The chemical composition of the seed of the genus Glycine was investigated on Glycine max (8 samples), G. gracilis (4 samples) and G. soja (7 samples) belonging to the subgenus Soja, and G. tabacina (3 samples) and G. tomentella (2 samples) belonging to the subgenus Glycine. On the chemical composition, characteristic differences between 2 subgenenus were observed, namely, the subgenus Soja was higher in protein and potassium content, and lower in carbohydrate and calcium content than the subgenus Glycine. In the subgenus Soja, the highest oil and potassium content and the lowest phosphorus and calcium content were observed in G. max, and the highest protein content and the lowest oil content were observed in G. soja. In the subgenus Glycine, however, the chemical composition, except calcium and magnesium was almost the same between G. tabacina and G. tomentella. Among the species, significant differenccs were observed in protein, oil, carbohydrate, potassium, and calcium content. Between chemical components, positive correlations were observed in the pairs of ash and potassium, phosphorus or magnesium content, potassium and phosphorus or magnesium content, and phosphorus and magnesium content. On the other hand, negative correlations were observed in the pairs of protein and carbohydrate content, oil and phosphorus content, and carbohydrate and potassium content.

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It is known that scented rice evolves peculiar flavor when it is cooked. As it was thought that scented rice might be useful for improving cooking quality of rice in aspect of flavor, the authors have been engaged in studying on the characteristics of scented rice. In this present paper, the sulfur-containing volatiles evolved from cooking rice of scented varieties (Otsune-bozu, K 10 and Shiroi-kichi, K 11) and ordinary one (Koganenishiki) were analyzed by two different gas chromatographs (FID and FPD). The results are summarized as follows: By a hydrogen flame ionization detector (FID), three sulfur-containing volatiles were identified as following compounds, viz. methyl mercaptan, dimethyl sulfide and dimethyl dlsulfide (Table 3 and 4). While by a flame photometric detector (FPD), five peaks on the chromatogram were recognized (Fig. 1) and identified as hydrogen sulfide (peak 1), methyl mercaptan (peak 2), dimethyl sulfide (peak 3), n-butyl mercaptan (peak 4) and dimethyl disulfide (peak 5) (Table 5). No qualitative differences in sulfur-containing volatile compounds in the head space were found between scented (Shiroi-kichi) and ordinary (Koganenishiki) rice varieties and also between hulled rice and milled one of the two varieties.

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The changes of light environment in crop canopies were investigated with four upland crops which were typical in the Kanto plain. And, the growth of competitive weeds was made clear clear, then we hypothesized about the period for weed-free maintenance after seeding required to escape crop yield reduction due to weeds. 1. The start of shading the surface of the ground by crop canopies after seeding was earliest in corn, but reduction of relative light intensity under crop was slow, and the degree of shading was small. The start of shading by soybean was a little late as compared with that of corn, but reduction of relative light intensity was rapid, and the degree of shading was large. The start of shading was the latest in peanut, but reduction of relative light intensity was the most rapid and the degree of shading was large as well as soybean. The characteristics of shading in upland rice were medium among these crops. 2. High negative correlation was found between logarithms of relative light intensity in the center of crop-rows on the surface of the ground and the number of days after seeding, then the regression lines were obtained. From these regression lines, the times when relative light intensity reduced under 20% were estimated, that is, about 76, 78, 63 and 71 days after seeding in upland rice, peanut, soybean and corn, respectively. And similarly, the times when reduced under 10%, were about 89, 86 and 73 days after seeding in upland rice, peanut and soybean, respectively. Reduction under 10% was not found in corn. 3. The linear regression was obtained between logarithms of relative light intensity in the center of crop-rows on the surface of the ground and LAI. From these regression lines, LAIs at the time when relative light intensity reduced under 20% or 10%, were estimated, that is, 4.9 or 6.6, 2.7 or 3.7, 2.3 or 3.3 and 5.2, in upland rice, peanut, soybean and corn, respectively. 4. At the time when relative light in the center of crop-rows on the surface of the ground reduced under 20% or 10%, the space of 40 or 30 cm-high from the surface of the ground in upland rice, 20 or 15 cm-high in peanut, 60 or 50 cm-high in soybean and 100 cm-high in corn kept the same value of relative light intensity, respectively. 5. In the early summer season when relative light intensitywas reduced by crop canopies, plant length or main stem length of weeds was 1-2, 7-13, 16-28, 39-52 cm in large crab-grass (Digitaria adscendens Henr.), 1-2, 6-12, 12-26, 20-43 cm in Chufa (Cyperus microiria Steud.), and 1>, 4-14, 9-25, 17-33 cm in common purslane (Portulaca oleracea L.)at 10, 20, 30, 40 days after seeding, respectively. 6. From above results. we build up hypothesis about the period for weed-free maintenance after seeding required to escape crop yield reduction due to weeds, as follows. Growth of large crab-grass is greatly diminished at the condition of relative light intensity under 10%. The relative light intensity in crop canopies reduced under 10% at the time of about 89 days after seeding, and the space of 30 cm-high was the same value in upland rice. On the other hand, plant length of large crab-grass grew about 30 cm at the time of 30 days after weed seeding. Therefore, 59 days which went back from 89 days to 30 days were estimated as the period for weed-free maintenance, in the community of upland rice and large crab-grass. It was expected that the growth of large crab-grass which emerged on and after 59 days after crop seeding was greatly diminished by crop canopies. The relative light intensity did not reduce under 10% in corn, but from its characteristics, less than 30 days were estimated, as the period for weed-free maintenance. The period for weed-free maintenance were estimated shorter in common purslane or Chufa. Their growth are greatly diminished at the condition of relative light intensity under 20%.

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The comparative study was conducted on the behavior of soil ammonium nitrogen and absorption of nitrogen by rice plants in four experimental fields with special reference to the accumulated effective thermal index (AETI). The soils of these fields were classified into Gray-Brown Soil, Peat Soil, Strong Gley Soil and Wet Andosol. The decrease of soil ammonium nitrogen after transplanting in all the fields was shown as an exponential equation of AETI. The amounts of nitrogen per unit area absorbed by rice plants (y) in each field were also indicated to be closely related to AETl (x). An exponential equation (y=cd^x) was obtained for the early growth stage, and linear one (y=ax+b), for the middle and late growth stages. However, it was noticed that the parameters of these equations differed considerably with difference of the soil type. Since the soil ammonium nitrogen was observed to be enough for rice growing in the early stage, it was assumed that the ability of nitrogen absorption of rice plant was the limiting factor for the exponential part. On the contrary, the soil ammonium nltrogen disappeared in the middle and late stages, the rate of mineralization of soil organic nitrogen was considered to be the limiting factor for the linear part. The recoveries of basal nitrogen in the rice plants ranged from about 40% in Gray Brown Soil to 20% in Strong Gley Soil. The maximum number of tillers stage came in all the experimental fields at the time when almost all of soil ammonium nitrogen disappeared. It was also recognized that the crossing point of the exponential and linear equations was approximately coincident with the stage. Therefore, the maximum number of tillers stage is presumably determined mainly by the nitrogen supply to the rice plants under the common cultural condition.

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[in Japanese]

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The author has reported in the previous papers a photometric method evaluating the quality of hulled rice using "Rice Inspector". In this experiment, some methods for estimating the quality of milled rice and the degree of milling were investigated. Several characteristics of rice grain were also studied upon the light transmittance with special reference to wave length and kernel characters. The results are summarized as follows: 1. Rice bran layers specifically absorbed the light of short wave length. Milled rice, therefore, transmitted greater amount of light in short wave range as compared with hulled rice. 2. Relative transmittance values (RTV) for the light in short wave range (420 nm) were markedly increased as the milling degree of kernel increased. The increment curve of RTV with milling was parabolic and flattened at the completion of milling (around 84% of milling degree). 3. These results suggested a possibility to estimate the degree of milling photometrically. So, the author proposed a calculating formula by which the degree of milling may be estimated regardless of variety and grain character. The proposed method was tested against the weighing method so far used. The result indicated the reliability of this new method. 4. On the other hand, long wave lights especially in near infra-red range were easily transmitted through the bran layers of rice kernel, but were diffused and reflectcd by opaque tissues in rice endosperm as were the lights of other wave length. 5. Therefore, a photometric method using a near infra-red ray (710 nm) was proposed for estimating the translucency of kernel and for evaluating the quality or the degree of ripening of rice endosperm without being influenced by bran layers. 6. RTV of milled rice was negatively correlated with the amount of imperfect kernels, but showed a highly positive correlation with RTV of hulled rice.

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A convenient method for estimating kernel color was investigated using the "rice inspector". And examinations were also conducted on the coloring substances in rice bran layers. In these studies, special attentions were directed to the specific photo-absorbing characteristics of colored rice. 1. Relative transmittance values (RTV) increased in accordance with the wave length of illumination light. And the inclination of this spectral transmittance curve was steeper for deeper-colored variety of brownish rice. 2. Spectral curve of RTV for greenish-colored kernel was featured by a peak at 540 nm, a bottom at around 660 nm and a remarkable ascent toward infra-red range. 3. Hulled rice with dark violet color containing anthocyanic pigment showed a quite different pattern of RTV curve. 4. Ratio of RTV at 710 nm and 660 nm was shown to be a suitable color index (green color index) showing the degree of greenish coloring of rice sample. And RTV ratio of 660 nm and 420 nm (brownnish-color index) made good estimations of coloring degree of brownish rice. 5. These two color indexes could estimate the respective degree of coloring independently without being obstructed by kernels of the other characters. 6. Brownish color of rice deepened during storage, and the deepening of color was more remarkable in darker-colored varieties. 7. Considering from light absorbing features of solvent extractive and coloring reaction in chemical reagents, brownish coloring substances were supposed to be polyphenolic tannin-like materials. 8. Classifying rice varieties into 4 groups, that is, yellowish-white, brown-colored, reddish-brown-colored and anthocyanic varietal groups was proposed according to the degree of coloring of kernel, anthocyanic pigmentation and ferric coloring reaction in rice bran.

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Changes in translucency and coloring of rice kernel in the course of maturation were examined photometrically by the "rice inspector". And the effects of dehydration, variety and vigor of kernel were also investigated. The results are summarized as follows: 1. Regardless of glutinosity, translucency of fresh kernel increased rapidly with the progress of ripening, until 15 to 20 days after anthesis, and thereafter the increment gradually declined toward maturity. The increase of translucency was considerably rapid in vigorous kernels as compared with weaker kernels. Some of the vigorous kernels of glutinous rice showed a little decline in their translucency in the last stage of maturity in accordance with the decrease of kernel moisture. 2. Fresh kernels of non-glutinous rice slightly increased their translucency by artifical drying in the later stages of ripening. On the other hand, those of glutinous rice markedly lost their translucency and turned opaque by drying. And this phenomenon (Ryokka) characteristic of glutinous rice was seen throughout the entire ripening period. 3. Another experiment on Ryokka cleared that in the course of artificial drying, fresh kernels of glutinous rice started to diminish their translucency at around 20% of moisture content and rapidly increased their opacity in the moisture range of 15 to 17%. 4. Greenish coloring of hulled rice attained its peak about 15 to 20 days after anthesis, and thereafter declined toward maturity in accordance with chlorophylous decomposition. 5. Red-brownish hue of the colored rice was remarkably deepened during maturation, especially in vigorous kernels. And this coloring tendency was more conspicuous for deeper-colored varieties. A test on artiticial drying of fresh kernel obviously showed that the dehydration of hulled rice encouraged its brownish coloring. 6. Results of some spectrophotometric investigation on rice extractives suggested that brownish coloring of rice kernel during ripening might be ascribed to bathochromic shift or bathochromic effect due to structural changes of polyphenolic tannin-like substances in rice bran.

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Photosynthetic ability of taro plant was investigated with an early variety, Ishikawa-wase, growing in pot. Photosynthetic rate of each single leaf was measured using the assimilation chamber as shown Fig. 1 for intact leaves. The results obtained were as follows: 1. Leaves developed successively with a time interval of several days. Total number of leaves in whole growing period showed 16-18. Life of the leaf differed with the leaf position. Duration from unfolding to withering was 40-45 days for lower leaves in early stage of growth and 55-80 days for upper leaves in later stage of that. There was large difference in leaf area among leaf positions. The higher the position of leat the larger the leaf area, excepting that a few leaves of uppermost position showed rather small leaf area. 2. Photosynthetic rate of each single leaf increased in new expanding leaf and reached a high level 14 or 15 days after expansion. It maintained the high level for about 10 days and, after that, declined gradually with aging. Thus, photosynthetic rate of single leaf varied with the leaf age. 3. The maximum rate of photosynthesis of single leaf under the conditions of light saturations was 30-35 mg CO₂/dm²/hr for lower leaves and about 20 mg CO₂ for middle and upper leaves. The light saturation point was about 70 Klx of radiation for younger leaves and 20-30 Klx for older leaves. 4. Optimum temperature for apparent photosynthesis of single leaf was approximately 30°C, while the photosynthetic rate did not show marked differences within the temperature from 22° to 35°C. 5. Temperature coefficient of dark respiration (O₁₀) calculated was 2.05 for younger leaf and 1.62 for older leaf. Therefore, effect of temperature on respiratory activity differed with leaf age. 6. There was large difference with leaf position in maximum rate of photosynthesis of whole leaf area, showing 200 mg CO₂/leaf/hr or more for upper leaves. That was due to the difference of leaf area of the position. Total value of maximum rate of photosynthesis accumulated for all of the leaves existing at the time of measurement showed marked increase from end of June, and it did not show the decline even in late September.

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To obtain suitable seedlings for mechanical transplanting, effects of light intensity and air temperature for raising seedlings were examined on the physical characteristics of the seedlings (i.e., buckling moment, buckling stress, section modulus of basal part, buckling index and natural deflection ratio of seedling). 1. Shading (40-70% of sun light intensity) had unfavourable effects on the physical characteristics of the seedling. Seedlings grown in shade were (1) thinner in basal section, (2) breakable in basal part, and had (3) lower resistance to buckling and bending, which were due to unbalanced top growth compared with undeveloped basal part. It is considered that the results mentioned above are because of the insufficient dry matter production caused by shading. 2. Two types were observed in the effects of air temperature to the physical characteristics of seedling. One was the indirect effect caused by growth difference, and another was the direct effect observed on the seedlings at the same leaf age. Remarkable difference was observed among the seedlings grown during same period under various air temperature conditions (day temperature 15-30°C). In the case of the seedlings grown during same period, gradual growth under lower temperature resulted in (1) a thinness in basal section and (2) a reduction in buckling resistance of basal part, but it resulted in also (3) an increment of structural rigidity in basal part and (4) higher resistance to buckling and bending, which were due to the well developed basal part with erect and short foliage. 3. In the case of the seedlings at the 4th leaf age, 24-30°C of day temperature (with 18°C of night temperature) was (1) thicker in basal section with (2) an increment in structural rigidity, and had (3) higher buckling resistance in basal part. This is due to the high dry matter production which is favourable under higher temperature condition than 20°C. The resistance to bending of seedling increased under lower temperature than 24°C, because of the well developed leaf sheath. Hence, rather lower temperature than 24°C might be adaptable for general improvement of the physical characteristics of seedling. 4. The suitable light intensity and air temperature for the physical characteristics were also favourable for raising seedlings with good physiological characteristics. By settlement of the suitable environment condition mentioned above, it is possible to obtain vigorous seedling suited for mechanical transplanting.

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