Effects of fruit thinning on the fruit growth and the variation of acid content in the juice of twenty-year-old Kawano-Natsudaidai trees were examined. The numbers of leaves per fruit in the thinned trees were 83 and 92, and 62 and 69 in the non-thinned trees. Fruit size and acid content in the juice were measured on both February 3 and April 26. 1) Fruit growth was superior in the thinned trees, and number of L, M size fruits was greater. The ratios of smaller fruits below S size were 47.2 and 49.1% in the non-thinned trees, and 2.1 and 23.3% in the thinned trees. The range of mean fruit weight in each bearing part (top, middle and bottom height of the tree and inner and outer part of the tree crown) measured in February was from 328 to 376g in the thinned trees, whereas it was from 257 to 381g in the non-thinned tree. 2) The variation of acid content in the juice examined in February ranged from 1.4 to 2.3% in the thinned tree, while it ranged from 1.5 to 2.9% in the non-thinned tree. Average acid contents of thinned and non-thinned tree were 1.78 and 2.19%, and the variation coefficients were 9.6 and 13.7%, respectively. The average acid content in each bearing part ranged from 1.74 to 2.01% in the thinned tree, and from 1.81 to 2.48% in the non-thinned tree. When the fruits were stored in room temperature after harvest in february and examined in April, the variation of acid content ranged from 0.9 to 2.0% in the thinned tree, and from 1.1 to 2.5% in the non-thinned tree. Their average acid contents were 1.45 and 1.68%, respectively. the acid content was lowered as a whole with storage, but its variation was not affected. 3) Significant negative correlations were found between acid content, fruit weight and the number of leaves per bearing shoot both in February and April observation. Correlation coefficients between acid content and fruit weight were r=-0.19 and -0.33 in the thinned trees, and r=-0.71 and -0.72 in the non-thinned trees. While those between acid content and the number of leaves per bearing shoot were r=-0.49 and -0.28 in the thinned trees, r=-0.37 and -0.17 in the non-thinned trees respectively.
Endogenous cytokinins in Delaware grape berries were separated and partially purified for, their identification and the relationship between seeded berry growth and free cytokinins in the berries were studied. 1. Cytokinin activities in the cluster just before anthesis and in the pericarp during flowering were markedly high. This activity in the pericarp decreased gradually thereafter and almost disappeared 50 days after anthesis. 2. There was a close relationship between cytokinin activity in seed and growth of seed. High activity of cytokinin was observed during the rapid growth stage of seed. 3. At least two free cytokinins were present in the seeded grape berries. Zeatin and zeatin riboside were supposed to be responsible for the activities in the ammonia eluated fraction (AE). 4. In addition to these free cytokinins, at least two unknown cytokinin-like substances were present in the grape seed.
This paper is a continuation of our preceding report and describes the effects of ethanol treatment for removal of astringency from the “on-tree” fruit of the Japanese persimmon, cv. Hiratanenashi, from the pre-bloom stage extending to the end of July on the reappearance of astringency and on changes in other fruit character-istics. Fruit or fruit buds at pre-bloom were enclosed in polyethylene bags containing 5 or 10ml of 5% ethanol until they completely lost their astringency. Then the bags were removed and the fruit was allowed to remain on the tree. 1) Except for the fruit treated in mid- or late July, soluble tannin reappeared in the fruit within one to two weeks after de-bagging with increasing degrees of reappearance in earlier treatments. Fruit treated before mid- or late June displayed astringency throughout the flesh tissue, while those treated later did so only in portions of the flesh tissue near the calyx end. 2) The browning of flesh tissue appeared strongly in the fruit treated at the end of June and later, except for the portion of flesh tissue near the calyx end where astringency reoccurred. In fruit in which astringency reoccurred in all the tissue, only minor and localized browning, if any, was detected at the distal end of the fruit. 3) Fruit shape and size were variously affected by the dates of ethanol treatment. Treatments applied between mid-May and mid-June tended to cause flattening of the fruit. Those treated between late June and mid-July showed reduced fruit diameter and distorted shape, while treatment at the end of July had almost no effect on fruit shape and size. 4) Mitotic activity of flesh tissue was most active from the end of May to early June, and almost ceased in late June and was located mainly in the calyx end of the fruit. Its possible contribution to the reappearance of astringency after ethanol treatment is discussed.
Some experiments were carried out to elucidate the effects of bulb size, removal of scaly leaves and foliage leaves and dormant condition on low temperature induction of flower buds in onion bulbs. The results were summarized as follows: 1. As the index of bulb size, bulb weight was used effectively in the following experiments. It was found that the larger the bulb size, the shorter the period of low temperature (9°C) exposure required for flower bud formation. There was recognized, however, the presence of the critical bulb size at which the period of low temperature required was minimized. Thus, in “Senshuki” the critical bulb size appeared to be about 100-150g in weight and the minimum period of low temperature exposure to be about 40 days, while in “Sapporoki” they appeared to be about 30-50g and 30 days respectively; the latter being recognized to be more sensitive to low temperature exposure. 2. Bulbs, when their scaly leaves were romoved in various degrees before planting, required longer periods of low temperature exposure according to the severity of the treatment. The periods required were shorter, however, as compared with the intact bulbs of the same size corresponding to that of the treated bulbs. The removal of foliage leaves after planting also increased the period of low temperature required. 3. The removal of scaly leaves and/or of foliage leaves resulted in remarkable decrease of carbohydrate contents of bulbs, which appeared to be related to the increase of low temperature requirement in treated bulbs. The results mentioned above may be explained well by assuming the accumulation of the precursor in the bulbs, which changed into the so-called florigen at low temperature exposure. This precursor appears to accumulate in higher density in inner scales and its concentration seems to change in parallel with carbohydrate contents. 4. When bulbs immediately after, or 30 days after, harvest were exposed to low temperature without water supply, they almost did not respond to, or required much longer period of, low temperature exposure for flower bud formation.
In order to investigate the possibility of shoot formation from cultured tissues of strawberry fruits (receptacles), effects of age and seeds (achenes) on callus and shoot formation from cultured fruit tissues were studied. 1. When fruit tissues with seeds two and seven days after anthesis were cultured on the medium supplemented with 0 or 0.1mg/l BA+1 or 5mg/l 2, 4-D, white friable callus was produced around the basal part of the explant and grew rapidly. When the callus was subcultured on the medium supplemented with 10mg/l BA+ 0.1mg/l 2, 4-D, shoots were formed. 2. When fruit tissues without seeds two and seven days after anthesis were cultured on the medium supplemented with 1 or 5mg/l BA+0.1 or 1mg/l 2, 4-D, green firm callus was produced from the entire surface of the explant and then shoots were formed from this callus. 3. When fruit tissues with seeds seven days after anthesis and fruit tissues with or without seeds twelve days after anthesis were cultured on the medium supplemented with 0.1 or 5mg/l BA+1 or 5mg/l 2, 4-D, pale green firm callus composed of very small cells appeared around the basal part of the explant, but no shoots were formed on this type of firm callus. 4. When fruit tissues with or without seeds seventeen days after anthesis were cultured, cell enlargement was observed but no callus was formed regardless of the concentrations of the growth regulators supplemented to the medium. 5. When shoots formed on callus were separated and subcultured on the basal medium without growth regulators, roots were formed within two weeks and young plantlets were established.
The shoot-tips of Cattleyas cultured on a solid medium turned brown, and eventually died. To reduce browning of tissue, the browning reaction of Cattleya was studied using the powder of freeze-dried leaves and partially purified polyphenoloxidases. In addition, the shoot-tips were cultured under condition where the browning of Cattleya tissue powder was reduced. 1. The spectrometric absorbance maximum of the browning substance was at 285nm. 2. Cattleya polyphenoloxidases had a pH optimum of 6.5 and the activity was greatly inhibited at a lower pH. Furthermore polyphenoloxidase activity or browning was inhibited with potassium cyanide, ascorbic acid, cysteine, thiourea and in a stationary condition. 3. The browning of shoot-tips was most effectively inhibited in a liquid medium in a stationary condition. The inhibitors had no effect or little effect on the browning on a solid medium. 4. Boiled ethanol extracts of Cattleya tissue were oxidised by cattleya polyphenoloxidases, and the major component of substrates were extracted with ethylacetate from acidic aqueous solution.
Since 1964 the author has endeavored to obtain useful novel mutants in flower plants by gamma-ray irradiation. Plenty of annual, perennial and bulbous plants were grown several times under different dosages of chronic gamma-ray irradiation in the gamma-field of the Institute of Radiation Breeding, Ohmiya. Among many mutants obtained in the series of experiments, especially two mutated strains, semi-double flowering wallflower and white-flowering moss verbena, are described in this report due to their apparent available characteristics and genetical stability of the recessive nature. Firstly, in the wallflower, Cheiranthus cheiri, many slightly-double or semi-double flowered plants were detected in the γ1-group which was raised from seeds produced by the single-flowered plants grown and irradiated in the gamma-field for about three months (ca. 4Kr) in 1972. The degree of their doubling of flowerlets was very variable, both between plant and plant and between flowerlets on the same inflorescence. These double flowers were possibly induced by a recessive gene and consisted of a few small spoon-like petallets mixed with pistils and stamens. In appearance, however, their inflorescences seemed to be inferior to those of the commercial cultivars, such as Double Early Wonder, due to somewhat tiny, poor flower stalks and lowered seed fertility. Next, in the moss verbena, Verbena erinoides, a pure-white flowered seedling was found in the Spring of 1973 among several purple-red ones spontaneously germinated around the parental plants which were irradiated in the gamma-field in 1972. General characteristics of the mutated plant were similar to those of nonirradiated plants, except for flower color. In detail, however, the size of the white flowerlet was a little smaller than the latter. Then, the mutant produced a few seeds under open pollination and raised five γ2 seedlings in 1975 and, furthermore, eight γ3 plants in 1976. All the plants showed pure-white flowers exactly like those of γ1 plant, without any genetic segregation. So, it was supposed that white-flowering was simple recessive against the colored. The white-flowering moss verbena might be available for carpet plants in the garden, even though the white-flowered V. erinoides var. alba Hort. had been described formerly by Dermen which, however, has not been found in any gardens in our country.
This experiment was designed to clarify the effect of the scaling and chilling duration on the leaf emergence of scale bulblet in the Easter lily cv. ‘Hinomoto’. The ratio of the weekly leaf emergence (WLE) became higher and the appearance of maximum WLE was hastened, as the scaling duration was lengthened. There was a tendency that leaf emergence was hastened and the period was shortened, as the chilling duration was lengthened. In general, longer scaling induced a higher total ratio of leaf emergence. The effect of chilling durations was dependent on scaling durations. In case of longer scaling, i, e., 6month-scaling, leaf emergence ratio was high, independent of chilling durations. In cases of shorter scaling, less than 4.5month-scaling, however, it was high, as the chilling duration was shortened. That is, longer chilling inhibited the leaf emergence. These results indicate that the scale bulblet in the Easter lily might be able to sprout leaves more easily with the advance of age which was presented as the scaling duration and that lengthening of higher temperature scaling might satisfy the requirement for the high temperature accumulation which would be necessary for leaf emergence.
Distribution of anthocyanins, especially 3-glucoside, in fifteen marketing cultivars with several pure bred strains of snapdragon was surveyed with chromatographic technique. In some strains derived from “Ball's Supreme Red” an adequate amount of 3-glucoside with 3-rutinoside was found. In fifteen marketing cultivars, a relatively large amount of cyanidin-3-glucoside was found in young petals of florets of two cultivars, and in others cyanidin or pelargonidin-3-glucoside was detected in only trace or no amount. Nevertheless, in such young flower petals of most cultivars and strains tested, 3-glucosides were detected. A quantity of two anthocyanins in each developmental stage of flower petals was investigated in a reddish purple strain containing a relatively large amount of cyanidin-3-glucoside. The results are summarized below. 1. The amount of cyanidin-3-glucoside per floret was decreased significantly from the half open stage of petals in all cases, while cyanidin-3-rutinoside had still been increased to senescence. 2. The ratio of 3-glucoside/3-rutinoside in palate was higher than in upper lip in all stages. 3. Decrease of 3-glucoside and increase of 3-rutinoside in palate after flower opening were obviously slower than in upper lip. From these phenomenon, it was assumed that 3-glucoside would be the precursor of 3-rutinoside in this case.
Employing the tomato fruit vibrated at 1G and 3G for 1hr and 5hrs respectively, changes in respiration rate, color development, firmness, soluble solids and titratable acid contents, constituents of sugars and organic acids, and organoleptic evaluation during ripening after vibration were studied from 1973 to 1975. An additional observation on the respiration rate of tomato fruit vibrated at different stages of ripeness was carried out in order to study the relationship between the fruit maturity and the physiological response to vibration. An increased respiration rate after vibration, which showed more intensive elevation at 1G than that at 3G, continued for about 60hrs after the vibration was terminated for every vibrating condition. In fruit vibrated at the turning stage of ripeness, the respiration rate was followed by an another sudden increase which seemed to be the climacteric rise of respiration. The climacteric maximum in the fruit vibrated at 3G was achieved at a slightly earlier time than at 1G, in spite of retarding the color development of the fruit surface and locular gelationous tissue. Citric acid, malic acid and titratable acid contents of tomato fruit vibrated at 3G increased temporarily during vibration. These high levels of acid contents decreased rapidly during ripening after vibration, and attained to the lower level at the full ripe stage of ripeness. Glucose and fructose contents showed little correspon-dence with the intensity of vibration. The poor organoleptic evaluation characterized by light taste and mealy texture was observed on the fruit vibrated at 3G vibration of turning stage. Moreover, changes in respiration rate, color development and acid contents during ripening after vibration were more striking in fruit vibrated at the turning stage of ripeness. From these facts obtained above, the physiological effect of vibration on tomato fruit was discussed. It was clear that some physiological disorder might have occurred in tomato fruit vibrated at an intensive vibrating accerelation exceeding the limited level of vibration, and that the physiological effect of vibration was sensitive in the fruit at the turning stage of ripeness. The careful consideration must be taken about the fruit maturity and the vibrating condition in the course of transportation of tomato fruit.
This study examines the role of glycolysis in respiration of banana fruits stimulated by ethylene. Monoiodoacetate inhibited the respiration of banana peel sections in the absence of ethylene, and the inhibitory effect was strengthened in the presence of the gas (100μl/l). The experiment of incorporation of glucose-1-14C, and glucose-6-14C to carbon dioxide showed a conversion of the pathway from HMP to EMP with the advance of age in peel sections. But the period of alternation of the pathway did not coincide with that of the respiratory increase. However the incorporation rate of each penetrated glucose-14C to carbon dioxide changed with the increase of the respiration rate of peel sections. While the content of reducing sugar increased continuously in pulp and peel, the levels of glycolytic intermediates such as G-1-P, G-6-P, F-6-P, F-1, 6-diP, dihydroxyacetone P and pyruvate corresponded to respiratory changes of climacteric in pulp tissue. Especially, the change of F-1, 6-diP content was remarkable among the intermediates. Although the respiration of peel sections decreased after removal of ethylene, the levels of G-6-P and F-6-P were higher in this tissue than in the tissue in which the respiration was continuously enhanced with ethylene. On the contrary, this tendency was reversed for F-1, 6-diP, dihydroxyacetone P and pyruvate. These results suggest that the respiration climacteric with ethylene may be related to the enhancement of glycolysis and the step between the F-6-P and F-1, 6-diP may be concerned with a regulation of this pathway in pulp and peel of banana fruits. An alternation of temperature caused a change of respiration in green banana fruits. While the respiration was stimulated at 30°C, the levels of G-6-P and F-6-P decreased and other intermediates (F-1, 6-diP, dihydroxyacetone P, phosphoenol-pyruvate, and pyruvate) had no change. This data indicates a difference of metabolism of glycolysis between the respiration climacteric and activated respiration by temperature alternation.
The brown colored lotus rhizomes are usually produced by common cultural practices. When the brown substances were formed high concentration on the rhizomes, their marketabilities were reduced extremely because of undesirable color. The browning substances were determined and their seasonal changes were also determined in this study. 1. The amount of brown substances increased continuously until late-Sept., then decreased steadily. Such seasonal change suggests that the brown formation and dissolving is caused by oxidation and reduction which is closely associated with the lotus growth and the soil conditions. 2. The smaller quantities of brown substances were situated in the first node of rhizome, but were larger in the later nodes, while the brown formation in each node itself was observed largely in the portion of growth direction of that node. 3. The analytical results of brown substances by fluorescent X-ray showed that Fe is a dominant and was followed by the small Mn. Other metalic elements such as Zn, Ni and Cu, though detected in a slight amount, were not at all clear why existed in this substances. It was supposed by some quantitative analysis that the brown substances exist principally in oxidized or similar formulas. 4. Since there is a strong relationship between Fe contents and L-values (color) in rhizome, the approximate contents of Fe or Mn could be obtained only by measurement of L-value with relation of equality linear function. 5. The amount of brown substances between experimental plot A and B differed considerably. The compost application (plot-B) reduced the accumulation of brown substances. Therefore, it was supposed that the compost plays as important role in diminishing functions of brown phenomenon.
To study the organic acid and carbohydrate metabolism of mandarin fruit after harvest, the metabolic processes of citrate-1, 5-14C (pH 3.49), glucose-1-14C (pH 7.0; G-1-14C) and glucose-6-14C (pH 7.0; G-6-14C) which were injected with a disposable syringe into a segment through the rind of the fruit were investigated during storage at 7±3°C for 50 days after injection. 1. The injected citrate-14C was incorporated into 14CO2 immediately after injection. The cumulative radioactivity of respired 14CO2 continued to increase rapidly and attained to 28.8% of total radioactivity after 10 days and 33.5% after 50 days. Meanwhile, the cumulative radioactivity of 14CO2 from G-1-14C and G-6-14C continued increase slowly and attained to 6.5% and 6.3% of total activity of the substrates after 50 days, respectively. 2. The rate of cumulative radioactivity of 14CO2 from the injected G-6-14C and G-1-14C was 0.34 for subsequent 2 days, 0.63 for 5 days, 0.68 for 10 days and 1.02 for 50 days after injection, respectively. These results may show that the hexose monophosphate pathway is the major pathway in the early stages of glycolysis of injected glucose and the glycolysis tends to shift to the Embden-Meyerhof Parnas pathway from HMP pathway in the latter period of the experiment. 3. The injected citrate-14C could be incorporated rapidly into the carbohydrates, amino acids, proteins and pectic substances. There remained only a half amount of the substrate in the anionic fraction after 10 days. The metabolic activity of glucose-14C was considerably low as compared with that of citrate-14C. Therefore, the remaining of glucose-14C in the neutral fraction was about 80% after 50 days. The rate of incorporation into organic acid-14C and amino acid-14C from the moiety of injected glucose-14C attained to about 20% of total radioactivity of the ethanol soluble fraction at the end of experimental period. From these results, it may be concluded that the rate of turnover of citric acid in mandarin fruit can be considerably high, even after harvest.
In order to obtain the primary data for determining maturity of Golden Delicious, Starking Delicious and Fuji apples, fruit samples were collected at 7-14 day intervals with a total of 4 to 6 harvests during the period of maturation and ripening. The rates of respiration and C2H4 evolution, and the internal C2H4 concentration were measured for 7 to 20 days beginning 1 day after harvest. 1. As harvest was delayed, the rise in respiration began sooner after harvest, and late harvested Golden Delicious and Starking Delicious apples showed a high rate of respiration at 1 day after harvest, which was associated with a subsequent increase, resulting in attainment of almost a climacteric peak at the last harvest. However, in late harvested Fuji apples, although the rate of respiration at 1 day after harvest became high, an initial decline in the rate was followed by a rise in respiration, which was less pronounced with delayed harvest, eventually disappear ing in the last harvest. 2. The increase in C2H4 evolution was observed during the climacteric rise in respiration, but in late harvested Fuji apples, except for the last harvest that showed an increase in C2H4 evolution without any respiratory upsurge, it occurred before the onset of the rise in respiration. 3. As harvest was delayed, the rapid increase in internal C2H4 concentration began sooner after harvest, and late harvested Golden Delicious and Starking Delicious apples showed a high internal concentration of C2H4 at 1 day after harvest, while late harvested Fuji apples showed a small increase in the internal concentration of C2H4 at 1 day after harvest, followed thereafter by a rapid increase in most fruits. 4. The internal concentration of C2H4, which increases rapidly as a rapid increase in fruit C2H4 production begins during the period of maturation and ripening, is considered to be capable of serving as an index of maturity.
Even though there is a relation between the physical properties of the peel of satsuma mandarin and preservability of the fruit during the distribution process, few papers have been reported on the gas permeability through the peel and other properties. In this paper, we presented the steady state and non-steady state methods to measure the permeability constants of CO2, O2 and N2 through the peel of satsuma mandarin. These methods were improved ones on the sweep gas method which was used to measure the gas permeability of packaging film. Furthermore some observations of the respiratory characteristics of the peel were performed in order to use in calculating the permeability constants. 1. Permeability constant of CO2 through the peel was measured by the steady state method. (1) 92 percent of CO2 production by the peel was exhausted from the albedo side. The amounts were 1.43×10-2[cm3/cm2/hr] for the fruit collected on Nov. 14 and 2.41×10-2[cm3/cm2/hr] on Dec. 15 in 1975 respectively (Fig. 3, Fig. 4). (2) CO2 concentration in the atmosphere enclosed with the hemispherical peel and plastic plate increased gradually and then reached its equilibrium state in more than ten hours. Equilibrium concentrations of CO2 were 4.7 percent for the fruit collected on Nov. 14 and 8.0 percent on Dec. 15 respectively (Fig. 5). (3) By substituting these values into equation (1), the permeability constants of CO2 through the peel of satsuma mandarin were obtained to be 11.3×10-4[cm3/cm/hr/cmHg] for the fruit collected on Nov. 14 and 11.5×10-4[cm3/cm/hr/cmHg] on Dec. 15 respectively (Tab. 1). 2. In measuring by the non-steady state method, permeability constants of CO2, O2 and N2 through the peel were 8.9×10-4, 5.2×10-4 and 4.7×10-4[cm3/cm/hr/cm Hg] in order (Tab. 1). 3. The difference of the magnitude of the permeability constants among three gases was proven by measuring the gauge pressure in the atmosphere enclosed with the hemispherical peel and plastic plate when both the flavedo and albedo sides of the peel were filled with different pure gas (Fig. 8).
In order to estimate weight loss percent of fruit and vegetables, we experimented with spinach. The results are as follows. 1. Equilibrium relationships between moisture content of products and relative humidity of the surrounding air can be easily determined within a few days by measuring the equilibrium relative humidity of the air in the small chamber in which products are kept at a constant temperature. 2. The equilibrium moisture content curves for spinach were expressed in the following equations. Adsorption: 1-rh=exp(-1.14×10-4•T•M1.169) 2-1 Desorption: 1-rh=exp(-8.70×10-5•T•M1.170) 2-2 rh=equilibrium relative humidity, expressed as a decimal T=absolute temperature of air [°K] Me=equilibrium moisture content (dry basis) 3. Weight loss percent of spinach after harvest can be obtained from Eq. (2-2) and the following equations. v=(1-M+100/M1+100)×100 M-Me/M1-Me=exp[-(K•t)n] K=8.254×108•exp(-7.383×103/T) n=6.24×10-3•v+0.537 v=water loss percent of product at any time after harvest M=moisture content (dry basis) at any time Me=equilibrium moisture content (dry basis) M1=initial moisture content (dry basis) K=rate of drying constant [hr-1] n=constant t=time in hours v=centigrade temperature of air [°C]