The aim of the research was to determine the impact of row covers on the growth, yield, and selected nutritional compounds contents in Chinese cabbage (Brassica rapa L. Pekinensis Group), cultivated in a field with or without non-woven fleece (17 g·m−2). Application of row covers accelerated the growth and development of the plants due to more favorable microclimatic conditions than in an open field. All tested biometrical parameters of the rosettes, determined after removing covers, were considerably higher than in the uncovered control. Therefore, direct covers could be successfully used for promote the growth of Chinese cabbage rosettes after transplanting. Total and marketable yields of covered plants were higher by 36% and 91%, respectively, than in the control. No external flower stalks were observed in either treatment, but about 50% of control heads had internal bolters. Row covering could be an effective prevention method against Chinese cabbage bolting in spring production in Central Europe. Laboratory analysis performed directly after removing covers showed higher contents of L-ascorbic acid, chlorophylls, and carotenoids in the plants in an open field. However, in the subsequent few weeks, such differences between treatments decreased and at harvest time, the level of these compounds was similar. Mature heads of control Chinese cabbage contained significantly more soluble sugars, crude fiber and thiocyanates than covered plants. The models were proposed to predict changes in fresh and dry weight as a function of time.
We compared anthocyanidin composition patterns and the expression of anthocyanin biosynthesis genes in Rhododendron kiusianum, R. kaempferi, and their natural hybrids from the Kirishima mountain mass. Compared with the habitat, phenotypic characteristics including tree height and flower color did not change in the transplanted individuals after cutting propagation. According to flower color measurements, R. kiusianum and R. kaempferi belonged to purple and red series, respectively, and their natural hybrids belonged to either the red or purple series. HPLC analysis showed that the petals of most R. kiusianum and natural hybrids contained both cyanidin and delphinidin series pigments, while the petals of R. kaempferi contained only cyanidin series pigments. However, one R. kiusianum individual in the purple series contained only cyanidin series pigments and one natural hybrid individual in the red series contained both cyanidin and delphinidin series pigments. These individuals were thought to be influenced by co-pigmentation or a lack thereof, respectively. All samples expressed F3′H, DFR, and ANS genes in real-time quantitative RT-PCR, and the F3′5′H gene was always expressed in samples containing delphinidin series pigments. These results suggest that the expression of F3′5′H is essential for R. kiusianun and its natural hybrids to produce delphinidin series pigments. This study showed that interspecific hybridization between wild species with purple series flowers and wild species with red series flowers varied the pigment composition and anthocyanin biosynthesis-related gene expression in the natural hybrids, suggesting that it caused the flower color variation in the wild populations in the Kirishima mountains.
The infection efficiency of Agrobacterium to cotyledon explants of Japanese apricot (Prunus mume) was markedly improved by sonication treatment. The use of sGFP(S65T) reporter gene in this study enabled direct observation of transgene expression, thus allowing the evaluation of Agrobacterium infection efficiency. Immature cotyledons of different cultivars and different developmental stages were subjected to sonication treatment of durations ranging from 10 sec to 2 min. When early-stage immature cotyledons of ‘Nanko’ were subjected to sonication treatment, the transient GFP expression frequency after co-cultivation was nearly 100% and GFP fluorescence was distributed over almost the entire cotyledon surface. In contrast, when the inoculation was carried out according to the standard dipping method, transient GFP expression frequency was less than 10% and GFP fluorescence was observed only in spots. The highest frequency of somatic embryogenesis (SEG) with GFP expression was obtained from 40 sec sonication treatment of May 14 ‘Nanko’ immature cotyledons. However, with younger cotyledons, which have a higher SEG frequency, 20 sec of sonication treatment was found to be sufficient to increase the infection frequency.
Japanese old azalea cultivars have various floral mutations. We isolated MADS-box class C homologous genes from wild-type Rhododendron macrosepalum to analyze the expression patterns in the floral organs of the narrow-petal mutational cultivars 'Hanaguruma', 'Gin-no-zai', and 'Seigaiha'. The AG homologous genes RmAG1-1/-2/-3 were 99-100% identical to RkAG1-1/-2, which was isolated from R. kaempferi. In 'Hanaguruma', 'Seigaiha', and the wild type, the relative expression level of RmAG in whorl 2 was much lower than that in whorl 3. In contrast, the relative expression level of RmAG in whorl 2 of 'Gin-no-zai' was approximately 15.5% of that in whorl 3. In 'Gin-no-zai', the petals with mutations were categorized as 1 of these 3 types: type 1, consisting of narrow petals with traces of anthers; type 2, consisting of narrow petals only; and type 3, consisting of petals that coalesced with the neighboring petals. The relative expression levels of RmAG gradually increased from type 3 to type 1 petals. These results suggest that the degree of staminoidy for the petals in whorl 2 is attributable to the expression levels of RmAG.
Bud dormancy allows most deciduous fruit tree species to avoid injury in unsuitable environments, synchronize their annual growth, and adapt to a temperate zone climate. Because bud dormancy affects next season's fruit production and vegetative growth, it is considered one of the most important physiological factors that control fruit production. Recent global climate changes require us to better understand the genetic factors regulating bud dormancy, especially those that induce dormancy release and subsequent bud break. In this review, environmental factors that affect the seasonal dormancy depth of Japanese apricot (P mume Siebold & Zucc.) and peach [P persica (L.) Batsch] are first outlined. Next, recent progress of genetic, biochemical, and molecular biological studies of Prunus dormancy regulation is described. Recent advances in functional genomics have promoted the discovery of gene function and gene networks associated with bud dormancy regulation. A group of candidate genes for bud dormancy regulation, the DORMANCY-ASSOCIATED MADS-box (DAM) genes in Prunus, are focused. Recently reported expressional analysis suggests a significant role for DAMs in dormancy release and bud break of Japanese apricot and peach vegetative buds. Transformation studies of PmDAM6 have demonstrated that it has an inhibitory effect on the apical growth of poplar (Populus spp.). As bud dormancy is a quantitative polygenic trait, not only Mills, but also other genes and gene networks appear to regulate bud dormancy. Ongoing and future studies will undoubtedly facilitate the unveiLing of the molecular aspects of bud dormancy regulation in temperate fruit tree species of Prunus.
Cut Eustoma grandiflorum (Raf.) Shinn. flowers are produced year-round in Japan; however, winter conditions are not favorable for flower production due to low sunlight levels. Here, we investigated the effect of CO2 enrichment after the flower budding stage on the growth and flowering of Eustoma ‘Bolero White’, which were grown under forcing culture for winter shipping. CO2 enrichment increased the fresh weight of plants, in addition to increasing the dry weights of leaves, stems, flower buds and open flowers, and roots. CO2 enrichment also increased the relative growth rate (RGR) by 32%, due to the net assimilation rate (NAR) being stimulated. However, CO2 enrichment had no effect on plant height or the leaf area ratio (LAR). Furthermore, CO2 enrichment increased the total number of flower buds and open flowers, in addition to accelerating flower bud development and the promotion of flowering. During the period of enrichment, the vegetative organs continued to grow in CO2-enriched plants, but not in the control plants. In conclusion, CO2 enrichment promoted flowering and improved the quality of cut flowers (i.e., increasing plant fresh and dry weight and the total number of flower buds and open flowers) of Eustoma under low-sunlight winter conditions.
Removing leaves around the grape cluster of Muscat Bailey A [Vitis x labruscana (Bailey) and Vitis vinifera (Muscat Hamburg)] cultivated in pergola style at the start of veraison increased the photosynthetically active radiation value by more than approximately 60- and 30-fold compared with those of the control and grape cluster from vines grown on ground covered with reflective film (reflective-film-treated grape cluster), respectively. The improved light exposure caused by leaf removal increased total anthocyanin concentration and changed the ratios of anthocyanin derivatives in the grape skins. Total anthocyanin concentration in the leaf-removal-treated grape skins 10 weeks after veraison increased by approximately 6.5-fold compared with that of the control. In addition, delphinidin-based anthocyanin concentrations in the leaf-removal-treated grape skins increased by approximately 7-fold compared with those of the control. Leaf removal up-regulated anthocyanin-synthesis-related genes in grape skins, such as CHS, F3'H, F3',5'H, and UFGT. In particular, the overexpression of F3',5'H in the leaf-removal-treated grape skins suggested that leaf removal contributed to the accumulation of delphinidin-based anthocyanins in grape skin. These findings are expected to improve viticultural practices with the aim of producing dark-colored red wine made from cultivars grown in pergola style.
Mature pollen grains of LiIium cultivar, with their germ pores folded in upon themselves, were observed under a scanning electron microscope (SEM). The conventional pretreatment process requires aldehyde fixation, dehydration, drying and metal sputtering for SEM observation. These complicated and laborious procedures can considerably alter the morphology of pollen grains. In order to omit this conventional pretreatment process, we established a novel technique utilizing an ionic liquid (IL) that is composed solely of ions, namely, a liquid salt that can remain in a molten state even at room temperature. IL-treated pollen grains could be observed under vacuum conditions without artifacts, and furthermore, a satisfactory SEM image could visualize pollen grains in a wet state. The possible direction of future studies on ionic liquids in the SEM field is also discussed.
Japanese apricot (Prunus mume Siebold & zucc.) fruits of 'Nanko' have softer flesh than those of 'Gojiro'. Therefore, there are differences in the processability of these cultivars. We investigated the characteristics of cell-wall polysaccharide degradation that significantly affects fruit firmness in these 2 cultivars at unripe, ripe, and drop stages. Fruit firmness of 'Gojiro' was maintained during unripe and ripe stages and decreased after the ripe stage, while that of 'Nanko' decreased constantly and was lower than that of 'Gojiro' at ripe and drop stages. Amount of the pectin and the hemicellulose substances decreased commonly in 'Gojiro' and 'Nanko' in the process of fruit softening, in addition, decrease in mol wt of these polysaccharides significantly synchronized with decrease in fruit firmness, suggesting that degradation of the pectin and the hemicellulose cause the softening of Japanese apricot fruits. The amount of neutral sugar (NS) and uronic acid (UA) in the pectin fraction and NS in the hemicellulose fraction in 'Nanko' decreased more than in 'Gojiro'. Moreover, the cellulose content of 'Nanko' decreased during the fruit-softening process. These results suggest that higher degradation of pectin, hemicellulose, and cellulose in 'Nanko' fruits would result in softer fruits than 'Gojiro'.
Researchers have predicted that most of the current satsuma mandarin-producing regions will become unfavorable for growing this citrus crop by the 2060s owing to global warming. To offer satsuma mandarin growers information for making replanting decisions, we estimated future changes in locations suitable for the cultivation of tankan (Citrus tankan Hayata), the leading subtropical citrus in Japan. The results of fruit-freezing experiments suggested that the threshold air temperature for the cold tolerance of tankan fruit is about -2 degrees C. The locations suitable for tankan were simulated on the basis of future annual mean air temperatures evaluated by the MIROC3.2-HiRes climate model under the SRES-A1B GHG emission scenario and future annual minimum air temperatures calculated from future daily minimum temperatures evaluated by this climate model and the current air temperature variability. The results of the simulation showed that most of the Pacific coastal area from the Kanto Plain and to the west will become suitable for tankan cultivation during 2031-2050, and that coastal areas of the current satsuma mandarin-producing regions in Japan should be suitable for tankan production by 2050. The inland area of southern Kyushu Island, despite its proximity to current tankan-producing regions, is predicted to experience temperatures causing a high frequency of cold injury to tankan fruits even during 2051-2070. Therefore, if satsuma mandarin production becomes difficult on account of increased global warming, tankan could be produced as a substitute in coastal areas of the current satsuma mandarin-producing regions. However, we predict that it will be difficult to produce tankan in inland areas of the current satsuma mandarin-producing regions.
‘No.80’ ( Capsicum chinense ) from the Caribbean is a valuable genetic source from the aspect of its non-pungent and highly aromatic traits. In the present study, the non-pungency, volatile components, and phylogenetic origin of ‘No.80’ were analyzed with another C. chinense cultivar, ‘No.2’ from Brazil, which is also non-pungent but less aromatic. Expressions and deduced amino acid sequences of acyltransferase ( Pun1 ) of ‘No.80’ and ‘No.2’ were normal compared with a pungent cultivar, ‘Habanero’. Insertions of 7-bp and 8-bp resulting in frameshift mutations were found in the coding regions of putative aminotransferase ( p-AMT ) of ‘No.80’ and ‘No.2’, respectively. Co-segregation of these insertions with the non-pungent phenotypes in F 1 and F 2 populations obtained from crossing ‘No.80’ or ‘No.2’ with ‘Habanero’ suggested that non-pungency in these cultivars arose from genetic mutations of p-AMT that occurred independently. Moreover, molecular phylogenetic analysis suggested that ‘No.80’, a close relative of ‘No.2’, originates from capsicums migrated from the South American mainland. In addition to pungency, we assessed the volatile components of the highly aromatic ‘No.80’, the less aromatic ‘No.2’, and their F 1 hybrid using gas chromatography. ‘No.80’ contained higher levels of aroma-contributing volatiles than ‘No.2’, which correlated with the stronger and weaker aromas of two cultivars. Further, the fruit of F 1 progenies emitted a number of volatile compounds between or higher than their corresponding parents. Based on these results, the approaches for breeding highly aromatic non-pungent cultivars are discussed.
The absorption of NO3- and growth of radish (Raphanus sativus L. 'Yukikomachi'), and the timing and interval of NO3- supply were examined to evaluate quantitative nutrient management (QNM) of nutrient solution in a hydroponic culture of radish plants. In experiment 1, the amount of NO3- required for growth to a marketable size (30-35 g FW of thickened axis) was presumed to be approximately 1000 mg/plant by the direct measurement of NO3- absorption of radish plants grown with the EC-based control management method (EC-based control method) of nutrient solution containing different concentrations (2, 4, 6, 8, and 10 me.L-1) of NO3-. In Experiment 2, plants were supplied with the total amount of NO3- (1000 mg/plant) at the beginning of the experiment or with 1/5 of the total amount of NO3- (1000 mg/plant) repeatedly 5 times every 4 days, and then their fresh weight and nutrient absorption were compared with the plants grown with the EC-based control method. Significant differences in the growth of thickened axes and leaves were not obtained among plants grown by three different methods. However, plants appeared to be supplied with an excess amount of nutrients because EC and NO3- levels were high at the end of cultivation. From the experiment in which plants were supplied with the whole amount of mineral nutrients containing 900, 800, and 700 mg/plant of NO3- at the beginning of the experiment in December, it became apparent that 800 mg/plant of nitrate would be sufficient for radish growth in the cold season. In conclusion, we propose the QNM method supplying the whole amount of nutrients required for crop growth at the beginning of cultivation so that radish plants could be produced without draining nutrient solution containing a large amount of NO3- from the hydroponic system into the environment.
Three new acylated cyanidin 3,7-diglucosides (1-3) were isolated from the red-purple flowers of Sophronitis wittigiana as its main floral anthocyanins. These three pigments were based on cyanidin 3,7-diglucoside as the deacylanthocyanin, and their structures were determined to be cyanidin 3-O-[6-O-(malonyl)-beta-glucopyranoside)]-7-O-[6-O-(trans-caffeoyl)-beta-glucopyranoside] as pigment 1, its demalonyl anthocyanin as pigment 2, and cyanidin 3-O-[6-O-(malonyl)-glucoside]-7-O-glucoside as pigment 3 by chemical and spectroscopic methods. On the other hand, five known acylated cyanidin 3,7,3'-triglucosides (4-8) were isolated from orange-red or red flowers of S. acuensis, S. brevipedunculata, S. cernua, S. coccinea var. xanthoglossa, and S. grandiflora as well as those of S. coccinea, and identified to be pigment 4 as Sophronitis coccinea anthocyanin 1 (SCA 1), pigment 5 as SCA 2, pigment 6 as SCA 3, pigment 7 as SCA 4, and pigment 8 as SCA 5 in comparison of the TLC, HPLC, and UV-Vis properties with standard samples of SCAs 1-5. These results showed that the three 3,7,3'-O-hydroxy groups of anthocyanins were all substituted with acylglucose and/or glucose residues in the orange-red or red flowers of six taxa of Sophronitis, whereas the 3'-O-hydroxy group was free from glucose in the red-purple flowers of S. wittigiana. Thus, the inactivation of 3'-O-glycosylation in cyanidin units might be involved in causing the blue color direction shift from orange-red or red to red-purple flower color of S. wittigiana.
The expression profiles of carotenoid metabolism pathway genes are one of the important factors that regulate carotenoid content and composition in the fruit of Citrus cultivars. To identify regulatory factors of gene expressions in the carotenoid pathway, expression quantitative trait loci (eQTL) analysis was applied using a hybrid population. In the analyzed population, significant eQTLs for phytoene synthase (PSY), phytoene desaturase (PDS), zeta-carotene desaturase (ZDS), beta-ring hydroxylase (HYb), and zeaxanthin epoxidase (ZEP) were detected. Among these eQTLs, eQTLs for HYb and ZEP were located on their responsible gene loci, respectively. This result indicates that the expression level of HYb and ZEP was influenced by cis-elements in their up-stream regions. Conversely, eQTLs for PDS and ZDS were located in different loci from those of the responsible genes, indicating that the loci were trans-regulating factors. It also suggested that expression levels of PDS and ZDS were regulated by a common transcription factor because their eQTLs were co-localized. Significant eQTL of lycopene beta-cyclase (LCYb) and 9-cis-epoxycarotenoid dioxygenase (NCED) were not detected in this population. The major factors to control gene expression depend on each carotenoid metabolism gene, and their combination might cause complex carotenoid metabolism and extend the variation of content and composition in citrus varieties. eQTL analysis was demonstrated as a powerful tool to identify cis- or trans-regulation for carotenoid metabolism genes, as well as in generating functionally defined markers for marker-assisted selection to increase the carotenoid content of citrus in breeding programs.
Some flowers including rose open in a rhythmic fashion during specific times of the day. We used time-lapse cinematography to understand the mechanism of rhythmic opening and perception of light in cut rose flowers. Cut rose flowers exposed to a 12 h light/12 h dark photoperiod started opening shortly before the light period had begun and stopped during the light period even when their leaves were removed, indicating that petals and/or sepals perceive light and synchronize flower opening to photoperiods. This rhythmic opening could be seen in constant darkness even though the time of flower opening shifted to an earlier point in constant darkness compared with the 12 h photoperiod, but it was not observed in constant light. We also evaluated the effect of exposing cut flowers first to a 12 h photoperiod and then shifting them to an 18 h photoperiod. During the 12 h photoperiod, flower opening started shortly before the light period had begun and stopped during the light period, while in the 18 h photoperiod, it proceeded in the middle of the dark period. These results suggested that changes of light to darkness or vice versa were important signals for the start and maintenance of rhythmic flower opening. In addition, we found that even a petal removed from a rose flower showed rhythmic growth when exposed to a 12 h light/12 h dark photoperiod, showing that petals could perceive light and synchronize their growth to the photoperiod.
Premature softening during low-temperature storage is a major issue in the red kiwifruit (Actinidia chinensis Planch.) cultivar ‘Rainbow Red’. The objective of this study was to investigate the effect of low temperature on ethylene sensitivity in this cultivar. We demonstrate how ethylene preconditioning at 4°C and 25°C interacted with more rapidly ripening at the lower temperature in ‘Rainbow Red’ kiwifruit. The expression of ripening-related genes ACS1, ACO3, EIL4, ERF14, and PGB was at the basal level during ethylene preconditioning at 4°C and 25°C, and rapidly increased with ethylene treatment following ripening. These results suggest that low-temperature storage enhances ethylene sensitivity in ‘Rainbow Red’.
To produce tomato fruits with 6% average Brix without decreasing yield, we investigated the effect of moderate salinity stress on Brix and yield in a single-truss, high-density tomato production system. Because tomato fruit development can be predicted from cumulative temperature, we also assessed cumulative temperature after anthesis as a potential indicator for determining the starting points of salinity stress treatments. When transverse diameters of the first fruit reached 4 cm (i.e., early increase treatment) or the first fruits were at the mature green stage (i.e., late increase treatment), nutrient solution electrical conductivity was slowly increased until the breaker stage from 1.8 dS·m-1 to 6.0 dS·m-1. Plants subjected to the late increase treatment produced tomato fruits with Brix values of 6% without reductions in marketable yield. We also increased nutrient solution electrical conductivity based on cumulative temperature after anthesis and found that early-treated plants produced tomatoes with higher Brix levels and yields than late-treated plants. In summary, moderate salinity stress to avoid excessive stress on plants increased sugar concentrations without decreasing fruit yield and resulted in tomato fruits with average Brix of about 6% when nutrient solution electrical conductivity was increased at a rate of 0.1 dS·m-1·day-1. Because seasonal differences in cumulative temperature influence the appropriate timing of salinity stress applications, further study is needed to optimize year-round growth under moderate salinity stress in single truss, high-density tomato production systems.
Two anthocyanins (pigments 1 and 2) were detected from the blue flowers of Nemophila menziesii 'Insignis blue' and the purple flowers of its variants as the main floral anthocyanins. These two anthocyanins were isolated from the blue flowers and elucidated to be petunidin 3-O-[6-O-(cis-p-coumaroyl)-beta-glucopyranoside]-5-O-[6-O-(malonyl)-beta-glucopyranoside] (1) and petunidin 3-O-[6-O-(trans-p-coumaroyl)-beta-glucopyranoside]-5-O-[6-O-(malonyl)-beta-glucopyranoside] (2), respectively, by chemical and spectroscopic means, and pigment 1 was confirmed as a new anthocyanin in plants. Two flavonol glycosides (pigments 3 and 5) and two flavone glycosides (pigments 4 and 6) were also isolated from the blue flowers, and were identified to be kaempferol 3-(6-rhamnosyl)-glucoside-7-glucoside (3), apigenin 7,4'-di-glucoside (4), kaempferol 3-(2,6-di-rhamnosyl)-glucoside (5), and apigenin 7-glucoside-4'-(6-malonyl)-glucoside (6) as major flavonoids. Among these four flavonoids, however, pigments 4 and 6 (flavones) were not detected in the purple flowers. These results might be attributed to color production in blue and purple flowers.
