A brief account of research in our laboratory on the mechanism of the cross incompatibility between evergreen azalea species and yellow flowered deciduous azalea, Rhododendron japonicum form flavum, i.e. mechanism of unilateral cross incompatibility and albino progenies appearance, is given. Furthermore, the strategy for obtaining vigorous green progenies effectively was also summarized.

View full abstract

The nursery stocks of two fig varieties, ‘Masui dauphine’ and ‘Houraishi’ (Ficus carica L.), were raised by cutting in a nursery, transplanted with changing tree density to an experiment field on July 8, 2004, and cultivated using straight-line training in the Agricultural Food and Environmental Science Research Center of Osaka Prefecture, Japan. The density grades per 1.0-a land area (100 m²) were 200, 66.7, 40, and 6.06. The growth of the aboveground vegetative parts of each tree was monitored at irregular intervals in 2005 by measuring the length and diameter of three organs, i.e. trunk, primary scaffold limb and fruit-bearing shoots. The linear dimensions of the three organs were transformed into dry weight values of woody organs and leaves, giving individual vegetative weight per tree. The fruit were harvested daily during the fruiting season from August to December 2005. The mean values of individual vegetative weight at different densities were approximated well by the reciprocal equation of the C-D effect (hereafter, the SK model), which was proposed by Shinozaki and Kira ca. 50 years ago. Mean annual fruit production per tree at a given density grade was also covered by the SK model, suggesting the clear effect of density on vegetative growth and fruit production in young fig monocultures. The coefficients of the equation conformed to conventional recognition about the poorer vegetative growth and richer fruit harvest in ‘Masui dauphine’ than in ‘Houraishi’. The observed density dependency of the reproductive allocation (RA) represented the decrease of RA with the increase of density in two cultivars although the predicted density dependency of RA was contradictory to that of the observation of the ‘Masui dauphine’.

View full abstract

The growth characteristics of the aboveground vegetative organs in two fig cultivars, ‘Masui dauphine’ and ‘Houraishi’ (Ficus carica L.), were analyzed by applying numerical techniques of logistic theory of the density effect to the results from our preceding study, which dealt with the influence of tree density on aboveground vegetative growth and reproduction in young fig monocultures. Three major growth characteristics, biological time (τ), growth rate (λ), and final yield (Y) in aboveground vegetative organs, were calculated by the theory, and their seasonal changes were examined. The τ and Y represented a sigmoid curve with respect to time, while λ peaked in late June or early July and decreased after mid-July. Throughout the growing season before defoliation, τ, λ, and Y were always larger in ‘Houraishi’ than in ‘Masui dauphine’, clearly suggesting the superiority of ‘Houraishi’ to ‘Masui dauphine’ in aboveground vegetative growth. The proposed index could express the distance between focal cultivars in terms of three growth characteristics. By comparing λ values of the cultivars with those of other herbs and trees, the status of cultivars in the biological gradient of plant growth rates was examined, and it was concluded that the cultivars are neither herbs nor trees but in-between. Furthermore, the effect of plant mass removal caused by natural or artificial events was incorporated into the reciprocal equation of the density effect in order to discuss leaf defoliation and shoot pruning.

View full abstract

Fluorochrome staining with chromomycin A₃ (CMA) was used to characterize and compare the CMA banding patterns of chromosomes of Clymenia, Eremocitrus, and Microcitrus, which belong to true citrus fruit trees (Citrinae, Rutaceae). All species had 2n = 18 chromosomes. These chromosomes were classified into six types based on the number and position of CMA-positive bands; A: two telomeric and one proximal band, B: one telomeric and one proximal band, C: two telomeric bands, D: one telomeric band, E: without bands, and Dst: type D with a satellite chromosome. Each species possessed three or four types of chromosomes and unique CMA banding patterns. The CMA banding patterns were 2C + 8D + 8E in Cl. polyandra, 2C + 9D + 7E in E. glauca, 1C + 11D + 6E in M. australis, 1B + 2C + 10D + 5E in M. australasica, 8C + 7D + 2E + 1Dst in M. inodora, 2A + 14D + 2Dst in M. warburgiana, and 2C + 9D + 7E in Sydney hybrid. Chromosome configurations of Cl. polyandra, E. glauca, M. australis, and Sydney hybrid resembled each other. This may indicate a common ground of chromosome configuration in the true citrus fruit trees. On the other hand, variability in Microcitrus chromosomes was also demonstrated.

View full abstract

We investigated marker-assisted selection of the pollination constant and non-astringent (PCNA) trait and inheritance modes of the marker locus in persimmon (Diospyros kaki Thunb.) using restriction fragment length polymorphism (RFLP) analysis. In two backcross progenies, FU-170 and FU-275, 5 of 71 and 23 of 101 offspring, respectively, were judged as PCNA genotype by the marker phenotype. The astringency type of individual offspring was determined by measuring the size of tannin cells and soluble tannin content in mature fruit, thus confirming complete co-segregation of RFLP markers and the non-PCNA phenotype in 32 and 68 fruit-obtainable offspring from FU-170 and FU-275, respectively; therefore, RFLP markers can be used for PCNA genotype detection. Their segregation ratio deviated significantly from that of disomic inheritance. We also discuss the possibility of polysomic inheritance of RFLP markers.

View full abstract

A cDNA, VlmybA1-2, for an anthocyanin regulatory gene of grape was constructed under the control of the cauliflower mosaic virus (CaMV) 35SRNA promoter and introduced into leaf disks and petioles of kiwifruit (Actinidia deliciosa) plants by Agrobacterium-mediated gene transfer. When the tissues were cultured on selection medium, red cells visible to the naked eye formed at the cut ends of the segments after approximately 2 weeks. The cells developed into calluses, adventitious buds, and reddish-purple plantlets after 2, 3, and 6 months of culture, respectively. The pigment produced in the leaves of the transformed plants was determined to be cyanidin 3-O-(2-O-β-xylosyl)-β-glucoside (cyanidin 3-O-sambubioside). As VlmybA1-2 can also produce red cells in tomato and eggplant, it may be useful as a visible marker to confirm efficient transformation in dicots.

View full abstract

A Citrus FT/TFL1 homologue (CuMFT1) was isolated from Satsuma mandarin (Citrus unshiu Marc.), and a high degree of expression was detected in mature seeds, indicating that its promoter is expected to induce the expression of a target gene in the late embryonic stage of Citrus seed. To obtain a seed-specific promoter useful for Citrus transgenic research, the 5′ upstream region of CuMFT1 was isolated from the BAC library, and its promoter activity was characterized using particle bombardment and transgenic Arabidopsis. The 2.4 kbp in the 5′ upstream region (CuMFT1 promoter) contained RY (CATGCAT), E-box (CANNTG), and distant B-box (GCCACTTGTC) cis-elements, which have been reported to promote seed-specific gene expression in plants. The CuMFT1 promoter fused to the uidA gene was directly incorporated into tissues from Citrus and its relatives using particle bombardment. The results showed that the CuMFT1 promoter conferred high β-glucronidase (GUS) activity in seed. The CuMFT1 promoter-GUS fusion construct was also incorporated into Arabidopsis, and transgenic Arabidopsis was evaluated by histochemical staining and fluorometric GUS analysis. The experiments revealed that the CuMFT1 promoter conferred quantitatively preferential expression in Arabidopsis seeds; thus, it was suggested that the cis-elements in the CuMFT1 promoter required for expression in Citrus seed were functionally conserved in the heterologous Arabidopsis plant. The CuMFT1 promoter could be utilized as a promoter regulating the quantitatively preferential expression in seed, and is useful for studies of seed development and manipulation by genetic engineering in Citrus and Arabidopsis.

View full abstract

In order to clarify the influence of the rootstock cultivar and fruit storage on the texture of cucumber (Cucumis sativus L.) fruit, we examined the physical properties of the fruit, i.e., flesh firmness, placental firmness, skin toughness, and the crispness index. Cucumber fruits from own-rooted plants and from plants grafted onto the three rootstock cultivars of ‘Shin-tosa’ (Cucurbita maxima Duchesne ex Lam. × C. moschata Duchesne ex Poir.), ‘Hikari Power Gold’ (Cucurbita moschata; for bloomless fruit production), and ‘King Kitora’ (C. moschata; for bloomless fruit production) were used as materials and were stored at 10 or 25°C for up to 7 days under humid conditions (wrapped in polyethylene bags). No distinct influences of rootstock cultivars on the physical properties of cucumber fruits just after harvesting were observed. In addition, there was no clear difference between own-rooted cucumber fruits and all grafted fruits. On the other hand, the flesh firmness and crispness index of fruits from all grafted and non-grafted cucumbers were increased by storage at 10 or 25°C under humid conditions. Differences in the values of physical properties between the fruits stored at 10 and 25°C were very small. These results indicate that the texture of cucumber fruit is affected by storage, rather than by the rootstock cultivar. Regarding fruits just after harvesting or those stored for several days in humid conditions, there was no evidence of a less desirable texture in bloomless cucumber fruits.

View full abstract

This study compared the concentrations of components such as nitrate, organic acids, free amino acids, cations and sugars in komatsuna (Brassica campestris var. perviridis) grown with carbonate, sulfate and chloride application (CO₃-TK, SO₄-TK and Cl-TK, respectively). The komatsuna was cultivated in 1/2000-a Wagner pots (6 hills per pot) filled with light-colored Andosol in a glasshouse for 37 days at soil water potential (SWP) right before harvesting of −6.2 and −62 kPa. And 26.5 mmol_c of carbonate, sulfate or chloride in the form of potassium salts was applied to each pot. Chloride application to the komatsuna induced relatively high concentrations of potassium, calcium and magnesium ions, and the low concentrations of malate, glucose and fructose on a dry weight basis (DWB). Carbonate application induced relatively high concentrations of malate and low concentrations of nitrate. Sulfate was almost between chloride and carbonate. Concentration variation was not substantial in free amino acids. Those tendencies were almost the same in both SWPs. Most of the variations in component concentrations were attributed to the regulation of ionic and osmotic balance to respond to chloride, nitrate and sulfate absorption, as judged from quantitative relationships among the components and water in the komatsuna. It seems that the absorption of nitrate is influenced by the pH of the soil. There were clear differences in glucose, fructose and malate concentrations among CO₃-TK, SO₄-TK and Cl-TK on a fresh weight basis just as on a DWB.

View full abstract

Irrigation with moderate salinity stress in a hydroponic system improves the inner and outer fruit quality of tomato (Solanum lycopersicon Mill. ‘House Momotaro’). We investigated the effects of 50 mM NaCl in a hydroponic solution on the levels of various metabolites, including soluble sugars, amino acids, and organic acids, and on the expression levels of salinity-responsive genes during fruit development. Under salinity, Brix (%), surface color density, and flesh firmness of the fruit were significantly enhanced, whereas fruit enlargement was suppressed. Salinity stress strongly promoted the accumulation of sucrose, citrate, malate, and glutamate, and slightly promoted glucose and γ-amino butyric acid in red fruit. At the transcriptional level, up-regulation of ethylene-synthetic 1-aminocyclopropane-1-carboxylate oxidase and down-regulation of photosynthetic chlorophyll a/b binding protein Cab-1B occurred earlier in stressed fruit than in control fruit. Additionally, the carotenoid-biosynthesis regulatory gene, Phytoene synthase 1, and phosphoenolpyruvate carboxykinase (PEPCK) were up-regulated under moderate salinity in the red stage. The expression profiles of these genes in stress-treated fruit were consistent with the changes in fruit quality, including earlier ripening and a deeper red color. Furthermore, the up-regulation of PEPCK suggested that gluconeogenesis is involved in the accumulation of sugars in salinity-stressed fruit.

View full abstract

Night break treatment was applied to Eustoma grandiflorum ‘Neilpeach Neo’ using different light sources to investigate growth and flowering responses. The seedlings were grown in a greenhouse and treated with night break treatment using a far-red fluorescent lamp, a plant growth fluorescent lamp, a daylight-type fluorescent lamp or an incandescent lamp, or were grown under non-treated conditions (control). Photosynthetic photon flux density (PPFD) at the top of the plant was 5 μmol·m⁻²·s⁻¹ under each light source. The red (660 ± 30 nm): far-red (730 ± 30 nm) ratio of the light sources was 0.01, 0.43, 5.00, and 0.65, respectively. The time from planting to flower budding was 46 days for plants grown under a far-red light fluorescent lamp, compared with 66 days in the control. The incandescent lamp and plant growth fluorescent lamp also reduced the time to flower budding; however, the daylight-type fluorescent lamp delayed flower budding by 4 days compared with the control. The light source regimes had little or no effect on the time to flowering after flower budding. The far-red fluorescent lamp, incandescent lamp and plant growth fluorescent lamp reduced the number of nodes on the main stem at the anthesis of the first floret, while the daylight-type fluorescent lamp increased the number of nodes. The far-red fluorescent lamp and incandescent lamp promoted internode elongation, while the daylight-type fluorescent lamp reduced internode length. Moreover, a red fluorescent lamp with a R: FR ratio of 105 delayed flower budding and flowering, and increased the number of nodes of the plants as compared with the control, regardless of the long day lengths in July and August. Thus, it is considered that the growth and flowering time of Eustoma grandiflorum can be controlled by long-day treatment carried out with the proper type of light source.

View full abstract

Seven anthocyanins, cyanidin 3,5-di-O-β-glucopyranoside, cyanidin 3-O-(6-O-(Z)-p-coumaroyl-β-glucopyranoside)-5-O-β-glucopyranoside, cyanidin 3-O-(6-O-(E)-p-coumaroyl-β-glucopyranoside)-5-O-β-glucopyranoside, cyanidin 3-O-β-glucopyranoside, cyanidin 3-O-(6-O-(Z)-p-coumaroyl)-β-glucopyranoside, cyanidin 3-O-(6-O-(E)-p-coumaroyl)-β-glucopyranoside, and cyanidin 3-O-β-galactopyranoside were isolated from the red flowers of Camellia saluenensis. Out of seven anthocyanins, cyanidin 3-O-(6-O-(Z)-p-coumaroyl-β-glucopyranoside)-5-O-β-glucopyranoside was found to be isolated from the red flowers of genus Camellia for the first time. The floral distribution of anthocyanin composition was also determined by HPLC analysis between C. saluenensis and C. pitardii var. pitardii.

View full abstract

Eleven anthocyanins were isolated from the flowers of 6 selected cultivars and identified as 3-O-rutinoside-5-O-glucosides of cyanidin, malvidin, pelargonidin and peonidin, and 3,5-di-O-glucosides of petunidin, malvidin, pelargonidin, cyanidin and peonidin, and pelargonidin 3-O-rutinoside and malvidin 3-O-glucoside, by thin layer chromatography (TLC), liquid chromatograph-mass spectrometry (LC-MS) and high performance liquid chromatography (HPLC) comparisons with authentic specimens. Of these anthocyanins, the first 4 and pelargonidin 3-O-rutinoside have previously been characterized as 3-O-rhamnosylglucoside-5-O-glucoside and 3-O-rhamnosylglucoside. In this survey, they were clearly identified as 3-O-rutinoside-5-O-glucoside and 3-O-rutinoside, for the first time. Anthocyanin composition in the flowers of 84 Gladiolus cultivars was surveyed by HPLC and divided into 18 groups (Groups 1–18) according to the anthocyanin pattern. Of these cultivars, 82 were first surveyed for anthocyanins, except ‘Blue Isle’ and ‘True Love’. The relationship between anthocyanin content and flower colors was discussed. Major anthocyanins of purple flowers were malvidin glycosides together with petunidin 3,5-di-O-glucoside as a minor component, but delphinidin glycoside was not detectable. Red flowers are due to pelargonidin glycosides. Though pink flowers consist of various anthocyanins, pelargonidin, cyanidin, peonidin, petunidin and malvidin glycosides, they were comparatively scarce compared with those of purple and red flowers. In many cases, anthocyanins were not detected from yellow and white flowers; however, a few yellow and white cultivars contained an extremely small amount of anthocyanins. Such cultivars had a colored spot or streak on the perianth, so their anthocyanins were detected by HPLC surveys.

View full abstract

To clarify the main causes affecting the mode of plastid DNA (ptDNA) inheritance in Rhododendron spp., ptDNA inheritance of progenies from diallel crosses among six evergreen azalea species belonging to series Kaempferia was investigated with PCR-SSCP analysis. Polymorphism was detected among parental species, except one combination between R. kiusianum and R. tosaense. Maternal ptDNA inheritance was observed in all crosses, whereas paternal inheritance was found in 16/28 crosses. High frequency (33.3 to 87.5%) of paternal ptDNA inheritance was observed in all crosses with R. transiens as a seed parent, whereas the frequency was relatively low (less than 8.3%) in the reverse cross, except R. tosaense × R. transiens. In contrast, no or slight (less than 12.5%) paternal ptDNA inheritance was observed in the cross with R. kaempferi var. macrogemma, R. kiusianum and R. simsii as a seed parent. When these species were used as pollen parents in the cross with other three species, i.e. R. transiens, R. kaempferi and R. tosaense, the frequency was usually high (45.0 to 90.9%, except R. kaempferi × R. kaempferi var. macrogemma).

View full abstract

Tomato (Solanum lycopersicum) is one of a group of plants that accumulate chalcones and flavanones. However, the molecular diversity of chalcones, flavanones, and their conjugate metabolites has not been investigated intensively. Here, we report the profiling of chalcones and flavanones in fruits of the dwarf tomato cultivar Micro-Tom using liquid chromatography Fourier transform ion cyclotron resonance mass spectrometry (LC-FTICR-MS). We identified eriodictyol chalcone and eriodictyol aglycones, along with naringenin chalcone and naringenin aglycones. To our knowledge, this is the first report that demonstrates the presence of eriodictyol chalcone and eriodictyol in tomato. We detected 26 conjugate metabolites of chalcones and flavanones. Chemical information obtained simultaneously by LC-FTICR-MS, including m/z values, MS/MS spectra, UV absorption spectra, and retention times, facilitated the elucidation of molecular formulas and conjugate structures of the metabolites. Eriodictyol chalcone and eriodictyol conjugates had the same modification patterns seen in naringenin chalcone and naringenin conjugates. Chalcones and flavanones were much more abundant in tomato fruit peel than flesh. Accumulation profiles during ripening were classified into three groups. The first group included metabolites that showed the highest accumulation levels at the breaker stage, and then decreased during ripening. The second group included metabolites that accumulated to the highest levels at the turning stage, and then decreased at the red stage. The third group included metabolites that accumulated gradually during ripening, and showed the highest accumulation levels at the red stage. These accumulation profiles were mapped onto a putative modification pathway deduced from conjugate structures. Mapping revealed that the conjugate metabolites upstream of this pathway accumulated earlier, and those downstream accumulated later during ripening. This result demonstrated that chalcones and flavanones undergo sequential modification as ripening progresses.

View full abstract