1. At the Horticultural Division of National Tohoku Agricultural Experiment Station, the authors have continued their attempt to culture apple trees in nutrient solution, and to grow normally throughout 4-5 years successively.
2. In 1951 and 1952, two-year-old non-bearing apple trees, of American Summer Pearmain, McIntosh, Jonathan, Starking Delicious, and Rall's Janett, grown in nutrient solution previously for a year, were cultured successively to study the sea-sonal nutrient (N, P, K) absorption.
3. 35-l grazed earthenware pots were used. During the season, the solution was aerated by bubbling method continuously, and was changed every other weeks at. the same time, chemical analysis of the solution and the measurement of plant growth(total weight, shoot length, etc.) were performed. The composition of the nutrient solution used were modified HOAGLANDS formula (Table 1), and in these solutions, enough residual nutrient ions were found even at the end of two weeks period.
4. It was proved from this study that, in water culture, apple trees are able to be grown more vigorously than the field condition, 5 years or more successively.
5. N absorption increased gradually from the time of growth start to midsummer, in parallel with the rising of atmospheric (water) temperature and growth increase, and reached its maximum at the time of the highest temperature (late July to early August). Then it decreased gradually with the descent of temperature, and, consequently, the N absorption after defoliation was little. Thus, seasonal absorption of N by apple trees in water culture was closely related to the change of atmospheric (water) temperature.
6. The seasonal absorption curves of K were quite different from that of the nitrogen. K absorption increased rapidly at the biginning of early growth, and reach its highest point in the early or middle June, when the shoots began their active growth. This highest level of K absorption continued for a while, till most shoots terminate their growth, however with several fractuations in the course. Then decline of absorption was apparent in accord with the decrease of shoot growth.
Apparently, absorption of K related closely to the growth of shoots.
7. The absorption curve of phosphorous was quite analogous to that of N, but, in this case, there was no maximum and absolute amount of absorption was much less than that of N absorption.
8. The absorption process of water (transpiration) was almost identical with that of atmospheric temperature, accordingly this process was analogous to that of nitrogen. The quantity of the absorbed water throughout the season was unexpectedly great.
9. It seems to be found there are some correlations between the nitrate absorption and growth of fibrous roots.
10. With few exceptions, the nutrient absorptions, especially N, were closely related to the growth rate of trees.
11. The mean absorption ratio of N, P, K wereseparately 100:13. 3:46.3.
12. The varietal difference of nutrient absorption process could not be ascertained.
13. The model figure for the seasonal absorption process of N, P, K and water, and for growth process is shown in Fig. 11.

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1. The optimum concentrations of nitrogen, phosphoric acid, and potassium in the sand culture solutions of grapes (variety: Delaware) were as follows:
That is, bearing trees seemed to require more quantitative phosphoric acid and potassium than nonbearing trees, though rather less nitrogen
. 2. When the number of clusters on a tree were the same, the increased concentration of phosphoric acid induced an increase in number of berries of a cluster, thus it resulting in the increased weight of a cluster.
3. With the increased concentration of potassium, the ratio of fruits to foliage increased in weight. But, the high concentration beyond a certain degree caused the reduction of fruit yield and also that of foliage growth.
4. The result of leaf analysis of bearing and non bearing trees at the optimum concentrations of the three fertilizer elments were as follows:

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Many reports have been published concerning the germination tests of pollen in many crops, but there on some factors affecting the germination of pea pollen. Four varieties were sown five times in the spring and one variety was sown four times in the autumn. The results obtained were as follows:
1. The germination percentage of pea pollen considerablly increased as the time during which pollen was placed on the artificial germinating medium grew longer from one hour to about 6 hours, but only slightly increased when the time grew longer than 8 hours. The elongation of pollen tubes showed similar results.
2. The artificial medium containing 1% agar and 20% sucrose is most suitable for the pollen germination.
3. There were no significant differences in germination percentage and development of pollen-tubes in the temperature range from 10°C to 30°C. 0°C and 40°C were very injurious to the pollen germiare only few reports in leguminous vegetables, es-pecially in peas. Then the studies were carried out nation.
4. The percentage of germination and the amount of growth of pollen was better in the dark than in the light.
5. The pollen gathered between 8a.m. and 5p.m. showed almost no differences in the germination percentage and elongation of pollen-tubes.
6. The germinability of pollen showed considerable differences according to the stages of bud deve-lopment. The fertility of pollen gathered from the buds of the day before anthesis, i. e. the day of the dehiscence of anthers, was the highest, and the pollen grains of the flowering day were rather poorer germinators. The pollen from the buds of the 4 days before anthesis did not germinate at all. Germinating ability was already recognized at the bud stage of 3 days before anthesis.

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The author studied the relation between the position of ovules in pods and their fertility, using a variety “Usui, ” in 1954. The ovules at the most proximal end of pods show the poorest fertility and then the most distal ovules follow them. The fertiitty of ovules increases very repidly as theirpositions approach to the center from both ends of the pods, and there are only little differences in fertility between the several positions near center. The most fertile position of ovules seems to situate at the more distal than the center. The percentage of ovule fertility as a whole was about 60%.

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This paper reports the results of the studies on the effects of foliage thiamin sprays on the growth and yield of sweet potatoes. Five vatieties, Norir, No. 1, Norin No. 4, Kanto No. 24, Taihaku, Shij Uimo were used.
The results obtained were as follows.
1. Sprayings of thiamin solution on the leaves of sweet potatoes promoted root growth, increased the number and length of roots, and increased the weight of stems and leaves.
2. Sprayings of thiamin solution on the leaves of sweet potatoes increased the percentage of large storage roots.
3. Sprayings was more effective in the first half than in the latter half of their growing season.
4. The most effective thiamin concentration for sprayings was 1 ppm, when 2 cc of the solu-tion was sprayed on one plant at intervals of ten days.

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In Japan, the Kintoki variety of carrot seeds are usually sown within forty five days after their harvest, without the removal of the pericarp or hairs. This results in very low germination. The following results were obtained from experiments performed in 1953 and 1954.
(1) Not only the green, but the brown mature newly harvested seeds also generally increased the germination power and speed by storage in the laboratory.
(2) In seeds of all stages of maturity, the germination was increased by the pericarp removal, soaking and drying (soaking in several hours and then air dried), and sun-drying treatments.
(3) The extent of increasing the germination by the above treatments differed by the stage of mat-urity of the seeds. In the matured seeds, the differen-ces were very distinct, whereas, in the immature seeds they appeared but slight.
(4) The effects of seed treatments on the germination decreased as time elapsed after the harvest.
(5) Greater influence of these treatments upon germination was shown in immature seeds than matured, but the difference between them become smaller and smaller by the elapse of time after the harvest.
(6) These treatments had greater influence upon the germination speed rather than on the germina-tion power.
(7) The effect of sun-drying upon germination was influenced by the period of treatment.
(8) The effect of soaking and drying on the germination was not directly proportional to the time or the hours of soaking; but it was found that about three to four hours of soaking seemed best.
(9) Combination of treatments had greater effect on the germination than any single treatment.
(10) The mechanism of improving germination by treatments must be very complex, and cannot be explained solely from the experiments performed.

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1) The present study was carried out to invest-gate the physiological influence of MH on onions on the last stage of bulb development. The spray of 0.15 percent solution of MH was made on May 22 and June 4, and the period of observation was from May 21 to June 17.
2) No significant differences were found in cont_??_nts of total sugar, reducing sugar, ascorbic acid and dry matter.
3) The activity of catalase and peroxidase was always lower in the treated onions than in the control, and similar tendency was found in the tetrazolium reaction.
4) The relation between the results mentioned and the internal breakdown of onions treated with MH was discussed to some extent.

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The present investigation deals with the variation of onion scales in accordance with bulbing, especially its relationship to the constitution of scales and the variety or the size of bulb on “Imaiwase” and other 3 varieties.
(1) Each scale of onion in bulbing period showed so remarkable inhibitance in the growth of blade and so remarkable thickness in the leaf-sheath, that the period is morphologically distinguishable from the vegetative growing period.
The author hypothetically named that inner condition in bulbing period “bulbing phase” again-st vegetative growing phase.
(2) After the cells differentiated as those of blade, they are multiplicative and the blade continues to grow. The increase of number of leaves ceases at the bulbing period, but inner scales within the bulb continue to increase until the death of all leaves.
Break over is caused by the no blade scales, and it appers at bulbing period. They do not held the tops, so break over is able to indicate the harvest time.
(3) According to investigation of the scale cells at bulbing period, those number scarcely increase already in the thickness of about 1cm in length. Then the thickness of bulbs is caused solely by enlargement of cells in scales. The thickened part gradually progresses from outer scales to inner scales, and the outmost varies to film-likescale.
(4) Degree of bulbing decided by the vegetative growth until the bulbing begins and by the bulbing period or the speed of bulbing. The speed is affected by nutrient condition and the profoundity of bulbing phase.
(5) In consequence, in the bulbs sown in autu-mn, those of early varieties (for example Aichishiro) may become flat of “thick scaled type” and those of late varieties globe of “many scaled type”; the form of scales is recognizable to be a charac-teristic of variety.
(6) The plants of many leaves grow up to large bulbs and the inner vegetation point begins to develop into inner bulblet at ealy time, so that the larger the bulb, the less the outer scales, and the larger the bulb, the more the bulblet scales.

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Seasonal changes of numbers of flowerlets, rayflowers and disk-flowers in flower heads were observed on eighteen commercial dahlia varieties for cut flower from early June to middle November in Tokyo.
In Kinkazan, Minamino-homare and Izumi, seasonal variations of the ratios of ray-flowers to disk-flwers were rather small; in Benitsubaki, Shinpi, John, Kozakura, Baby Royal, they were very large; and in the other varieties, they were intermediate.
Six varieties were grown under short day condition in August, and were also grown under long day condition after middle September. By these treatments, it was found that numbers of flowerlets per flower head were not affected by photoperiod, but is affected by temperature.
Ratios of ray-flowers to disk-flowers were affected by both photoperiod and temperature, though degree of response was varied with varieties. Varieties were classified into the following three types according to their response to photoperiod and temperature.
1. The ratio is not affected by photopeiod, but is markedly affected by temperature……………… Kozakura type (Kozakura, Honoho).
2. The ratio is not affected by temperature, but is markedly affected by photoperiod…………………John type (Izumi, Karyu, John).
3. The ratio is affected both by photoperiod and temperature…………… Matsuno-yuki type (Matsuno-yuki).

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1. The flower bud formation in Chaenomeles extus-coccine CARR. occurred in the lateral buds, which included several flower buds, of two year old shoots.
2. The initial stages of flower buds in Toyo-nishiki variety were observed from the beginning of September, 1953 to the end of the month in Ka-gawa Prefecture. No flower bud at the stage of initial petal formation was observed in that period.
3. On October 7, the initial formations of petals and stamens were distinguished individually, and they developed normally, pistil formation occurred on October 17. The flowers commenced to bloom on October 27 and continued to the end of March.
4. In azalea, the flower bud formation occurred in the terminal buds, which included 3 or 4 flower buds, of current shoots.
5. The cluster differentiation stages and prediffer-entiation stages of the flower buds were observed on June 20 in Beni-giri variety (R. obtusum), and on July 20 in Oomurasaki variety (R. Oomurasaki). The flower bud differentiation stages in each bud of both varieties observed on July 10 in Beni-giri variety, and on July 30 in Oomurasaki variety.
6. The flower bud development in these varieties. progressed very quickly, and the initial formation of pistils were observed on July 10 in Beni-girl variety, and on August 19 in Oomurasaki variety. But, then they developed very slowly. The initiall formation of pollens and ovules were distinguished on September 18 in the former and on October 18 in the latter.
7. The flowers commenced to bloom on April 10 in Beni-giri, and on April 27 in Oomurasaki variety.

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This investigation has been undertaken to know the resistance of sweet peas to low temperature. The resistance to low temperature is measured by the time required to cause freezing injury on the crop leaves. In addition to the test of hardiness, the reducing sugar content and dry matter of leaves are measured to find the correlation coefficient between them.
The following tables summarize the results obtained

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