The effect of the growth and development of pericarp tissues on the occurrence of the various types of black stain on fruit skin was examined in Japanese persimmons (Diospyros kaki Thunb.), ‘Fuyu’and‘Saijo’to define why ‘Saijo’is experientially said to be more susceptible to the disorders than‘Fuyu’. 1. Dotty type occurred most frequently in both cultivars. In‘Saijo’, disorders of vertically striped type gave the next higher rate of occurrence, followed by those of vertical line-like and broken line-like types. However, in‘Fuyu’, vertical line-like type occurred most often after dotty type, both of which occurred more often than the other types. 2. Broken line-like and cloudy types occurred mainly in the apical and median portions of fruit, while wavy and vertical line-like types were observed mostly in the basal portion in both cutivars. 3. In both cultivars, the rate of growth differed largely with the portions of fruit examined, decreasing successively from the base to the apex. 4. The cuticle layer of fruit in‘Saijo’was thinner than that in ‘Fuyu’in the early stage of growth. Also, the development of epidermal and sub-epidermal cells in‘Saijo’was inferior to that in‘Fuyu’. 5. The characteristic disorders in‘Saijo’were vertically striped and broken line-like types. These seem to be the typical ones caused by rapid enlargement of fruit in the late stage accompanied by the expansion of fine splits on the skin.
Schlieren pattern in analytical ultracentrifugation and reactivity to acetaldehyde of tannins of Japanese persimmon fruit (Diospros kaki) were investigated using cvs. ‘Fuyu’, pollination constant non-astringent (PCNA) type, and‘Hiratanenashi’, pollination variant astringent (PVA) type. 1) To study the schlieren pattern, tannins extracted from both cultivars with aqueous acetone were separated into two fractions (F-I and F-II) by size exclusion chromatography on CPG-10 2000Å. After the tannin concentrations were equalised, these fractions were incubated at 40°C and subjected to ultracentrifugation at pre-incubation (0 day), 1 and 3 days of incubation. The schlieren patterns revealed that F-I and F-II fractions from both cultivars contained three or four tannin components, and that the sedimentation coefficient of each component from‘Hiratanenashi’ was larger than the corresponding component from‘Fuyu’. Moreover, the components of the F-I fraction from‘Hiratanenashi’changed or shifted remarkably during incubation; two faster components (26S and 23S) disappeared and one slower component (6S) appeared. Conversely, the components of both fractions (F-I and F-II) from‘Fuyu’and F-II fraction from‘Hiratanenashi’were stable. 2) To characterize the reactivity of tannins to acetaldehyde, coagulation times of the fruit juice bathed in acetaldehyde vapor were compared between‘Fuyu’and ‘Hiratanenashi’at different tannin concentrations and pHs. A longer time was needed for coagulation as the tannin concentration became lower and when the pH value was between 3.0 and 5.0. The fruit juice from‘Fuyu’coagulated more slowly than that from‘Hiratanenashi’. The present results suggest that tannin substances from‘Fuyu’distribute mainly in a lower molecular weight range and have a milder chemical property compared with those from‘Hiratanenashi’.
Experiments were conducted during the de-astringency in persimmon fruits by ethanol treatment to determine the optimum conditions of ethanol extraction for the quantitative analysis of tannin and sugar contents, the relatiouship between the decrease in tannin concentration and loss in astringency, and the behaviour of ethanol during the penetration into fruits. 1. The tannin concentration was greatest when fruit tissue was homogenized and extracted with 70% ethanol. In astringent fruits on the course of de-astringency, a small increase in tannin concentration was observed when the 70% ethanolic extract was heated to boiling. 2. When fruit tissue was homogenized and extracted with a decreasing concentration of ethanol, there were a decrease in non-reducing sugar and a corresponding increase in reducing sugar, indicating the conversion of non-reducing to reducing sugar. The total sugar concentration did not change significantly. The accurate determination of sugar content was achieved by homogenizing and extracting fruit tissue with 70% ethanol and immediately heating these extracts to boiling. 3. There was a relatively high correlation between the degree of astringency and tannin concentration when fruit tissue was homogenized and extracted with 70% ethanol and then heated. Fruits containing about 0.2% of tannin were slightly astringent, and fruits containing less than about 0.1% of tannin were almost non-astringent. 4. The penetration of ethanol gas into fruits occurred mainly through the peel surface. The rate of ethanol penetration into fruits increased proportionally to ethanol gas concentration in the surrounding atmosphere. There was little effect of either cultivar or holding temperature on the penetration rate.
A correlation between early drop of fruit and indole derivatives was investigated using histochemical techniques. In vitro and in vivo, the indole derivatives formed a blue pigment with a peak of absorbency at 618nm by p-dimethylaminobenzaldehyde-nitrite reaction and a correlation between the concentration of the pigment and absorbancy at 620nm was observed. At all stages of seed development the embryo was found to give a strong reaction while the endosperm gave a weak or no reaction, and the nucellus gave a moderate reaction. The relative content of indole derivatives in the embryo, endosperm and nucellus tissue was calculated. The relative content of these derivatives in embryos was very low until the 50th day after full bloom, but showed a marked increase between the 50th and the 90th day, and remained at a very high level until harvest. The relative content in the endosperm and nucellus tissue was very low in all stages. Early drop of fruit was enhanced by a high night temperature (25°C) for 30 days beginning on the 10th day after full bloom. A reduced rate of fruit enlargement for two days was utilized to distinguish potential drop fruits. Potential drop fruits abscised within 6 to 10 days after that distinction. Fruit drop process was divided into four stages (potential drop fruit stage A, stage B, stage C and abscission). Since no difference in the concentration of indole derivatives was recognized between fruits of stage A and the persistent one, the indole derivatives are considered to have no correlation with early drop of fruit.
Changes in flavor and aroma components and their relationships to maturation in satsuma mandarin (Citrus unshiu Marc.) fruit were investigated. Fruit of′Sugiyama unshu′, a mid maturing cultivar, were sampled from sunshine and shade positions in the tree canopy, at intervals of about 1 month, from August 4 to December 11, 1978. 1. Percentage variations in volatile flavor components of peel. In the peel of sunshine-fruits, the most pronounced percentage variations were found in d-limonene and terpinene. d-Limonene increased gradually, while terpinene decreased rapidly till early October, and thereafter they remained relatively constant. α-Pinene decreased from August to September, and thereafter, it remained relatively constant together with δ-elemene, decyl aldehyde, perillyl aldehyde and γ-elemene. β-Pinene, nonyl aldehyde, trans-sabinene, linalool, β-caryophylene, α-terpineol, p-cymene, β-copaene and geranyl acetate decreased, while mircene increased. In the peel of shade-fruits, d-limonene increased during August to September, then remained relatively constant, whereas terpinene decreased markedly till early October, and then increased slowly. α-Pinene, camphene, β-pinene, trans-sabinene, decyl aldehyde, linalool, β-caryophylene, β-copaene and geranyl acetate remained relatively constant. p-Cymene, nonyl aldehyde, β-farnesene, α-terpineol, perillyl aldehyde and γ-elemene tended to decrease generally, whereas myrcene and δ-elemene increased. The total content of volatiles in the peel of fruit in sunshine and shade positions in the tree canopy continued to increase until early October, and then decreased gradually, although it was higher in the peel of sunshine-fruit than of shade-fruit. 2. Percentage variations in volatile flavor components of juice. In the juice of sunshine-fruit, in early November, d-limonene was the most abundant component, followed by terpinene, myrcene, p-cymene, β-caryophylene, geranyl acetate, δ-elemene, α-pinene, β-pinene, α-terpineol, trans-sabinene, β-copaene, γ-elemene and linalool. After one month, d-limonene decreased markedly, and neither geranyl acetate nor trans-sabinene was detected, whereas the other components increased considerably. The increase was especially significant for nonyl-aldehyde, which was not present at all in the previous month. In the juice of shade-fruit, in early November, d-limonene was the largest component, followed by terpinene, linalool, myrcene, β-caryophylene, p-cymene, geranyl acetate, α-terpineol, β-copaene, α-pinene, trans-sabinene, β-pinene, δ-elemene and nonyl aldehyde in this order. After one month, both d-limonene and terpinene decreased greatly. Furthermore, myrcene, p-cymene, β-pinene, trans-sabinene and nonyl aldehyde could not be detected, whereas the other components increased markedly. The increase was especially significant for γ-elemene, which was not present at in the previous month.
Pectic substance fractions and their concentrations in satsuma mandarin (Citrus un-shiu Marc. ) fruit were investigated in relation to maturation. The fruits of′Okitsu Wase′, an early maturing cultivar, and′Silverhill′, a common cultivar, were sampled at maturation from September 3, 1973 to January 28, 1974. 1. Early maturing cultivar The contents of water- and sodium hexametaphosphate-soluble pectins in the peel increased, but that of the sodium hydroxide-soluble fraction decreased from early September to early December. Thereafter all of the fractions increased slightly. Water- and sodium hexametaphosphate-soluble pectins in the pulp increased rapidly during late December, and thereafter decreased gradually. Sodium hydroxide-soluble pectin in the pulp increased rapidly from early September to early January of the following year, and then decreased. In the segment wall, water- and sodium hexametaphosphate-soluble pectins increased gradually from early September to early January of the following year. The decrease was slower in sodium hydroxide-soluble pectins which continued to decrease until January. 2. Common cultivar Sodium hexametaphosphate- and sodium hydroxide-soluble pectins in the peel decreased slowly throughout maturation. Water- and sodium hexametaphosphate-soluble pectins in the pulp decreased gradually from early September to mid-October, and thereafter remained relatively constant up to early January of the following year. Sodium hydroxide-soluble pectins in the pulp decreased markedly from early september to late October, and thereafter increased rapidly up to late January of the following year. The water-soluble fraction in the segment wall gradually increased until late November, and thereafter decreased slowly. Sodium hexametaphosphate-soluble pectins in the segment wall increased gradually from early September to late December, and then decreased gradually. The sodium hydroxide-soluble fraction in the segment wall decreased gradually from early September to late January of the following year.
The application of organic materials stimulated ethylene evolution in waterlogged soils. The application of dead and fresh grape leaves, dead citrus leaf, fresh citrus root, dead Japanese pear leaf, dead peach leaf, dead persimmon leaf, or rice straw greatly increased ethylene evolution. Evolution of ethylene from organic materials in the soil, which seems to require microbial activity, was markedly affected by soil temperature, soil moisture, and soil aeration. The amount of ethylene evolved from redried or fermented organic materials was markedly reduced to between one-25th and one-40th of that evolved from non-redried or non-fermented materials. The application of dead grape leaf, which caused greatest ethylene evolution, markedly inhibited the growth of ′Muscat of Alexandria′ grapevine cuttings.
Muskmelons (Cucumis melo L.) were grown with nutrient solutions to examine the effect of stage and duration of exposure to diluted sea water treatments at stage I (transplanting to pollination), stage II (pollination to fruit net development) and/or stage III (fruit net development to harvest) on the growth at harvest in experiment I and the growth at the end of three stages in experiment II. Experiment I Whole plant dry weight and fruit fresh weight tended to increase with reduced exposure to diluted sea water and to decrease with increased sea water concentrations. Fruit fresh weight increased and Cl and Na contents in leaves remained unaffected when plants grown in diluted sea water at stage I were grown in base nutrient solution at stages II and III. The shorter the duration of the treatments the lower the Cl and Na contents in leaves. Experiment II The deleterious effect of treatment solution on growth generally decreased with plant age and reduced exposure to treatment solution. The exposure to treatment solution at stage III reduced whole plant dry weight and fruit fresh weight, but did not affect leaf+stem+root dry weight. Saltiness in fruit increased with longer exposure. Cl and Na contents in leaves at harvest were significantly higher when exposed to treatment solution at stage III. Osmotic potential of leaves was proportional to that of the nutrient solution at each stage. As a result, early stage till pollination and fruit development stages were most sensitive to saline conditions when whole plant dry weight, and fruit fresh weight and quality of muskmelons were used as index of salt tolerance, respectively.
This paper was designed to study seed germination and embryogenesis in Calanthe aristulifera, Calanthe izu-insularis and Calanth amamiana. The results may be summarized as follows. 1. The ovaries of C. aristulifera, C, izu-insularis and C. amamiana rapidly increased in size and reached their final size about 60 days, 50 days and 70 days, respectively after pollination. 2. The seed and embryos of C. aristulifera, C, izu-insularis and C. amamiana rapidly increased in size, and reached their final size 70 days and 80 days, respectively after pollination. 3. Ovule formation occurred 38 to 40 days after pollination in both C. aristulifera and C. izu-insularis, and 43 to 45 days after in C. amamiana. Double fertilization occurred 48 to 50 days after pollination in both C. aristulifera and C. amamiana, and 43 to 45 days after in C. izu-insularis. The mature embryo sac was observed to contain 5 to 6 nuclei regardless of species. After pollination, C. aristulifera, C. izu-insularis and C. amamiana required 95 to 100 days for the completion of embryo development. 4. Proembryos of C. aristulifera, C. izu-insularis and C. amamiana on the tetrad stage were all classified as A2 type, according to Veyret′s classification. Similarly, embryos of C. aristulifera, C. izu-insularis and C. amamiana on and after the tetrad stage seemed to belong to the E type (Liparis pulverlenta type). The mture embryo was observed to be derived from the apical cells of proembryo in C. aristulifera, C. izu-insularis and C. amamiana. 5. Three to five endosperm nuclei were observed in the embryosac after fertilization in C. aristulifera, C. izu-insularis and C. amamiana. 6. The seeds of C. aristulifera were able to germinate after the intermediary stage (80 days after pollination), those of C. izu-insularis after the time between the octant and intermediary stage (80 days after pollination), and those of C. amamiana before the tetrad stage (60 days after pollination). The highest percentage of seed germination was obtained when the seeds were harvested near the mature embryo stage. When culturing C. izu-insularis for germination, dark conditions were better than light, and Hyponex medium was better than Murashige and Skoog medium.
Forcing methods of tree peony (Paeonia suffruticosa) timed for New Years Day were investigated. Garlic paste applied to the flower bud after chilling promoted bud sprouting and leaf extension. This treatment also accelerated flowering, advancing harvest time to the middle of December. Pre-chilling treatment had a similar effect on flowering although the effectiveness depended on the cultivar. A combination treatment of pre-chilling and garlic paste resulted in flowering at the end of November when applied to a cultivar in which dormancy was less deep.
In order to establish a long-term storage procedure for chestnuts, both precooling, by room cooling, pressure cooling and vacuum cooling, and cold-storage with polyethylene pouches were investigated. Results obtained were as follows: 1. Vacuum cooling gave the fastest cooling rate, followed by pressure cooling and by room cooling. Vacuum cooling, however, gave rise to white spots on the shell of chestnuts which was considered to be an undesirable selling factor. Of the three precooling treatments mentioned above, pressure cooling was thought to be the best. 2. The weight losses during cooling were 1.6% for pressure cooling and 2.8% for vacuum cooling. In the latter case, the loss was approximately equal to the result calculated from the temperature reduction, assuming that almost all of the latent heat of vaporization came from the product. 3. The extent of mold growing on the shell or scar of the stored chestnuts increased with increasing storage temperature and storage period. Almost all of the chestnuts which were stored at 10°C for 4 months or at 5°C for 6 months were spoiled. 4. To evaluate an elastic modulus of chestnut flesh, cylindrical specimens were cut out from chestnuts along with long and short axis parallel to the seed scar. In chestnuts stored at 1°C, elastic modulus of the long axis flesh changed with the storage period. 5. The sucrose content of the chestnuts stored at 1, 5 and 10°C increased rapidly during the first month, particularly at 1°C. Conversely, the starch content of the chestnuts decreased during the above period. 6. The LL size chestnuts were more suitable for storage than L size ones. Since both the respiration rate and the weight loss of these chestnuts were lower than in L size. 7. The shelf life of the LL size chestnuts was 3 months at 1°C, 2 months at 5°C and 1 month at 10°C.
The effect of fluctuating temperature on chilling injury in the fruits of eggplant, snap bean, cucumber and sweet pepper was investigated, comparing with those held at steady temperature. In the fluctuating temperature treatment (square-wave form), samples were kept on the fluctuating conditions which were combined with the amplitudes of fluctuation at ±5°C, ±3°C, ±2°C or ±1°C and the periods of onecycle for 24-hour, 12-hour or 6-hour respectively, when standard temperature was 6°C which seemed to occur chilling injury. The decrease in the occurrence of pitting injury of eggplant fruit was directly proportional to the amplitude of the fluctuation and the length of the fluctuating period. The increase in chlorogenic acid content was also delayed as the fluctuating amplitude widened. At a standard temperature of 6°C, the conditions of fluctuating temperature at which chilling injury of eggplant fruit was clearly ameliorated were an amplitude of ±5°C and a period of 12-hour or 24-hour. The fluctuating temperature promoted the amelioration of pitting injury of snap bean fruit as effectively as that of eggplant fruit. It could not, however, be observed that the temperature fluctuation had a positive effect on the amelioration of chilling injury of cucumber fruit and sweet pepper fruit. Although in cucumber fruit pitting injury occurred more often at the fluctuating temperature than at a steady temperature of 6°C, this was probably due to the greater chilling-sensitivity of cucumber fruit compared to eggplant fruit.
It has been reported that chilling injury in mume (Japanese apricot) fruits usually occurs much sooner at 5-8°C (moderate low temperature) than at 0-1°C, and that a cold-shock treatment by hydrocooling in ice water immediately after harvest is effective in retarding the development of the chilling injury. This paper deals with the mechanism of the cold-shock treatment. 1. As an index of membrane permeability, the rate of K+ion leakage from tissue slices into water was measured at various temperatures ranging from 1°C to 20°C. While the leakage rate of chilling-insensitive potato tuber decreased as the temperature was lowered, that of chilling-sensitive cucumber fruits showed no decrease at low temperatures, remaining at an almost constant level below 10°C. However leakage rate of mume fruits, showed an unusual increase at moderate low temperatures (5-8°C). Using 4 cultivars of mume fruits, ‘Yosei’‘Nanko’‘Gyokuei’and ‘Gojiro’it was found that the temperature at which the unusual increase of K+ion leakage occurred on harvest day was almost the same as that at which severe chilling injury occurred during storage. 2. When‘Oshuku’mume fruits, a very chilling-sensitive cultivar, were given a cold-shock in ice water for 2 hours and then stored at 6°C, chilling injury was retarded. Except for a temporary rise soon after the treatment, the rate of K+ion leakage remained at a constant low level. However, in untreated fruits, the rate of K+ion leakage increaesed markedly during storage at 6°C. Fatty acid composition of membrane lipids was analyzed, and C16:0 was found to be most abundant, followed by C18:2, C18:3, C18:1, C16:1, C14:0, C18:0 in that order. The ratio of unsaturated fatty acids to total fatty acids was 52%, a relatively low value compared with other commodities, suggesting a lower tolerance to chilling temperature. Cold-shock treatment increased the above ratio. Total phenol content gradually increased both in the untreated and treated fruits during 6°C storage, the values being slightly lower in the treated fruits. Activities of polyphenol oxidase and peroxidase increased during 6°C storage. No relation tocold-shock effect was found. NADH-cytochrome C reductase activity, an index of activity of the enzymatic system involved in unsaturation of fatty acids, increased rapidly during the cold-shock treatment and remained at a higher level than in untreated fruits throughout the 6°C storage period. 3. From these results, it was concluded that the effect of the cold-shock treatment was to accelerate the desaturation of fatty acids in membrane lipids.