The native habitat, phenology and embryo development of Glehnia littoralis Fr. Schm distributed in areas surrounding Shimane Peninsula, Japan were investigated in order to facilitate preservation of natural habitats and develop herb applications as a local genetic resources of this plant. Several wild populations of G. littoralis were found in the sandy beach areas of Yumigahama (Yonago, Tottori pref.), Iwami-Kaihin Park (Hamada, Shimane pref.) and other beaches. The protection and increase of G. littoralis population has been promoted in the beaches of Yumigahama and Sotozono (Izumo, Shimane pref.). In the wild habitat of this plant, the following phonological events were observed: Foliation from the end of Feb., flower bud emergence from the mid Apr., flowering from early May to mid Aug., fruit development, maturation and abscission at the peduncle from early July, leaf yellowing and abscission from Sep. and dormancy from the beginning of Dec. Embryos in the seeds began to enlarge under cold stratification for fifty days. GA treatment and removal of pericarp also promoted embryo development and germination.
Using 7 pairs of simple sequence repeat (SSR) primers developed for Japanese chestnut, we identified the SSR genotypes of 7 chestnut cultivars that originated from the Korean peninsula and compared them with those of 17 Chinese chestnut cultivars, 32 Japanese chestnut cultivars, and an interspecific hybrid obtained by crossing the above species. The 7 SSR loci of all cultivars were successfully genotyped, except KT006a for which no amplification products were obtained from 3 cultivars of Chinese chestnut. Among the 36 alleles observed in the 17 Chinese cultivars, 26 were shown to be species-specific alleles, while 37 of the 47 alleles observed in the 32 Japanese cultivars were shown to be specific to Japanese chestnut. The SSR genotypes of the Korean cultivars were also identified and comprised 2-9 alleles per locus (average: 5.14 alleles). By comparing the results to the species-specific alleles, we considered that ‘Myeonsan 9’, ‘Myeonsan 13’, ‘Myeonsan 60’, ‘Inhungwanglyul’, and ‘Han 6’ are Japanese chestnut cultivars; ‘Hamjong 3 ho’ is a Chinese chestnut cultivar; and ‘Ooshiro’ is an interspecific hybrid. A synonymous relationship or a bud mutation was estimated between ‘Han 6’ and ‘Tanzawa’, and between ‘Ooshiro’ and ‘Riheiguri’.
A solid phase enzyme immunoassay (EIA) for the quantitative determination of the phytonutrient component, limonin glucoside, in citrus juice was developed. Limonin glucoside and limonin were in aqueous and methylene chloride fractions respectively when juice was partitioned with methylene chloride. The assay was carried out by indirect competitive immunoassay (ICEIA) with a biotin-avidin system (BAS) using anti-limonin antiserum (Yamamoto and Matsumoto, 1999) and limonin glucoside-ovalbumin conjugate as the solid phase. The assay showed a high sensitivity within a range extending from 10 pg to 100 ng of limonin glucoside. Limonin glucoside and limonin concentration in the juice of 128 cultivars of citrus were determined by ICEIA-BAS. Limonin glucoside constituted over 90% of the total limonin in juice from almost all cultivars except for pummelos. The limonin glucoside concentration in juice was high in all navel oranges and a few mandarins at more than 100 ppm. Juice from pummelos, yuzu and its relatives, lemon and kumquat contained low concentrations of limonin glucoside. Limonin, the bitter component, was high in juice from pummelos, navel oranges and others. However, there did not seem to be a problem of bitterness in the many remaining cultivars because the limonin concentration in their juice was low.
The leaves of pepper plants contain abundant iron, calcium and vitamins. We have bred a pepper cultivar ‘Kyotona’ as a new leafy vegetable. In this report, nitric oxide (NO)-generation inhibitor was investigated in young pepper leaves and stems. Pepper leaves or fruits were tested for in vitro NO-generation inhibitory activities in a mouse macrophage RAW 264.7 cell. Acetone extracts from the leaves showed marked inhibitory activity on NO-generation. Then we tried to isolate NO-generation inhibitors from acetone extracts of leaves by column chromatographies. As a result, apigenin was isolated as one of the inhibitors of NO-generation. Major polyphenols in ‘Kyotona’ were investigated by HPLC. It was demonstrated that major polyphenols in ‘Kyotona’ leaves and stems were apigenin glycosides and luteolin glycosides. The average contents of apigenin glycosides and luteolin glycosides were 29.3 and 227.0 μmol·100 g−1FW, respectively.
Lettuce (Lactuca spp.) and chicory (Cichorium spp.) are known as traditional medicinal plants with several pharmaceutical effects attributed to the sesquiterpene lactones (SLs) present in their latex. Genetic variations of SL concentrations in lettuce and chicory were investigated using HPLC from the perspective of lettuce breeding to obtain higher SL concentrations. Lettuce cultivars (L. sativa L.) showed lower SL concentrations than wild Lactuca species and cultivated Cichorium species. It is assumed that breeding efforts for better taste with little bitterness in cultivated lettuce resulted in low SLs concentrations because SLs are primary components of bitterness in Lactuca and Cichorium. Intraspecific variation of SL concentrations among 3 morphological types of cultivated lettuce was observed and lines of crisp-head type, a most popular head formation type, showed a lower SL concentration than those of the leaf-type and cos-type. A few lines with high SL concentrations found in this experiment are available to breed lettuce with a high SL concentration.
Nara prefecture certifies Yamato-mana (Brassica rapa L. Oleifera Group) as the traditional vegetable of the Yamato District, and is providing support for its cultivation and marketing. However, Yamato-mana has not yet been widely distributed and sold because the harvested product is not uniformly sized and its outer leaflets are likely to turn yellow soon after harvesting. Therefore, to overcome these problems, efforts are underway to breed an F1 hybrid of Yamato-mana using its nature of strong self-incompatibility. To estimate S-haplotypes in six varieties of Yamato-mana sampled in different locations in Nara prefecture, we cloned class-I SLG and class-II SP11 from these varieties by PCR. In total, 31 genes were confirmed from sequences of amplified fragments, including 27 class-I S-haplotypes and 4 class-II S-haplotypes. Cluster analyses, based on S-haplotypes accumulated in each variety, classified the six varieties into three groups: Nara prefectural agricultural experiment station/Nanto varieties, Takada/Gojo/Fukase varieties, and Yamato agricultural farm variety.
The application of silver nitrate is a common option to induce staminate flowers in gynoecious cucumbers in order to maintain their progenies. The present study examined the effect of silver nitrate on the number of staminate flowers, and the performance of seeds produced by the induced staminate flowers. Six concentrations of silver nitrate at 0, 100, 200, 300, 400 and 500 ppm were applied to a gynoecious cucumber ‘ChibiTaro’. The number of staminate flowers increased at higher concentrations between 200 and 500 ppm, while there were no staminate flowers at 0 and 100 ppm. The staminate flowers induced at different concentrations were then pollinated separately on pistillate flowers of another gynoecious cultivar ‘Rensei’. The number of seeds per fruit after 500 ppm treatment was significantly higher than those after 200 and 400 ppm, although there was no consistent relationship between the number of seeds per fruit and silver nitrate concentration. The hundred seed weight showed a smaller value after 500 ppm treatment compared to those after 300 and 400 ppm but germination percentages of seeds were not significantly different among the concentrations either at harvest time or after eight years of storage. Microscopic examination of acetocarmine stained pollen of induced staminate flowers confirmed the absence of significant differences in pollen viability among the silver nitrate concentrations. Silver nitrate is therefore regarded as an effective growth regulator for inducing staminate flowers efficiently, without adverse effects on pollen viability, seed productivity or germinability.
The relationships between volumetric water concentration in branches (θbranch) measured by time domain reflectometry (TDR) and soil moisture, potential evaporation, leaf water potential (LWP) and fruit quality were investigated in order to evaluate the efficiency of θbranch for optimal water management to obtain high quality fruit. The θbranch at the base of the trunk began to increase in April, reaching the highest value in July, then gradually decreased and reached the lowest value in mid-October including that during the harvesting period. After harvesting, the θbranch increased slightly, and then became stable in winter. The decrease in θbranch from summer until harvesting and the increase after harvesting were related to the soil moisture. The seasonal changes in θbranch of the trees as long as the LWP was controlled around -1 MPa corresponded to the potential evaporation. Moreover, it was found that water stress condition was reflected in changes in θbranch, LWP, and fruits quality. Although the relationship between θbranch and LWP was unclear, our results suggested that θbranch measured by TDR would be a useful indicator for water management in Satsuma mandarin orchards.
To establish a spray pollination system for peach (Prunus persica Batsch) fruit cultivation, we investigated the effects of pectin methylesterase (PME) and polygalacturonase (PG) concentrations in pollen suspension media on pollen germination and pollen tube elongation. Furthermore, the rates of fruit set and fruit quality of ‘Kawanakajima Hakuto’ peach were compared with hand pollination and spray pollination using various suspension media. The improvement of pollen tube growth was observed at either 0.1 mg·L−1 PME or PG. Rates of fruit set in spray pollination treatments were significantly lower than that by hand pollination treatment. Among the suspension media tested in this study, the combination of 10% sucrose, 0.04% XG and 0.1 mg·L−1 PME or PG gave the highest rates of fruit set. There were no significant differences in fruit quality between spray pollination and hand pollination. Based on these findings, the addition of PME or PG in the pollen suspension media for spray pollination can improve the fruit set in the spray pollination of peaches.
Coloring area ratio in Eustoma picotee petals often increases in the winter, leading to a reduction of commercial value. It has been thought that encountering a low temperature before flowering causes this increase. We studied the effects of temperature on the picotee pattern of ‘Candy Marin’, which is a very early flowering cultivar, using artificial climate chambers under a 12-h light condition. Under constant temperature conditions, the picotee coloring area rate was the highest at 20°C and a negative correlation was found between the rate and growth temperature. Changing daytime and nighttime temperatures to 19°C and 25°C decreased the ratio. Even if the plant encountered 5°C at night, the picotee coloring area rate was kept low by encountering 35°C in daytime, suggesting that day-time treatment at high temperature could avoid increasing the rate in the winter season. The temperature condition reducing the picotee coloring area rate tended to decrease growth amounts as well. We also found that increase in the coloration area ratio is not directly related to an increase in the anthocyanin-flavonoid concentrations.
In the present study, we investigated a simple pollen preservation method that could be used by growers with the objective of achieving a steady supply of pollen for hand pollination of Japanese pepper (Zanthoxylum piperitum (L.) DC.) in protected cultivation, which enables advance shipping. We used temperature conditions that could be reproduced by home-use refrigerator-freezers. After preserving fresh pollen from the early and full bloom stages at 5°C or −20°C, pollen germination rates were measured on agar media. The results showed that germination rates comparable to fresh pollen were maintained for 20-30 days at 5°C and for 10 months at −20°C. Blooming was observed following hand pollination using fresh pollen or fresh pollen that was washed with an organic solvent and then preserved at −20°C for 10 months. These findings indicate that this method allows the use of pollen from the previous year for hand pollination of Japanese pepper.
The flesh firmness of sliced tomato (Solanum lycopersicum L. ‘Reiyo’), cultivated under two different nutrient control systems with various amounts of supplied nutrients, was evaluated by acoustic vibration measurement. A whole tomato was placed between acoustic vibration probes, and the elastic indices were calculated using the second resonance and fruit diameter. The elastic indices measured at harvest and after 21 days of storage distinguished the firmness of fruit cultivated under different control systems and amounts of supplied nutrients. The elasticity index showed a higher correlation with the firmness of sliced tomato than that of the intact tomato. The correlation coefficient between the elasticity index and the sliced tomato firmness was as high as that between the intact tomato firmness measured by destructive methods and the sliced tomato firmness. As a consequence, acoustic vibration measurement might be available to nondestructively evaluate the flesh firmness of sliced tomato.
A remote measuring method for volumes of fruit like rotational bodies was developed using digital images, and the precision of this method was examined using detached fruits. Further, based on these principles, remote measurement of volumes of attached fruits in an apple cultivar and a pear were carried out seasonally using several types of field photography devices. Each coordinate on a fruit outline in a side photograph was read in pixel units along the fruit shaft using an image analysis program. The volume of each very thin rotational disk composed of each radius and one pixel thickness was calculated and totaled. Cavity volumes were similarly calculated from cavity outlines in other images photographed at a 45-degree angle. The latter was used to deduce the fruit volume from the former. The relations between the measured volumes and the remote measured volumes were fairly good in several cultivars of apple, pear and grape. Photography for remote measuring in the field became possible using a device that allowed regulation of the height and angle in simultaneous photographs from two directions and maintained the attitude of cameras at 45 degrees.
The relationship between fruit quality and planting density (varying from 330 to 3178 trees·ha−1) was studied in 7- to 11-year-old ‘Starking Delicious’ apple trees (Malus domestica Borkh.) grafted onto M.9, M.26, M.7 and MM.106 and grown under a no-pruning system. On all rootstocks, fruit weight decreased as planting density (ρ) increased. The density effect on fruit weight (ω) was represented by ω = K1ρ−k1, where K1 and k1 depend on the relative solar radiation or light interception of the previous year, the current year and rootstocks. The watercore intensity index and soluble solids decreased as planting density increased, but flesh firmness increased. The density effect on watercore intensity index (μ), soluble solids (δ) and flesh firmness (ζ) was represented respectively by μ = K2exp(−k2ρ), δ = K3ρ−k3 and ζ = K4ρk4. The density effect on acidity (η) was represented by η = K5ρk5 for mature fruits, and η = K5ρ−k5 for immature fruits, and in these equations, when planting density for high-quality fruit production was set, an applicable equation was η = K5ρk5. K2, k2, K3, k3, K4, k4, K5 and k5 depend on the meteorological element in the canopy of the current year and rootstocks. These findings suggest that planting density for high-quality fruit production can be set using the equations described above, and that the high-quality fruit production capacity that set planting density possesses is demonstrated by harvesting when the fruit has reached the appropriate stage of maturity.
Effects of temperature on node numbers of flower bud differentiation of Gloriosa superba L. were investigated using three genotypes, ‘Misato Red (MR)’, ‘Tropical Red (TR)’ and ‘Rose Queen (RQ)’. Tubers of each genotype were kept at 30°C for 23 days to enhance sprouting, and then were planted in a greenhouse with soil temperature controlled at 19.1±0.6°C or 31.6±1.0°C. Flower buds initiated at the same node order under both temperature conditions in MR and TR, whereas RQ produced larger numbers of leaves at a higher soil temperature. When tubers were kept at 15 to 40°C for 56 days under dry conditions, flower initiation occurred at 30°C or below in MR and at 35°C or below in TR during the temperature treatment, but did not occur in RQ, indicating a longer juvenile phase of RQ. Whereas 30°C was suitable for leaf differentiation, node numbers of flower bud differentiation were smaller at a lower temperature in all genotypes. MR tubers treated at 30°C for 25 days and TR and RQ tubers treated for 15 days followed by 15°C for 15 days showed lower node numbers of flower bud differentiation compared with tubers treated at 30°C for 30 days. Since 30°C enhanced vegetative growth but inhibited flower bud differentiation in Gloriosa, tubers kept at 30°C followed by 15°C showed less vegetative growth. The present results show that genotype differences in node number of flower bud differentiation can be due to the differences in juvenile phase length and temperature-related phase transition.
To develop a flowering forecasting model in ‘Kawazu-zakura’ (Prunus lannesiana Wils.) cherry tree, short stems in the ecodormancy stage were exposed to six contact temperatures (0, 5, 10, 15, 20 and 25°C) under dark conditions. The developmental rate (DVR) and temperature showed a high correlation. DVR and temperature (T) were used to develop a model, DVR = 0.045T (0 < T ≦ 25) DVR = 0 (T ≦ 0). It was confirmed that the model was suitable under outdoor conditions in Minamiizu region. Cut branches were cultivated in a greenhouse that controlled the daily minimum temperature at 5, 10, 15, and 20°C under natural day length. Higher temperature hastened the blooming date but decreased the flowering rate, flower size and quality. The optimal temperature for obtaining the cut flowers of ‘Kawazu-zakura’ was thought to be a daily minimum temperature of 10°C.
Once bananas are induced to ripen with ethylene, edible life is only 6 days when stored in an ambient condition after treatment. A method to slow down the ethylene-induced ripening process has economical significance for marketers and consumers. The application of 1-methylcyclopropene (1-MCP), a strong inhibitor of ethylene action, was conducted to maintain the eating-ripe condition of banana fruit. Several conditions for application of 1-MCP including timing (before, during and after ethylene treatment), stages (color 1, 3 and 5) and concentrations (0.1, 0.3, 0.5, 1.0 and 10 ppm) were studied. Preclimacteric banana treated with 0.3 ppm 1-MCP delayed the initiation of ripening, but was much less effective in extending the edible life. Simultaneous treatments with 0.3 ppm 1-MCP and 100, 250 or 500 ppm ethylene at the preclimacteric stage caused uneven peel degreening. The higher the concentration of ethylene, the more quickly degreening would be observed in this simultaneous treatment. Banana ripening induced by ethylene could be slowed down by exposure to 0.3 ppm of 1-MCP at color stage 3. We conclude that 1-MCP is a promising postharvest treatment for extending the edible life of bananas to more than 12 days at 25°C when applied at color stage 3.
Long-term storage of Japanese chestnut (Castanea crenata Siebold & Zucc.) fruit using a polyethylene bag was carried out between October 2004 to September 2005. In order to create different O2/CO2 compositions in the bags, we used 1, 2, or 5 layers of polyethylene bags. The concentrations of soluble sugars and starch and the microstructure of cotyledonary parenchyma cells were investigated as fruit quality factors. The rate of sound fruits was decreased for all treatments at 2 months of storage. When 5 layers of polyethylene bag were used, all fruits lost their commercial quality at 10 months of storage. At 3 months of storage, there were large differences in gas composition among the treatments. The higher number of polyethylene films facilitated a decrease in the O2 content and increase in the CO2 content. Scanning electron microscopic observation of cotyledonary parenchyma cells demonstrated that the degree of starch breakdown in each treatment was also different at 3 months of storage. Starch breakdown was extensive when 1 or 2 layers of polyethylene bag were used but was decreased when 5 layers of polyethylene bag were used. These morphological differences indicate that gas composition in the bags affects fruit respiration and reserves mobilization. The amyloplast density and starch concentration in sound fruits were relatively high at 11 months of storage when 1 and 2 layers of polyethylene bag were used. At this stage, although the sound fruits rate was low (approx. 50%), a high amount of storage reserves was retained in these fruits. These findings suggest that the amount of storage reserves in chestnut fruit at harvest affects fruit storability; in other words, well-matured fruits have a good potential for long-term storage.