Respiration rate of each part of the rice plant was measured from the seedling stage to the maturity. Respiration rates were measured both at constant temperature, 30°C., throughout the whole season, and at the natural temperature. They were represented both as mg. of CO₂ out-put per hour per mg. dry weight (Fig. 1 and 2), and as that per plant (Fig. 4). The maximum respiration rate shown from 10 to 20 days after transplanting is responsible for the maximum value of relative growth rate at that time (Fig. 3). Apparent peaks, though rather small they are, in respiration rates were observed at the time of the differentiation of ear-primordia, formation of germ cells, and heading.

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Amount and composition of internal atmosphere in the rice plant is measured (Table 1). Diurnal change of the composition of the gas in the base part of root, shown in Fig. 1, is found to be affected by the intensity of solar radiation (Fig. 2), soil temperature, and possibly the periodicity of cell division in the root. Seasonal change of the oxygen and carbon-dioxide percentage in the gas of the root seemes to suggest the trend of physiological activity of the root. The change of gas composition corresponds to the change of respiration rate of roots, reported in previous paper.

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Experiments on wheat seedlings have been reported already. In the present report, soybean seedlings are used as material. Soon after the spray of 2, 4-D, abnormal increase in respiration is observed : maximum increase is about 50% over that of control plant (Table 1). We found that a whole plant does not die at the same time ; cotyledon and lower part of hypocotyl are more resistant but the uper half of hypocotyl is distinctly more susceptible to 2, 4-D. Then we separated a plant into, three parts and measured their respiration. Contrary to our expectation, respiration increase in the susceptible part is not really greater than that of resistant parts (Table 2). Nexttime, seedlings were separated into three parts, as above, before treating with 2, 4-D, and their respiration was measured with two hours' interval (Fig. 1). Respiration of susceptible part is originally higher than that of resistant parts but if it is cut off and separated from the other parts of the body, its respiration decreases suddenly, indicating that the original high rate of respiration is possible only when the enough food material is available in the tissue. The active tissue, respiring vigorously, based on the continuous supply of food material from the other tissues, should be most susceptible to 2, 4-D, because the increase of respiration will cause a drastic exhaustion of the tissue unless the transport of food is also promoted by 2, 4-D.

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The effect of micro-wave treatment on the spinach seeds soaked in 20°C water for 2 days are as follows :- 1. Germination. - In the case of large seeds, there is observed the influence of micro-wave treatment when the seeds are radiated over 1 min., whereas in the case of small ones, the radiation over 3 min. is required. 2. Seed stalk development. - The large seeds are highly significant in developing the seed stalk by 1 min. radiant and the small seeds seem to be slightly affected by 3 min. radiant. Moreover, in examining the sex ratio expressed on seed stalks, we notice apparently the less males in the cases of both large and small seeds when treated as well as in the case of small seed of non-treatment, as compared with the case of non-treated large seeds. 3. Sex ratio. - There are no differences in the sex ratio neither in micro-wave treatment nor in non-treatment, but when we divide the male individuals into pure male and morphological female (the latter is as useful as the pure female), we can observe the increased number of morphological female by 1 min. treatment of large seeds. 4. Comparing large seeds with small ones, the sex ratio of female and male is almost equally expressed, but the morphological female and pure female, those are both useful, are more numbered in small seed case than in large one.

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1. Effect of the depth of sowing, i. e. 1 cm, 3 cm, and 5 cm-depth, of wheat, naked barley, hulled barley and oats upon the consumption of stored foods in endosperms and upon the early growth of plants was studied. 2. The process of consumption was identical and the endosperm exhaution occurred at the same time in all lots of each kind of plants. 3. The dry weight of plumules was generally heavier and that of radicles was lighter under deeper sowing. 4. The development of foliage leaves was promoted under shallower sowing. 5. In all 5 cm-depth lots, the foliage leaves appeared already from the coleoptiles under soil, but the appearance of plumules on the surface of soil was very irregular, because of their insufficient penetrating power through the soil. As the stored foods in seeds were almost exhaused under soil, in all 5 cm-depth lots the 5 cm-depth sowing might be very disadvantageous to the following growth of plants.

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1. In germination and early growth, conspicuous difference was not recognized among these three cyclic wave numbers of Ultrasonic Waves. 2. As for germination itself (both average day number for germination and germination percentage), very promotive result was not obtained in the experimented conditions. 3. As for early growth, its result was now promotively and now suppressively depending on the stimulus intensity of Ultrasonic Waves. Promotive result was generally obtained by radiating for the short time (one minute of five) Ultrasonic Waves upon the seeds soaked in water and then contained in watered vessels. In this case it is easy to be mistaken that germination itself has been promoted. On the contrary early growth was suppressed in the case when intensive stimulus (for instance ten minutes of more radiation) was given. 4. More than five minutes seemed to have no meaning on the effect of Ultrasonic Waves on experimented farm crops in germination and early growth. 5. Clear qualitative difference was not recognized between treatment plot and control on outer morphological characters of experimented samples especially young seedlings except the quantitative one on the plant height, the root volume and soforth.

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A brief study from agricultural and historical points of view was made on the development of windbreaks on the Musashi plain in the Kanto district. Significance of the windbreak for farming in that district, where fields are very often exposed to strong winds in the season from January to March, had attracted farmers' attention from old times, and been mentioned in many of the literatures and narratives referred to by the author. Nowadays, we can see many farm-fields which are provided with well-arranged windbreaks. On the other hand, however, we also find some fields with much disarranged windbreaks or even with none. The author indicated the fact that the extent of completion of windbreaks might be considered to relate more directly to the origin of the village to which it belongs than to the lay of the field and its soil conditions. The villages on the plain may be divided into two types as are shown in Fig. 1 and 2 according to the mode of land allotment and the shape of the field owned by each farmer. The village type of Fit. 1 is unsuitable for establishing windbreaks and the type of Fig. 2 is suitable. And the older settlements are generally of the former type and their windbreaks are disarranged or lacking, while the newer ones are of the latter type and are furnished with well arranged windbreaks. The author examined the kinds of plants used as windbreaks in that plain, which changed in accordance to the change of economical conditions of the farmers, the most probable chronological order being assumed as follows; Utsugi (Deutzia crenate Sieb. et Zucc.)-tea plant (Thea sinesis L.)-azalea plant (Rhododendron spp.)-spindle tree (Euonymus japonica Thund.)-Sawara (Chamaecyparis pisifera Endl.)

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Among the paddy rice varieties cultivated in Japan, the varieties suitable to rich field are found generally to have shorter height of plant and higher nitrogen content per dry matter during the growing period than varieties suitable to poor field. By heavy dressing of nitrogen, the former increased the number of tillers and the amount of nitrogen in the plant more prominently than the latter.

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1. Effect of irrigation at different times of growing season on the tillering and yield of rice plants in direct sowing culture was studied in the glass house. 2. In the plots receiving no irrigation during early stage of growth, the tillering period was delayed as compared to the other plots. 3. In the plots, which received irrigation from the 12th leaf stage on, plants continued to tillering until the latest time. 4. Plot having no irrigation during early stage of growth showed low percentage of available tillers (tillers bearing ears) but the plot received irrigation from 9th leaf stage on gave high percentage of available tillers. 5. Irrigation from the 3rd leaf stage on causes secondary and tertially tillerings formation. 6. Irrigation from the 6th leaf stage causes the largest number of stems than all thier plots. 7. Irrigation from the 9th leaf state and from 12th leaf stage result in the greater yield than all other plots. In the usual method of rice culture which contains transplanting the practice named "Nakaboshi" (dry up the paddy field at a certain time) is said to be useful to obtain the greater yield. However in the case of direct sowing culture, it was found that the irrigation starts at that time gives the best effect on yield.

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"Aichi-Asahi", a late variety of the rice plant, was exposed to various photoperiodic treatments at the different stages of development in seed bed. The short-day treatment induced premature heading, ie, an abnormal heading response takes place during the earlier period in addition to the natural heading in the later period. The treatment increases the number of the panicles of the premature heading, and at the same time decreases the number of the days required for its heading. The effects of the treatments on inducing the premature heading were clearly expressed by an index : Premature Heading Inductivity = (Number of days from the Beginning of Premature Heading to That of Natural Heading) ÷ (Number of Days from the Beginning of photoperiodic treatment to That of Natural Heading) × 100. As the seedling grew, the shorter duration of shortday treatment was "suffieicut for inducing premature heading and the greater response was observed. These results suggest that the photoperiodic response becomes greater as the plant develops. Almost perfect correlation was found between "Inductivity" and the number of the panicles of premature heading. (Correlation coefficient r=0.96 ± 0.02 in the 1st experiment, r=0.95 ± 0.02 in the 2nd expt.) The long-day treatment followed to the short-day cancelled the latters' effect. More remarkable effect of inducting premature heading was observed with the seedlings transplanted to fields than that to pots. It may suggest that temperature, nutrition, etc. may somewhat modify the response of rice plant to photoperiods.

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In the preceding paper, we reported on the premature heading caused by short-day treatment in seed-bed stage, with reference to the premature heading inductivity of the rice plant. Both in pot- and in field-experiments it was observed that the short-day treatment resulted in not only a induction of premature heading, but also delaying of the natural heading in the later period, in cases where the premature heading inductivity being large, the heading is much delayed. The long-day treatment combined with short-day seems to concel the delay of heading, although the effect of long-day alone was not always remarkable. The short-day treatment caused an increase in plant height and a decrease in number of tillers, in seed-bed, as compared with control plants. After transplantation a gradual decrease in height-growth and increase of number of tillers was observed. But the growth became vigorous again after the premature heading, and at the final stage the plant was slightly higher and evidently more tillers than the control plants. On the other hand the long-day treatment resulted in the lower plants having many tillers in seed-bed, but after transplantation the plant height increased and no more difference was observed between the treated and the control except the number of tillers was slightly few.

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1) Time of withering of each leaf expressed by a particular index : "Seedling-age at the time of withering of a given leaf." 2) Rate of growth of seedlings as expressed by the length of time interval between the appearance of the successive leaves was accelerated by the supply of nitrogen fertilizer. The index "Seedling-age at the time of leaf withering" was also affected ; it became larger than the seedlings supplied little or no. 3) Only under the sufficient supply of nitrogen, phosphate fertilizer exert the effect of increase of the index.

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(1) The authors intended to forecast the yield by judging the growing process of rice plants. For this purpose they tried to analyze the factors constituting the yield of rice crop and to trace up their growing processes. (2) The following four factors were considered to constitute the yield of rice crop. (i) Number of panicles per unit area. (ii) Number of spikelets per panicle. (iii) Fruiting percentage. (iv) Weight of 1, 000 grains (brown rice). (3) First of all, the annual variations of these four factors were studied as fundamental data for forecasting the values of them. Using the data of the studies on climate-adaptability of the crop performed at Konosu Agricultural Experiment Farm, in which nine varieties - including early, intermediate and late maturing ones - were used as material, the annual variations of the factors were investigated by calculating coefficients of variation through nineteen years. (4) The results obtained were as follows : (i) Variation coefficients of the number of panicles ranged from 10.2 % t 15.6 %. The less was the number of panicles in varieties, the greater was the coefficient of variation ; the correlation coefficient between them had been so significant that it was r = 0.88. (ii) Coefficients of variation of the number of spikelets per panicle ranged from 6.5 % to 16.6 %, and those of intermediate maturing varieties were smaller than that of any other varieties in general. (iii) Coefficients of variation of the fruiting percentage and the weight of 1, 000 grains were 5.0∼9.1 %, 2.2∼4.4 % respectively, and only the slight differences among varieties were seen. (5) It was found in every variety above mentioned that both the number of panicles and the number of spikelets per panicle showed the largest variation, the fruiting percentage followed next, and the weight of 1, 000 grains was in final order. (6) These results obtained are very useful for the yield-forecast of rice crop because of the following reason : it is supposed that the order of these four factors determined in the growing period of rice plant may be such as the first, the number of panicles, the second, the number of spikelets, the third, the fruiting percentage and the fourth, the weight of 1, 000 grains ; this order agrees with the descending order of values in their annual variations. That is, the larger is the annual variation in the factors, the earlier it is determined in the stage of growth. (7) The annual variations of these four factors are available as the accuracy-index of the yield-forecast. For example, the number of panicles, the number of spikelets per panicle and the fruiting percentage, exactly being forecasted and only the weight of 1, 000 grains remaining unknown, we can decide that the yield forecast is, under about 70 % probability, within 3.3 % probable error which is the mean value of variation of 1, 000 grains weight.

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By using the data of experiments for nineteen years on climate-adaptability of rice crop at Konosu Agricultural Experiment Farm, correlation coefficients between the yield of rice crops and its constituting factors and among those individual factors were calculated. And the results were summarized as follows. (1) Correlations between the yield and the number of panicles were possitive in all varieties, and differences of the coefficients among early, intermediate and late maturing varieties were insignificant. (2) Correlation coefficients between the yield and the number of spikelets per panicle were high in early varieties and low in late ones. (3) Fruiting percentages were most strongly correlated with the yields in late varieties and most weakly in intermediate ones. (4) Correlation coefficients between the yield and the weight of 1, 000 grains were low in early varieties and high in late ones. The later the maturity of a variety was, the higher its coefficient became. (5) In short correlation coefficients between the yield an its constituting factors, except the number of panicles, were very different in earliness of varieties. The factors strongly correlated with the yield were considered to act as the limiting factors of the yield determination component in consequence of their insufficient development caused by unfavourable environmental conditions in the growing stage in which their values are destined. (6) Correlation coefficients between the number of panicles and, spikelets were possitive in early varieties but significantly negative in late ones. This seemed to be closely connected with the fact that a meteorological good condition in the second and third decades of July increased the number of panicles of all varieties and of spikelets of early varieties but obviously reduces the number of spikelets of late varieties, and the later it matures the more decreases the number of spikelets. (7) Number of panicles was negatively correlated in general with the fruiting percentage and the weight of 1, 000 grains in early and intermediate varieties. (8) Correlation coefficients between the number of spikelets and the fruiting percentage or the weight of 1, 000 grains seemed to scarcely relate to the important characters of varieties. (9) The fruiting percentage of late varieties were strongly correlated with the weights of 1, 000 grains. This seemed to be based on the fact that these two factors of late varieties are greatly influenced by the air temperature in September and October. (10) From the relation between number of panicles and other three factors it was suggested that the values of the three factors can be predicted, however may it be much or little, at the growing stage during which the number of panicles can be forecasted. And also the yield-forecasting method on late maturing varieties which is seriously desired at the present time may become practicable to a certain extent at the stage when the fruiting percentage can be foreseen by utilizing the correlation between the fruiting percentage and the weight of 1, 000 grains in late varieties.

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By examining the curves of tillering in rice obtained from the data of experiments in nineteen years on climate-adaptability of rice in Konosu Agricultural Experiment Farm, differences among the curves of early, intermediate and late varieties and the relations between panicle number and curves of tillering were studied. And the results were summarized as follows. (1) The authors discovered the fact that there had been no differences among early, intermediate and late maturing varieties so far as the date of the highest point of the curve is concerned. When the plants were cultivated under similar conditions and transplanted on the same day, the highest point of the tillering curve of each of all the varieties fell on the same date, irrespective of varieties and cultivating methods. (2) In the case of normal transplanting condition, it was pointed out that the beginning of young panicle formation always occurred before that highest point of the curve in early varieties, almost at the same time in intermediate varieties and always after that in late varieties. (3) The period from the date of beginning of tiller-vanishing to that of heading was short in early varieties and long in late ones. As a result of it, it was well understood that, according to the average in thirteen years, an early variety decreased 12.6 %, an intermadiate one 41.1 % and a late one 70.8 % of all vanished tillers by their heading time. (4) The percentages of panicle numbers to maximum tiller numbers, as an average of thirteen years, were 79∼72 % in early varieties, 71∼64 % in intermediate ones and 66∼62 % in late ones. As a whole, it seemed that the earlier a variety matured, the higher the percentage of the successful panicles became. (5) Regarding the finishing period of successful tillering in thirteen years, there was a nine-day interval, at least, between earliest and latest year. So that, it was proved that it had been very difficult to forecast panicle numbers by means of the tiller numbers in that period. (6) According to the result of investigation of the correlation between panicle numbers and tiller numbers of every point of tillering curves it was proved that the methods of forecasting panicle number by means of tiller numbers had been unavailable until the period of the maximum tillering or the young panicle formation. Moreover, as correlation coefficients between panicle numbers and tillering numbers in these periods ranged at about 0.88∼0.62, forecasting the number of panicle may not be done satisfactorily even in these periods.

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The thirty eight successive years' statistics of rice production per unit area (=tan) in each of the eleven counties of Hokkaido Prefecture were analysed applying the definition of bad harvest as given formerly by the author being taken into account. From the chronological data. On rice yield during thirty eight years at those eleven counties, it was concluded that "Oshima" County belongs to the north-east type, "Hiyama" and Shiribeshi" to the intermediate type and other eights to the north type in regard to bad harvest (fig. 8). It was observed that the north type consisted of four regional linkage groups : I-IV, between the trans-mode percent and the estimated rice production (koku/tan) for 1950 (fig. 9), and these groups laid in a wavy arrangement from north-east, Okhotsk Sea Coast of "Abashiri" County to south west (fig. 10). Therefore, the bad harvest of Hokkaido prefecture might cames from the Okhotsk Sea.

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This paper deals with results of investigations on the regional variation of yield stability of the paddy rice crop in Kyushu district. Remarkable variations among different regions can be recognized as shown in Fig. 1. Region number and yield stability (%) are as follows : The most stable region (1), 5.8 %. Stable regions (2)∼(4), 7.1∼-7.8 %. Unstable regions. (5)∼(10), 9.3∼11.9 %. The most unstable regions (11)∼(12), 13.8∼15.9 %. The most stable regions can be found in the plains of the coastal area of Ariake-kai where farm managements are of intensified form and the most unstable regions are dispersed in the islands and the mountainous parts where managements are unintensified.

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This paper deals with the results of investigations of factor influencing the regional variation of yield stability of the paddy rice crop. The following factors were taken into consideration, i. e., climatic conditions, atmospheric damages, soil conditions, irrigation systems, insect and disease injuries, intensity of farm management, percentage of farmers having side jobs, size of farm management, and the proportion of paddy fields to the whole farm. These various factors were closely related to the yield stability of each region respectively.

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The temperature around the young panicle in the leaf-sheath of paddy rice plants was found to rise remarkably when the weather was windy and when the plant was exposed to direct sunlight, the phenomenon was more conspicuous, the same relation was observed either under high air temperatures in summer or under lower air temperatures in autumn.

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It is said that in the south-western parts of Japan the extremely high temperature during summer season exerts an unfavorable effect on the growth of rice plant, resulting in the serious occurrence of Helminthosporium leaf spot or "Akiochi", In order to ascertain whether such an occurrence of the disease or "Akiochi" in these districts is promoted by the abnormal plant nutrition due to high water temperature or not, some solution culture experiments were carried out in 1951, in which quantities of nutrients absorbed by rice plant during definite intervals were determined under different water temperature. Results of experiments are as follows: (1) The higher water temperature than optimum (about 30°C) reduced the absorption of nutrients in the order K₂O>, SiO₂>, NH₃-N>, MnO>, P₂O₅ in one experiment (Table 1, A) and in the order SiO₂>, K₂O>, NH₃-N>, P₂O₅>, MnO>, CaO in another experiment (Table 1, B) From this fact the serious occurrence of Helminthosporium leaf spot and "Akiochi" in the south-western parts of Japan may be partially attributed to the absorption inhibition of some nutrients such as silica and potassium caused by high water temperature. (2) The lower water temperature than optimum also reduced the absorption of nutrients in the order SiO₂>, PiO₅>, K₂O>, NH₃-N>, MnO>, CaO (Table 1, B). (3) Mitsui (1950, '51) has found that the uptake of nutrients is reduced by hydrogen sulphide in the order K₂O>, SiO₂>, NH₃-N>, MnO>, MgO>, CaO and considered that when aerobic metabolism of root is retarded by hydrogen sulphide the absorption of ions of high value of hydration is far more extremely reduced than those of low value of hydration. The results of our work indicate that the reduction of nutrients absorption caused by the temperature relationships shows a striking similarity with the reduction caused by hydrogen sulphide as to the order of ions reduced. It may be suggested, therefore, that not only hydrogen sulphide but also supraoptimal or low temperature retards the normal aerobic metabolism of root and causes reduction of nutrient absorption according to the order of degree of hydration.

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In order to demonstrate the influence of hydrogen sulphide added to nutrient solution on the nitrogen metabolism of rice plant, we determined the amounts of nitrogen fractions such as ammonium-N, amide-N, soluble-N and protein-N per 1 gram green or dry weight in the plant treated with different amounts of hydrogen sulphide. The results of experiments are as follows: - (1) When a large amount of hydrogen sulphide is added to the solution, ammonium-N, protein-N and total-N decreased, while on the contrary soluble-N often increased, and every when soluble-N did not show any increase, ratio of soluble-N to protein-N decreased. (2) The fact that the ratio of soluble-N to protein-N increases due to hydrogen sulphide seems to indicate that protein synthesis in the plant might be disturbed by hydrogen sulphide. And such a disturbance in protein synthesis may be attributable in part to the reduction in the absorption of some nutrients such as potassium, which is known to promote the protein synthesis, and in part to the retardation of the normal aerobic metabolism (respiration) due to hydrogen sulphide.

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To make clear whether the serious occurrence of Helminthosporium leaf spot or "Akiochi" in the south-western parts of Japan is accelerated by the abnormal plant nutrition due to high night temperature of air or not, two experiments were carried out in 1951 : in one experiment influence of night temperature treatment for a month after heading upon the growth and nutrition of rice plant was studied, and in another experiment quantities of nutrients absorbed by rice during 24 hours after 10 a. m. September 14 were determined under different night temperature conditions. The results of the experiments are as follows : - (1) High night temperature treatment for a month after heading speeded up the ripening of plant and also retarded the normal development of grains, resulting in the loss of yield. The treatment also diminished the percentage contents of potassium and silica in stems and leaves, and increased the susceptibility to Helminthosporium leaf spot (Table 1). (2) Both high and low night temperature of air reduced the absorption of nutrients in the order K₂O>, SiO₂>, NH₃-N>, MnO>, P₂O₅ (Table 2). Therefore it is suggested that both supra-optimal and low night temperature retard the normal aerobic metabolism of root and cause the reduction of ions absorption according to the order of hydration. (3) From these results the serious occurrence of Helminthosporium leaf spot or "Akiochi" in the south-western parts of Japan may be attributed in part to the absorption inhibition of some nutrients such as potassium and silica caused by high night temperature.

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1. Under the too deep sowing, not only the 1st internode but also the 2nd internode makes large elongation. 2. The first tillering bud, which is usually located on the 1st stem-node, was observed in this case to be forced to move from the original position and placed on the surface of the 1st internode. 3. It appears just like an adventitious bud originated from the 1st internode, but microscopical examination proved that this is a true first tillering bud, but located at abnormal position.

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We measured the amount of co₂ exhaled by the rice plants which were cultivated changing the opening time of flood irrigation and obtained the following results. 1) During the experimental term from 10th of July to 26 th of Sept., we found twice the increasing tendency of the amount of co₂ exhaled in every plot, the first it was found at the time of tillering and secondly just before heading. 2) The first max. exhalation of the transplanting plot was delayed more than ten days to that of the direct planting. This may be attributable to the physiological hindrance caused from transplanting and is correspond to the fact that the max. tillering of the former was more than ten days later than that of the latter. 3) The amount of co₂ exhaled showed some tendency to increase at fifth day after starting flood irrigation, this may come from the sudden change of cultivating condition. 4) The amount of co₂ exhaled by the rice plants which were cultivated in the pots of field state throughout the experiment showed various results according to the amount of water in the soil. This may be counted to the affinity of rice plant to water. 5) The amount of co₂ exhaled seemed to concider rather with the cultivating method than the growing condition of rice plant.

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1. To explain the mechanism of the resistance of rice varieties against the salt, 120 varieties were tested at the field where the salt injuries happened usually. 2. At this field, as the concentration of chlorine became higher in the later term of rice plant growth, the heading term influenced on the degree of these injuries (20-24th Aug. and 20th Sep.) very much. 3. It was considered, to become higher the concentration of chlorine from 20 th to 24 th Aug. made the sterilizing percentage of the varieties which met with it at the reduction division period higher, and the weight of 1000 grains of the late mature varieties and the harvest weight were lightened as the concentration became higher from both Sep. 4. From this result, it was recognized that the varieties which avoid the injuries must be considered, too.

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(1) Investigations were made of the absorption of water, NaCl, and the symptoms of its injury in rice seedlings, cultured with nutrient solutions containing various amount s of NaCl. (2) The quantity of absorption and the growth in height showed on the whole the same tendency. In the section of concentration 0 %∼0.1 %, both the absorption and the growth were normal. In the section of 1.0 %∼2.0 %, the absorption was restricted and the growth was hardly detectable. In the section of 0.3 %∼0.7 %, the results lay between those cases. (3) The symptoms of salt injury on the leaf blades indicated the same tendency as the above-mentioned aspects. In the section of 1.0 %∼2.0 %, the whole blades wilted. (4) In each section of investigations, the lost in amount of the salt in the nutrient solution was almost the same as the amount of the salt contained in the blades. That is to say, during the investigation the salt absorbed by the plant mostly accumulated in its leaf blades.

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The experiments concerning with the influence of artificial lodging to the damage of stem rot disease in rice varieties were studied. Lodging at early as svell as at late stage of growth accelerated the damages of the disease in certain varieties, but the periodic influence of lodging on the damages were not recognized. The varieties highly damaged by disease on lodging generally showed low resistance to stem rot under mormal condition.

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(1) From the results of this experiment, if we transplant early the rice seedlings in the hot bed of the high thermo-sensitive varieties as Hokukaido's Norin-15 etc. and after the 1st time rice harvest, transplant the temporary planted rice seedlings of the varieties capable of bearing good yield under late transplanting as Norin-25 etc., it has been found that the rice culture of two times a year is possible at Mito, Ibaraki Prefecture. On this case, it is key point in Mito that the harvest of the 1st time rice culture is possible by July 20th. The total yield of the 1st and the 2nd time rice culture was about 150 % of the normal rice culture. (2) Generally speaking from these experiments ; 2 places besides Mito in Ibaraki Prefecture and 4 places in Koti, Mie, Shizuoka and Kanagawa Prefecture, the two time rice culture is possible in the land where the mean air temperature in May is higher than 16°. But the higher the mean temperature of May, the easier the practice of 2 times cropping of ride is possible. On the two time rice-culture in Japan, the writer will call tentatively the land where the mean air temperature in May is 16°∼17°C is the North-limit zone (North Kanto, Tosan including North half in Gifu Prefecture and Hokuriku districts) and the land where higher than 17°C is the zone where 2 times of cropping may be made without particular difficulty (South Kanto, Tokaido, Kinki, Tyugoku, Shikoku and Kyushu districts). The latter tentatively may be classified into three districts, according to the manner of the cultural practices.

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1. As the results of comparative cultivation tests of rice plants raised from semi-transparent seeds and opaque ones of each of five glutinous upland strains, it was found that number of days from the date of protrusion of panicle to that of maturation varied in accordance with the differences in the practice of irrigation, and the use of different amount of phosphorus manures supplied, and the disuse of manure. But no constant relations could not be found between transparency of seeds grains and time of maturation. 2. Every plants raised from the grains of these two sorts mentioned above, produced both transparent and opaque grains, and therefore, it was considered that the transparency of the grain would be changed by the influence of environmental conditions.

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1. With purposes of examining the milling yield and quality of milled rice and of classifying the quality of milled and brown rice, milling tests were carried out in condition of 94 % milling over the rice samples selected from the adapted prefectures representing each block. 2. As to the milling yield and quality of milled rice, there are some significant differences among the grades and blocks, too. The exiting grading of rice is not necessarily reasonable because of the a/m significant differences among the grades. 3. Qualities of brown rice have connection with the quality of milled rice and respects with milling yield. And this point was figured out by way of calculating their correlation coefficients and of analysis of variances.

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The effect of some treatments in the application of nitrogenous fertilizer on the quality of gluten in wheat grains was investigated. The following results were obtained. (1) It appeared that among four kinds of protein analyzed, gliadin and glutenin contents in the grains were markedly varied by the nitrogenous fertilizer treatments, while both leucosin and globulin to hardly reveal any variation in percentage. (2) It was found that the ample supply of N-manure resulted in a better gluten character, while the small quantity of N-manure exerted a detrimental influence upon the gluten quality, as compared with grains grown without N-manure. The sufficient and proper supply of N-manure improved the quality. Excess of N-manure produced lighter crumped grains. These grains seemed to be rather good in gluten quality but poor in starch contents. (3) In the case of a certain amount of N-manure applied, dressing of a considerable quantity of N-manure in March improved the quality of grains not only in protein contents but also in glutinous character than the application of a greater part of N-manure at seeding time. Excessive application of nitrogen in March tended, however, to increase gluten contents of the grains, but deteriorate the gluten quality. (4) Nitrogen application as late as the heading and flowering time had a tendency to raise the gluten content in the grains, but did not exert a good influence upon the gluten character.

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T/R value is always greater in the overdamp plot than in the check plot; this inclination is slrown more remarkably with progress in growth. The growth of root-hair is rate in the overdamp plot; even in the part not lignified, the number of root-hairs is only 11 % of that of the check plot. The remarkable retardation in growth of the top appears already in the first decade of March. This may be partly due to the ill-balance of absorption surface of the above-mentioned root and microchemical ill change promoted with the rise of soil temperature, and may be due especially to lignification. As in the overdamp plot, the main root is prevented from growing, the growth of the lateral root, especially of secondary and lower orders is promoted, for its compensation, resulting in the formation of an abnormal root system.

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Previous works published by Sudo (1941) and by the present writer (1949) on sterility in barley indicate that the leading cause is non-pollination depending on the abnormal dehiscence of anthers, which resulted from their functional weakness at the flowering time. The present work dealing with the residual antumn habit has been designed to obtain an information on the mechanism of this functional weakness in flowering from the physiological point of view. When winter barley variety is sown in spring, provided completely with the necessary conditions for cancellation of autumn habit by chilling for more than 30 days at 1°C before sowing, the flowering takes place normally, , resulting in fewer occurrences of sterility. However, if the necessary conditions are not given sufficiently, that is, duration of chilling is in the range of 20 to 30 days, the flowering delays for about 2 weeks compared with that of the completely verbalized, and sterility occurs in considerably high percentage as shown in Fig. 1. [graph] Moreover, when the chilling period is shortened to less than 20 days, the plants sown in spring fail to reach ear formation in that season and the formation of leaves and tillers is extremely promoted without setting any flowers, the plants remaining the "rosette" stage. As seen from this "rosette" phenomenon, it will be obvious that vegetative growth and reproductive growth belong respectively to the essentially different phases in plant growth : The former includes the leaf growth and tillering, while the letter includes elongation of culm after the ear formation and the growth of spike. In the early stages, as the reproductive organs involving culm and eat have little, if any, ability to produce carbohydrates and other materials necessary for their growth in quantity by themselves, the materials employed for their growth are drawn from the vegetative organs consisting of leaves and roots. Then the amount of dry weight of the reproductive organs is plotted against days curves represented by Fig. 2 are obtained. The circles represent the 40 days treatment, the crosses, 20 days treatment. These curves show S figures on the whole, but nearly straight lines before and after flowering time. So the increment in dry weight per day, dWc/dt, is easily obtained by calculating the regression coefficient. In the 40 days and 20 days treatment, these values are 92.4 and 51.8 in mg. respectively. The photosynthesis is, in general, proportional to leaf area, consequently to leaf dry weight. Therefore, the quotient, dWc/Wl, where dWc and Wl denote the increment in dry weight of the reproductive organ per day and the leaf dry weight present at the measuring time of dWc respectively, comes to indicate the "transloca- [graph] tion efficiency". Indicating this quotient as percentage, 9.5 % and 4.0 % are obtained in the 40 days and the 20 days treatments respectively at the flowering time as shown in Table 1. The culm weight divided by the leaf, C/L or C. L ratio, is considered to be the mean values of translocation efficiencies which are seen in every stage of growth period between the time of estimation of this ratio. [table] C. L ratio is, for the most part, of the same meaning as the formula of BAKHUZEN'S "structural efficiency", and is of equal value to the translocation efficiency as a criterion of efficiency indicating the intensity of material migration from the vegetative organs to the reproductive ones. It is likewise a more convenient method from the point of view of experimental procedures. 1.1395 and 0.7542 are, as C. L ratios, obtained in the 40 days and 20 days treatment respectively, and they correspond fairly well with the translocation efficiencies and are as parallel with the tendencies of sterilizing percentage as the translocation efficiencies. In the present experiments, it should be noted that this C. [the rest omitted]

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It is observed that the wheat plants sown on 15, 22 and 29 in September stopped their elongation at mean temperature of 8.2, 8.9 and 9.6 °C respectively. in field, but the plants sown on 6 and 13 in October, being perhaps due to the growth by endosperm, could elongate at such lower temperature as 6.5 and 5.5 °C, respectively.

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1. The experiments about the parthenogenesis induced by delay-pollinating and radiating of X-ray, were conducted. 2. The fertility of pistilate flowers decreased with days from silking, and the parthenogenesis could be induced by delay-pollinating after this rapid decreasing of fertility. 3. A few kernels were parthenogenically obtained by application of pollens radiated by X-ray, but there was no significant differences among the lots of X-ray treatments. 4. It did not reveal accumulative effects to use delay-pollination and X-ray radiation simultaneously. 5. Number of chromosomes of plants developed from the parthenogenic kernels, was 20 (2n). 6. Therefore, it may be concluded that the parthenogenesis induced artificially by these methods belongs to the category of diploid pseudogamy.

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The well developed was given on the aerenchyma tissue on the submerged portion of the stem in wild soy-bean plants. briefly report. It may throw some light on the explanation of the resistance of soybeans against wet conditions of soil.

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1. It was observed that early type soybean varieties (which are suited for seeding in spring) had been seriously damaged by some insects for these few years. 2. Investigations were made on the kinds of the insects, the extent of the damage by each insect, and the relations between the damage and the soybean varieties or the date of planting. 3. Both Nezara antennata SCOTT and Riptortus clavatus THUNB. damaged soybeans ; especially in the case of the latter, the damage was serious. 4. The damage of soybean seeds by the insects varied with the stage of development of seeds. In the earlier stage of maturing the damage was more serious than in the later stage. 5. The early type soybean varieties were more seriously damaged by the insects than the late type ones (suited for summer seeding). In the above two type soybeans, the earlier the date of flowering, the more serious was the damage. 6. The earlier the date of planting, the more serious the damage, in the both type soy-beans. The later the date of planting, the better the yield of early type soybeans, which was the reverse to the normal case in which greater yield is produced by early seeding.

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The authors intended to study morphologically and physiologically. the mechanism of occurrence of aborted seeds in soy-bean. 1) The primordia of all ovules in an ovary differentiate simultaneously, regardless of their position in the ovary. However, the developement of embryo-sac is somewhat faster at apical ovules, and also the increased numbers of nucleus are recognized in pro-embryo of apical ovules. Accordingly we suppose that the time of fertilization is earlier in apical ovules. 2) The volume-increase of pods and seeds closely related to their water content, because the curve of increase shown by seed and pod resembles to the curve of water content. Both seeds and pods reduce the water content after 10∼15 days after fertilization, but after 20∼25 days only the seeds continue to reduce their water content, while the pods do not. 3) After fertilization from 8 to 25 days, numbers of embryocell increase conspicuouslly and growth of the embryo-cells proceeds rhythmically repeating alternately the resting and growing paces. 4) A conversion of size among seeds in a pod usually occurs during growth ; that is, in the early stage of embryonal developement, the apical seed is largest, while at the successive stage the basal one became largest, and at the latest stage the central seed is larger than others. Accordingly ripening course of seeds takes turn twice ; and this turning takes place earlier in two-seeded-pod than in three-seeded pod, but takes place later, or does not entirely in pods on plants which grown under unfavorable condition.

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The causes for occurrence of aborted seeds in the soy-bean pod are classified as follows : 1. Existence of ovule, failed in functioning the fertilization. 2. Collapse of embryo. 1) There are two types identified in the former case ; one is of extremely tiny structure and the other is deformed into "pod in pod". In this case, we could find out neither abnormality nor abortion of pollen and ovule throughout the morphological and physiological observations. The causes for fertilization failure which recognized more frequently at basal ovule are accounted for the protandry that behaved slightly in general and also for position of basal ovule, which is located farther from the stylar end and disadvantageous inreceiving pollen. However, on the other hand the basal ovules are situated at the position rather favorable for absorbing water and nutrients, and therefore the infertilized basal ovule, where the embryo-sac has been degenerated, developed rarely into ovary shape or small pod, shape. 2) As the second case, the collapse of embryo means the ovule that fertilized but failed to develop into mature seed. There are clearly found two critical peaks, one is at pro-embryo and the other is at cotyledonous stage. Namely, the arrested development is observed at the stage of urgent growth of embryo and then at the time of remarkable reduction of water content from the ovule. Presumably the causes for collapse of embryo are as follows ; the one is due to the insufficient water supply and the lack of proper nutrients at the time of vigorous growth of embryo, and the other cause is that at the urgent growth stage the formation of embryo is unbalanced with the vigorous division and growth of embryo-cell.

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This investigation has been undertaken to know the influence of temperature on the germination of soybean seeds. In this investigation the coefficients of germination (GASSNER, 1926) are used to discuss the comparative superiority of germination at each temperature. The coefficients of germination obtained are as foffows. [table] According to this investigation the minimnm, optimum and maximum temperatures for the germination of soybean seeds are as follows. Minimum 2∼4°C Optimum 34∼36°C Maximum 42∼44°C

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(1) The flowering order in Valencia peanut plant, a variety having very few branches, was observed. (2) Within certain period after blooming of the first flower in a cluster, the first flower in the cluster on the next nodes of the same branch blooms, in succession from the lowest node toward the branch end. The relation may be expressed by a line as follows : y=a+bx, wherby represents the days that the flower on the x-th node takes until its blooming after that of the flower on the first (x=l) node of the same branch. (3) The same rule with a very little modification may be applied to blooming order in the variety Chiba-Churyu-43 of which the branches show a more complex mode of growth.

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Fxberimental plants of peanut were grown uniformly with loamy soil, each being planted in a pot, and every pot was placed in a wooden box filled with soil in which fruiting was led to take place. Three different classed of soil, with three different moisture contents respectively, were compared in the effects upon fruiting process. As the result it was presented, that the yields and the quality of seeds, were generally highest when they developed in the sand soil with rich moisture. Sandy loam soil with medium moisture also gave a good result.

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(1) The leaves, the stems, and the root-tubers of the sweet potato were chemicaly analysed with the course of its growth. (2) Between the ratio of <K₂O>/N of the fertilizer given and that of the plant treated, highly positive correlation is proved to exist. (3) The development of the root-tuber in the early stages of its growth depends upon the ratio of <K₂O>/N in the plant. When <K₂O>/N becomes greater, the weight of root-tnber is subject to the amount of leaves and stems.

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Distribution of fresh, dry, weight and percentage of the latter against the former of tuberous root in F₁ plants of sweet potato were investigated in conformity with the data of the seedling selection experiments in Chiba Experiment Farm of Kanto-Tusan Agricultural Experiment Station and Kagoshima Experiment Farm of Kyusyu Agricultural Experiment Station, in the aim of contribution to the selection of the prospective cross combination. Consequently the most productivities were shown in the frequent medium percentage of the dry matter (30∼38%). Accordingly when the miximum of calorie products per area are desired, we may expect the medium percentage more than the high percentage of dry matter. Therefore it will be advisable to make use of the productive varieties in case of the selection of cross combination. As there are very high correlations between fresh and dry yield, we may mark F₁ individuals in respect of fresh weight primarily and then in point of dry matter percentage secondarily.

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The date of sprouting, the number and length of sprouts at the 45th day after bedding, and the number of cutting shoots produced for 35 days from may 26 to June 30, were investigated with 32, varieties of sweet potato. The observations were arranged by means of the correlation calculation. There is a significant correlation between the length of sprouts and the date of sprouting but none among the number of sprouts and the date of sprouting or the length of sprouts. There is a very strong positive correlation between the number of cuttings and the length of sprouts as well as the internodal length of them. The number of cuttings and the number of sprouts show fairly significant correlation, but there is no marked correlation between the former and the date of sprouting. The results indicate that the number of cuttings correlate more highly with the length or internodal length of the sprouts than the number of them or the date of sproutings.

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1. This report concerns on the yielding efficiency of variety test of sweet potato cultivated in all prefectural Agricultural Experiment Stations of Japan from 1939 to 1948, the cases investigated amount to 7500. 2. The distribution of per tan yield of sweet potato root tuber occupys 50-1600 Kan, and the Mo. 675 Kan, M. 632 Kan, σ 225 Kan, and the curve shows a beautiful monomodal symmetrical distribution. 3. The mean per tan yield of sweet potato tuber is about 630 Kan and displays no difference in both the northern and southern regions of Japan. 4. The distribution of per tan yield of sweet potato vine occupys 50-1700 Kan, and the Mo. 450 Kan, M. 553 Kan, σ 282 Kan, and the curve shows a monomodal asymmetric distribution, and its center of gravity inclines to the left. 5. the mean per ten yield of sweet potato vine is about 550 Kan and displays an increase in the north-eastern region and displays a decrease in southern region. 6. The distribution of sweet potato tuber percentage, that is, the ratio <per tan yield of sweet potato tuber/per tan yield of sweet potato vine > occupys 10-500 %, and the Mo. 100%, M. 143%, σ 76.8 % and the curve shows a monomodal asymmetric distribution, and its center of gravity inclines to the left. 7. The mean sweet potato tuber percentage is 143 % and displays an increase in the south-western region and displays a decrease in the northern region. 8. The auther compared the sweet potato yield with the rice yield according to Calorie calculation. The minimum, mean and maximum Calorie of the per tan yield is respectively 500, 000-1, 500, 000-2, 500, 000 in rice, and in sweet potato 500, 000-3, 000, 000-6, 500, 000.

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This investigation is one of a series of experiments carried out under the title of physiological studies on potato plants. It has long been known that potato tubers are an important source for the supply of ascorbic acid (Vitamin C) as a dietary essential for human nutrition. Although a great number of studies on the ascorbic acid contents in potato tubers [graph] have recently been reported by many investigators, few data concerning the influence of ascorbic acid on the tuberization and maturity of the potato tubers, especially on the accumulation of starch in the new tubers, are available. In the present investigation, in extending the work on the carbohydrate metabolism of potato tubers, particular attention was given to a study on the physiological interrelationship between the accumulation of starch and the variation of ascorbic acid content in the potato tuber during the time of its development. The analysis was carried out on the following fractions, namely, total ascorbic acid, reduced ascorbic acid, oxidized ascorbic acid, reducing sugar, non-reducing sugar, and starch during the period from late May to the beginning of August. The experimental results obtained may be summarized as follows: (1) The ascorbic acid metabolism during the stolon elongation stage. The stolon arises in the axis of underground main stem soon after the germination. The total ascorbic acid and the reducing sugar contents in the stolon increase with the development of the stolon. At this stage, however, the amount of ascorbic acid, especially in the reduced form, in the stolon tips was less than that of the following stage ; the decline of the ratio of reduced form/oxidized form of ascorbic acid may be pointed out as a characteristic feature at this stage. (2) The ascorbic acid metabolism during the tuberization stage. The duration of this stage is very short, from the middle of June to late in June. The tips of the stolons began to swell into a spindle shape as soon as the elongation ceased and then gradually became tuberous through the deposition of starch in them. As a characteristic feature at this stage a conspicuous increase of ascorbic acid content and a decrease of reducing sugar content in the stolon tips were recognized. When reviewing the works of PURR (1934), HANES (1935) and NISHIDA (1951) which state that the ascorbic acid is very effective for inhibiting amylase activity it is very interesting to assume that the ascorbic acid in the potato tubers may act as an activator in the formation of starch in the stolon tips. In the previous paper, the authors have reported the fact that the amylase activity declined rapidly with the development of new tuber. This experimental evidence reported by the author added confirmatory support to the previous assumption of inhibitory effect of the ascorbic acid upon the amylase activity. At any rate, a close relationship between the accumulation of starch and the increase of the ascorbic acid content in the new tubers is supposed to exist. (3) The ascorbic acid metabolism during the tuber maturing stage. When the tubers attained maturity the leaves gradually died, and the onset of ripening of the new tubers roughly coincided with the yellowing and drying up of the vines. With the increasing maturity of the tuber the rate of increase of the ascorbic acid content in the new tuber slackend gradually. With respect to the detailed ratio of the constituents of ascorbic acid, an increase of the reduced form and a decrease of the oxidized form were recognized. Accordingly the ratio of reduced form/oxidized form of ascorbic acid also rose. Concomitant with these changes of the ascorbic acid content according to the tuber maturity, the starch content in the new tuber increased steeply.

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The present investigation is one of a series of experiments carried out under the title of physiological and morphological studies on potato plants. In the previous papers (1949, 1951), the authors have reported some assumptions concerning the mechanism of sprout tuber formation due to the senility of mother tubers. Judging from the results described in the above papers, it seems very reasonable to assume, therefore, that the irregular tuber formation of potato plants, such as sprout tuber, might be attributable to the changes of the reserve substances in the mother tuber and of the respiration rate of the sprout and tuber according to their storage conditions. In recent studies on the tuber formation of potato plants, the authors (1952) have made it obvious that the accumulation of ascorbic acid and the variations of carbohydrates contents in the potato tuber stand physiologically in a close interrelationship, namely, that the ascorbic acid may serve as an activator in the formation of starch in the potato tuber. The purpose of the present, investigation was chiefly to determine the relation between the variations of ascorbic acid and carbohydrate contents in the abnormal tuberization of potato plants under the various conditions, with a view to narrowing the problem whether the ascorbic acid may also act as an activator in the formation of starch in the abnormal tuberization of potatoes. The variety "Irish Cobbler" was used as material. The fractions analysed in the present experiments were similar to those described in the previous papers, so full descriptions are omitted here. The experimental results obtained may be summarized as follows ; (1) Under the storage conditions of dried and high temperature, the accumulation of starch and the rapid acceleration of growth in thickness of the sprout were recognized. With regard to the ascorbic acid content in the sprout tuber under these conditions, the content of oxidized form was much greater than that of the reduced form of ascorbic acid. The low content of the latter may be attributable to the oxidation of reduced ascorbic acid due to the high temperature condition. Accordingly, the accumulation of starch in the sprout tuber was less than that in the control tuber. (2) Being accompanied with the development of sprout tuber arose directly on the mother tuber, due to its senility resulting from long storage in a cellar. The accumulation of starch and the increase of ascorbic acid, especially of the reduced form, in the sprout tuber ran parallel. Accordingly the increase of the ratio of reduced from/oxidized form of ascorbic acid was one result. (3) When the seedlings of potatoes were placed in the dark, the ascorbic acid content in the tips of etiolated sprouts was much higher than the content in other parts of the sprouts. In the new tubers formed on the axils of the sprouts, however, the highest amounts of ascorbic acid and starch contents were recognized. (4) Judging from the results described above, if may be concluded that the localization of ascorbic acid in the tissue of potato plants tends to be parallel to that of the starch. Hence, in the case of the tuberization of potato plant, it seems very probable that the ascorbic acid, especially in the reduced form, plays an important role in the accumulation of starch and in the development of the tuber.

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The plants cultured on the field ordinalily were sprayed with 2, 4-D solution on 14. Aug. at the rate of 20 gr or 100 gr per Tan (nearly 0.25 acre), the dose being believed somewhat little for eradicating such vigorously growing plants. After the spray, chemical analyses were made three times (on 19, 26 and 31. Aug.) with regards certain constituents of sprayed plants as well as non-sprayed ones. The main results obtained are shown below. (1) The amount of crude protein as well as pure-protein decreases in leaves, but increased in stems, and total amount of protein increases in sprayed plants which is believed noteworthy in their use as fodder. (2) The reducing sugars, total sugars and soluble non-nitrogenous substance increase in their amounts in sprayed plants (leaves as well as stems). (3) The crude ash contents decrease in leaves, but not in stems. (4) The amount of crude fiber decreases in stems, but never in leaves. (5) The activity of Vitamin C reduces markedly in leaves which is the same as in the previous study. (6) In the present study, it is observed that a kind of injurious insect, Anomala rufpcuprea Mutschulsky assembled to sprayed plants to eat their leaves, 5 day after spraying. This fact deserves attention from various points of view especially from killing plants by 2, 4-D.

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1. The authors investigated the artificial germination of sugar beet pollen on cultural media, using the pollen of Variety "Hon-iku No. 398" at the flowering time in 1950. 2. In the case of common cultural media, the best result was obtained when it consisted of 25 % sucrose and 1 % agar. But, on the whole, the percentage of germination was very slight (less than 25 % at maximum) in ordinary media. 3. The addition of "boric acid" to the cultural media promoted the germination very extensively, and the dose of" boric acid" at the rate of 0.005 % concentration was most favorable. 4. The optimum PH value for pollen germination was 4.6. 5. Consequently, the cultural media of PH 4.6 and containing 0.005% of "boric acid" induced the successful germination of 8.0%. 6. In the case of cultural media using "organic acid" and "pepton", an application of "citric acid" and "tartaric acid" some degrees (about 20 %) and, "pepton was most effective showing germination percentage as much as 50 %, while the control plot showed about 14 %. 7. The length of pollen tube elongated more vigorously and velocity of pollen tube growth became faster when the "boric acid" was added to the cultural media. 8. No germinated pollen was found in the distilled water when used as cultural media. But the germination percentage was as high as about 30 % when the water contained 0.005 % "boric acid". 9. In the investigation on vitality of sugar beet pollen, the germinating percentage decreased remarkably on the 4 th day and none was obtained on the 7 th day, when the pollen was wrapped up in parchment paper and stored in the room.

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