The influences of night temperature on the water economy of oats adapted to a cool climate and upland rice adapted to a hot climate were observed. The results of the experiment were as follows: (1) Cool night temperature of air was favorable to the growth and yield of oats, but the plant delayed in heading to some extent. On the other hand, it was unfavorable for the growth and favorable for the ripening of upland rice. As the reason of this fact it might be concluded that the large diurnal ranges of air temperature promoted the ripening of crops. (2) The amount of water transpired through oat plant per day was largest from the beginning of heading to the earlier stage of maturity, and that in upland rice plant was largest at the heading stage. (3) The water requirement of oats on cool night was less than that on warm night through almost every stage of growth, while that of upland rice was higher on cool night during vegetative growth periods and lower after heading. In other words, water economies during these stages were to be carried out efficiently on cooler nights. These results concerning upland rice seemed not ot agree with those obtained by BRIGGS

抄録全体を表示

It has previously been shown by the writer that the weakness of dehiscing power of anther is the most critical factor governing the incidence of sterility in barley. An attempt was made to measure the dehiscing power from the physical points of view. For this purpose, two factors, namely the velocity and weight of pollen grains were measured on the plants sown at three widely separeted dates in the spring. The velocity, presented in the order of sowing date, was 13.9, 9.8 and 6.3 cm/sec, respectively. The weight of pollen grain was determined by two different methods, (1) subtracting the weight of empty anther from that of the same filled with pollens, and dividing the remainder by the number of pollens, (2) multiplying the specific gravity by volume of pollen grain. The first and the second method gave approximately similar results. The weight of a single pollen was (110, 122 and 96) x 10^-9 gr. respectively. Since two factors, velocity and weight, were obtained, the momentum of pollen was calculated as the product of these two factors. Representing the momentum with ratios of integer, it was found as 2.5 : 2.0 : 1.0, and obviousey corresponded in close negative correlation to the sterility percentage; 7.1, 12.5 and 31.1.

抄録全体を表示

During the period of germination of oat seed, the scutellum was found to grow up to the top of the grain. This phenomenon is characteristic to oats plant. The epithelium of the scutellum became large in area according to the expansion of the scutellum. Therefore, the absorption of food materials in the grain by the scutellum may possibly be more vigorous in oats than in other cereals.

抄録全体を表示

Experiments on the influences of 2.4-D upon the sweet botato plant under various conditions were carried out by the authors. The 1st experiment: Growth of sweet potato plant sprayed with 2, 4-D, its slip being planted in different ways of method, was examined. The 2nd experiment: Effect of 2, 4-D on the growth of sweet potato plant grown from the slip of different property was examined. The 3rd experiment: Growth and yield of sweet potato plant as affected by different amount of 2, 4-D applied at different gowing stage were observed. The results obtained were summerized as follows: (1) Injury of 2, 4-D upon the growth and yield were reduced by adopting the vertical planting method or by using the hardened slips. On the contrary, in case of horizontal planting method or using soft slips the injury of plant became severer. (2) Comparing various stages of the growth between each other, the sweet potato plant was found most noticeably suseceptible to the injury of 2, 4-D at planting stage. The data of the experiments showed the increment of weight in the top and root were highest when 2, 4-D was applied at 7th day or 14th day after planting slips. The dry matter percentage in tuberous root decreased, and besides the neck-portion of it became thick when sprayed with 2, 4-D.

抄録全体を表示

Generally, the origin of the root nodule of peanut plant develops in the cortex at the base of the lateral root. According to this investigation, it was found that there was no connection between the location of root nodules and the radiating direction of the protoxylem in the central cylinder of the lateral root. The process of the infection of root nodule bacteria may be divided as follows. (1) Infection through epidermis {root hairs. other epidermal cells.} (2) Infection through broken epidermis {broken epidermis caused by the lateral root. other broken epidermis.}

抄録全体を表示

In the present investigation particular attention was given to a study of the influences of the concentrations and the sorts of sugars upon the tuber formation of potato stem segments cultured under sterile condition. Potato of the variety "Irish Cobbler" was used as material. When the potato stem segments were cultured in the syntheic medium containing low concentration of sucrose, such as 2% and 4%, the growth of lateral buds arising from the stem segments was recognized, but there resulted no tuber formation. On the other hand, by the cultures with high concentrations of sucrose as 6%, 8% and 10%, the tuber formation occurred at the tips of lateral buds of the stem segments and, at the same time the rate of tuber formation was accelerated in proportion to the increase of sucrose concentration in the medium. The effects of maltose, glucose, and fructose on the tuber formation were similar to that of sucrose. Judging from the results described above, it may be assumed that the tuber formation on the potato stem segments under the sterile culture is closely related to the amount of sugar added to the culture medium.

抄録全体を表示

With a desire to see the variations in ascorbic acid content, and in amylase and phosphorylase activities at the time of sprouting of potato tubers, the present investigation was carried out. At the sprouting period of the normal and greening potato tubers, ascorbic acid (especially reduced form) contents decreased remarkably, which in turn caused striking rise of amylase activity, while the phosphorylase activity falled gradually. Judging from these results, it may be assumed that the enzymatic degradation of reserve starch in potato tubers may be hydrolytic, as catalyzed by amylase system, rather phosphorylytic, as catalyzed by phosphorylase system. on the other hand in the old tubers, owing to the senility of the tubers, lowering of ascorbic acid content and of amylase and phosphorylase activities were recognized.

抄録全体を表示

1. The authors found in many of the preparations of the bud, that had dropped, the proembryo having been formed by fertilization. Almost every flowers and pods which had dropped were observed to contain immature grains which stopped their devdopment at the end of proembryo stage or at the cotyledonous stage. 2. Flower-drop which took place most frequently seemed to be caused by stopping of development of the seed, in which firstly the elongation growth of embryo cells became inactive, nextly it stopped and, at last, the whole embryo and endosperm deteriorated as shown in figs. 4. 5. 6. 7.

抄録全体を表示

Investigations were undertaken on the effects of respiratory inhibitor upon the growth of rice plant. Constant volume of the solution saturated by H₂S were added to the nutrient solution of water culture of rice plants. The external and internal changes in the root observed were as follows. 1) Root growth was inhibited by H₂S and the parts severely injured showed necrosis 2) From the parts just above the necrotic portion, many lateral roots grew forming a bunch like a lion's tail in its appearance. 3) Occasionally in old roots the lateral roots were hindered, by the exoderm that had been strongly ligified, from protruding outside, and elongated themselves into the lysigenous intercellular spaces of the cortex. (Eig. 1 and 2). Such phenomena took place by solution cultures both with and without H₂S. Therefore, it may be understood that the anaerobic condition of culture solution was the direct cause for the root injury, and H₂S might have promoted it.

抄録全体を表示

(1) Rice plants were grown experimentally by late seeding and transplanting, being thus exposed to cool weathers at their blooming periods, and their flowering and fruiting capabiliy as affected by air temperature was studied. (2) Blooming was found to occur rather more prosperously when the temperature rose even only in a slight extent after a period with lower temperatures which were sub-optimal for blooming, than when it remained unchanged at somewhat higher levels. (3) Decline in fruiting percentage of the flowers due to low temperatures at blooming stage was proved dependent on the growth condition of the plant previous to that stage. Plants which had suffered from shortness of temperature, not being vigorous enough at their flowering stages, showed higher reduction in fruiting percentage by low temperatures, compared with those grown up under favourable conditions. (4) The optimum temperature for flowering in rice plant under natural conditions seemed to lie between daily maximum from 27.5O° to 32.5°C., or more precisely, from 29.5° to 32.5°, and daily minimums from 17.5° to 22.5°, or more precisely from 19.5° to 22.5°C. With a daily maximum temperature below 24.5°C blooming was restrained remarkably.

抄録全体を表示

1. The present experiments were carried out as a part of the cooperative research undertaken by the working party on rice breeding of the International Rice Commission, to make clear the fundamental characters concerning the earing time of the rice plant. 2. Twenty varieties supplied by 8 countries were grown from their earliest seedling stages under 4 different day-length conditions, viz. 10.5 h., 11.5 h., 12.5 h. and the natural day-length. 3. Vegetative growth periods under the optimum day-length were 40-60 days for Japanese varieties, 40-70 days for Burmese varieties, 50-80 days for Indian varieties and 70-150 days for Javanese varieties. 4. The longer limit of the optimum day-length was about 12 hours for Japanese varieties, and it was clearly shorter for the southern varieties with two exceptions, Heenati (Ceylon) and Gendjah Ratji 277 (Java). 5. Only the above exceptional varieties could produce the ear under the natural day length of Tokyo. 6. Under the optimum day-length, the varieties of longer vegetative growth period produced more leaves in the main stem, and a longer day-length than the optimum increased the number of the leaves, with the exception of Javanese varieties of very long growth period.

抄録全体を表示

Starch accumulated in the tissue of rice plant varied in amount according to the growth of the plant, and the size of the grain changed nearly in direct proportion to the amount of them. The process of transformation of starch grain in the tissue of the plant was studied, the results being as follows. (1) The cells newly formed by cell-division contained at first many granules but no starch grains, while a little later, the proplastids in them formed swellings in each of which a small starchgrain (single or more often completely compound) appeared. (Fig 1). Starch grains thus formed developed in size during the slow growth of the cell. But they soon disappeared when the cells grew rapidly, the former probably being consumed for the growth of the cells (Fig 3, I, II, ) Thereafter, in the photosynthetic tissues, the proplastids enlarged their volume and developed into chloroplasts, and henceforth some of them often produced minute temporay starch grains (Fig 3, A). In the majority of parenchymatous tissues except that of the root, the proplastids developed into leucoplasts or amyloplasts in which very large shaped compound grains were formed again (Fig. 3). (2) In the leucoplasts of the parenchyma of leaf sheath, starch grains of largest sizes were formed just when the largest amount of starch had been accumulated in that tissue, and similarly in the parenchyma of internode, the largest grains were seen at the beginning stage of the spike fruiting (Fig. 2). Henceforth the starch grains in leaf sheaths diminished in their sizes and disappeared when the leaf became old and died. In internodes of the culm they similarly diminished with progress of fruiting; but about a month later when the fruiting process nearly came to an end, they were again accumulated and increased in their size in the lower internodes till the crop matured completely (Fig. 3). (3) As the starch grains were found to change their size according to the growth of cells as described above, it may be said that the younger or upper internodes and younger or inner leaf generally contain smaller starch grains (Fig. 5, 6), and in the internodes of the upper portion of the culm contain the larger ones (Fig. 7). In the other tissues and parts the simlilar relations were observed. Besides, the dimensions of starch grains seemed to vary according to the species of plant and to environmental factors. (4) Starch tissues was not found in the root except that of root-cap where small starch grains were usually seen (Fig 4).

抄録全体を表示

1) Crop damages were investigated in two varieties of rice plant "Tozan No. 59" and "Chukyo-Asahi" by comparing two plots, one caught in the storm and one guarded by a wind break. No injury due to the storm was found in the latter plot. 2) In "Tozan No. 59", the plants attacked lodged entirely and the nutrient translocation into kernels was checked remarkably for a few days, resulting the inferior grains remaining on panicles as blasted or chalky kernels, while the superior grains continuing their deverlopment barely into deformed or milk-white kernels, with the exception of some vigorous grains among them maturing into ordinary kernels. The yield of rice was 70 percent of that in the guarded plot. 3) In "Chukyo-Asahi", the leaves were splitted into two or three parts and the hulls were slightly chafed in the plot caught in storm. Accordingly, the kernel development was somewhat checked, and chalky, deformed, milk-white and brown kernels increased. The yield of rice was about 10 percent lower than that in the guarded plot.

抄録全体を表示

1) Chafing of hulls was severe on the upper branches of a panicle and on the inferior grains on a branch. 2) The close correlations were found between the degree of chafing and discoloration of hulls, and between the degree of discoloration of hulls and the degree of injury in kernels contained. Yet, even if the degree of chafing was the same, the younger the grain, the severer were both discoloration of hull and injury in kernel.

抄録全体を表示

Rice seedlings grown in pots were fixed with their axis in a horizontal position and checked from upward bending for about ten days at each of six different stages of growth of their seventh leaves, as mentioned in the figure, and then were allowed to grow vertically. When the eleventh leaf emerged out from the sheath, measurements were made on the length of both sheathes and blades of all the individual leaves. As a result of the measurments, the growth of both sheathes and blades were more or less suppressed, according to their stages of embryonic development when they were displaced into a horizontal position, being hidden within the sheathes. The extents of the growth-suppression in the seventh, eighth, ninth and tenth leaves in comparison with those leaves of the control plants are illustrated in the figure.

抄録全体を表示

1. The author investigated the records of paddy rice harvest by Mr. Akio MIZUSHiMA, an old farmer resident in Okayama Prefecture, written by him and his ancestors from 1865 to 1948 continuously. 2. From the data presented in the manuscripts, it was demonstrated very clearly that the rice yields at his fields had not only been kept higher than the average of the contry but also been improved year by year steadily by the owners through that period. The author made statistical calculations on the data and obtained the following formulae showing relations betwen the year (x) and the yield (y-kokw) of rough rice per tan, at three fields of his own. [table]

抄録全体を表示

In relation to the abnormal rice growth on new lands or old lands uncropped to rice for several years, investigations were made on the various features of abnormal rice growth, its occurrence, its relations to soil conditions, varieties, cultural conditions and methods of irrigation. The various grades of abnormality in the development of rice panicles from the formation of primordia to the seed-completion, characterized the phenomenon, and the fact was made clear that it was due to the water-lodged condition in certain kinds of soil. The author concluded that the phenomenon might fall into the same category, considered from its characteristic features and conditions for its occurrence, as the straighthead of rice reported in the United States of America, and discussed on its probable causes. The most effective method of prevention is to dry the paddy field for abut 10 days just before the plant forms panicle primordia.

抄録全体を表示

To elucidate the influence of H₂S on nutrient absorption and metabolism of nitrogen and carbohydrate, a solution culture experiment was carried out. Just after the addition of H₂S to the solution, absorption of K₂O and SiO₂ was inhibited at first accompanied with such disturbances in carbohydrate metabolism as an increase in reducing and non-reducing sugar contents, and a decrease in starch content. But afterward when the inhibition of nutrients absorption and carbohydrate metabolism became extreme, nitrogen metabolism was also disturbed, resulting in the increase in soluble-N content and decrease in protein-N content.

抄録全体を表示

The occurrence of "Akagare" disease of rice plants was tested by pot experiments using paddy soil on which the disease habitually occurs. Want of potassium and suppling butyric acid and hydrogen sulphide to the soil promoted the occurrence of the disease, but drainage of water about 3cm a day decreased its occurrence. The occurrence of the disease appeared to be highly correlative to the lowering of Eh value of plant and soil, to the increase in soluble-N content and soluble-N/protein-N ratio and to the root-rot.

抄録全体を表示

Developmental processes of young panicles in rice plants were traced up on all individual tillers of 3 hills at an interval of 1-2 days. As the result, it was ascertained the beginning, middle and late stages of every developmental period of young panicles of the plants in a field as a whole can be identified externally by examining the morphological characteristics of the plant.

抄録全体を表示

The paddy and soybeans in the drug wastes preserved in the Shosoin Treasury were investigated morphologically and microchemically. (1) As to size and shape, half of the grains of the paddy appears to belong to Japonica, one third of them to the medium and one sixth of them to Indica type. All these grains of the paddy are about 16% lighter than the paddy of the present. The incessant action of natural oxidation covering 12 centuries has brought about partial carbonization of the endosperm. The transverse section of the endosperm tip shows a white and black mosaic. The endosperm fragments respond to the iodine solution as the nonglutinous. (2) The soybeans of the treasury exhibit the medium size and shape between those of the wild form and the summer varieties. The Shosoin soybeans weigh about 21% lighter than the contrasting soybeans of nearly the same size, and retain the minimum water contents of soybean, viz. 8.9%, while those of the summer varieties hold about 12% in general. Besides it is noteworthy that the cotyledon parenchymatous cells of the Shosoin soybeans are about 37% narrower than those of the contrasts. Despite under such circumstances, no significant sign of chemical deteriolation in soybean protein and fat in the plasm, exclusive of pectin in the middle lamella of the cell wall, is observed under, a microscope.

抄録全体を表示

I. Localization and activity of phosphorylase in rice plant. Higher activity of phosphorylase was found in the tissues of the stem (especially at nodes), the leaf, the neck of ear and the arista in rice plant. The localization of phosphorylase was proved to coincide with that of natural starch synthesis, except in the embryo of an early stage of germination. Therefore, phosphorylase seems to be closely connected with the synthesis of starch. II. Histochemical demonstration of phosphorylase in the cells with high amylase activity. No starch was found in the natural wheat leaf. However, when the amylase activity was inhibited artificially with mercuric chloride and pH was made suitable for phosphorylase activity, starch was formed by the action of phosphorylase in the tissue of the wheat leaf. Therefore, the reason why starch is not synthetized in the natural leaves of wheat seemed to be due to the high amylase activity and inadequate value of pH for phosphorylase activity. In order to make histochemical demonstration of phosphorylase in the cell of high amylase activiy, mercuric chloride must be added in suitable concentration for inhibition of amylase activity. The optimum concentration of mercuric chloride was found to be M/100, 000 in the leaves of wheat (var. Saitama No. 27 and Norin No. 50).

抄録全体を表示

The variation in the iron, manganese, zinc and copper levels in the leaf of rice plant of the susceptible variety was found definitely related to the intensity of susceptibility of the plant to wilting disease. In general, high concentration of those elements strengthen the plant's resistance: the phenomenon was proved not to be dependent on the nitrogen, magnesium, calcium or silica levels in the plant body.

抄録全体を表示

When we observe the profile of frozen soil, we find frequently a cavity formed underneath the root system of a plant. Its profile shows a lenticular shape generally, but sometimes it shows a different one. Under the ridge of rye, cavities are often connected each other and make a long hole like a tunnel along the ridge. Cavities can be found under any kind of crops-rye, wheat, barley, rape, hairy vetch, red clover and orchardgrass, and even under the stubble of plants-maize, millets, soybeans and weeds. The plant roots are found cut by such a cavity formed underneath them. The condition of the cavity varies with the development of the root system. The more vigorous the growth the deeper is the place of its formation under the same kind of plant. When the plant has very poorly developed root system, its roots are cut directly by the icicle layer without forming cavities. Therefore, the formation of cavity is much related to the field practice of crop cultivation. On the inner surface of cavity there are ice crystals, which may be considered as sublimates of vapor from unbrozen part of the soil. The mechanism of cavity formation will be explalined as follows. In the process of icicle-layer formation, it develops spreading horizontally beneath the frozen layer in the soil; but at the parts straightly below the plants, the icicle formation is avoided by the dense distribution of plant roots. With the thickening development of the icicle-layer the frozen surface soil layer is heaved as a whole, and the plant bodies grasp in the latter with their roots are pushed upwards, remaining cavities beneath it, and thus the roots distributed there are stretched and broken finallly (Fig. 2).

抄録全体を表示

Potted plants of the lowland rice variety, Norin 37, were used for the measurement of the ventilating pressure at intervals of bout 2 weeks after transplanting. The results obtained are as follows: 1. The ventilating pressure varied with the degree of expansion of stomatal openings and with the number of green leaves. Particularly important was the position on the stem where the lowest green leaf was attached. 2. Specific differences between the main culm and tillers in the ventilating pressure were discernible at the growth stages prior to heading, but they diminished towards maturity. 3. Seasonal changes in the ventilating pressure was recognized decidedly, the pressure being lowest at the stage of differentiation of ear-primordia. 4. Oxygen transference from the top to the roots might reasonably be affirmed.

抄録全体を表示

Microscopic observations have revealed that the crop plants tolerant against the injury of excessive soil moisture are characterized with a highly developed ventilating system and that the reverse is true for those susceptible. The ventilating system may furnish the crop root with sufficient oxygen transported from the top. In the illustration figures of the present report the following abbreviations are used: Ab, axillary bud; ae, aerenchyma ; ca, cavity; ck, cork; co, cortex; cr, crown root; en, endodermis; ep, epidermis; ls, leaf-sheath; ly, lysigenic air space; pa, partition, pe, pericycle; pm, primary meristem; rv, reinforced vascular bundle; sm, secondary meristem; sp, sieve portion; St, stipula; sv, separated vascular bundle; va, vascular bundle; wp, wood portion.

抄録全体を表示

A study was made for the purpose of preventing the injuries of the strong seasonal wind in Atsumi Peninsula. This locality is marked by complicated masses of hills, which render remarkable topographical effects to the wind direction and its force. And so suitable windbreaks for protecting fields are desirable according to the lay of lands. The study consisted of the following three parts: 1) Investigations of the relation between the wind and the lay of land; 2) Indoor experiments by means of model windbreaks and hills set in the stream of air from an electric fan; and 3) Examination of the influences of the actual windbreaks set on the hills. Resuls obtained are summarised as follows: Wind velocity increased at the top and end of a hill and was reduced in front and back of it. Wind directions, at a certain distance from the base of a hill, are the same as those of the mean flow. In the narrower vicinity of a hill, however. those are diversified by the influence of the undulatory topography. Above-mentioned relation was proved true in the indoor experiment, too, by which the effect of windbreaks at various points were investigated. Windbreaks (W_s) located near the top or the end of a model hill were found most effective, the best places for them being confined within a narrow bound, and the calming effect was reduced when it was located apart from those points (see Fig. 2). The windbreaks set near the top or the end of a hill could seperate easily the stream line of wind from the ground surface and performed a large calm region on the leeward, while by those at other locations such an effect was very small. And the results of the outdoor experiments showed that this fact might be applied also under natural conditions.

抄録全体を表示

The critical growth stages of crop platnts for soil erosion in the cropping systems ordinary in Tohoku District were investigated by the data from erosion control experiments considered together with the rainfall characteristics observed at Tohoku Agr. Exp. Sta. in Morioka. It was found that the critical stages for erosion corresponded generally to the periods when the ground-cover furnished by plant stands is vulnerable in the course of cropping system coinciding with the periods of excessive rainfall.

抄録全体を表示

The results of the author's experiments indicated that two-year rotaion of sawa-millet, wheat and soybean brought about soil erosion in a lower extent comared with that by the conventional cropping systems in Tohoku District. The explantion of the good results may be as folows: (1) Either millet or soybean itself protect soil effectively against erosion; (2) Wheat was planted by trashy cultivation, and soybean was interplanted before the wheat harvest, both the procedures tending to protect the soil.

抄録全体を表示

Seeds were treated with nitrate solution and were germinated on moist filter paper in a dark thermostat kept at 25°C. The germination of seeds was found to be affected by suppling nitrate from outside. Tomato, tabacco, lettuce and radish seeds could be accelerated in germination under the ordinary air and the air with lowerered oxygen concentration when presoaked in 0.02∼0.005 M potassium nitrate solution. The effect of nitrate, however, was not decisive on barley and maize seeds.

抄録全体を表示

The tea buds were sprayded with MH-30 Solution (0.05, 0.1, and 0.3%) and were investigated cytologically from 4 to 11 days after the treatment. Nuclear division was inhibited, but even during this period buds grew gradually at 21°C. In treated cells chromatin granules were larger than those in the controls in the resting stage. After prophase nuclear threads congealed together (Fig. 2). In metaphase and anaphase large chromatin mass was seen instead of chromosomes, although it seemed to recover around 12∼13 days after the treatment according to the concentration of MH. The cells which completed nuclear division seemed to grow gradnally in spite of MH treatment.

抄録全体を表示

This experiment was conducted as a part of studies on physiological and ecological characters of paper mulberry plants. An auto-irrigating nursery bed designed by the junior author in 1941 was used to regulate the soil moisture contents. Each of five plots was kept at a different levels of moisture, 40, 50, 52, 60, and 90% of the water capacity of the soil by controlling the under ground water plane at 90, 42, 30, 20 and 10 cm below the soil surface, respectively. The sesults obtained are summarized as follows: 1) The number of sprouting root-cuttings were 9.4, 31, 2, 25, 0, 25.0 and 17.2% for 40, 50, 52, 60 and 90% moisture levels, respectively. The highest was the sprountig percentage in the plot of 50% moisture, and the lowest in the of 40%. 2) The average total length of branches per plant was 61, 3, 74.3, 100.7, 20.1 and 7.0cm for each plot, respeatively. The 52% moisture plot was of the highest value and 90% of the lowest. 3) Some disparity was found in the optimum soil moisture contents both for sprouting and growth. 4) The optimum soil moisture content for the growth of paper-mulberry as far as the authors experiments were concerned seemed to be lower than those for any of such crop plants, as cotton, flax or jute observd by other investigaters (T. SASAKI and G. NISHIKAMA 1938, K. YOSHIDA 1936, T. TAMAI and H. KATAYMA 1943), and it is particulary worth noticing that its optimum is remakably lower and narrower in range compared with that for jute. 5) Moreover its sprouting is considerably influenced by the thickness of root-cuttings, rather slender ones sprouting better than thicker ones.

抄録全体を表示

Experiments were carried out in the purpose of finding a method of testing the cold resistance in tea plant varieties by measuring the permeability of the cell. 1. The higher the resistance of the variety to cold, the more permeable were the leaf cells for water and solutes, the deplasmolysis taking place in shorter periods. 2. It was a simple method for judging degree of cold resistance of the variety to observe the deplasmolysis phenomena in the leaf tissues treated with plasmolysing solutions, comparing it with those in the Yabukita variety as a standard. 3, The deplasmolysis time was shorter in the triploid plants which showed higher resistance to cold, the osmotic pressure of its cells being lower than that of the diploids. The method was recognized to be highly available for estimating the strength of cold resistance of tea plant varieties.

抄録全体を表示

The author studied the water absorption characteristic of sugar cane plant from various angles for many years. The results are summarized here introducing a formula for calculating the amount of water required in irrigation of the plant. The results of measurement with autoirrigators or tensiometers are summarized as follows. 1) The cane plant proved itself to have two processes, active and passive, in water absorption. The passive absorption was larger in water amount than the active. Therefore, the top size of the cane plant affected remarkably the absorption. To certain extent, the water absorption in the cane plant inreased porportionally with its stem length. 2) As the water absorption was largely influenced by environmental conditions, distinct diurnal changes in water absorption were observed as shown in Fig. 1. The data in Fig. 1 were obtained by automatic recorders, which were designed by the author. On fine days, the diurnal variation in absorption showed one maximum point, the curve running nearly parallel with that of evaporation. 3) Such paralellism between water absorption and evaporation was also observed on a solareclipse day, Sept. 21, 1941 (TAMAI, 1943). 4) The same paralellism was also observed on each of other normal cases. The correlation between those two phenomena was high, r=0.74∼0.92 5) The relation between water absorption and length-growth over the whole growing season (14 months) was studied. Absorption intensity increased with the length growth of the plant to some extent (Fig. 2). It gradually decreased, however from autumn to the year end. The amount absorbed during July to September was one-half of that for the whole growing season. 6) The relation among the growth stages concerning the water absorbing capacity of the root per unit area of leaf was, as follows: young plant <middle aged plant> old plant; though the differences among them were not so large. 7) From the experiments on the water absorption above mentioned, following estimates were obtained. Average amount of water absorbed per day per stem =291∼300cc Water requirement =242∼287cc These values are nearly the same as those by other investigators. Calculating from these data, the amount of water required in sugar cane fields, which produce 150000 kin of canes per hectare, may be 700∼850mm in depth during the whole growing season. As a general principle, the amount of water absorbed by the cane plant may be calculated from the following two factors; (1) the size of plant (cane yield) (2) the evaporation from water surface (II) A formula for calculating the water amount required in irrigation of sugar cane. A formula was deduced from the results above mentioned and other data (TAMAI and BABA, 1942) as follows. The water amount for the cane irrigation, [numerical formula] Where E···Evaporation observed by means of evporating dishes during the growing season of sugar cane plant. a···Absorbing coefficient concerned in the cane yield; cane yield···50000→200000 kin per hect., (kin=0.6kg) a·········0.5→2.0 b···Evaporation coefficient concerned in the physical property of soil; gravelly sand→clay, b···0.3→1.0 c···Percolation coefficient concerned in the physical property of soil; gravelly sand→clay, c···0.3→1.0 The values 0.36, 0.5, 0.25 in the formula are constant for the cane field producing canes of 100000 kin per hectare. Using this formula, the author could calculated nearly reasonable values of the amount of irrgating water at three places under different weather conditions (Table 1).

抄録全体を表示

(1) On the old leaves of Jerusalem artichoke plant, of which growth had stopped, 1% urea solution was sprinkled at the rate of 100 c. c. per pot. After the treatment, observation of growth and chemical analysis of the plant materials were made twice a week. (2) The green colour of the leaves became deep, and the tuber growth increased by 17%. However, the height of the top and the dry weight of it showed almost no changes. (3) Increase in crude protein and true protein was proved in the leaves and stems as well as in the tubers, while the ratios of true protein to crude protein decreased more or less. (4) In the leaves, almost no change was observed in carbohydrate contents. In the stems, however, the content decreased rapidly after the sprinkling treatment with urea solution. Poly-saccharide decreased remarkably, while reducing sugars increased to a great extent. Almost no change was seen in total sugar. (5) The urea sprinkling with suitable quantities, when applied 1 or 2 weeks before harvest improved rapidly the quality of leaves and simultaneously helped the tuber growth, thus serving double prupose.

抄録全体を表示