The nitrogen compounds of the rice plant, which was supplied with nitrogen at the early spikelet initiation stage and the full heading stage, respectively, were investigated to manifest the nitrogen metabolism during ageing. The main results may be summarized as follows: 1) During the period from the early tillering stage to the full heading stage, the protein and RNA levels in the leaf blade increased largely accompanying with high level of the soluble nitrogen, whereas in the ripening period, the protein and RNA levels decreased rapidly in spite of high level of the soluble nitrogen, on the plant supplied with nitrogen at the two different growth stages. 2) Especially in the leaf sheathes and culm the soluble nitrogen responded strikingly to the nitrogen supply and accumulated largely in these organs, whereas in the leaf blade the soluble nitrogen not so much increased as the protein, before heading stage. Accordingly, it was clear that the protein level in the leaf blades was correlated intimately with the levels of soluble nitrogen in the leaf sheathes and culms during growth except the ripening period, in which the protein and RNA level decreased. 3) In the leaf blade, aspartic acid, glutamic acid, alanine, asparangine and glutamine were predominantly present as compared with valine, leucine, proline and arginine, in the free amino acids at the early tillering stage. The relative composition of these amino acid was not essentially chaged before heading stage even by the nitrogen supply, because protein assimilation proceeded rapidly in these periods However, in the ripening period, valine, leucine and proline appeared in larger amounts in the plants supplied with nitrogen at the two stages mentioned above. Similarly, in the detached leaves, larger amounts of valine, leucine and proline appeared during senescence accompanying with the protein breakdown. Therefore, changes of the free amino acids content in the ripening period well agreeded with changes of those in the detached leaves. 4) In the leaf sheathes and culms, on the other hand, alanine, asparagine and glutamine were predominantly present, and asparagine was richer than glutamine at the early tillering stage. These free amino acids decreased rapidly in amounts from the early spikelet initiation stage to the boot stage, and tended to increase largely in the plant supplied with nitrogen at the early spikelet initiation stage. However, in the ripening period, arginine and proline as compared with asparagine and glutamine predominantly appeared in the plant supplied with nitrogen especially at full heading stage.

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The results obtained in the present study were summarized as follows: 1. Abscisic acid (1∼10 mg/1) accelerated the senescence of the rice leaf sections. Such effects of abscisic acid were almost reversed by high concentrations of kinetin (1∼5 mg/1); whereas low concentrations of kinetin (0.01∼0.1 mg/1) partially overcame the effect of abscisic acid. Accordingly, in the presence of abscisic acid, the level of kinetin required for chlorophyll retention instead increased. It is to be assumed that there is an antagonistic interaction between abscisic acid and kinetin. 2. It was suggested that the effect of abscisic acid in accelerating senescence was mediated through its inhibitory action on RNA synthesis which was reversed almost or partially by kinetin, since a relatively high ratio of RNA to DNA due to kinetin pretreatment was lowered according to the following transfer from kinetin to abscisic acid.

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This experiment was undertaken to determine the effect of sulfur dioxide on the respiratory rate both at the seedling and at the highest tillering stages of rice plants. The respiratory rate was measured in the laboratory under a controlled temperature of 30°C, exposing the plants to various concentrations of SO₂, which were determined by a SO₂-analyzer of self recording system. The results obtained were as follows: 1. The respiration rate of rice seedling decreased linearly with increasing concentration of SO₂. 2. The respiratory rate of rice seedlings was suppressed by the treatment of SO₂ for one hour at a concentration of 60 ppm, showing no recovery after the gas removed. At the concentrations of 1, 4 and 10ppm the seedlings responded intricately, as seen in fig. 3. 3. The respiration rate at the highest tillering stage of rice plants was accelarated by exposing the plants to SO₂ at the concentrations of 1, 5, 10 and 15ppm, respectively. By the treatment of SO₂ at the concentrations of 40 and 60 ppm, it was always retarded. As the treatment hour was prolonged, the concentration of the gas effective to acceralate the respiration rate was declined. 4. As to the accumulated value for 4hours, the respiration rate increased linearly with increasing concentration of the gas. It showed the highest value at about a concentration of the 5 ppm, thereafter declining with increasing concentration of the gas. 5. From the above-mentioned facts it was suggested that both an increse and a decrease in the respiration of rice plants treated by the gas may lead them to decrease in dry matter production.

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This experiment was undertaken to examine an injurious effect of sulfur dioxide on photo-synthesis and absorption of sulfur into leaves of the rice plant. The results obtained were as follows: 1) Both apparrent and gross photosynthesis were depressed by the fumigation of sulfur dioxide. Apparrent photosynthesis was completely restrained one hour after the plant was exposed to the gas, when treated cotinuously at higher concentrations such as 20 and 40 ppm. 2) At the concentrations of 6, 10 and 20ppm, the depression of apparent photosynthesis caused by the fumigation of sulfur dioxide for one hour was restored to the original state almost two hours after the gas was removed, but not restored at the concentrations of 30 and 70 ppm. 3) When the rice plant was fumigated with sulfur dioxide at the concentrations up to 20 ppm, sulfur content in the leaves of this plant increased remarkably, showing only slight increase as the concentration of the gas became higher. The content of sulfur absorbed in the leaves was, however, increased in proportion to the length of fumigation period.

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[in Japanese]

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Mat rush seedling has been generally transplanted in early winter (11∼5°C); it takes a relatively long days for striking root because of low temperature. Little was known about relationship between rooting ability of mat rush and temperature. In the privious paper, authors reported the relation between rooting ability under constant temperature. In this paper, authors report the effect of natural temperature on rooting of the seedlings from Oct. in 1966 to Feb. in '67. The results obtained are summarized as follows: 1. Number of roots newly emerged, length of roots newly elongated and rooting ratio (number of rooted seedlings/number of seedlings) after transplanting were investigated on the 7th day, 14th and 21st after transplanting. 2. Number and length of the roots and the rooting ratio were found to be increased rapidly in Oct. transplanting plot (20.5°C in soil temp.) and Nov. plot (15.3°C), slowly in Jan. plot (7.0°C), in Dec. plot (9.2°C) and Feb. plot (8.2°C) they were almost medium of those. 3. It was observed that the accumulated temperature of soil during 14 days after transplanting correlated with the number and the length of roots and the rooting ratio. 4. As the results, the practical low limit of the daily mean tenperature appeared to be about 7°C and the accumulated temperature for a fortnight to be above 100°C for rooting of the seedling.

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The effect of visible light of low energy on the lamina inclination was investigated in order to make clear photomorphogenesis in rice seedlings. By an irradiation of 5 min/day for 7 days, an inhibitive effect on the lamina inclination of 2nd leaves in etiolated seedlings was distinctively observed at all the wave length of visible light used (fig. 3). By the irradiation for 4 days, a decrease of the inhibitive effect on the inclination was detected by green light (fig. 4). The lamina inclination in etiolated rice seedlings was the most sensitive at age in 4 and 5 days after seeding (fig. 5). At this sensitive stage, the irradiation with 2 times of 10 min by red light (650 nm) did not make to induce any inclination of leaves, but a slight inclination was induced by blue (400 nm) and green (500 nm) light. The inhibitive effect on lamina inclination appeared even by 1 min of blue, green and red light (fig. 6). From this result, it was confirmed that such low energy as 42μW/cm² of red light is able to affect the lamina inclination. By the irradiation of visible lights used the elongation of internode was inhibited. But the sheath elongation of 2nd leaf was contrarily stimulated, and the lamina length of 2nd leaf was not almost affected by all the lights used.

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[in Japanese]

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[in Japanese]

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In order to know the varietal defferences of stalk-strength, the experiments were carried out in 1964∼1966 at Hatano Tobacco Experiment Station. Five varieties; Shirodaruma, Shirohatano, Shirogiri, Odaruma and Ky 57, were selected for this study. After stalk-cutting, tobacco stalks were fixed in a vise at the base and horizontally loaded at the free end as cantilever beams, for deflection observations. For beam bending tests, each stalk was cut at the base of the plant and divided into several sections. These samples were used for testing at once to minimise drying. Results obtained were as follows. 1. The deflection of tobacco stalks were different with varieties and Ky 57 and Shirodaruma showed the largest value and Odaruma, Shirogiri and Shirohatano followed in order. 2. The flexural rigidity of stalks in the maturing stage were much larger than in the early growing stage, and in all stage Shirogiri showed the largest value and Shirodaruma showed the smallest value. 3. The values of bending moment at breaking were large in order of Shirohatano, Shirogiri and Odaruma, while Shirodaruma and Ky 57 showed smaller values. 4. The bending stress showed different values with each variety and through all stage Ky 57, and Shirodaruma were the weakest and Odaruma, shiro hatano and Shirogiri fellowed in order, although some differences in the value itself were observed with growing season. 5. Among these varieties Shirodaruma has the tendency to suffer from stalk break and root lodging because of it stalk characteristics. 6. From these results, auther suggested to prevent these damages of Shirodaruma by earlier transplanting.

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The mechanism of the excessive vegetative growth of sweet potatoes and the varietal differences were observed from the viewpoints of the soil physical conditions and the ecological charcteristics of roots. The results obtained may be summarized as follows. 1. If the aeration be suppressed owing to the compact soil, it would show a decrease in the weight of tuberous roots and an increase in T/R ratio, thus resulting in the excessive vegetative growth of sweet potatoes. In this case the varietal differences were observed. Norin No. 1 was subject to the excessive vegetative growth more readily than Okinawa No. 100. 2. It was proved that such varietal differences have bearing upon the differences in the distribution and the weight of non-tuberous roots. Namely, the non-tuberous roots of Norin No. 1, as compared with those of Okinawa No. 100, intruded more readily into such soil condition which caused the excessive vegetative growth, thus showing an increased rate of distribution of nonteberous roots in that place. In the case of the variety which is likely to subject to the excessive vegetative growth, it showed such characteristics that the weight of non-tuberous roots was great, and the ratio between the weight of tuberous roots and the weight of non-tuberous ones was low, and it was observed that those characteristics had high correlation with the ratio between the weight of tuberous roots and the total weight of dry matter, and it was proved also that those characteristics have an effect on the distribution of the dry matter. 3. On the other hand, varietal differences were observed also in the thickening of tuberous roots. It was proved that since Norin No. 1 was affected more greatly by the bulk density of soil than in the case of Okinawa No. 100, the thickening of tuberous roots of Norin No. 1 was more liable to have restrictions than the latter owing to the compact soil.

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[in Japanese]

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Effect of kinetin on organ formation in rice callus tissue was studied using Maede's medium containing yeast extract, vitamines and 2, 4-D. The following results were obtained. (1) When kinetin was added in to the medium containing 2, 4-D at 10^-7M, shoot formation in callus was promoted as concentration of kinetin increased. Root formation was not influenced by addition of kinetin. (2) Shoot-like protuberances appeared in callus tissues at 10 to 14 days after transfer of callus in to the test medium. Numerous protuberances did not make any growth, and they turned to be necrosis for 30 days after the transfer. Few protuberances developed to normal shoots, while a half of the shoots were albino. (3) Varietal difference was not observed in the effect of kinetin on shoot formation in the callus tissues of various varieties, which are Te-Tep, Norin-8, Norin-29, Kyoto-asahi and Tan-ginbozu. (4) It is necessary for acceleration of kinetin action to contain yeast extract and/or casein hydrolysate in the medium. Adenine failed to exert any effect on shoot regeneration in callus tissues.

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In this paper, a morphological complex characteristic of rice varieties was estimated by principal component analysis using all the data of three nitrogen feltilizer levels at each plant spacing level (spacings in the row were 5 cm, 15 cm and 25 cm, respectively). The present results obtained were as follows: (1) A morphological complex characteristic of each variety at each plant spacing level can be shown by two principal components which are indices of the morphological characteristic. These indices were as follows: 5 cm plot X₁=0.506x₁+0.381x₂-0.170x₃-0.170x₄+0.512x₅+0.574x₆ X₂=-0.278x₁+0.452x₂+0.588x₃+0.608x₄+0.059x₅+0.053x₆ 15 cm plot X₁=0.450x₁+0.227x₂-0.332x₃-0.357x₄+0.462x₅+0.532x₆ X₂=-0.307x₁+0.605x₂+0.462x₃+0.482x₄+0.200x₅+0.142x₆ 25 mm Plnt X₁=0.425x₁+0.194x₂-0.321x₃-0.341x₄+0.462x₅+0.550x₆ X₂=-0.294x₁+0.644x₂+0.474x₃+0.503x₄+0.247x₅+0.151x₆ (2) The meaning of the first index in each plant spacing was mainly concerned with the total weight per plant of the variety at given condition. (3) The meaning of the second index was different in each plant spacing; namely, in the 5 cm plot it was mainly concerned with the plant type whether variety was a long-culmed, heavypanicle type or short-culmed, tillering type. But, in the 15 cm and 25 cm plots, these were concerned with the quantity of individual plant yield of variety together with the plant type mentioned above.

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According to the rice experiments previously reported, studies on the varietal differences in morphological complex characteristic of two-rowed barley varieties were carried out at Minamikawauchi Division, Tochigi Agrcultural Experiment Station. Thirty varieties of two-rowed barley were cultured under standard fertilization level, and plant spacing in this experiment was determined by seeding rate per are; namely, quantities of seed sowed were 0.4 kg, 0.8 kg and 1.2 kg per are, The following six characters were employed to obtain the indices of morphological complex characteristic: calm length (X₁), panicle length (X₂), number of panicle (X₃), total weight per plant (X₄), panicle weight of the longest stalk (X₅), and panicle weight per plant (X₆). The indices of a morphological complex characteristic were estimated by principal component analysis, which is one of the multivariate analysis. The present results were as follows : (1) A morphological complex characteristic of each variety at each plant spacing level can be shown by two principal components which were indices of the morphological complex characteristic. These indices were as follows; 0.4 kg/a plot X₁=0.427x₁+0.187x₂+0.249x₃+0.519x₄+0.401x₅+0.531x₆ X₂=-0.342x₁-0.255x₂+0.758x₃+0.118x₄-0.296x₅+0.137x₆ 0.8 kg/a plot X₁=-0.084x₁+0.343x₂+0.273x₃+0.543x₄+0.412x₅+0.580x₆ X₂=-0.654x₁-0.325x₂+0.620x₃+0.001x₄-0.417x₅+0.114x₆ 1.2 kg/a plot X₁=0.332x₁+0.259x₂+0.208x₃+0.526x₄+0.414x₅+0.576x₆ X₂=0.626x₁+0.296x₂-0.622x₃-0.315x₄+0.456x₅-0.195x₆ (2) The meaning of the first index in each plant spacing was mainly concerned with quantity of individual plant yield of variety at a given condition. (3) The meaning of the second index in each plant spacing was mainly concerned with the plant type whether the variety was a long-culmed, heavy-panicle type or short-culmed, tillering type. The sign of second index was, however, different in each plant spacing, namely short-culmed, tillering type varieties were plus sign in 0.4 kg and 0.8 kg per a. plots, but in 1.2 kg per a. plot it was minus sign.

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According to the line previously paper (5), studies on the varietal differences of a morphological complex characteristic of two-rowed barley varieties were performed with the data from three plant spacing levels being put together, and plant spacing levels in this experiment were determined by seeding rate, which were reported in previously paper (5). The present results were as follows: (1) A morphological complex characteristic of each variety in this experiment can be shown by two principal components. These indices were as follows; X₁=0.202x₁+0.341x₂+0.385x₃+0.512x₄+0.402x₅+0.521x₆ X₂=0.687x₁+0.074x₂-0.538x₃-0.117x₄+0.445x₅-0.147x₆ (2) The meanings obtained in this case were also the same results as rice variety experiments reported already. The meaning of the first index was mainly concerned with the quantity of individual plant yield of variety at given condition. (3) The meaning of the second index was mainly concerned with the plant type whether the variety was a long-culmed, heavy panicle type or short-culmed, tillering type.

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It is important for the improvment of the ability of photosynthesis of soybean plants to clarify the genetic mechanism controlling photosynthesis of the plants. The authors determined the ability of photosynthesis of F₁ and F₂ generations in 1967 and in 1968. The results are as follows: 1. In the analysis of variance of the net photosynthetic rate, significant differences were observed among the data of each surveying date. Then the photosynthetic rat was represented as a relative value against the average rate of photosynthesis surveyed every day, instead of using the absolute value. The ability of photosynthesis of F₁ of Norin-1×Harosoy was lower than that of Harosoy, but showed no significant difference from that of Norin-1. The photosynthetic rat of F₁ of the reciprocal cross between Harosoy and Manshu was also lower than that of Harosoy, but showed no significant difference from that of Manshu in the most cases. Therefore, the low ability of photosynthesis of Norin-1 and Manshu was noticed as a dominant character. 2. The rates of photosynthesis of F₂ generations of Norin-1×Harosoy, Manshu×Harosoy and Miyagi-shirome×Hakuho (6) indicated the normal distribution without any exceptions. It suggests that the genetic mechanism controlling the ability of photosynthesis is quantitative. 3. Regarding the relationship between the photosynthetic rate of F₂ and the total N content per unit area of leaf, the following relationship was ovserved, i. e., the individuals of high and low photosynthetic ability were observed among the individuals with high N content, but there were few individuals of high ability of photosynthesis among the individuals with low N content. The same relationship in the cace of total N content was also observed among the thickness of a leaf, the leaf fresh weight per unit leaf area and the rate of photosynthesis. But these were observed only in the cases of leaves of middle and lower positions. No relationship was observed with the growth habit, flower color, ped's pubescence color and the leaf shape (ratio between the length and width), and in most cases, no relationship with the leaf dry matter weight per unit leaf area was observed. There was a progeny in which any certain relationship was not observed between the number of days for plant growth and the ability of photosynthesis, or there was a progeny in which few individuals of high ability of photosynthesis were found in the late-maturing plants. 4. From the results, the fellowing possibilities were discussed: (1) the possibility to improve the photosynthetic ability of the variety with low ability, and (2) the possibility that introduce the high ability of photosynthesis of the blant of indeterminate growth habit to the plant of determinate growth habit by retaining the growth habit itself.

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[in Japanese]

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[in Japanese]

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To investigate the composition of photosynthetic products translocated from the leaf of flue-cured tobacco plant, ¹⁴CO₂ was supplied to a part of mesophyll, and the distribution of ¹⁴C among various compounds in the veins of 1st order of branching and the midrib was traced during the period of 180 minutes after ¹⁴CO₂ feeding. Results obtained were summarized as follows: 1) In the veins of 1st order of branching and the midrib, about 70% of the total ¹⁴C was found in sucrose, and a little amount of ¹⁴C in glucose and fructose. Therefore, it was concluded that sucrose was the main transport substance in flue-cured tobacco plant. 2) The assay of ¹⁴C-components of cationic fraction in the veins of 1st order of branching and the midrib showed that most of ¹⁴C in fraction was incorporated into serine at the time of 30 and 60 minutes after ¹⁴CO₂ feeding, thereafter, ¹⁴C-serine decreased. On the contrary, the radioactivities in aspartic acid, glutamic acid, glutamine, and γ-aminobutyric acid increased with time. 3) Radioactive malic acid was found in the mesophyll and the veins of 1st order of branching, but not in the midrib, 4) In the veins of 1st order of branching, the incorporatibn of ¹⁴C into the insoluble fraction and the hydrolysis of the translocated ¹⁴C-sucrose were found to be more profound than those in the midrib. From these facts, it was inferred that the ¹⁴C translocated into the veins of 1st order of branching was more actively utilized for formation of the tissue, comparing with the ¹⁴C in the midrib.

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It is well known for long that a soybean leaf slters its inclination in response to the intensity or derction of light on the leaf surface. This study has for its object to find quantitatively the actual state of leaf orientation-adjusting movement and to clarify the relationship of the adjusting movement with the high-yielding ability of soybeans, thus attempting to apply the findings to the high-yielding soylbean variety breeding project. In the present report, the author makes report on the results of the study which was conducted in 1965 to obtain the general information on the leaf orientation-adjusting movement in soybean plants and the changes in its effect on the light intensity on the leaf surface. 1. In early September, 1965, the author made the measurement on the entire leaves of one hill of the soybean plant comunity of Azeminori variety which was planted on May 19 and grown on a one-piece-per-hill basis, 60 cm between rows and 20 cm between hills; i. e., the azimuth of leaves and the angle of leaf inclination were measured under different climatic conditions, and the ligh intensity on the leaf surface was measured as well. In the present report, the author should like to make the report on each of the typical cases observed under both of cloudy and fine weather. 2. About the direction of leaf, the leaves having an angle of 45°with the direction of row were predominant in number (fig. 2), but abut the angle of leaf inclination, a marked difference was observed according to the climatic conditions (fig. 3), i. e., under the cloudy weather, the leaf surface which inclined upward at the angle of 0°to 30°showed an increase, while under the fine weather, horizontal leaves decreased and such leaves which inclined downward at the angle of more than 15°increased. A marked difference was observed in the adjusting movement between the two coditions. 3. Regarding the distributtion percentage of leaf number and leaf area according to the ligh intensity on the leaf surface, the distribution percentag was even to a fairly great extent under the cloudy weather, while under the fine weather, two types quite different in the distribution percentage were observed, i.e., one was of unsaturated type with low light intensity on the leaf surface, and anothor was of saturated type with high light intensity on the leaf surface (fig. 4). This fact seems to endose the light saturation theory concerning the photosynthesis of soybean plant oommunity that "even if the light becomes stronger, the light intensity on the surface of the leaves of light insaturated type shows no increase, causing an increase only in the light intensity on the surface of the leaves already saturated with light. As a result, the light becomes unavailable even though it becomes stronger". However, when applied a different measuring method, it would give rise to a different relationship between the increase in the external light and the increase in the light intensity on the leaf surface (as shown in fig. 4, the distribution percentage of leaf number and leaf area differs under the fine weather). Moreover, there is no gainsaying that, with the changes in the direction of the sunlight, the light intensity on the surface of the leaves insaturated with light in the lower layer of soybean plant community will show an increase to a fairly great extent owing to the sunbeams that may come through. Accordingly, it is considered that the light saturation phenomenon in the photosynthesis of soybean plant community of fairly luxuriant growth can be observed only in the specific cases. For this reason, the established light saturation theory concerning the photosynthesis of soybean plant community is required to be re-examined. 4. Respecting the relationship of the direction and inclination of leaves with light intensity on the leaf surface, no specific trend was observed under the cloudy weather. [the rest omitted]

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Since the leaf orientation-adjusting movement is after all the alteration in the leaf inclination the author devised the analytical method based upon the value of actual measurment of the three elements for determining the leaf orientation: φ (azimuth of leaf), θ (main angle of leaf inclination) and ψ (sub-angle of leaf inclination) given in fig. 1 and 3, and applied the devised analytical method to the soybean leaf acting a typical adjusting movement, thus attempted to make investigations into the fundamental pattern of the leaf orientation-adjusting movement and its significance for the dry matter production. 1. The author took the alteration in the leaf inclination (i.e., leaf orientation-adjusting movement) as the change in the horizontal system of co-ordinate at the intersection between the normal on the leaf surface and the celestial sphere, and proposed such method which clarifies the change by using figure drawing and calculation based upon the value obtained from the actual measurement of the three elements necessary for the determining the leaf inclination. The method to draw figures was indicated in fig. 2 and 4 and the calculation was made by using the following expression. 1) The expressions to find out the horizontal system of co-ordinate P (intersection of the normal on the leaf surface with the celestial sphere) : x=-cos φ sin θ cos ψ + sin φ sin ψ y=-sin φ sin θ cos ψ - sin φ cos ψ z=cos θ cos ψ (1) 2) The expressions to find out φ' (azimuth) and θ' (altitude) of the normal on the leaf surface: φ'=tan^-1y/x θ'=sin^-1z (2) 3) The expressions to find out the angle α of the direction of the sun (or the brightest light in the sky) with the normal on the leaf surface: α=cos^-1 (cos φ_s cos θ_s·x+sin φ_s cos θ_s·y+sin θ_s·z) (3) where φ_s : Azimuth of the sun θ_s : Altitude of the sun Notes : Azimuth : O^o : south, + : the east circuit line, and - : the west circuit line Main-angle of leaf inclination (θ) : + : upward inclination, - : downward inclination Sub-angle of leaf inclination (ψ) : + : turning-up to the left direction from the leaf base to the leaf apex, - : turning-up to the right direction from the leaf base to the leaf apex 2. The soybean plant was grown in a pot in isolation. By taking Madison variety acting a typical adjusting movement as a sample, the actual measurement was made extending over the duration from early to mid-September, 1965, in order to measure the three elements necessary for determining the leaf inclination for each of the leaflets in the compound leaf according to the selected hours on fine days and according to the climatic conditions at the same hours. Basing upon the value obtained from this actual measurement, the changes in the co-ordinate of normal on the leaf surface were observed by the figure drawing and calculating methods. Thus the fundamental pattern of the leaf orientation-adjusting movement was investigated. As to the changes in the three elements measured according to the selected hours on fine days, at first, the changes in each leaflet was observed according to the selected hours (changes in the compound leaf on the uppermost node are given in fig. 5), and the changes were classified according to the selected hours (fig. 6). α was also obtained by using tha calculating method (fig. 7). The changes due to the climatic conditions were observed also in the same ways (figs. 9 and 10). 3. The survey results indicated that, in the case of isolated individual small in the leaf number, as in the case with the present report, a remarkable adjusting movement was shown by the entire leaves. [the rest omitted]

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The growth of rice plants grown under high temperature "35-36°C" (H), low temperature "21±1°C" (L) and control "31±1°C (C) of cultur solution supplied with (S) and without=(N) silicic acid were compared with each other. The results obtained are as follows : 1. The growth of rice plants of N was inferior to that of S, and under the high temperature the dry weight of rice plants of N was especially small. 2. The amount of silicic acid adsorbed by the rice plants of SL was smaller than that of SH, and that of SC was larger than those of SL and SH. 3. The amounts of nitrogen, phosphorus and potassium absorbed by the rice plant of NH, especially the amounts of these elements in panicle were comparatively smaller. The amounts of nitrogen and potassium absorbed by the rice plants of LN were smaller than those of CN, but the amount of phosphorus absorbed by the former was larger than that of absorbed by the letter. The accumulated amounts of these three elements in the panicle of rice plants of N were respectively smaller than those of S. The contents of total sugar in the rice plants of NH and SH were smaller than those of C, but those of L were lager than those of C. The contents of starch in rice plant of S were lager than those of N in three treatments. The difference (ratio) of starch content between S and N was especially lager in H. 4. The growth of rice plant raised without silicic acid under the high temperature of cultur solution was considerably poor. As to treatment L, the growth amounts of S and N were a little smaller than that of control, respectively. Under the high temperatur of culture solution the growth of rice plant was poor, but the growth of rice plant grown under the low temperature was only a little poorer than that of control. It was recognized from the above mentioned facts that silicic acid ameliolates the growth retardation of rice plant grown under the high or low temperature.

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In order to know the effects of silicic acid on the growth of rice plant under the high and low air temperature conditions, the present study was planned as follows, that is, plot (N) in wich no silicic acid was supplied, plot (s) supplied with SiO₂ 10 ppm and plot (S) supplied with SiO₂ 100ppm were set up in each treatment of high air temperature (H), low air temperature (L) and control (C). The following result are obtained. In the rice plant grown under sufficient amount of silicic acid, the amounts of nitrogen, phosphorus and potassium absorbed, the accumulated amounts in the panicle of these elements, and the production and accumulation of total sugar and starch in the panicle were respectively larger than in the rice plant of N wich had been raised without SiO₂. As a result of it, the production of dry matter of rice plant supplied with sufficient SiO₂ was larger than that of rice plant without SiO₂. The productions of dry matter of rice plant of HN and LN were especially inferior to those of other treatments. In the treatment H, C and L the weights of dry matter were proportionally increased to increasing amount of silicic acid supplied. In the treatment H and L the differences between the amounts of growth of rice plants in S and N were respectively larger than in the control. Accordingly, it was clearly recognized that the sufficient supply with silicic acid reduced the bad influences on the growth of rice plant under the high and low air temperature.

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