1. With certain varieties of apples, a number of cross pollinations were conducted in 1961 for the purpose of breeding. Among the many F1 seedlings in 1962, albino seedlings were found, which ceased their growth soon after the sprouting and died away. The relation of the frequency of albino to the cross combination was investigated. 2. Of 29 cross combinations, 14 crosses segregated the normal seedling and albino at the rate of 3:1, while the other 15 crosses produced no albino seedlings. Thus, it suggests that such varieties as Golden Delicious, Jonathan, Megumi, J. G-93, etc. had a recessive lethal gene in the heterozygous type respectively, and albino seedlings had recessive lethal genes in the homozygous type. On the other hand, those varieties as Yellow Transparent, Red Gold, Starking, Winesap and G. Y-172, seemed to have no lethal gene and never produced albino seedlings.
1. With 6-year old treees of Japanese pears (Nijisseiki) under sand culture, two experiments were conducted separately at different stages of fruit growth. One was performed during the division period of flesh cells from March 20 (12 days before sprouting) to May 19 (fruit thinning time). The objective of it was to observe the effect of N, P2O5 and K2O on the size of cells and their number per fruit in relation to fruit size. The data obtained on May 19 showed that non-application of any of the three nutrients retarded inclusively 20 to 37% of cell number per fruit, 4 to 12% of cell size, and consequently 17 to 21% of fruit size. Fruit growth at its beginning stage was more influenced by cell division than cell enlargement, the activity of cell division being inferior in the order of at N minus plot, P2O5 minus plot and K2O minus plot. 2. Another experiment was carried out during the enlargement period of flesh cells from May 19 to Aug. 21 (harvest time), to investigate the effect of concentration of each nutrient on the cell size and fruit size. As the result, both cell size and fruit size were most superior at 80 or 160ppm N, at 80 ppm P2O5 and at 160ppm K2O respectively among different plots of each nutrient. The lower the concentration of each nutrient than these values, the more inferior were both cell size and fruit size. The trend was most remarkable at N minus plot, followed by K2O minus plot and P2O5 minus plot in the order.
Effects of high and low night temperatures and varying amounts of fertilizer (small, medium and large) in the nursery on the growth of tomato plants were examined, based on the following idea: Reproductive growth is closely related to vegetative growth in tomato plants. In consideration of this relation, the author proposed the following formula for reproductive growth: R/T=(R/V)•(V/T) where R, V and T represent the amount of reproductive growth, the amount of vegetative growth, and time, respectively. With this formula reproductive growth (R/T) may be analyzed in terms of two components: (1) the relative growth of the reproductive and vegetative parts (R/V); and (2) the vegetative growth (V/T). The bud diameter of the first flower on each inflorescence was used as a measure of reproductive growth and the total dry weight of a plant as a measure of vegetative growth. When the log of the bud diameter was plotted against the log of the total dry weight of a plant, a linear relation was observed and the points were fitted by a regression line. On the basis of this relation it was possible to analyze the effects of the nursery conditions on the first component of reproductive growth from the shifting of the slope and the level of the regression line. A low night temperature exerted a differential effect on each component of reproductive growth. The first flower bud on every inflorescence was initiated at an earlier stage of vegetative growth with low night temperatures and this resulted in an increase of R/V. On the other hand, the rate of vegetative growth preceding the unfolding of foliage leaves decreased with low night temperatures. A large amount of fertilizer led to a reduction in the both components. The initiation of the flower bud on the lower inflorescence occurred at a later stage of vegetative growth when a large amount of fertilizer was used. The vegetative growth preceding the unfolding of foliage leaves also declined when a large amount of fertilizer was used. An interaction between temperature and amount of fertilizer was observed. The effect of low night temperatures was largest when a medium amount of fertilizer was used and was decreased or nullified by using a large amount. Following flower bud inititaion, the relative growth of the bud on each inflorescence and vegetative part was not largely affected by the external conditions in this experiment. The regression coefficients did not deviate significantly from 0.66. Bud growth was measured in length, and vegetative growth by weight. If the third power of length is proportional to the weight, it is possible to compare the relation between bud and vegetative growth in the same weight unit by trebling the regression coefficient. About 2.0 was obtained by multiplying 0.66 by 3. It was, therefore, presumed that the relative growth rate of the bud was generally twice as high as that of the vegetative part. But an increasing slope of the regression line was observed in successive inflorescences with high night temperatures and bud growth attained to three times as large as the vegetative growth in the third inflorescence. Performance of the tomato plants following transplanting seemed to be largely characterized by nursery conditions and the plants grown at low night temperatures and with a mdium amount of fertilizer yielded the most superior results.
1. Experiments were carried out to examine the effects of light intensity during the growth upon the branching in pea. The varieties tested were GW for the strain of arvense and Usui and World Record for that of hortense. 2. The plants in the field or in pots were shaded from emergence to harvest under cheese-cloth tunnel of synthetic textile (“Vinylon”). In some experiments in the latter half of the growing period the cover was removed and further in a supplementary experiment the row was mulched with straw to restrict the quantity of light the young plants receive. The light intensity in the tunnel was controlled by varying the number of cheese-cloth layers. 3. In all the varieties tested, shading accelerated the internode elongation in the main stem. The trend was most remarkable in the variety GW. 4. In shaded plants, branching at lower nodes of the main stem was arrested while the production of upper branches stimulated. The inhibition of the development of lower branches was enhanced as the shading became heavier. The effect of restricted light intensity was quite as remarkable in the short-term shading during the early growth stage as in the shading throughout the growing period. 5. The influence of shading on the subsequent growth of developed branches varied from one experiment to another. Temperature, varietal difference in branching and other unidentified factors might be herein involved. 6. In the previous reports, the authors have made it clear that long photoperiod, high temperature and application of gibberellic acid are favourable for the development of upper branches and inhibitory to the branching at lower nodes. In the present experiment, shading has proved itself to be another factor which demonstrates the same effect on the branching in pea. The current experimental data have afforded the evidence that these four factors are all potent in raising the content of auxin and/or gibberellin or in enhancing their activity in higher plants. As the consequence and in fact, these facts are in common in encouraging the internode elongation of the main stem of pea plants. Associating with these connections, a brief discussion was developed. 7. The foregoing results suggest the important role of light intensity in the morphogenesis of pea plants and offer data for the practical considerations in the culture of this crop.
Cryptotaenia japonica HASSK., hence forward referred to by its generic name alone, is a member of Umbelliferae. It is a herbaceous perennial plant indigenous to the Far East Asian temperate zone and is commonly cultivated throughout Japan as a vegetable crop. It grows widely in the mountainous regions of the country in wild state and is called as“Mitsuba”in Japanese. Thirty-six wild-grown stocks and five cultivars of Cryptotaenia, collected from various parts of Japan, were cultivated in Sakai, Osaka prefecture. The morphological and ecological studies were made during 1955-1958 on varietal differences among the cultivars and characteristic differences between the wild strains and the cultivars of Cryptotaenia, . The geographical differentiations among the wild strains were also investigated. 1. In comparison with the wild strains, all of the cultivars had generally more valuable morphological characters as a vegetable crop and uniformity among the cultivars. Green color of the leaf and stem, erect plant type and large size of the plant are very distinctive features. On the contrary, the wild strains showed a wide range of variations in characters and the plants generally tended to be more prostrate in plant type, but there was no apparent relation between the characters and geographical conditions of the native habitat. 2. In regard to the bolting and flowering time, all of the cultivars and the wild strains collected from warm climate zones showed the tendency of earlier bolting and flowering than those from cooler climate zones. It was found that the time of bolting and flowering of the wild strains is related to the latitude and temperature of the areas where they were collected. 3. Varietal differences of premature bolting of the cultivars distributed in both Kanto and Kansai districts were investigated by means of four different sowing trials at different time. It was found that the cultivars of Cryptotaenia can be divided into two main ecological types, namely the Kansai Ao-mitsuba of early-bolting and the Kanto Shirokuki-mitsuba of the late-bolting. Both types seem to have been selected for the special methods of cultivation in these two districts. 4. A similar geographical trend as seen in the bolting and flowering time was found in the seed dormancy of wild Cryptotaenia collected from cool climate zones when they were sowed immediately after harvest, while strains having none or shallow dormancy were found in both of the cultivars and the wild strains collected from warm climate zones. Effective treatments for breaking the seed dormancy are also investigated, and a chilling pretreatmemt at 5°C for 10-60 days was effective, but the optimum period of chilling varies with strains.
1. Wayahead, May King and Great Lakes varieties grown in the field were sampled at intervals of 10 days for the analyses of carbohydrates and nitrogen compounds in the tops and for the estimation of auxin, gibberellin and nucleic acids in the apical buds of lettuce plants. Carbohydrates and RNA contents increased with growth of the plant and reached to their peaks just before the flower bud differentiation, and then decreased with the development of flower organs. Seasonal changes in auxin contents were the same as those in carbohydrates and RNA contents, but auxin contents temporarily decreased just before the flower induction, nearly corresponding with the peak time of RNA contents. Seasonal trend of nitrogen compound contents was in contrast with that of carbohydrates. These tendencies were same in every varieties, though the contents of carbohydrates and RNA at maximum level were higher in Great Lakes (late variety) than in Wayahead and May King (early varieties), and the highest auxin contents were seen in Wayahead followed by May King, and Great Lakes in descending order. 2. Seasonal changes of the contents in native gibberellin-like substances and nucleic acids in apical buds of plants treated with high temperature were investigated. Gibberellin-like substances in apical buds of plants grown under the natural conditions were hardly detected until the flower bud differentiation, and increased rapidly after the flower induction, whereas the gibberellin-like substances in the plants treated with high temperature appeared soon after the treatment and increased remarkably after the floral initiation in similar manner as that of control plants grown under the natural conditions. Both the contents of DNA and acid soluble substances were scarcely affected with age of the plant and by the high temperature treatment. The content of RNA increased with growth of the plant grown under the natural conditions, but it decreased soon after the high temperature treatment, and increased to the peak before the flower induction. The content of RNA in the treated plant was one half, as low as that of control plant grown under the natural conditions. 3. The flower induction was inhibited by the foliar applications of auxins, but was promoted by the sprays of nucleic acids. The results of gibberellin applications showed that the stem elongation was induced both at high and low temperatures, but the floral initiation was induced by gibberellin applications only at high temerature. 4. From the above-mentioned results it may be concluded that the auxin contents increase with age of the plant and they promote the RNA metabolism, and that the flower bud differentiation is induced by the qualitative conversion of RNA which is affected by the temporary reduction of auxin level in the apical bud of lettuce plants.
The present investigation was undertaken in an attempt to elucidate the physiological basis of pollen degeneration in male sterile vegetable crops. Free amino acids from pollen grains, anthers, female organs and leaves of fertile and sterile plants were analyzed by paper chromatography. The vegetables used in the study were three cultivars of onion, two of Welsh onion, cabbage and tomato, and one of radish and red pepper. 1. Numbers of ninhydrin-positive spots in the chromatograms of fertile anthers prior to the dehiscence were as follows: onion, 17; Welsh onion, 15; cabbage and red pepper, 14; radish and tomato, 13, and no definite varietal difference was found in the amino acid composition in these materials. Marked differences, however, were found in the chromatograms between fertile and sterile anthers in the stage as shown in Figs. 1-3. That is, the chromatograms of fertile anthers had a considerably large spot of proline, which was either lacking or very faint in sterile anthers of any crops. The evidence of a positive relation between the content of praline and pollen fertility was obtained. Moreover, it was found in onion that the spot of asparagine from sterile anthers was considerably smaller than that from fertile ones (Fig. 2a). 2. At the stages from metaphase-I to anaphase-II in tomato, however, proline was very faint both in fertile and sterile anthers, and no chromatographic differences could be detected in the composition of free amino acids, either qualitatively or quantitatively, between fertile and sterile ones (Fig. 4a). 3. No definite difference was found in the free amino acid composition of female organs prior to the anther dehiscence or of leaves at the flowering time between fertile and sterile plants (Fig. 4 b. c and Tables 2 and 3). 4. In conclusion, it may be assumed that the difference in the proline accumulation between fertile and sterile mature anthers is related with the pollen degeneration in male sterile vegetable crops.
Pigmentation of flowers in red is a very complex phenomenon. Various flower colors in many species have been shown to be due to genetic factors. Even if the necessary genes are present, however, synthesis of anthocyanin will not occur in a plant unless environmental conditions are favorable. Of environmental factors regulating anthocyanin formation, sunlight and temperature influence it directly in some plant tissues. To obtain flowers of good color under glasshouse conditions, temperature and light must be regulated by means of heating or cooling and supplementary lighting or shading, especially during the winter or summer season. The authors attempted in the study to obtain an information on the effects of temperature and sunlight on the coloration of rose flowers. The influence of temperature on the form of epidermal cells in the petal is also presented in this paper. As the materials, two varieties of garden roses were used. Using a variety of Hybrid Tea, Crimson Glory, the authors have followed the formation of red pigments quantitatively at various temperatures in the phytotron. After the differentiation of flower buds about 3 weeks after pruning, the potted plants were treated at various temperatures. At 20° and 10°C petals became dark red and showed a velvet-like appearance. According to anatomical observations, anthocyanin distributed only in the epidermis on the adaxial and abaxial surface of the petal. In the vertical section, the thickness of the upper epidermis of the petal treated at 20° and 10°C is much greater than that treated at 30°C. On the other hand, the upper epidermis showed a flat structure and red color did not appear at noon-and/or night-temperature of 30°C. In the experiment of the measurement of color, and the analysis of pigments in petals, the roses were treated at 13° and 23°C after the bud formation. At 23°C the petals have a purplish hue and become bluish purple red later. On the other hand, at 13°C they have a red hue and a lower luminosity, and become brown later. Paper chromatographic analysis showed that the anthocyanins in Crimson Glory variety are cyanin and chrysanthemin. Of these pigments, cyanin is the highest in content. The anthocyanin content of petals at 13°C is much higher than that treated at 23°C. Using a variety of Floribunda, Masquerade, an attempt was made in this paper to elucidate the effect of sunlight on the development of flower color. The flowers of the variety change their color ranging from yellow to red as the age of petals advances. Flower buds were covered with colored cellophane prior to their opening, which was removed after two weeks. Although the flowers bloomed, red color did not develop in their petals. Regardless of light quality, the anthocyanins were not formed at lower light intensity. It therefore appears that the flowers of Masquerade require high intensity of sunlight for development of their red color. There was a rise in anthocyanin content in the petals as the time advanced after flowering. In the petals of Masquerade, the anthocyanins are cyanin and chrysanthemin. Of the two anthocyanins, chrysanthemin has highly increased in content with advancing age of flowers.
The author reported in a previous paper that an application of 50ppm of NAA at three-day intervals inhibits the flower bud differentiation of December King chrysanthemums placed under an incandescent lamp of low light intensity. This report is a continuation of that study. NAA was employed as the auxin, and combined with gibberellin, ascorbic acid, thiamine or tryptophane. In addition, urea was applied with the NAA. These chemicals were sprayed on chrysanthemums receiving different light intensities. The inhibitory effects of NAA, GA or tryptophane in single or mixed solutions for flower bud formation were examined using Shintoa chrysanthemums grown under an artificial short day conditon. The limiting light intensity for flower bud inhibition was 8 to 12lux without auxin spray and only 2 lux with auxin spray. Inhibition of flower buds caused by 100ppm of NAA spray was the same as those illuminated with light of about 40lux. However, the formative effect of 100ppm was quite strong. The concentration of 50ppm showed weak formative damage, but caused little inhibitory effect on flower bud formation. This dosage was equivalent to the effect of light intensity of 40lux, if supplemented with light of 2 to 3lux. Application of ascorbic acid slightly inhibited flower bud differentiation of December King chrysanthemums. Therefore, the spray solution of 25 ppm of NAA and 50ppm of ascorbic acid resulted in an inhibitory effect as did 50ppm of NAA. This was also true when 25ppm of NAA were mixed with 1% urea. Thiamine showed a similar response but its effect was weaker than that of ascorbic acid. Tryptophane inhibited flower bud differentiation at dosages of 100ppm and 200ppm, but showed no appreciable influence on Shintoa or December King varieties when sprayed with a mixed solution of ascorbic acid. The response to gibberellin was far greater. It slightly inhibited flower bud formation at 50ppm. When mixed at this concentration with 50ppm of NAA, gibberellin inhibited flower bud formation to a greater degree than the application of 50ppm of NAA alone. This response suggests that there is a synergistic relationship with gibberllin and auxin in inhibiting flower bud formation. From these results it is concluded that equal quantities of 50ppm of NAA and 50ppm of GA inhibit flower bud differentiation of chrysanthemums when applied at three day intervals under a low light intensity of 2 lux.
As well known, Lythrum salicaria is a tristylic plant, having long-styled, mid-styled, and short-styled plants. The materials under study, Lythrum salicaria LINN. var. roseum superbum Hort., were raised from commercial seeds. The styles of long-and mid-styled plants in these experiments were longer than those of materials in the previous works (Table 1). In these experiments the pistils were collected at intervals after legitimate and illegitimate unions, and killed in 94 percent alcohol. Next, the materials were immersed in lactic acid to soften, squashed, and stained with 0.5 percent lactic-blue. After being differentiated in lactic acid, mounts were made in a drop of glycerine. The results obtained may be summarized as follows: When the long-styled flowers were legitimately pollinated, the longest tubes penetrated the ovary within 11 hours after pollination. In the long-styled flowers illegitimately pollinated, the longest tubes elongated only a length of about 5mm within 48 hours after pollination. The tube length was less than half the distance from the stigma to the ovary. The longest tubes of mid-styled flowers after legitimate unions penetrated the ovary within 10 hours after pollination. When illegitimately pollinated, the longest tubes of mid-styled flowers grew a length of less than 2mm within 24 hours after pollination. In the short-styled flowers legitimately pollinated, the longest tubes reached the ovary about 3 hours after pollination. While the longest tubes of short-styled flowers illegitimately pollinated elongated only about 1mm within 9 hours after pollination. There was then the arrest of pollen tube growth (Table 2, and 3). These results are essentially in accord with those by SCHOCH-BODMER (1937, 1945) and by ESSER (1953) although differing somewhat in details.
Vegetative propagation of amaryllis, which is successful at high temperature, generally results in a poor performance in summer through autumn, as thickening of bulblets is depressed by cool temperature immediately following their formation, and many of them decay.
Some experiments have been carried out for the purpose of establishing the day-length treatment for cut flower production of dahlia plants during winter season. This report deals with the optimum day length and minimum intensity of supplementary light for flowering of dahlia. Two varieties (Akane and Futarishizuka) bred in Japan were selected for the materials. Cuttings were made using the lateral shoots of plants grown under outdoor conditions in autumn or spring. The top of cutting was cut off at the lowest node to induce the new lateral shoots after rooting. Then, plants were shifted for day-length treatment. The results were as follows: 1. The day-length after the middle of September was not preferable for growth and flower formation of dahlia. 2. The growth of shoot was inhibited under the day-length shorter than 12 hours, while it was enhanced under that longer than 13 hours. 3. Blind flowers increased under the day-length shorter than 12 hours, while normal flowers were yielded under that longer than 13 hours. However, flowering delayed as the day-length became longer. 4. The total number of florets or the number of ray flowers increased with increasing day-length, while the number of disc flowers decreased to the contrary. 5. The optimum day-length was 13 hours for the variety Akane which hardly exposed the disc, and 14 hours for the variety Futarishizuka which readily exposed the disc. 6. Minimum light intensity for artificial irradiation in the long day treatment was 20 to 36lux. 7. Dahlia seems to be an indefinite short day plant according to the results of this study. 8. However, the day-length longer than a certain level is necessary for growth and flower formation. The limiting day length may be laid down about 12 hours, and growth or flower formation is suppressed under this limit.