The present experiment, with the same purpose as the pretlious report, was undertaken to make clear the effects of calcium deficiency at the early growth stage on the development of tillering buds in rice seedlings by a water culture method. The results obtained are summarized as follows: 1. In the calcium-deficiency-treatment at the early growth stage, the tillering buds in each stem-nodes of the plants developed as well as control plot and tillered. But in case the period of calcium deficiency became too long, their developments were inferior. Especially, in case the PH of nutrient solution was low, this tendency was noted as remarkable. 2. These results shown above is thought to be due to the following causes; 1) All essential elements needed for the growth of rice seedlings, with the exception of CaO, are included in nutrient solution. 2) The leaf blades with the exception of those portion aflected by calcium deficiency symptons, retains the functions of a perfect leaf. 3) The amount of calcium needed for the development of tillering buds is very small when compared with those for nitrogen, phosphorus and potassium. 4) In case the period of calcium deficiency extends for a long period, the deficiency of calcium itself becomes the limiting factor. And especialy, in case the PH of nutrient solution is low, the development of tillering buds is remarkably inhibited by the double obstacles of the calcium deficiency and the low PH of nutrient solution.

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This paper deals with the relationship between tobacco growth and organic matter content of soil in the sand-dune field in Yonago from 1964 to 1966. Results obtained were as follows; (1) The cultivation without manure reduced the yield of fluecured tobacco by about 10% in the non-manured fields for a year, and about 15% in the non-manured fields for two years as compared with the manured fields. (2) Fifty to sixty percent of added organic material was consumed for a year. Consumption of organic matter in the non-manured fields for one year was about 10% less than in the manured fields. Added organic matter in the non-manured fields was consumed perfectly for two years. (3) Organic nitrogen content in the soil varied according to organic matter content, NO₃-N in the soil markedly decreased by early summer regardless of manure. The level of NO₃-N in the manured soil was slightly higher than those without manure in the latter half stage of growth. (4) In the case without manure, nitrogen and magnesium uptake by tobacco plant were markedly decreased in the latter half stage of growth, and also dry weight of tobacco plant varied in parallel with nitrogen absorption. It is concluded that the manure serves as an important source of mineral nitrogen in the latter half stage of growth.

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It is generally accepted as impossible to produce seed of Chinese matgrass under the natural conditions in Japan where the temperatures in autumn are too low. Studies were made in order to find out the possibility of seed production of Chinese matgrass by speeding up its flowering date at high temperature in summer (evading cool climate in autumn), through due photoperiodic treatment by making the best use of the responses of Chinese matgrass to photoperiodism. Effects of photoperiodic treatment on the heading date, stem growth, seed setting, and viability of seed obtained were examined. The test results can be summarized as follows: (1) Long-day (24hours) treatment promoted stem elongation. In case where long-day treatment was started in June, the promoting effect was greatest, but no heading was found in the case of long-day treatment plot. (2) Short-day (8 hours) treatment inhibited stem elongation. The inhibiting effect was remarkable in case where short-day treatment started in June was continued lasting for long days. The earlier the short-day treatment was started, the more in the number of stems per hill. Short-day treatment hastened the heading date, but the later in the start of short-day treatment, the less in the number of days from the start of treatment to the flowering date, and the more in the number of spikelets on the stems. (3) It was, after all, clarified that the seeds produced from the spikelets bearing flowers during the period ranging from mid-July to late August and collected in late September had germinating ability. Particularly, excellent seeds were produced from the spikelets bearing flowers during the period from late July to early August. For producing such excellent seeds, the short-day treatment started in early July is deemed most effective. (4) Seeds of excellent quality were 1.4 to 2.2mm in length, 0.3 to 0.5mm in width, 0.2 to 0.3mm in thickness, and about 120 mg in 1, 000 grain weight.

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The present paper is a report on the formation of first internode and beginning of internodal extention in rice shoots, and it also describes the varietal differences and ecological responses to the varying times of cultivation. Definitive nodes and internodes are here defined as those that are clearly delimited in longitudinal median sections of living shoots as observed using dissecting microscope. By these easy methods, the first discernible internordal lacunae are considered here as an index of internodal extension. From the results of this observation on the morphogenetic process, the author proposed that the stem development may be divided into the following three phases; viz. previous phase of internodal lacunae formation named "Primitive phase", process of subtle elongation of basel telescoped lacunae (Crown-internodes) named as "Primary phase", and the following phase showing the rapid and long extension of upper internodes (Culm-internodes) named as "Secondary phase". It is observed that the stage of first internodal formation in the Primary phase may correspond to time far previous to differentiation of panicle primordium. The plant-age as measured by the number of leaves is about 5.5. And in most plants, first extended internode is that between 5th and 6th node, however, the locus of this node keeps lower in short-term varieties and in plants planted late, but upper in long-term varieties and in early planted plants. The number of extended internodes in Primary phase may be found 5 or 6 in most plants, and are less in short term varieties but more in long-term varieties. However, ecological variations due to the varying of planting times are a little. These internodes are 1-2 mm in length at the beginning of formation, and are extended just about 3 mm in full length. And the internodes which are extended over 3 mm in length may be regarded as the internodes of Secondary phase. At the stage of onset in Secondary phase, the panicle is 0.4∼1.0 mm in length, and the stage ranges from the branch differentiation to early time of spikelet formation. And the plantage is 11.0∼14.0 leaves, leaf number index is 83 to 87, and the Secondary extension of internode begins from the node of 10∼13th leaf. Each above-mentioned value is revealing the range of varietal differences. It seems that the "crown" of Grasses may be divided into two types with or without of "crown-internode"-Rice-type crown (with) and Wheat-type crown (without). From the results of this studies, the author stated that the simple method using dissecting microscope may be useful for identifying the internodal formation and extension not only at the Secondary phase but also at the Primary phase, without any trouble as by paraffin method.

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Method and some experimental conditions of an alkali test were investigated in December 1963 through observations and tests on the disintegration of milled white rice kernels in dilute alkali solution. Ten milled rice kernels of duplicated samples collected from the 1963 crop, were treated in 20 ml of potassium hydroxide solution in a covered Petri dish, and laid in a room temperature regulated at 20±0.5°C. After 24-hour treatment, the degrees of kernel decomposition were evaluated in accordance with a descriptive scale (Table 1). Ventral and inner portions of kernel were less resistant to alkali as compared with the other portions of kernel. And, in the course of kernel decomposition, bursting of ventral side and turning of endosperm tissue inside out were observed (Fig. 1) in the most of japonica and some of indica varieties. So, a new 10-grade decomposition index (Table 1) considering the abovementioned decomposition features was used in this experiment to show the degree of kernel disintegration. And minute differences in the decomposition were discerned clearly by this index, especially for the japonica varieties. On the optimum concentration of KOH test solution, a clear difference between jappnica and indica varieties was revealed. And 1.4 to 1.5 % and 1.7 to 1.8 % solution of KOH seems to be suitable for japonica or easily decomposable varieties and indica or alkali resistant varieties respectively (Fig. 2). In case of usually milled rice kernels, under or over-milling in slight extent did not considerablly affect the decomposition degree of the kernels, though scaring of bran layer in the initial stage of milling process abruptly decreased the alkali resistibility and abnormally high milling revealed a progressive susceptibily to alkali in the inner layers of endosperm tissue (Fig. 3). Gracks formed in the milled kernels increased the decomposition values of the kernels (Table 2).

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Alkali tests on which the author have reported in the previous paper, were conducted during December 1963 on the milled kernels of 124 rice varieties from 1963 crop. Effects of air temperatures shading and nitrogen application in ripening period were also investigated in relation to alkali digestibility. Most of indica varieties showed their stronger resistibility to alkali than japonica varieties as was already reported by many researchers. Shape of kernel had no clear relation to alkali digestibility in the case of japonica varieties. In indica rice, however, some varieties of big breadth-thickness ratio were less resistant than narrow-grain varieties. Glutinous kernels showed no substantial differences from nonglutinous ones, suggesting that amylose content of kernel had little effect on alkali digestibility of rice kernel. kernels of late season varieties which ripened in low temperature were more digestible rather than early or midseason varieties ripened in hot or warmer season. High temperature (30°C) treatments in ripening periods considerably increased alkali resistance of rice kernels. Shading treatments in the same periods and heavy nitrogen application just prior to heading decreased alkali resistance of kernels. It is considered therefore that environmental conditions which accelerate the development of kernels may increase their alkali resistance through denaturization of synthesizing starch and structural strengthening of endosperm tissues. Green kernels and injured kernels such as milky-white kernels which obsuructed thier ripening by some in jurious causes and kernels collected from kernel-attaching position of inferion strength such as the second kernel from the top on each panicle branch were more digestible as compared with normal kernels and kernels from vigorous positions. Alkali digestibility of milled rice kernel is thought to be mainly dependent upon the nature of endosperm starch being controled by hereditary characters as well as environmental conditions.

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Method for eveluating the alkali digestibility of rice flour was investigated. And a rapid alkali test could be done by measuring light transmission rate of alkali-treated flour paste with a modified turvidmeter. The procedure of test is as follows. 500 mg sample of rice flour is put in a flat-bottomed glass container 50 mm in internal diameter. After being wetted wits 1.2ml of distilled water, the sample is added with 25ml of 2.2% potassium hydroxide solution. The flour-alkalii suspension is then stirred magnetically at 120 r. p. m. for 10 minutes on a water bath which is also stirred magnetically and regulated at 40±0.5°C. The paste is cooled with runnihg water to room temperature and set in the measuring apparatus together with glass container. A modified turvidimeter having a light beam of vertical direction was used for measuring light transmission of the paste. Alkali decomposition value is represented by percent light transmission. The procedure can be satisfactorily applied to rice starch sample as well. Compound starch granules in alkali-treated starch pastes of various light transmission rates were observed through a phase-different microscope. And a close relation was revealed between alkali decomposition value and disintegration of starch granules. Rate of light transmission or alkali decomposition value, therefore, may be said to be an adequate indicator for evalualuating the alkali digestibility of pulverized rice whose major component is starch. Rice flour pulverized finer than 120 mesh or coarser than 40 mesh considerably affected the decomposition value. So the test should be done on a fixed mesh of flour within the range of 40 to 120 mesh.

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Powder method of alkali test on which the author has reported in the previous paper, was applied for an investigation of varietal difference in alkali digestibility of rice flour. Effect of air temperatures on the alkali digestibility was also tested during the ripening periods of rice. Special emphasis was laid upon the comparison of digestibility of milled white rice, rice flour and rice starch. The results were summarized as follows. 1. Alkali decomposition values for rice flours of 108 varieties showed analogus tendency to the values for milled white rice which had been tested previously. All the materials being obtained from the sama source. A highly significant correlation was found between the decomposition values of the two materials, but some difference in regression line was shown between japonica and indica varieties. 2. The values of the powder test were negatively correlated to the mean air temperatures during the ripening periods of 20 day after heading. High temperature treatment (30°C) in the ripening period decreased the decomposition values, whereas low tempertures (23 and 13°C) increased. The effect of temperature was more conspicuous for japonica varieties than for indica ones, indicating higher sensitivity to temperature of the former. 3. Difference in cultural season resulted in different values of alkali decomposition of rice. Late-season-cultured rice showed higher digestibility as compared with early- or mid-season-cultured rice. 4. Alkali digestibility of rice starch which had been separated and refined by alkylbenzen-sulphonate solution was quite analogous to that of rice powder of the same source. 5. The results mentioned above may lead to the conclusion that alkali digestibility of rice is exclusively depending on the digestibility of starch granule. 6. Air temperature which seemed to be the most influential of all the environmental factors in ripening season may cause some changes in micellar structure with in the developing granules of starch, and as a result, a change in swelling character which is connected with alkali digestibility.

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[in Japanese]

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[in Japanese]

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From these studies investigated on positions in panicle of ventral white, basal white, milky white like white core and milky white kernels, we considered on relations between shapes of white opaque parts and positions in panicle of these kernels. Based above consideration, we intend to make clear up the mechanisms of development of these kernels. Results are summarized as follows; 1) Milky white kernels developed at inferior positions in panicle as in Figure 1, and shapes are shown in Figure 2 to 13. White opaque parts of milky white kernels have many different shapes as shown in these figures. 2) Ventral white kernels developed at superior position in panicle as in Figure 1, and shapes are shown in Figure 14 and Figure 15. 3) Milky white like white core kernels developed in high prcentages in the second and the third grains of secondary branch of middle parts in panicle as in Figure 1, and shapes are shown in Figure 16 and Figure 17. 4) Basal white kernels developed in high percentages in the second grain of upper branches in panicle as in Figure 1, and shapes are shown in Figure 18 and Figure 19. 5) We make diagram of developmental process of superior medium and inferior spikelet as Figure 20. This figure is made by the consideration that inferior spikelets develop very slowly and need long days for full ripening. As shown in Figure 20, the most rapidly development time of superior spikelet corresponds to the early development time of medium spikelet (about several days after flowering). As same as above mentioned, the most rapidly development time of medium spikelet corresponds to the middle development time of inferior spikelet (about twenty days after flowering).

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The extraction and measurement of acid-soluble nucleotides in rice plants were studied at their different growth stages. Nucleotides were separated by Dowex-1 anion exchange column chromatography followed by paper chromatography. About eleven peaks were detected on the extracts from all stages of growth by using the column chromatography. The peaks of nucleotides obtained were corresponded to AMP (peak II), UMP (IV), unidentified nucleotide (V), ADP (VI), UDPG (VII), ATP, UDP (VIII) and UTP (IX), respectively. Small quantities of cytidine and guanosine nucleotides were also detected. Peak II, corresponding to AMP, was the most abundant in the seedling stage. The level decreased gradually until 30 days before heading, but rose again toward the mature stage. Peak IV, corresponding to UMP, was not clear in the samples from the stage of seedling to 8 days after anthesis. But at the mature stage, the clear peak was obtained. Peak V, which had absorbance amximum at 236 mμ (at pH 2), wsa not yet identified. It gave values of 1.72, 0.24 and 0.10 for the absorbance ratios 250 mμ/260 mμ, 280 mμ/260mμ and 290 mμ/260mμ, respectively. There was a large amount of this compound in all growth stages except seedlings. Peak VI, which did not give a single peak, seemed to be due to ADP. Also smaller quantities of guanosine nucleotide and ADP-glucose might be contaminated. This peak increased with ripening. Peak VII, corresponding to UDPG, decreased toward the stage of maturity from the seedling stage. Peak VIII contained ATP with smaller quantities of UDP. This peak rose at the ripening stage, but decreased again at the maturity. It was confirmed that the relative value of each nucleotide is changed from the stage of seedling to maturity. The relationship of these results to the mechanism of ripening of rice plant is discussed.

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A number of single cells and cell aggregates were produced from rice callus tissues in liquid medium at 25-30°C. The freely suspended living cells and aggregated cells were containing one or more of spherical granules, 2.8μ of average diameter. The granules disappeared with acetone, ethanol, ethylene glycol, formalin, isopropanol, pyridine, triethyl phosphate and chloroform methanol mixture. They were also stained blue by 1% or 0.02% Nile blue. But the colour was not removed by 5% acetic acid or 0.5% hydrochloric acid. From these results, it is revealed that the granules are composed of liquid, acidic lipids.

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1. In case of an identical variety being used and sown on a definite date, the dry weight of rice plants at the neck-node initiation stage was positively correlated with the amount of nitrogen at that stage and, furthermore, with the number of panicles and with the number of differentiated rachis-branches. In case of used varieties and sown dates being different, however, the correlation coefficient was considerably decreased. 2. The dry weight increased during the period from the neck-node initiation stage to the late spikelet initiation stage was positively correlated with the amount of nitrogen absorbed during this period and also with the number of differentiated secondary rachis-branches. The photosynthate produced in the period was progressively increased in leaf-blades in proportion to the total quantity with increasing nitrogen content in leaf-blades at the neck-node initiation stage or at the late spikelet initiation stage and, moreover, with increasing amount of nitrogen in the whole plant absorbed in the period. 3. The more amount of nitrogen was absorbed by the plant during the period from the neck-node initiation stage to the late spikelet initiation stage, the more amount of dry matter was produced in the period, but the less amount of stored carbohydrates was found in sheaths and culms at the late spikelet initiation stage or at the heading stage. 4. The dry weight increased during the period from the late spikelet initiation stage to the heading stage was positively correlated with the amount of nitrogen absorbed in the period as well as the amount of nitrogen in the whole plant at the heading stage. 5. The amount of stored carbohydrates at the heading stage had no connection with the amount of nitrogen absorbed during the period from the late spikelet initiation stage to the heading stage. However, in case of an equal amount of nitrogen being absorbed by the plants by the time of late spikelet initiation, the amount of stored carbohydrates in sheaths and culms at the heading stage was progressively increased with increasing amount of nitrogen absorbed in the period. 6. A negative correlation was found between the dry matter increased during the period from the late spikelet initiation stage to the heading stage and the number of degenerated rachis-blanches.

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Pelargonium denticulatum had been the most popular of all Pelargonium species in Japan, but in 1954 three types of P. roseum, viz., varieties "Italy", "France" and "America", were introduced into Japan in the hope of obtaining better and more oil. P. roseum plants are more spreading and shrubby with vigorous growth than P. denticulatum, but the former is lower in yearly yield of oil per hectar. However, the oil of P. denticulatum is inferior to P. roseum in quality. B₁ No. 10 was newly grown by the back cross of P. roseum "France" and P. denticulatum. In the oil yield rate, B₁ No. 10 showed an intermediate value between P. roseum and P. denticulatum higher than P. roseum by 20-50 per cent, and also maintained a quite high oil yield in spring and late autumn seasons. Concerning the quality of extracted oil, B₁ No. 10 was not inferior to P. roseum. The main components of the oil being citronellol and geraniol, the components existed generally in a free state. As a result of examining in the variation of citronellol and geraniol by gaschromatography, it was found that there was seasonal variation. That is, when the oil contents of them both in early period of growth were compared, the percentage of geraniol showed a higher value, but as the temperature got higher in summer the percentage of geraniol decreased, and on the other hand the percentage of citronellol significantly increased. However, as the temperature got lower in the months of November and December, the percentage of citronellol decreased and that of gernaniol again increased. The optical rotation of essential oil was also high in the season of high temperature and low in the season of low temperature. This is probably due to the increase and decrease in percentage of 1-citronellol. We can conclude that the seasonal variation of the percentage of citronellol and geraniol is due to a biochemical oxidation-reduction reaction. It is considered that geraniol is changed into citronellol mainly by phytochemical reduction during summer season, and that the percentage of geraniol is increased by dehydrogenation in late autumn season. The quality of geranium oil greatly depends upon the proportion of content of geraniol and citronellol. It has been reported that the above mentioned proportion is defferent according to the producing land and species, but as described above, the phenomenon that the oil content percentage is significantly different in different seasons of oil extraction can not be overlooked.

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The relation of photosynthesis to light condition was investigated with soybean plant population. Diurnal changes of photosynthesis, horizontal light intensity both total and diffuse were recorded on 3 or 4 successive days of various weather conditions. From these data, light-photosynthesis relation was investigated with refernce to the proportion of diffuse light component to the total light. On the other hand, the manner of light distribution on photosynthetic system was investigated under various light conditions by measuring the illumination intensity on individual leaves. The results obtained were as follows: (1) Photosynthetic rate of soybean plant population depended not only on total amount of light but also on its proportion of diffuse light. When the total light intensity was same, the photosynthetic rate varied with the proportion of diffuse light, that is, the photosynthetic rate increased with increase in the proportion of diffuse light. (2) Under fine or clear condition the proportion of diffuse light was very low and many sun flecks were formed on photosynthetic system of the population. A major part of light was concentrated to these limited regions, resulting in a uneven distribution of light on photosynthetic system. On the contrary, under hazy or clowdy condition, the proportion of diffuse light was higher and distribution of light on photosynthetic system was relatively even horizontally as well as vertically. (3) Rates of the photosynthesis under various light conditions were calculated from illumination intensity at surface of leaves and light-photosynthesis curve of single leaf. Then, the photosynthetic rates so obtained were compared with each other. Under same total light intensity, the calculated rate was consistently higher when the proportion of diffuse light was higher, Further, the ratio of the two rates, calculated under higher as well as lower proportion of diffuse light, was fairly coincided with the same kind ratio of the two rates obtained by direct measurment of photosynthesis of population. From this, it was concluded that a higher photosynthetic rate under a higher proportion of diffuse light based mainly on more favorable distribution of light on photosynthetic system-even distribution of light.

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Soybean variety Shirobana-Sai-No. 1 growing in pot was subjected during the growing period of 5th or 6th leaf on main stem to various shading treatments. Photosynthetic capacity of the leaves were measured under various light intensity, and light-photosynthesis curves obtained with the leaves of different treatments were further investigated to know the photosynthetic properties of leaf as subsequently affected by light condition. The results obtained were as follows: (1) The photosynthetic capacity at higher light intensity decreased with decrease in light intensity in a given period by shading. (2) The earlier the beginning of shading, the more the depression of photosynthetic capacity at higher light intensity, though the shading after the leaf had fully expanded also caused a somewhat depression of photosynthetic capacity. (3) Cessation of shading showed a trend of recovering photosynthetic capacity. The recovery was complete when the shading ceased at the time of unfolding of the leaf, whereas it was incomplete for the cessation at the time of full expansion of the leaf. (4) Admitting some exceptions, photosynthetic capacity at lower light intensity increased by shading, while decreased by cessation of shading. (5) Respiratory activity of the leaves decreased by shading, while increased by cessation of shading.

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The canopy structure of crop communities plays an important role in both the diminish of radiation flux within the canopy and the photosynthesis of crop communities. In this paper the geometrical structure of a corn canopy was investigated as a preliminary to further study of the canopy structure and the photosynthesis relationships. The stand structure of the crop is well characterized by the distribution of the leaf. The orientation of a leaf is exactly determined by two parameters; the inclination angle of a leaf or a leaflet (foliage angle) and the azimuth angle of the normal on the upper surface. In 1966 and 1967, the vertical distribution of leaf area density, foliage angle and azimuth angle of corn plant canopies were determined with a silhouette method specially deviced for this purpose. Horizontal silhouettes of all leaves were projected on a graph by using values of the abscissas and the ordinates of the base (P₁), top (P₂) and tip (P₃) of each leaf blade. The silhouette of each leaf was determined by eye-fitting the length of the leaf blade (1) through the three points (P₁, P₂ and P₃) (see Fig. 1). The vertical distribution curves of the leaf area density in both years were characterized by the establishment of a peak with high density in the upper or middle layer of the canopy (see Fig. 3). Normalized height distribution curve were found to be approximated by the following formula (see Fig. 5). fLD=a+bz'+cz'²+dz'³ The constants (a, b, c and d) in the above formula showed clear change with the growth of the crop (see Table 1). The distribution function of the leaf area in relation to the foliage angle approached to approximately uniform distribution with growing the crop, agreeing well witht he results reported by Ross and Nilson (1966) (see Fig. 6). Though the distribution function of the leaf area in relation to azimuth angle was different from each other, the distribution in the layer with the highest leaf area density intended to be approximately uniform with respect to the azimuth (see Fig. 7).

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The structure and the cellulose microfibril orientation of cell walls of cortical fibre cells, parenchymatous cells and vessels were observed with the technique of microscopic chemistry and polarized microscopy. The cell wall of the cortical fibre is composed of three layers, and the vessel has two kinds, dominant and recessive, of microfibril orientation, as illustrated in Fig. 1 (p. 603). It is important that, in all cases, the cellulose microfibrils cross each other at the angle of about 84°or about 58°Notes. Photos. 1-10. Cortical fibre cell. Photo. 1. Transverse section. The outer layer (S₁) is formed first, and followed by the middle layer (S₂) and the inner layer (S₃). Photos. 1A', 1B' and 1C' are photographed between crossed nicols. PW Primary wall. Photos. 2 and 3 are the transverse sections of the middle layer and the outer layer, respectively, swollen with cuprammonium. The middle layer shows several lamellae. Photos. 4 and 5. The cortical fibre cells swollen with sulfuric acid, show the helices of the outer layer. Photos. 6 and 6'. Surface view of a single wall of the outer layer. Photo. 6 is the wall stainde with iodine, and 6' is photographed between crossed nicols. The axes of pits and striations run in the same direction. Photo. 7. Surface view of a single wall of the middle layer. Photo. 8. Surface view of a single wall of the inner layer. ST Station. Photo. 9. The inner layer's helices of the cortical fibre swollen strongly with cuprammonium. Photos. 11-15. Parenchymatous cell. Photo. 11. The transverse section of a cell wall, swollen with sulfuric acid and stained with iodine, shows many lamellae. Photo. 11 is photographed through polarizer. The dichroism of iodine can be recognized. Photo. 11' is photographed between crossed nicols. Photos. 13 and 14. Surface view of a vertical single wall bearing two sets of striations crossing each other at the angle of about 84°. Photo. 15. Surface view of a horizontal single wall having striations running at random. Photos. 16 and 17. Annular vessel. Photos. 16' and 17' are photographed between crossed nicols. Microfibrils run horizontally in the hollow rings. Photos. 18 and 19. Pitted vessel. Photos. 18A and 19A are focused on the basal plane, 18B and 19B at the top. The direction of pit axes shows that microfibrils run downward along an S helix. Photo. 20. The cell wall of a vessel, swollen with sulfuric acid, shows several lamellae. Photo. 21. Surface view of a single wall of the vessel. Two sets of striations cross each other at the angle of about 84°in 21 A and B, and at the angle of 58°in 21C and D.

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This experiment was undertaken to examine an injurious effect of sulfur dioxide to crop plants under the light intensity of 20 k lux and under the dark condition, by exposing the plants to sulfur dioxide of 20 ppm. The results obtained are as follows. 1. An injury was observed on the leaves of both rape and barley even under the dark condition, increasing the degree of injury in accordance with an extention of treatment time for which the plants were exposed to the gas. 2. Rape, in the flowering stage, showed no significant difference in the susceptibility to the gas between the plants in the light and in the dark, though there occurred, in the vegetative stage, that the plant was more severely injured in the dark than in the light. In barley, however, the plant in the light was always damaged more severely than that in the dark, 3. The leaves of both plants absorbed sulfur either they are in the light or in the dark. Particularly, the sulfur content of the leaves of rape increased linearly with an extention of treatment time, showing higher content of sulfur in the light than in the dark. 4. The degree of injury appeared on the leaves possitively correlated with the sulfur content of the leaves, but in rape the considerably high content of sulfur did not cause any visible injuries on the leaves.

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For the purpose of obtaining some data serving as the basic ones for analyzing the relationship of rice growing seasons or areas to rice yields, authors tested the seasonal changes in NAR of rice plants, i. e., the seasonal changes in NAR in response to those in solar radiation and air temperature. For this test, Fujiminori Variety's young seedlings (at the fourth-leaf fully developed stage) grown in soil cultures were used as samples. The test results might be summarized as follows: 1. It was noted that NAR at the daily mean air temperature of 15°to 21°C changed favorably in proportion to the increases both in solar radiation and air temperature, but at the temperature of 21°to 30°C, NAR changed in response only to the increase in solar radiation, irrespective of air temperature. 2. Based upon the test results showing the above-mentioned seasonal changes in NAR as well as upon the daily mean solar radiation and air temperature at Zentsuji (in Shikoku), authors could observe the probable seasonal changes in NAR as described below in the months from late April to late October. 3. It was estimated that NAR took a rapid upward trend in the month from late April to late May, but in June it showed a rather retarding trend. After the opening of July, however, NAR continued to take the upward trend again, thus reaching the peak in late July and then it dropped with rapidity.

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Histological aspects of the formation and growth of callus tissue derived from root-tuber of sweet potato have been reported in this paper. When the tissue disk which was obtained from root-tuber was placed on a White's medium containing 0.5% yeast extract and 2, 4-D (1 mg/1) or NAA (20 mg/1), it was recognized that the cell division which occurred in some starchy cells in the surface region of tissue disk induced the formation of meristematic tissue. Then, the meristematic tissue on the lateral side of tissue disk grew vigorously to form callus tissue which had layers of meristematic cells in the surface region. The obvious difference between 2, 4-D and NAA medium was observed in the structure of callus. Many "vascular bundle-like tissues" which were consisted of tracheid-like tissue and cambium-like tissue were observed in the callus on NAA medium. On the other hand, even tracheid-like element was scarcely observed on 2, 4-D medium. It was recognized that vascular system of the root differentiated in callus tissue did not connect with the above mentioned "vascular bundle-like tissue" of the callus, but was observed as closely connected with the secondary vascular bundle of root-tuber included in the original disk.

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Two sets of rice plants cultivated under submerged conditions were used, one serving as a test set, the other as a control. One set placed in front of an electric fan where it was exposed to wind velocities from about 0.6 to 1.0 meter per second during day time. The control set was protected from the fan and the natural wind (Fig. 1). The experiments reported here show that the transpiration rate increases about 4.5 to 12 percent and the average length of the crown roots increases about 13 percent by wind. As for the differentiation of the endodermis, though there was no significant difference in the cell wall thickening between both sets, the ratio of the passage cell number opposite to the protoxylem of the stele, were greater in the treated plants. Judging by the data concerning the stimulating effect of the "mild" wind on root length as well as the number of passage cells, it may be reasonable to think that the ability of roots to absorb water can be induced by the acceleration of transpiration.

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The experiments on the water absorption in the different parts of the root of rice plant were carried out, with specially designed micropotometers (Fig. 1). The results obtained show that the water absorbing capacity in the different parts were different, and the most active absorbing zone came between root tip and the part where the first lateral root emerged. The microscopical observation has shown, within this limit, that the differentiation of the endodermis was in the state of casparian dot stage. Furthermore, the differentiation of the xylem vessel in the stele also keep intimate correlation with the differentiation of the endodermis (Fig. 21). Taking in view the results obtained, it is suggested that the stage of the differentiation of the endodermis in a root can be used to detect the zonal differentiation of water absorption.

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In order to study the application of polyethylene mulches to upland rice culture in Kanto District, the whole growth process of the plants was investigated under unmulched and mulched condition. The varieties were upland rice Norin glutinous No. 20 (early-maturing) and Norin glutinous No. 1 (medium-maturing). Upland rices were sown on April 11 and 25 in the mulched plots, on April 25 and May 15 in the unmulched plots, respectively. All fertilizers were applied as base in the mulched plots, but nitrogen was top-dressed in addition to the base fertilizer as that of customary culture under the unmulched plots. The results obtained were as follows. 1. Under mulching culture emerging-and vegetative-period was reduced, because of higher soil temperature, and then, in each variety, the heading time sown on April 25 was advanced 8 days compared with the unmulched plots. Especially the heading time was advanced on the end of July, even Norin glutinous No. 1 which was medium-maturing, when it was sown on the bound period of early seeding under mulching condition. From above results, it can be suggested that the mulching culture of upland rice in Kanto District is usefull to avoid dry-spell damage during the later summer. 2. The leaf emerging velocity of upland rice under mulching culture was earlier, and showed prosperous growth in the early period, and then a number of panicles were formed. The weight of 1, 000 grains and the percentage of ripened grains were inc reased, too. But the number of spikelets per panicle was inferior to the unmulched plots. As a result, the yield of each varieties was not different between unmulched and mulched plots. 3. But upland rice in mulched plots showed shorter leaf blade, smaller leaf-blade·leaf-sheath (including stem) ratio and shorter internode. From these phases of growth, upland rice could utilize sunlight efficiently and had resistance to lodging. And the tendencies were remarkable in early sowing. These facts were due to prosperous growth in the early stage and decreasing nitrogen content in leaves in the late stage. On the basis above mentioned facts, it is suggested that the more increased yield under mulching culture can be obtained accoring to top-dressing before reduction division stage.

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For the weed control in the plastic mulching culture, authors contrived "Herbicidal Film" which was made polythylene films mixed, coated or printed with herbicides. Mixed ones were formed after having been mixed herbicides with source solution of polyethylene. 1. The mixed or coated herbicidal films were more effective for weed control than printed ones, no clear difference was recognized between the mixed herbicidal films and the coated ones, both were excellent. 2. The sorts of effective herbicides for herbicidal films were those which display their actions with being absorbed and translocated by plants, and those which display their actions with contact on plants were non-effective. The matter above mentioned was due to the fact that almost herbicides melted out from the films and get into active during a day after mulching. 3. It is said that less doses of herbicides are required on mulching culture than common culture, because of higher soil temperature, much soil moisture and uniform emergency of weeds under the films. With an experiment on the herbicidal films, the same result as that of above mentioned were obtained. So comparing with the common culture, about two-thirds doses of herbicides used for herbicidal films were as effective as those of common. And more doses may cause the injury of crops.

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Shading treatments at different growth stages, reduced the dry weight of rice plants at maturity. Shading treatment during the period from the neck node initiation stage to the late spikelet initiation stage, reduced the dry weight of shoot at maturity, but not that of ear. Shading treatment during the period from the late spikelet initiation stage to the ear emergence, reduced the dry weight of ear at maturity, but not that of shoot. Shading treatment during ripening period, reduced the dry weights of ear and shoot at maturity. The dry weight reduction resulting from shading treatment was greater in extents in the case of ear than in the case of shoot at maturity. Therefore, the ratio of ear to shoot at maturity was greater for the treatment shaded during the period from the neck node intiation stage to the late spikelet initiation stage than for the control. And the ratio of ear to shoot at maturity was greater for the control than treatments shaded during the period from the late spikelet initiation stage to the ear emergence and ripening period respectively. In this experiment, the ratio of ear to shoot at maturity had no definite relation either with the ratio of the dry weight increased after the ear emergence to that at the ear emergence, or the ratio of the number of spikelets to the dry weight at the ear emergence, However, in all the treatments excepting those shaded during the period from the late spikelet initiation stage to the ear emergence, the ratio of ear to shoot at maturity was positively correlated with the ratio of the dry weight increased after the ear emergence to that at the ear emergence. And, in all the treatments excepting those shaded after the ear emergence, the ratio of ear to shoot at maturity was positivily correlated with the ratio of the number of spkelets to the dry weight at the ear emergence. In the treatments shaded during the period from the late spikelet initiation stage to the eer emergenece or ripening period, no definite relation was found between the dry weight increased after the ear emergence and the number of spikelets. From these facts, it could be said that the ratio of ear to shoot at maturity was first determined by the ratio of the number of spikelets to the dry weight at the ear emergenece, and then by the ratio of the dry weight increased after the ear emergence to the munber of spikelets.

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1. The root systems of peanuts were consist of numerous lateral roots derived from the main root weighed more than 95 percent of the total roots. Adventitious roots derived from hypocotyl and ramifications were quite few in number and poor in growth. 2. The primary branch roots emerged densely from the part near to the base of the main root, but they decreased gradually as nearer to the root apex. 3. The primary, secondary and tertiary branch roots were generally observed, while the fourth and subsquent ones were rarely. 4. The secondary and tertiary branch roots were so short in length that they were not so much complicated, and seemed that it facilitated the gynophors to push into soil and the pegs to grow. 5. With regard to the emergence of hypocotyl roots, varietal differences were recognized. Namely, in cases of Spanish and Valencia types, the emergence of roots from hypocotyl was very difficult, while in the cases of Virginia and Southeast Runner types, it seemed somewhat easy. 6. It was considered that such meager root system was closely related to the differenciation of the cortex of the hypocotyl, particularly of cortex cells, as well as to the growth of hypocotyl roots. Accumulation of cell membranes resulting from the collapse of the cortex cells and the formation of cork layer seemed to restrain the development and elongation of the primordial roots. 7. Adventitious roots developed from the ramifications just above the ground were observed at latter growth stage, more in cases of prostrate type varieties. 8. It was proved that the development of such adventitious roots was strongly affected by the moisture-content in the soil. From these results, it can be concluded that the functions of peanut roots are exclusively performed by the main root systems, and the part played by the adventitious roots is quite temporary.

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Rice and barley seedlings which were raised out of doors were used as plant material. Tiller buds which had been growing and terminal buds were taken out from these seedlings and were grown on artificial agar medium supplied with various concentrations of IAA from 10^-4 to 10^-7 M and zero under the condition of presence or absence of gibberellic acid and kinetin, in order to get basic information as to the relationship between the growth of tiller buds and growth substances. In case of barley, the growth of the tiller buds without LAA was much better than that with IAA. The growth was poor at the concentration 10^-5 M which has been recognized to be the optimal concentration for the growth of shoots in various kinds of plants. The growth to terminal buds showed almost the same behavior as that of tiller buds to various concentrations of IAA. In case of rice, on the other hand, the growth of tiller buds was highest at the concentration of 10^-5 M of IAA, being very poor without IAA. The growth of terminal buds of rice without IAA was inferior to that with IAA. In any case of the experiments reported here, no tendency was recognized that the optimal concentration of IAA for the growth of tiller buds is lower than that for terminal buds as suggested sometimes to explain the reason why auxin produced at the terminal bud inhibits the growth of the axillary buds. Besides, in most of the tiller buds and terminal buds of rice plants, roots developed, unlike in case of barley in which very little root development took place.

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This study was carried out to verify the varietal difference in the activity of photosynthesis per unit of leaf area and the stability against environmental conditions. For this study, the leaves adhering to the soybean plants were used as sample and the activity of photosynthesis was measured at the stage when the leaves showed the maximum photosynthetic rate, in the laboratory under the conditions of the saturated light intensity at leaf temperature of 26 to 29°C, with ordinary atomospheric concentration of CO₂. The results are as follows: 1. Coefficient of variation in photosynthesis among plants of different varieties varied as much as 5 to 25 percent. 2. Variations in photosynthetic rates among varieties were less than some ± 20 percent as against the aggregate average rate of all the different varieties. 3. Absolute vaule of photosynthesis varied with the environmental conditions, but it was verified that the varieties of high activity of photosynthesis indicated high rates of photosynthesis without exception, when all the different varieties were tested in comparison. 4. Varietal difference being found in the photosynthetic rate according to different varieties as stated above, photosynthetic rate can be taken as a target characteristic for selection in the breeding process.

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This Study was attemped to get a clue available for the improvement in the activity of photosynthesis of soybean varieties. The result are as follows: 1. Frequency of occurrence of improved varieties showing the high photosynthetic rate increased in the cases of combinations with the parent varieties of high photosynthetic activity. 2. Most of the improved varieties were selected so that their photosynthetic rates became practically as high as, or higher than those of their parent varieties having the high activity of photosynthesis. 3. By means of breading tecniques, it would become possible to increase the photosynthetic rates of soybean varieties appeciably higher than the present level. It is deemed possible enough to raise the photosynthetic rates, at least, of Kanto-Tosan soybean variety group in Japan.

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[in Japanese]

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The utilizing efficiency of solar energy (Eu) in dry matter production of plant population consists of two components: one is the efficiency for absorbing the solar energy by the stand (α) and the other is the efficiency for fixing the absorbing energy for dry matter production (Eφ). With the aim to find out the actual values of these components as well as the utilizing efficiency in a rice population, measurement of the following items was carried out using rice plants, Norin No. 29 which were cultivated in the paddy field at the density of 16 hills/m² (25×25cm): total incident energy (S), the rate of energy reflection by the canopy (albedo, a), the rate of energy transmittance at the surface of flooding water (t), the rate of energy reflection by the surface of water, the amount of dry matter produced in a certain period (ΔW), the leaf area index (LAI), and the heat of combustion per gram dry matter. Measurements were made continuously from August to October. The results are as follows: 1. The albedo (a) of the rice population before heading stage was almost constant (22%). However, it decreased gradually after heading to reach 18 per cent at maturity. This decrease may be related to the fact that the albedo of ears is lower than that of leaves (table 1). 2. The decrease in the rate of energy transmittance by the canopy according to the advancing growth stage was attributed both to the increase in LAI before heading, and to such changes in the structure of the crop stand as the emergence of ears and decrease in the inclination of leaf-blade after heading (fig. 6, table 1). 3. The efficiency for absorbing the solar energy (α) increased with the growth of rice plants to reach the maximum value (about 70 %) on 30 days after heading. The change of α was closely related to that of t (fig. 4). 4. The heat of combustion per gram of each organ in each growth period was measured by use of a calorimeter. The value, K, was in the following order: Leaf-blade>Leaf-sheath>Root but its variation during the whole growth season was as small as four per cent (table 2). The mean value of K of the whole plant was 3.76 Kcal per gram. 5. The efficiency for fixing the absorbed solar energy (Eφ) was calculated by the following formula: Eφ=(K·ΔW)/(α·ΣS)×100 (%) The value of Eφ for 40 days in total before and after heading varied between 4.1 and 6.9, maximum value being seen at heading stage (table 3). 6. The utilizing-efficiency of incident energy (Eu) is given by the following formula: Eu=(K·ΔW)/(ΣS)×100 (%) The value of Eu fluctuated from 0.8 to 3.7 by growth stage, maximun value being found at heading stage (table 3).

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