervals plot. 6. Choice of suitable cutting time of Ladino clover should be judged, not only from the apparent status of the growth but also from the consideration of the regrowing ability after cutting. In this test, cutting of the 30-day intervals was superior in productivity to that of the 15-day intervals, with higher assimilation and storing abilities of carbohydrate.

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Fertilization of polar nuclei with a male nucleus completed within 5 hours after anthesis at temperature of 28°C to 31°C. The endosperm primary nucleus thus formed began the first division without rest stage, while the zygote took about 10 hours' rest. By the 3rd day, a multi-nucleate layer of endosperm was formed in the, periphery of the embryosac cavity (Figs. 1, 9 and 10). On the 4th day, cell membrane formation occurred at first from the embryonic end and extended to the entire of the peripheral tissue. Coincidently, all the cells divided inwards, thus forming two-celled layers' endosperm (Fig. 11). From the 5th day onward, the development of the endosperm tissue was observed by the increment of cell layers and their cell numbers in the cross section in the middle part and in the longitudinal section of a caryopsis. A possible explanation of this development process was tried to be given by following the GORDON's theory that "the development of cereal endosperm can be attained exclusively by the division of the cells in the outermost cell layer". Ranging over the 4th to the 5th day, cells of the outermost layer (4-1) might have repeated periclinal divisions, thus forming 3 cell layers (5-1, -2, and -3), and at the same time, half the number of the layer (4-1) divided in a circumferential direction, . and the remaining half in a longitudinal direction. The cell layers which have been formed by The 4th day (4-2 and -3) were squeezed into the central portion of the embryosac cavity and folded. As a result, the folded cell layers came to be arranged in numerous concentric circular cell layers (5-4, -5…-11) surrounding the respective central point (Fig. 16). About 32, 000 cells were counted throughout the entire tissue of the 5th day's endosperm. Ranging, over the 5th to 6th day, the outermost layer (5-1) might have divided inward 3 times and added 3 layers (6-1, -2, and -3) to the outside of the 5th day's tissue, and on the other hand, the layer (5-1) divided once in a circumferential direction, but not in a longitudinal direction. Ranging oyer the 6th to 7th day, it showed the increment of 2 cell layers (7-1 and -2) in a radius direction, and half the number of the layer (6-1) might have divided in a circumferential direction. Total number of the cells reached 95, 400 (Fig. 14). Extending over the 7th to 8th day, 2 cell layers increased in a radius direction, and the half of the layer (7-1) divided in a longitudinal direction. Extending over the 8th to 9th day, the last division of the layer (8-1) occurred in a radius direction. Thus 19 to 20 cell layers were formed in the dorsal radius, 15 to 16 cell layers in the ventral radius and 13 to 14 cell layers in the lateral radius (or central point to side surface of endosperm). (Fig. 15). The endosperm cells formed amounted approximately to 180, 000 in the aggregate. From the 10th day on, no increase was found in the number of cells. Increment in the number of endosperm cells has continued after the stage where the embryosac cavity had been filled up with endosperm tissue. Nay, it was clarified that the increase in the number of cells was rather markedly in the later; stages (Table 2). It was observed that the development of endosperm tissue formation was actuated, from the incipient stage of nucleus, in the dorsal side somewhat earlier than in the ventral side (Figs. 9, 10, and 11). This fact may be related to the observation that the antipodal tissue developed for the 3 days after fertilization and then degenerated (Figs. 4, 5, 6, 7 and 10).

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In the course of an investigation to know the reliable estimate of resistance of wheat varieties to scab, it was found that a given floret of a wheat head could be successfully inoculated by the improved method in the out-or indoor experiment. The improved method of inoculation was done as follows; 1. Clip off the wan from all of the spikelets of a wheat head. 2. Remove the immature grain from the floret to be inoculated. 3. Two little holes were pricked with a pin in the outer glume and inoculate with scac. 4. Put a small amount of boiled spinach leaves, as nutrient of scab, between the inner and outer glumes of the inoculated floret. 5. Wrap the treated head with wrap film. 6. Keep the plant thus treated at 20∼25°C. This improved method was expected to be of use for the systematic and reliable comparison among the varietal responses to scab. The reason was that the scab lesion, if only the terminal spikelet was inoculated, was assumed to spread downward to various distance depending upon the varietal responses. But the degree of lesion from the artificial inoculation did not always coincide with the degree of damage received in the field by unknown reason, which must be clarified by the future works.

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The previous report (vid. Proc. Crop Sci. Japan. Vol.35: 3.4) revealed that any floret of a wheat head can be infected by the improved method of inoculation, though no agreement was observed between the spread of scab lesion and the degree of damage in the field. In this study, it was attempted to inoculate scab onto the rachis, using several varieties resistant and susceptible to scab, to know whether or not the degree of lesion by the artificial inoculation reflects the varietal response. The rachis could be inoculated with success by the following way. 1. Two little holes are pricked with a pin in a segment of a rachis from which all the spikelets had been removed. 2. The treated segment is inoculated with scab and wound with a piece (7×20 mm) of a boiled spinach leaf. 3. The inoculated rachis is wrapped with wrap film all over the length. 4. The treated plant is kept at 20∼25°C. In this case it must be noted that the number of segment in a rachis was limited to 12∼13 and only the terminal segment was inoculated, for the convenience of comparison of varietal responses. Negative results were obtained as in the case of inoculation onto head, that is, the degree of lesion by the artificial inoculation was not always in parallel with the degree of damage in natural conditions.

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According to the previous reported line (2, 3, 4), studies on the varietal differences in morphological characteristics of rice were carried out. In this paper, a morphological characteristic was estimated by principal component analysis using all the data of three plant-spacings at high-nitrogen level and non-nitrogen level. The result at standard nitrogen level was already reported in the previous paper (4). The present results Were as follows: (1) A morphological characteristic of each variety at each nitrogen level can be shown by two principal components which are indices of the morphological characteristic. These indices were as follows: High-nitrogen level: X₁= 0.445x₁+0.314x₂+0.288x₃+0.361x₄+0.500x₅+0.490x₆, X₂= -0.339x₁+0.422x₂+0.638x₃+0.529x₄-0.056x₅-0.131x₆, Non-nitrogen level: X₁= 0.462x₁+0.262x₂+0.273x₃+0.341x₄+0.531x₅+0.514x₆, X₂= -0.306x₁+0.515x₂+0.585x₃+0.538x₄-0.053x₅-0.078x₆ (2) The meaning of these indices was not changed by the levels of nitrogen application, even if the result of previous report (4) was considered together. The first index is concerned chiefly with the yield of an individual plant, and the second index is concerned chiefly with the plant type whether it is a long culm, heavy panicle one, or a short culm, high tillering one. (3) The plant type showed by the second index varied with plant-spacing at each nitrogen level, and these variations could be classified into three types as mentioned in the previous paper (4).

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In this paper, studies on the varietal differences of a morphological characteristic of rice variety were carried out considering all plant-spacings and nitrogen levels together. The present results were as follows: (1) The morphological characteristic of rice variety could be shown by two principal components which were indices of the morphological characteristic. X₁= 0.459x₁+0.186x₂+0.309x₃+0.374x₄+0.515x₅+0.505x₆, X₂= -0.391x₁+0.300x₂+0.645x₃+0.536x₄-0.136x₅-0.187x₆ (2) The meaning of these indices was entirely the same as in the previous papers (4, 5), and the first index was concerned chiefly with the yield of an individual plant. The second index was concerned chiefly with the plant type whether it is a long culm, heavy panicle one, or short culm, high tillering one. (3) The plant type showed by second index varied with plant-spacings at each nitrogen level, and these variations can be classified in to three types as mentioned in the previous papers (4, 5). At the same time, the plant type varied with nitrogen level at each plant-spacing, and in these variations several pattern can be seen as given at the figure in page 184.

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The experiments conducted up to the present day revealed that spraying on the leaves of field-grown tobacco with a solution of transpiration suppressants resulted in the advancement of leaf quality and reduction of nicotine content. The nicotine content in the sprayed leaves is estimated 10-30% lower than that in the non-sprayed ones. Following experiments were con-ducted to find out the cause of the reduction of nicotine content. The leaves of tobacco grown on the field were primed at different 3 ripe stages : immature, mature and overmature stage : after upper and lower surfaces of a half of the leaves Were sprayed immediately after the topping with a solution of a transpiration suppressant. Comparison of nicotine content between the fresh and dry leaves of the non-sprayed and the sprayed leaves showed that the reduction of nicotine content chiefly occured after the leaves attained to mature stage. The reduction of nicotine content in the mature leaves could be detected not only in the sprayed leaves but also in the non-sprayed ones. It is a well known fact in Japan that mulberry leaves which have been stained by evaporated nicotine from the neighboring tobacco field often gives a poisonous influence on the silkworm. The next experiment indicated that, in the leaves which had been kept in N₂, much loss of nicotine occurred during the incubation period or after drying of the leaves, whereas, in the other leaves treated with O₂, only slight decrease could be detected. The author ascertained, in the other experiment, that the leaves which had been kept in CO₂ exhibited higher free nicotine to total nicotine ratio than those which had been kept in the air. Free nicotine is known to be easily evaporated than compound ones. Thus it is probable that the production of free nicotine has an intimate connection with the O₂ starvation, in the inner systems of the leaf and the reduction of the content with it's evaporation from the surface of fresh or drying leaves. The loss of nicotine from the non-sprayed leaves might presumably be caused by the O₂ starvation due to stomata closure which customally observed after the leaves attained to mature stage. In the sprayed leaves, the surface of the mature leaves with closed stomata would bb covered with the film of the transpiration suppressant. As such a condition of the leaves will prevent the exchange of air efficiently, an advanced O₂ starvation would be resulted. This, in turn, will work toward the production of the leaves with lower nicotine levels than those in the non-sprayed ones.

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Lodging is one of the most serious injuries of the. grain production of wheat and barley. Though a lot of experiments concerned with this phenomenon have been reported, most of them have dealt with strength of culms, and few of them with. environmental factors causing lodging. This series of studies was made to make clear the effects of environment, especially wind and rain, on lodging of wheat and barley plants. A mobile wind tunnel which was able to be moved in fields (Fig. 1) was constructed for this purpose. Preliminary tests were made to determine the way of treatment with this wind tunnel. Eight varieties of wheat and barley were used for these tests, and the measurements of wind velocity in the wind tunnel were simultaneously made. Plants grown in pots were carried into the wind tunnel with wind velocities of 9 and 13 m/sec for 10 and 20 min. Inclined angles of culms during and after the treatments were measured to determine the lodging resistance of varieties. Results obtained are as follows: 1. Distribution curves of wind velocities in the wind tunnel were obtained (Fig. 2 and 3), and favorable place in the wind tunnel for the test were made clear. 2. Inclined angle during wind treatment varied with varieties (Fig. 4), and the variation of lodging resistance in field agreed with this tendency. 3. Lodging resistance was in best accord with the ratio of recovered angle after treatment to inclined angle during treatment (Table 2). 4. Stiffness of culms did not always agree with lodging resistance (Table 2).

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Wind is one of the most important factors which cause lodging. This paper mainly deals with the effect of wind on lodging. Inclined angles and the rates of lodged culms of variously treated plants, such as thinned and leaf- or ear-removed, were measured in a mobile wind tunnel blowing 15m/sec of wind velocity. The measurement of drag force by wind were made with a drag meter (Fig. 1) in the wind tunnel. Winds over wheat and barley fields were observed by small cup anemometers. The shear stress which plant surfaces exerted on wind was calculated by aerodynamical method. Results obtained are as follows: 1. Wind treatment (15 m/sec, 1 hr) were caused lodging. Sekitori-sai no. 1 (barley) lodged because of culm breaking, and Norin no. 61 (wheat) because of culm breaking and bending (Table 1). 2. Lodging was increased by thinning treatment, and the contributions of, various organs of barley to drag force were different from those of wheat, that is, leaves was 20 %, ear 50 % and culm 30 % in barley, and leaved wad 30 %, ear 10 % and culm 60 % in wheat. 3. Both total drag force and the force of unit silhouette area exerted on Hagane-mugi (barley) were higher than those on Norin no. 61 (wheat), because of higher values of silhouette area and drag coefficient (Fig. 2, 4 and 5). Total drag force was related to the third power of wind velocity (Eq. 8), and the force of unit silhouette area was to the second power of wind velocity (Eq. 6) both in the case of wheat and barley. 4. The shear stress obtained by observations of wind was different from the drag force obtained by wind tunnel experiments. But the tendency of the shear stress reported here was in good accord with that of rice fields described by Tani (Fig. 9). 5. It is considered that the discrepancy between the drag force and the shear stress needs further experiments under field and laboratory conditions, and Reynold's similarity theory could afford to solve this problem.

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The drag forte exerted on plant by wind is a fundamantal force for the lodging of plants. The authors previously reported the relationship between the force and wind velocity. This paper deals with varietal difference of the force. Nine barley and four wheat varieties were used as materials. Plants were grown in bots (barely) and in field (wheat), and the latter were transplanted in pots before the measurement of drag force in a wind tunnel. Four experiments were made to measure the force using whole and leaf- or ear-removed plants, and the fifth one was made using detached culm with or without flag leaf and ear. Results obtained are as follows: 1. The drag force exerted on a whole plant varied with varieties, and the force on each organ also. varied (fig. 1). 2. The difference of the drag force on a whole plant seemed to be due to the difference of the force on leaves in barley varieties and of the force on culms in wheat varieties. 3. The tendency of the force of varieties obtained by detached culms agreed with the force obtained by whole plants (fig. 3). 4. The drag force on leaves was closely related to leaf area, and drag coefficient (of leaves) to bending rigidity of leaves which was considered to be related to leaf flattering. 5. It is considered that total drag force on plants consists of silhouette area and drag coefficient. The extent of the former might be due to the size of plants and bending rigidity of culms, and the latter to the roughness of plant surface and flattering of plants. 6. It could not be found that drag force was related to the strength of culms (fig. 5).

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Lodging of wheat and barley plants is regarded to be directly due to wind and rain. Wind forces exerted on plants or plant canopies were determined by mobile wind tunnel and measurement method of wind velocities over fields in previous papers. This paper deals with the influence of rainfall on lodging. Experiments with artificial rain and observations of rain and lodging in fields were made during ripening stage of wheat and barley plants in 1963 and 1964. Rainfall was supposed to affect lodging by increasing fresh weight of plants through wetting their surface, and increasing inclined angle of culms with kinetic energy of rain drops. Results obtained by artificial rainfall treatment indicated that lodging was caused by rain especially in case of weak wind (about 3 m/sec) when plant surface was fully wetted, and higher rainfall intensity led to heavier lodging both in field and isolated tiller. It was concluded from the results of observations of rain and lodging of plants that the lowest precipitation which caused lodging was about 3 mm, and no relationship was established between rainfall intensity and lodging. This was due to the fact that lodging was so often because of repeated rain in 1963. Results obtained by these experiments and observations seemed to support the above supposition concerned with influence of rainfall on lodging. Another influence of rainfall on lodging might be supposed, that is, rainfall would increase soil moisture and decrease soil hardness, resulting lower culm-support of soil. This will be discussed in a later paper.

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1) The present study was carried out in order to determine the differential effects of fog-culture (spray-culture) and water-culture on the growth of crops. The following crops were used in this experiment: wheat, tobacco, oats, broad bean, barley, Italian ryegrass, tomato, rice and sweet potato. 2) The growth of roots of all the crops was significantly more rapid in fog-culture than in water-culture. 3) The favorable effect of fog-culture on top growth was not clearly seen as in the case of root growth, but it was excellent in wheat, tomato and sweet potato. 4) The dry matter increment (g / plant / day) of tobacco, broad bean, tomato and sweet potato was significantly more in fog-culture than in water-culture. 5) The dry matter increment of root (g / plant / day) in fog-culture was significantly more than in water-culture, with wheat, oats broad bean, Italian ryegrass, tomato and sweet potato. 6) The top-root ratio of the plants grown in fog-culture was lower in comparison with those grown in water-culture in all the experimental crops with the exception of tobacco. 7) In general, the growth of wheat, tobacco, broad bean, tomato, sweet potato was more excellent in fog-culture than in water-culture, but the difference was not clear in rice.

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小麦農林27号または小麦農林4号を種々の温度周期の下で処理し, バーナリゼーション効果の差異について研究した。(1) 40日間毎日0℃または10℃で0～24時間, 18℃で残り時間処理した。毎日の低温処理時間の長短に応じてバーナリゼーショソ効果に差がみられた。(2) 夫々数日間の低温(0℃)処理と高温(20℃)処理とを低温処理日数の合計が所定日数に達する迄くり返した。低温処理または高温処理の連続日数が増加するに従いバーナリゼーション効果は減少し, 低温処理連続日数が10日内外の時処理効果の減少が顕著であった。しかしこのような処理連続日数の増加にともなうバーナリゼーション効果の減少は低温処理温度を10℃とした時または高温処理温度を15℃とした時には少なかった。以上の結果から低温でのバーナリゼーショシ処理が数日以上連続した場合, その処理効果は高温により消去され易くなるものと考えられる。

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In 1963, "Kanto two-rowed .Barley No. 2" crop was seeded on the upland farm of alluvial sandy-loam soil, and grown with usual cultural methods. Changes .in the size .and weight as well as in a few chemical components of barley kernels were traced at 5-day intervals after the full heading stage. The temperatures and sunlight intensity during the ripening period in the year were somewhat above in the normal. The results are given below. (1) Panicle weight was on a rapid increase for 30 days after full heading, but the increasing rate for the former 10 days was lower than that for the latter 20 days. Panicle weight increased slightly from the 30 th day after full heading up to the ripening stage. (2) Kernel length was on a very rapid increase for 10 days after full heading, but in the first half period the rate of elongation of kernels was higher. For the subsequent 5 days it increased, reaching a peak on about the 15 th day after full heading. After that almost no change in the length was observed. The width of kernels was on the increase up to about the 25 th day after full heading. Thereafter, it increased slightly up to the ripening stage. The thickness of kernels increased for the period from the 5 th day to the 35 th day after full heading, but the increasing rate was higher in the former half-period than in the latter half. Afterwards it continued. to show a slight increase up to the ripening stage. (3) The grains more than 2.5 mm in diameter began to appear from about the 20 th day after full heading. No. 1. grain ratio reached the standard value on about the 30th day to the 35 th day after full heading. (4) 1, 000 kernel weight showed a rapid increase from the 10 th days about the 30 th day after full heading, reaching a peak at about the stage between the 35 th day to the 40 th day after full heading. Thereafter, it decreased slightly. Almost similar trend was observed in respect of the kernel weight per liter. (5) Hull weight ratio showed a rapid decrease up to about the 20 th day after full heading. Thereafter, it decreased slightly, reaching the minimum on around the 35th day after full heading. (6) Crude-protein content showed a rapid decrease from about the 10 th day after full heading, reaching the minimum on about the 25th day after full heading. Thereafter, crude-protein content increased up to about the 40 th day after full heading and thence it showed a slight decrease again. (7) Starch value showed a rapid increase for 20 days from the 5 th day after full heading. Afterwards, it increased slightly. (8) Crude fat content increased slightly after full heading, reaching the maximum on about the 30th days after full heading. Thereafter, almost no change was observed. (9) Ash content decreased from around the 5 th days after full heading, reaching the minimum on about the 30 th day. Afterwards almost no change was observed. From the above results, it was evidenced that the ripened grains being about the 35 th day to the 40th day after full heading showed the highest yield and quality.

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ダイズの子実生産に対する各肥料要素の役割を明らかにするために, 自動灌漑礫耕装置を用いて, 開花期間中だけ主な肥料要素の各一つを欠除させた試験を行ない, 次の結果を得た. 1) 開花期間中NまたはCaの供給を中断すると, 生育が大きくおさえられ, 落花・落莢率が高まり, 子実生産も影響された. 各肥料要素の欠除で, 一般に地上部の生育が根の生育よりも大きく影響された. しかし, NとCa以外の要素欠除では生育や子実生産に対する影響は大きくなかった. 2) 処理によって, 欠除した要素の体内の含量, 含有率は大きく低下した. N欠除ではさらにCaとMgも低下した. 一般に成分的に大きく影響された器官は葉身と葉柄であった. 3) それぞれの要素の欠除状態にあるとき, N, Ca, Mgは対照区に比らべて根にとどまる割合が多く, PとKは地上部に配分される割合が高かった. 4) Ca含有率と落花・落莢率との間に高い負の相関が認められ, Caが莢の形成に重要な役割を持っていることが示された. すなわち, 低Caで落花・落莢が高まり, 粒数が減少し, これが子実生産に影響した. 5) 地上部栄養器官で, K, Ca, Mgの間に相補的な関係が認められ, これら要素の吸収と分布は相互に関係しあっていることが示された. 6) 要素欠除植物への欠除要素の葉面散布は, 多くの場合その含量, 含有率を高め, とくにCa欠除植物へのCa散布は子実生産に対するCa不足の悪影響を若干軽減した. しかし, N欠除植物へのN散布はかえって生育が抑えられ, 全粒重も軽く, Nの葉面散布を有効にするには一定の条件が必要であることが示唆された. 7) 開花期間中のK, MgまたはPの欠除で生育や子実生産への影響が小さかったのは, これら要素が体内で再移行し易いためと思われる. 一方NまたはCa欠除で影響が大きかったのは, これらがこの時期に多量に必要なことを示している. とくにCaは再移行しにくい形になることが欠除の影響を大きくしたと思われる.

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On the basis of the fact that the nitrogen content was negatively correlated with the starch content in rice plants, some trials had hitherto been conducted which had intended to diagnose the nitrogen requirement of rice plants at the panicle initiation stage by knowing the relative starch content which was easily known by the iodine reaction in leaf-sheaths. The authors, therefore, examined from 1958 to 1965 the relation between the nitrogen content and the starch content at the neck-node initiation stage (the initial stage of panicle differentiation) as well as the heading stage with a special view to evaluating the diagnosis of nitrogen requirement by iodine reaction as above mentioned. The results may be summarized as follows. 1. A high and positive correlation coefficient was always found between the starch content in the rice plant and the staining degree of a leaf-sheath by iodine solution. In particular, the strongest correlation was obtained when the third leaf-sheath counted from the uppermost developing leaf was used. 2. In cases of an identical variety being used and transplanted on an identical date under an identical season with different amounts of basic ferfilizers without top dressing, a strong and negative correlation coefficient was always found between the nitrogen content and the starch content in the rice plant. However, in case of varieties, transplanting dates, seasons and topi dressings being different, the correlation coefficients markedly decreased in most cases. 3. The nitrogen content seemed to be negatively correlated with the starch content in the rice plant by nature. The correlation coefficient between them, however, decreased markedly when the rice plant had been subjected to abnormal weather conditions or top-dressed with nitrogenous fertilizers just before the plant was sampled, presumably because the nitrogen content had not yet come to be balanced with the starch content in the plant. 4. The effect on yield of top-dressing at the panicle initiation stage had no connection with the content of nitrogen or starch in the plant at the neck-node initiation stage, but it was closely connected with the number of spikelets per unit area, i. e. the effect was progressively remarkable with the decrease in the number of spikelets. 5. Only in the following case one might decide, from the diagnosis by iodine reaction, the top-dressing at the panicle initiation stage to be necessary for the rice plant, i. e. only whenth e rice plant showed not only a severe iodine reaction but also a small amount, of nitrogen absorbed at the neck-node initiation stage and the plant could also be estimated to absorb a small amount of nitrogen during the period from the neck-node initiation stage to the final stage of spikelet initiation : in other words, only when the plant might be expected to have a small number of spikelets per unit area : and moreover the plant could be expected to be subjected to fine weather conditions after heading. Accordingly, the diagnosis by iodine reaction in the rice plant to judge the necessity of the top-dressing to the plant at the panicle initiation stage may be said to be of little utility value.

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1. Studies on the effects of gibberellin on the spikelet formation were carried out in 1965 and 1966 years, using a special variety of paddy rice "Akaho" which has a genetic character to manifest various abnormalities in spikelets even under the usual cultivating conditions. Gibberellin was applied at the stage just before the panicle differentiation, at the concentration of 100 ppm mixed in the nutrient solution. 2. The symptoms of abnormalities in the control spikelets varied considerably by year and the expression of genetic character on the spikelet formation was seemed to vary according to the environmental factors. 3. Since almost all kinds of the spikelet abnormalities were promoted by the treatment, the physiological conditions caused by the exogenous gibberellin were considered to be quite similar with those induced by the genetic factors concerned with the abnormal formation of spikelets. 4. Though the number of spikelet organs was increased as seen in other varieties, the development of primary branches and spikelets in a panicle was decreased remarkably by the treatment in "Akaho". The latter part of above results was different from what were obtained in the previous experiments on other varieties that every organs in the panicles had been promoted by the exogenous gibberellin. So, the optimum concentration of exogenous gibberellin should vary with the kind of organs or the varietal factors. 5. From the facts that the development of morphologically perfect stamens in a spikelet changes from two to eight in number by spikelet and the percentages of spikelets which have stamens more than or less than six in number increase conspicuously, the exogenous gibberellin is thought to make the physiological conditions very unstable and variable in a panicle by locus. 6. Frequent occurrence of the slightly feminish Intermediate organs and the increment of pistils per a spikelet in number give the impression that the exogenous gibberellin promotes the female tendency in "Akaho", making a rather contrast to that obtained from the previous experiments on other varieties. The above results indicate that the effect of gibberellin on the sex expression may not be specific to the male or female but vary with the internal and external factors. 7. Some considerations were tried on the development of intermediate organs and the appearance of multi-stigmatic pistils and several conflicting phenomena obtained in this and the previous studies were indicated deferring. the decision of the question to the future investigations.

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