(1) In order to estimate the amounts of the nutrient elements absorbed by 25 year old Japanese persimmon trees (Fuyu), trunk circumference .and linear growth of branches, leaves and fruits were weighed and analysed. From this datum, amounts of growth and nutrient elements absorbed for one year by the tree were calculated. In addition, amounts of nutrient elements contained in branches pruned in winter were estimated. (2) The dry weight of new tissues in these trees was as follows. _??_ (3) Total amounts of nutrient elements contained in new tissues were as follows (per tree). _??_ Sum of these elements in shoots leaves and fruits was 70% of N, 68% of P2O5, 79% of K2O, respectively, of total of these elements in all new tissues. (4) Average amounts of the nutrient elements absorbed by these Japanese persimmon trees were 9.96kg of N, 2.36kg of P2O5 and 9.24 kg of K2O, when persimmon trees were planted at a rate of 18 trees per Tan(about 114 acre) and produced 452 Kan (1695kg) fruits. (5) The amounts of absorbed nutrient elements, when yield of fruits was 100 Kan (375kg) per tan in 9 and 25 year old trees, were as follows. _??_ This datum showed that amounts of nutrient elements absorbed by 9 and 25 year old trees we-re almost the same. (6) The amounts of nutrient elements contained in pruning branches were as follows (per Tan). _??_ The amounts of nutrient elements contained in pruning branches were 7_??_14% of total amounts of these elements absorbed by these trees.
1. To know the effects of winter soil temperature on the growth of citrus trees in sloping citrus groves where the soil temperature is generally several degrees in centigrade higher than that of flat land, the growth of potted seedlings of sour orange, trifoliate orange and Yuzu (Citrus Junos) was observed under the different treatments of soil temperature during winter. The fresh weight and N, P, K contents were measured of the top and root of excavated seedlings. 2. The higher soil temperature promotes the bud sprouting about 10 days in spring. 3. The later shoot growth of evergreen sour orange as well as initial growth was much larger in high soil temperature than in low soil temperature, but the difference of shoot growth of deciduous trifoliate orange between the treatments was decreased and almost disappeared by the middle of April. 4. The fresh weight of sour orange seedlings was also significantly larger in high soil temperature than in low one, but no difference was found for the trifoliate orange. The assimilation of sour orange leaves or the absorption by root during winter, which might be promoted by some-what higher soil temperature during winter, seems to be very effective for the later growth of the shoot especially for the evergreen fruit trees. 5. There was no definite difference in N, P, K concentration of shoots or roots between treatments. But the thickness of roots during winter or much growth of shoot and root until later season in higher temperature plots shows the active absorption by roots in warm soil during winter in such as sloping orchards or groves.
Effects of soil application and foliage spray on grapevines suffering from “Ebi” disease (boron deficiency) were studied for three years. The results were as follows. 1. Experiment on Koshu-sanjaku variety (own-rooted, fourteen years old, sandy loam soil): Boric acid was applied at the rate of five pounds per tan (about 1/4 acre) and was mixed with the surface soil to the depth of 10 cm on March, 1952. The treatment improved setting of berries and increased average weight of cluster, and this effects were yet significant three or more years after the application. 2. Experiments on Delaware variety (vineyard A, own-rooted 30 years old, clay soil: vineyard B, own-rooted 12 years old, clay soil: vineyard C, own-rooted 20 years old, clay soil): Soil applications of boric acid at the rate of five and ten pounds per tan on March or April were effective to increase average weight of clusters for more than two years. Foliage sprays of 0.3 and 0.5%, boric acid were also increased the cluster weight and yields. 0.5% spray was more effective than 0.3% spray. 3. Experiments on Koshu variety (grafted, 35 years old): Effects of soil application at the rate of ten pounds per tan and foliage spray of 0.5 solution of boric acid were tested. Both treatments were effective to reduce the abnormal growth of the vines and to improve the setting of berries. 4. Boron content in the leaves of the treated Delaware and Koshu-sanjaku varieties was about two times as much as the untreated one. 5. Penetration rate of boron applied to the soil was determined by chemical analysis. Boron reached 60cm depth faster in the sandy soil than in the clay soil. The more the quantity of the boric acid applied, the more the available boron in the soil.
(1) To know effectiveness of chemical thinning with naphthalene acetic acid on apples, (the varieties; American Summer Pearmain, Jonathan, Rall's Janet, Indo) those experiments had been performed at three orchards, that is, Agr. Exp. farm and Economical farm of Iwate Univ. and Koiwai farm. Naphthalene acetic acid were sprayed two times of one week and two weeks after full bloom. The effects of chemical thinning on the fruits, leaves and harvested fruits were obssrved. (2) The suitable stage of spraying was likely to lie between one or two weeks after full bloom, but was not clear which stages were better. The influence of concentration of naphthaleneacetic acid indicated that best thinning occur at 10 ppm on Ameri-can Summer Pearmain and Jonathan and at 20 ppm on Rail's Janet and Indo, but it seems to be difference in tree vigour. The injury of NAA spray on the leaves is very slight at 10 and 20 ppm, but was severe at 40 and 80 ppm. From this point the favourable concentration for apple thinning was about 10_??_20 ppm. (3) It was found by those .experiments that NAA spray was irrelative to biennial bearing habits at any concentration. But about reference to this points we should have still more experiments. (4) By the more tests on stages, methods of spray and appropriate concentration chemical thinning will be useful, if not at all, complemented by the hand thinning.
The effects of seed-sowing dates on the pod characters of the dwarf variety Masterpiece were studied. The seeds were sowed ten times, namely on 15th and 30th in April, the same in May, 14 th and 29th in June, the same in July, and 13th .and 28th in August. The results were as follows: (1) The length of pod of the 15th-April-plot was the longest of all, and the later the sowing date, the shorter the length of pod until 14th-July-plot. The length of pod of the 14th-July-plot was 57% of that of the 15th-April-plot. After 14th-July sowing, the length of pod again became longer until that of the 28th-August-plot which was 75% of that of the 15th-April-plot. (2) The number of ovules per pod indicated the same tendency as the length of pod. (3) The tendency of the number of seeds per pod in relation to sowing dates was similar as above, but the minimum point became later and the degree of decrease was greater than those of above-mentioned. Those of the 29th-July-plot and 13th-August-plot were the least and were 29% of that of the 15th-April-plot. The number of seeds per pod of the 28th-August-plot increased a little and was 36% of that of the 15th-April-plot. (4) The weight of seeds per pod behaved similarly as the number of seeds per pod, but the degree of decrease was remarkable as the sowing date became later. That of the 29th-July-plot was the least of all and was only about 10% of that of the 15th-April-plot. (5) The number of pods per plant showed a little different tendency from the others. The plants of three sowing dates next to 15th-April had more pod than those of the first sowing date, 15th, April. But later than the 14th, June, the number of pods per plant decreased until the 29th-July-plot. Those of two sowing dates in August again increased. (6) The gross tendency that appeared through the above-mentioned terms seemed to be summarised that the bad effects became suddenly evident from the 14th-June-plot and the worst results were seen in the July-sowings and the effects recovered afterwards. It is assumed that high temperatures at the time of flower-bud differentiation and at the flowering period have bad effects on some pod characters and the set of pods resulting the decreased yields.
The present paper reports the effects of light, temperature, sugar and fertilizers on the thiamin activity for the earlier growth of sweetpotatoes when sprayed on the leaves. The results obtained were as follows: 1. Thiamin application was more effective for the growth in the dark than in the light. 2. Under temperatures unfavorable for the growth, thiamin was more effective than under favorable. 3. Combined application of thiamin with sugar was more effective for the growth of root than single application of thiamin or sugar, whereas the growth of top was retarded by the single spray of sugar. 4. When applied in optimum quantity by soil application, phosphorus was the most effective of the three manurial elements for the thiamin activity, but when applied surplusly, nitrogen which was otherwise the most unfavorable for the growth was the most effective.
Poor germination of carrot seeds is an important problem for both seedmen and carrot growers. The author tried to elucidate what factors are the causes of the poor germination in the carrot seed production. Control of number of umbels per plant by pruning resulted in the increase in seed weight and seed size, bnt did not improve germinability of seeds. When the umbels were harvested separately, the germinability of seeds in the first order umbels was highest, that in the second order umbels next, and that in the third order the lowest. But in the seeds grown under glass, difference was scarecely found among the seeds in the umbels of different orders. In order to clarify the effect of rainfall during seed maturing, carrot plants grown in one foot diameter clay pots were transferred into the glasshouse at different stages of seed development, from flowering to firm brown seed stage. Rainfall at the flowering stage often made the flowers sterile and that at the ripening stage lowered the seed germinability. Early flowering plants produced seeds of higher germinability than late flowering ones did. Judging from these results, the seed germinability in the third order umbels, which flower latest, is decreased by rainfall and high temperature at their ripening stage. For the purpose of improving the germinability of carrot seeds, therefore, it is advisable to prune off the umbels so as to leave only the umbels of the second order in such cases as in the variety “Kuroda” in Kyushu.
Effects of artificial illumination on Japanese iris (Iris Kaempferi) were examined. It failed to flower when put under artificial illumination from September 1, but it flowered when treated from October 1. It seemed that Japanese iris required some period of short days before the beginning of illumination for its flowering. Then, four lots were prepared and each lot would be illuminated from Sept. 1 to April 1 next year. The 1st lot was kept on short day conditions from Oct. 1 to Oct. 10 when artificial illumination was discontinued. In the same manner illumination of the 2nd lot was discontinued from Oct. 1 to Oct. 20 and illumination of the 3rd lot was discontinued from Oct. 1 to Oct. 30. The 4th lot was not given any short photoperiod until this experiment was finished. As a result the 1 st, 2rd and the 3rd lots flowered, but the 4th lot failed to flower. In addition to the formal experiment, two more trials were prepared. Plants which were used for the 1st experiment were kept on long day conditions from Sept. 1 last year to May 31 and didn't flower. Then short day treatment was given for 15 and 30 days from June 1. These plants flowered in August. Plants which were used for the 2nd experiment were kept on long days from Sept. 1 last year. Illumination of these plants was discontinued on March 31, April 30 and May 31. As a result the plants where illumination was discontinued on March 31 and April 30 flowered in August, but those where illumination was discontinued on May 31 failed to flower. It seemed that the blooming in August was because of exposure to natural short day periods in spring after the illumination had been discontinued on March 31 and April 30. And it was because of no exposure to short photoperiod that the plants where illumination was discontinued on May 31 failed to flower.
This paper reports the results of the influence of storage temperature on the sprouting of stored onion. (1) High temperature (above 28°C) in storage inhibited remarkably the growth of inner scals of onion and delayed sprouting, but high temperature promoted breaking of dormancy so markedly, that the storage under high temperature followed by ordinary temperature accelerated the sprouting. (2) It seemed that low temperature neither breaked nor prolonged the rest period of onion bulbs, but it clearly inhibited the growth of inner scales, and made their sprouting delayed. (3) The relation of season of harvest to sprouting in stored onion, and requirements of stored temperature for onion are discussed.