1. Short day and lower night temperature favor the pistillate flower formation of the cucumber plant, and on the contrary, long day and higher night temperature favor the staminate flower formation. 2. In this report, the cucumber plant was set under the changed day length and night temperature during the various stages of the plant growth in the nursery bed, for the purpose of detecting the responding ranges of the plant portion, influenced by the adverse conditiont at the respective stages. 3. The respective 10 days sequence of the growth period of the plant in the nursery bed is denominatod as I-, II-, III-and IV-period. 4. The response reveals itself at the higher nodal successions as compared with the histological survey of the floral primordia. It seems that the physiological changes brought about by the influence of the day length and night temperature precede the formative effect. 5. When short day and lower night temperature prevailed during the II-III period of the plant growth, the antagonistic influence of the long day or higher night temperature during the IV-period failed to balance the preceding treatment. The effect of the short day and lower night temperature prevailed only during the III-period of the plant growth, was fairly balanced by the antagonistic influence of the IV-period treatment. 6. It seems that the day length and the night temperature affect the physiological condition of the plant according to the duration period of the treatment. The physiological conditions in its turn influence the sex determination of the successively developing flowers. 7. Practically, the most careful control of the suitable day length and night temperature is needed during the II-III periods.
1. Experiments were carried out in 1955 in order to study the effects of the concentration of NaCl in the culture solution on the growth, flowering, fruit bearing and chemical composition of the egg-plant, in sand culture under the glasshouse condition. HOAGLAND's nutrient solution was used as the basic solution, and in the NaCl treatment, the concentrations of Nacl added ranged between 2, 000 and 14, 000ppm at intervals of 2, 000ppm. “Shinkuro” variety was sown on Feb. 1 in the sand seed bed, and young plants were transfered on May 7 to the washed river sand in 5-gallon glazed crocks. Nacl treatments were initiated on May 23 and continued till July 23. 2. The growth of plants was reduced almost in inverse proportion to the increasing concentration of NaCI, bu tno other specific symptoms appeared in the NaCl treatments. 3. No harmful effects of NaCl treatments on the fertility of pollen and its rate of germination were observed. 4. Both the number of flowers and the rate of the occurrence of perfect (long-styled) flowers decreased with the increase of NaCl concentration, but the influence of NaCl on the rate of fruit bearing was not evident. 5. With the increase of NaCl, the yield of fruits was reduced markedly, while the quality of fruits and the seed set appeared not to be affected. 6. Leaf analyses gave the following results. The contents of both Na and Cl increased almost in proportion to the concentration of NaCl in the solution, but Cl accumulated at the higher rate than Na. With the increasing concentration of NaCl. the contents of N and P increased slightly, while Mg and Ca, especially the latter, decreased markedly. The content of K showed the peak at 4, 000ppm of Nacl. Carbohydrates decreased with the increase of NaCl.
Investigations on the heredity of characters in the turnip hybrids between the following pairs were carried out; Yonagokabu×lyohikabu, Iyohikabu×Yonagokabu, Yajimakabu×Hikonekabu, Tennojikabu×Yajimakabu, Hinokabu×Tennojikabu, Yurugikabu×Tennojikabu, Hikonekabu×Tennojikabu, Sapporomurasakikabu×Shogoinkabu, Sapporomurasakikabu×Hakatakabu, Shogoinkabu×Omikabu, Shogoinkabu×Hakatakabu, Hakatakabu×Kokabu, Oyabukabu×Hakatakabu, Kokabu×Sapporomurasakikabu The results may be summarized as follows. 1. European type×Japanese type Generally in the hybrids that comes from this crossing, European type appears viz. pubescent leaves dominate glabrous leaves, and in plant form the divergent character dominates the upright character. 2. Leaf shape In the hybrid between the type with deeply dissected leaves and the type with entire (or sha-llow dissected) leaves, the intermediate form app-ears. 3. Root shape Generally in regard to root shape, the hybrid shows the intermediate form between parents. 4. Colouring and pigment in the root a. In colour of root above the ground green is dominant over white. b. Both in leaves and in root, purple colouring is completely dominant over red colouring. And from the chemical point of view, it may be said that cyanin type shows complete dominance over pelargonin type. c. In the hybrid between the red coloured root type and the white ones, pink coloured root type has not shown up, but purple ones has appeared. And our chemical survey identified the pigment of the hybrid with cyanin. 5. Texture of root, rate of root growth and bolting In any case the intermediate form (between pdrents) appears. 6. Epidermal types of seed In the hybrid between A type and B type, A type dominates B type. (The anatomical observation of the transverse section of seeds shows that A type is characterized by distinct feature of cells, swelling when they absorb water. On the contrary, in B type, epidermal layer seems only membranous, possessing indistinct feature.)
1. In Shôgoin, a variety of the Japanese radish, the activity of incompatible pollen on stigmas after bud-pollination was more rapid than that of compatible pollen after crossing of open flowers (table 1, 2, 3 and 4). The fact that immature stigma was more receptive than mature one indicates that in the Japanese radish pollen is inhibited to some extent on the mature stigma even though it is compatible. The result is fully in accord with that of the broccoli by SEARS (1937). 2. Table 5 gives the percentage of pollen ger-mination after self-pollination in variety Minowase. The germination of pollen was decreased. No emptied pollen grains which had exhausted their contents into their tubes were found on the stig-mas. Pollen-tubes usually ceased to develop, when they were about as long as the diameter of a pollen grain. Nearly all of the tubes failed to penetrate the stigma. Some tubes bended or coiled around the papillae. 3. Minotetra-Daikon (4x=36) is a tetraploid variety induced by colchicine method. The beha-vior of pollen after self-pollination in Minotetra-Daikon was similar to that of Minowase (table 6). Consequently, it seems that Minotetra-Daikon is also self-incompatible. 4. The results of cross-pollination in variety Minowase (2x×2x) are shown in table 7. The percentage of pollen germination was large. Numerous emptied pollen grains were found on the stigmas. The tissue of the style was penetrated freely by pollen-tubes. The longest tubes could be found in the ovary in about 6 or 8 hours after pollination. 5. Both cross-compatible and-incompatible combinations were found in the cross-pollination of variety Minotetra-Daikon (4x×4x). The pollen and tube behavior of the cross-compatible mating was similar to that of cross-pollinition in variety Minowase. On the other hand, the pollen be-havior of cross-incompatible mating closely resem-bled that of the self-pollination (table 8). 6. The following results were obtained in the combination between Minowase and Minotetra-Dai-kon (_??_2x×_??_4x). The percentage of pollen germination was large. Many emptied pollen grains were found on the stigmas. However, the longest tubes failed to penetrate the ovary in about 24 hours after pollination (table 9). It seems probable that the tube growth of 2x pollen is slower than that of x pollen. 7. In the combination between Minotetra-Dai-kon and Minowase (_??_4x×_??_2x), the percentage of pollen germination was large as shown in table 10. However, there were individual differences in the percentage of emptied pollen grains and in the length of the longest tubes. Previously NISHIYAMA (1949) reported that in the combination between Minowase and Minotetra-Dai-kon (_??_2x×_??_4x), the development of many cap-sules was found to be normal. When matured, however, most of the seeds were empty and shrivelled, and no viable seeds were obtained. In the reciprocal crossing (_??_4x×_??_2x), the development of capsules produced was weak, and the majority of seeds obtained were small, but filled and viable. These small and plump seeds were determined to be triploid. Cytological studies of the failure of seed development in these crossings will be reserved for the future.
Dormancy of perilla (Perilla ocymoides L. var. crispa BENTH.) seed was studied. 1. Dormany of perilla seed continues for about three to five months after harvest, and it is very deep for the first month after harvest. 2. Germination of perilla seed is light-favored. In some cases, however, it is dark-favored for some period after harvest, and turns to light-favored thereafter. Causes of this variability in photosensitivity are not known yet. The grade of photosensitivity does not vary after dormancy has disappeared. 3. Causes of dormancy of perilla seed exist mainly in seed coat and partially in embryo. 4. Effective dormancy breaking treatments are decoating, sulfuric acid treatment and prechilling. Prechilling is most useful in practice. 5. Perilla seed aquires germinating ability in high temperature through aging or prechilling. 6. Dry seeds in normal air-humidity, as well as wet ones, are affected by light condition. Germination percentage in darkness is higher when the seeds have been kept under light than when kept in darkness. 7. Germination rate of perilla seeds is low when sown in soil. The rate increases considerably when the seeds have been presoaked under light for about one day.
The influences of various agricultural chemicals mixed with thiamine on thiamine activity in plants were tested. The results obtained were as follows: 1. The thiamine foliar sprays mixed with acidic Gramin spreader are desirable, but those with alkaline Bordeaux mixture are undesirable for the yield of crops. 2. In the case of mixture with acidic chemicals such as Gramin spreader, improved Rino spreader or nicotine sulphate, the stability of thiamine is comparatively high, but that in the by mixture with alkaline chemicals such as Bordeaux mixture orlime sulfur is comparatively low. 3. The thiamine stability in the mixture with fertilizers for foliar sprays such as urea or Yogen is comparatively high.
(1) The first flower bud formation in Gardenia occurs in the terminal bud on current shoot which develops; in spring, and after the first flower bud is formed, two or three lateral shoots appear from the base of the first flower bud, and then the second flower bud formation occurs in the tip of these shoots. (2) In G. jasminoides ELLIS, the time of the first flower bud differentiation was at the end of July, and the second was at the beginning of September, 1955 in Kagawa. However in G. jasminoides ELLIS var. ovalifolia NAKAI, the first flower buds were differentiated at the end of July, and the second was differentiated at the end of August. (3) The first flower buds progressed their de-velopment to stamen or pistil formation stage at the beginning of September, about 40 days after flower buds were initiated, and they were observed macroscopically. Then some of the buds droped in winter, but others developed in spring, and flowered in July. (4) The second flower buds also developed to stamen or pistil formation stage within 40 days, but they were not observed macroscopically until the next spring. Flower buds in early stages were observed almost every month from September to May. The flowers of G. jasminoides ELLIS, began to bloom on July 1, 1956, and in G. jasminoides ELLIS var. ovaliforia NAKAI, on June 26, 1956. (5) No shoot appeared from the base of the second flower bud until, the following spring when two or three shoots appeared, but no flower bud differentiation was observed in these shoots until the end of July. (6) In Magnolia denudata DESR., flower bud differentiation occurred on May 12, 1955, in Kagawa, and progressed their stages of development normally to pollen mother cell formation stage on July 7, 1955. And the flower buds of pollen forma-tion stage were also observed on February 16, 1956. The flowers began to bloom on March 20, 1956.
The original tetraploid shoot of Fiveleaf Akebia was obtained by treating seeds with colchicine solution in spring of 1951 at Sakata's Plant Breed-ing Station in Chigasaki. Thereby several clonal individuals were isolated or propagated by the layering method. These tetraploid plants (2n=64) have showed larger, thicker, deeper-colored leaflets and thicker stems, but grown more slowlythan the normal diploid (2n=32). And the lightpurple col-ored inflorescences, which consisted of a few pi-stillate florets at the base and of several stamin-ate ones a tthe top part, appeared firstlyin spr-ing of 1956 on the matured tetraploid and diploid plants grown at the farm of the Utsunomiya University. Each organ of inflorescences of the tetraploid was distinctly enlarged in comparison. with that of the diploid, as shown in many other examples of the induced autotetraploid flower plants. Although the normal diploid plant did not bear fruit at all in spring of 1956, possibly, due to the genetical occurrence of self-incompatibility for seed production, the induced tetraploid succeeded in producing nice-shaped fruits. They are resulted probably from the fertilization of pollen of the diploid stamens with eggs of the tetraploid pistils. Hereafter the new tetraploid Fiveleaf Ake-bia will be suitable for the miniature or potted plants in the horticultural culture and also it will be a valuable material for the induction of the genetically interesting triploid plant.
The experiments were carried out to search the most suitable season for cutting in ornamental trees and shrubs. Cutting was made inevery month throughout the year, with the plants of 50 kinds. 1. With conifers, spring is believed to be suitable season for cutting and generally cutting of conifers is not made in the other season. In our experiments, it has been found that conifers have rather longer season for cutting and the following plants showed good results in cutting made in fall: Kyaraboku (Taxus cuspidata var. umbraculifera), Yew podocarpus (Podocarpus macrophylla), Common cryptomeria (Cryptomeria japonica), Tatsu-nami-hiba (Chamaecyparis obtusa var. breviramea), Sawara (Chamaecyparis pisifera). Especially Kai-zuka-ibuki (Juniperus chinensis) showed good results in September cutting. 2. With evergreen broad-leaved trees and shrubs, cutting is made in general in summer, and it can be made in spring as well as in fall with plants of a few kinds. So far as our experiments concerned, the following plants showed better results in fall cutting: Sweet bay tree (Laurus nobilis), Narrowleaf firethorn (Pyracantha angustifolia), Common camellia (Camellia japonica var. hortensis), Sasanqua tea (Camellia sasanqua). 3. In deciduous trees, it is believed that cutting is made chiefly in spring with few exception. In our experiments, it 'was showed that cutting is possible in August with cherry tree (Prunus yedoensis) notwithstanding that it has been believ-ed to be impossible. These results may give a hint of the possibility of cutting in the many other plants which have been thought unsuccessful in cutting, by means of cutting before the stems become ripe or hard. 4. In these experiments, many evergreen trees showed better results in cutting made earlier than the time believed suitable in spring and showed good results in fall cuting. The reason why these experiments showed good results in the season other than the season believed suitable may be due to the following fact: the district where our Experiment Station is located, is warmer and more humid in winter than the central part of Japan. And these relationships are to be studied in the future.
The previous report pointed out that the growth substance could be successfully used to delay chrysanthemum flowering. This paper discusses certain practical procedures for the application of growth substance. The results of the experiment are summarized as follows. (1) Variety “Okayama Heiwa” was propagated on May 25 by cuttings, planted on June 18 and pinched on July 12. (2) The growth substance (NAA) of 5, 10, 50, 100 and 600ppm were applied by spraying during the growing season from early August to late September. The flower bud differentiation had not begun at the termination of the spray application. (3) The doses of more than 50ppm were ef_??_ective in delaying flowering, but at concentrations above 100ppm, inhibition occurred to the growth of plant. At concentration of 100ppm flowering was delayed 12 days. (4) The auxin supply before flower bud differ-entiation was effective in delaying flowering, but this was not the case when the auxin was supplied after budding. (5) The number of leaves on the plants treated with 50 and 100ppm of NAA increased over that of the control. This fact indicates that the auxin accelerates the vegetative growth in spite of its inhibition of flowering. (6) The same effectiveness was obtained by either application every 3rd day or everyday. Therefore the former may be recommended as more practical because of its cheeper cost and less labour.
Growing chrysanthemum all year round in Japan is accomplished by two different methods. One method is the application of either short day treat-ment or long day treatment to Autumn flowering chrysanthemum. This group of chrysanthemum is responsible to short day treatment in both stage of flower bud initiation and flower bud development. This is similar to both American and European methods of culture. The other method is the utilization of various types of chrysanthemums which have different blooming time hereditarily. In this case either short day treatment or long day treatment is seldom required. Many varietis of August and September flowering chrysanthemums, as well as Summer and Winter flowering chrysanthemums which usually bloom from May to July, and from December to January respectively, are used for this purpose. August and September flowering chrysanthemums have been bred recently, while Summer and Winter flowering chrysanthemums have existed for many years. In this experiment, the responses of flower bud initiation and flower bud development to photo-periodism and temperature were examined, and ecological classification of chrysanthemums were attempted. The classification were made as follows: