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Masahiro Mii - One of the best experts on this subject based on the ideXlab platform.
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induction of embryogenic callus and cell suspension culture from shoot tips excised from Flower Stalk buds of phalaenopsis orchidaceae
In Vitro Cellular & Developmental Biology – Plant, 2001Co-Authors: Ken Tokuhara, Masahiro MiiAbstract:Embryogenic calluses were induced from 73% of Phalaenopsis shoot-tip explants excised from Flower Stalk buds by culturing for 7 mo. on New Dogashima Medium (NDM) containing 0.5 μM α-naphthaleneacetic acid (NAA), 4.4 μM 6-benzylaminopurine and 29.2 mM sucrose. The sucrose concentration was increased to 58.4 mM 4 mo. after initiation of the callus culture. These calluses were successfully subcultured as cell suspension cultures in liquid NDM supplemented with 5.4μM NAA and 58.4 mM sucrose. By simply reducing the sucrose concentration to 29.2 mM, the cells grew into plantlets through a developmental process similar to that of Phalaenopsis seedlings. The occurrence of somaclonal variants was less than 10% in six out of eight genotypes examined. These results suggest that the embryogenic callus and cell suspension culture could be utilized as the materials for micropropagation and breeding of Phalaenopsis orchids.
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somaclonal variations in Flower and inflorescence axis in micropropagated plants through Flower Stalk bud culture of phalaenopsis and doritaenopsis
Plant Biotechnology, 1998Co-Authors: Ken Tokuhara, Masahiro MiiAbstract:Somaclonal variations in Flower and inflorescence axis were investigated among the plants micropropagated through protocorm-like bodies induced by Flower Stalk bud culture of various cultivars of Phalaenopsis and Doritaenopsis. Eighteen hundred to 14, 750 micropropagated plants were grown for each of 11 genotypes in greenhouses for 1-1.5 years till Flowering. Somaclonal variations appeared in Flower and inflorescence were classified into 9 categories irrespective of cultivars. The frequencies of these somaclonal variations in each genotype ranged from 0 to 100%, but most of the cultivars showed variations less than 10%. Changes in leaf shapes and ploidy level were not detected in these variants. Possible mechanisms involved in these variations and the problems of the micropropagation method used in this study were discussed.
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micropropagation of phalaenopsis and doritaenopsis by culturing shoot tips of Flower Stalk buds
Plant Cell Reports, 1993Co-Authors: Ken Tokuhara, Masahiro MiiAbstract:Green Protocorm-like Bodies (PLB) with high multiplication capacity were induced from shoot tips of Flower Stalk buds having 1 or 2 leaf primordia using New Dogashima Medium (NDM) containing 0.1 mg l−1 α-naphthaleneacetic acid (NAA) and 1 mg 1−1 6-benzylaminopurine (BAP). These PLB were subcultured on the same medium. More than 10,000 PLBs were obtained from a few buds on a single Flower Stalk within one year. After transfer onto NDM containing no plant growth regulator (PGR), the PLB developed into plantlets. The micropropagation method formulated in this study was applicable to 12 different genotypes. These results suggest that the methodology could be used on a commercial scale for vegetative propagation of Phalaenopsis and Doritaenopsis.
John P Clarkson - One of the best experts on this subject based on the ideXlab platform.
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first report of fusarium oxysporum causing a vascular wilt of statice limonium sinuatum in the u k
Plant Disease, 2017Co-Authors: Andrew Taylor, Isabel Sims, Alison C Jackson, John P ClarksonAbstract:Statice (Limonium sinuatum) is grown commercially in many countries as a cut-Flower crop. Fungal and oomycete pathogens reported for this plant include Colletotrichum, Botrytis, Cercospora, Rhizoctonia, and Peronospora (Moorman 2016). In the UK, 80% of all statice production (2.5 ha, value $800,000) is through a specialist grower in Lincolnshire. In 2016, 30% of the 70,000 statice plants raised at this nursery were affected by a vascular wilt. Symptoms observed on approximately 1 m tall Flowering plants (cv. Velvet Wings) consisted of wilted leaves and Flower Stalks, often progressing down one side of the stem, followed by leaf necrosis and plant death. Brown staining of vascular tissue was observed in dissected stems and, in advanced infections, mycelium was evident at the stem base. Isolations were carried out from 18 plants by excising 2 to 3 cm sections of infected stem, surface disinfecting in 5% sodium hypochlorite for 2 min, rinsing in sterile water and plating on potato dextrose agar (PDA) containing 20 µg/ml chlortetracycline. After incubation at 20°C for 4 days under natural light, fungal colonies were sub-cultured onto PDA and grown for a further 10 days. Cultures displayed morphology typical of Fusarium species, with a peach/pale pink color. Macroconidia were 3-septate, straight or slightly curved, 16.1 to 25.7 µm x 2.8 to 5.4 µm. Microconidia were abundant, elliptical or reniform, 6.1 to 12.4 µm x 1.6 to 4.9 µm. DNA was extracted from four isolates, and the translation elongation factor 1-α (EF1-α) gene amplified by PCR and sequenced using exTEF-F/ FUexTEF-R primers (Taylor et al. 2016). All isolates shared identical EF1-α sequences (GenBank accession number KX822794) and were confirmed as Fusarium oxysporum using BLAST analysis. The sequences were 99% identical to the EF1- α sequences of a wide range of F. oxysporum isolates with the greatest homology to F. oxysporum f. sp. freesia (KP964900, 99.7% over 989 bp). To confirm pathogenicity, statice (cv. Velvet Wings) plants produced by tissue culture were raised in pots. Once the first Flower Stalk reached approximately 30 cm, plants were removed, the bottom third of the root system excised and the remaining roots soaked in a conidial suspension (1 x 106 conidia/ml) for 5 min. As a negative control treatment, F. oxysporum isolate Fo47, a biocontrol strain known to be non-pathogenic on a range of hosts (Aime et al. 2013), was used to inoculate plants in the same way, while noninoculated control plants were soaked in sterile water. All statice (six plants / isolate or control treatment) were then replanted in compost and pots placed in a randomized design in a temperature controlled glasshouse (25°C day, 18°C night, 16 hour photoperiod). After 20 days, typical wilt symptoms were observed in all the plants inoculated with the four F. oxysporum isolates from statice, and after 40 days all the plants were dead (e-Xtra). All noninoculated control plants and those inoculated with F. oxysporum isolate Fo47 remained healthy. The pathogen was successfully re-isolated from infected stems with the fungal cultures exhibiting the same morphology as described previously. Furthermore, following DNA extraction, amplification and sequencing of the EF1-α gene of the re-isolated fungi, all sequences were 100% identical to those obtained for the original isolates, thus fulfilling Koch’s postulates. To our knowledge, this is the first report of Fusarium wilt of statice. Further work is required to establish the host range of this potentially new forma specialis.
Ken Tokuhara - One of the best experts on this subject based on the ideXlab platform.
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induction of embryogenic callus and cell suspension culture from shoot tips excised from Flower Stalk buds of phalaenopsis orchidaceae
In Vitro Cellular & Developmental Biology – Plant, 2001Co-Authors: Ken Tokuhara, Masahiro MiiAbstract:Embryogenic calluses were induced from 73% of Phalaenopsis shoot-tip explants excised from Flower Stalk buds by culturing for 7 mo. on New Dogashima Medium (NDM) containing 0.5 μM α-naphthaleneacetic acid (NAA), 4.4 μM 6-benzylaminopurine and 29.2 mM sucrose. The sucrose concentration was increased to 58.4 mM 4 mo. after initiation of the callus culture. These calluses were successfully subcultured as cell suspension cultures in liquid NDM supplemented with 5.4μM NAA and 58.4 mM sucrose. By simply reducing the sucrose concentration to 29.2 mM, the cells grew into plantlets through a developmental process similar to that of Phalaenopsis seedlings. The occurrence of somaclonal variants was less than 10% in six out of eight genotypes examined. These results suggest that the embryogenic callus and cell suspension culture could be utilized as the materials for micropropagation and breeding of Phalaenopsis orchids.
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somaclonal variations in Flower and inflorescence axis in micropropagated plants through Flower Stalk bud culture of phalaenopsis and doritaenopsis
Plant Biotechnology, 1998Co-Authors: Ken Tokuhara, Masahiro MiiAbstract:Somaclonal variations in Flower and inflorescence axis were investigated among the plants micropropagated through protocorm-like bodies induced by Flower Stalk bud culture of various cultivars of Phalaenopsis and Doritaenopsis. Eighteen hundred to 14, 750 micropropagated plants were grown for each of 11 genotypes in greenhouses for 1-1.5 years till Flowering. Somaclonal variations appeared in Flower and inflorescence were classified into 9 categories irrespective of cultivars. The frequencies of these somaclonal variations in each genotype ranged from 0 to 100%, but most of the cultivars showed variations less than 10%. Changes in leaf shapes and ploidy level were not detected in these variants. Possible mechanisms involved in these variations and the problems of the micropropagation method used in this study were discussed.
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micropropagation of phalaenopsis and doritaenopsis by culturing shoot tips of Flower Stalk buds
Plant Cell Reports, 1993Co-Authors: Ken Tokuhara, Masahiro MiiAbstract:Green Protocorm-like Bodies (PLB) with high multiplication capacity were induced from shoot tips of Flower Stalk buds having 1 or 2 leaf primordia using New Dogashima Medium (NDM) containing 0.1 mg l−1 α-naphthaleneacetic acid (NAA) and 1 mg 1−1 6-benzylaminopurine (BAP). These PLB were subcultured on the same medium. More than 10,000 PLBs were obtained from a few buds on a single Flower Stalk within one year. After transfer onto NDM containing no plant growth regulator (PGR), the PLB developed into plantlets. The micropropagation method formulated in this study was applicable to 12 different genotypes. These results suggest that the methodology could be used on a commercial scale for vegetative propagation of Phalaenopsis and Doritaenopsis.
Andrew Taylor - One of the best experts on this subject based on the ideXlab platform.
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first report of fusarium oxysporum causing a vascular wilt of statice limonium sinuatum in the u k
Plant Disease, 2017Co-Authors: Andrew Taylor, Isabel Sims, Alison C Jackson, John P ClarksonAbstract:Statice (Limonium sinuatum) is grown commercially in many countries as a cut-Flower crop. Fungal and oomycete pathogens reported for this plant include Colletotrichum, Botrytis, Cercospora, Rhizoctonia, and Peronospora (Moorman 2016). In the UK, 80% of all statice production (2.5 ha, value $800,000) is through a specialist grower in Lincolnshire. In 2016, 30% of the 70,000 statice plants raised at this nursery were affected by a vascular wilt. Symptoms observed on approximately 1 m tall Flowering plants (cv. Velvet Wings) consisted of wilted leaves and Flower Stalks, often progressing down one side of the stem, followed by leaf necrosis and plant death. Brown staining of vascular tissue was observed in dissected stems and, in advanced infections, mycelium was evident at the stem base. Isolations were carried out from 18 plants by excising 2 to 3 cm sections of infected stem, surface disinfecting in 5% sodium hypochlorite for 2 min, rinsing in sterile water and plating on potato dextrose agar (PDA) containing 20 µg/ml chlortetracycline. After incubation at 20°C for 4 days under natural light, fungal colonies were sub-cultured onto PDA and grown for a further 10 days. Cultures displayed morphology typical of Fusarium species, with a peach/pale pink color. Macroconidia were 3-septate, straight or slightly curved, 16.1 to 25.7 µm x 2.8 to 5.4 µm. Microconidia were abundant, elliptical or reniform, 6.1 to 12.4 µm x 1.6 to 4.9 µm. DNA was extracted from four isolates, and the translation elongation factor 1-α (EF1-α) gene amplified by PCR and sequenced using exTEF-F/ FUexTEF-R primers (Taylor et al. 2016). All isolates shared identical EF1-α sequences (GenBank accession number KX822794) and were confirmed as Fusarium oxysporum using BLAST analysis. The sequences were 99% identical to the EF1- α sequences of a wide range of F. oxysporum isolates with the greatest homology to F. oxysporum f. sp. freesia (KP964900, 99.7% over 989 bp). To confirm pathogenicity, statice (cv. Velvet Wings) plants produced by tissue culture were raised in pots. Once the first Flower Stalk reached approximately 30 cm, plants were removed, the bottom third of the root system excised and the remaining roots soaked in a conidial suspension (1 x 106 conidia/ml) for 5 min. As a negative control treatment, F. oxysporum isolate Fo47, a biocontrol strain known to be non-pathogenic on a range of hosts (Aime et al. 2013), was used to inoculate plants in the same way, while noninoculated control plants were soaked in sterile water. All statice (six plants / isolate or control treatment) were then replanted in compost and pots placed in a randomized design in a temperature controlled glasshouse (25°C day, 18°C night, 16 hour photoperiod). After 20 days, typical wilt symptoms were observed in all the plants inoculated with the four F. oxysporum isolates from statice, and after 40 days all the plants were dead (e-Xtra). All noninoculated control plants and those inoculated with F. oxysporum isolate Fo47 remained healthy. The pathogen was successfully re-isolated from infected stems with the fungal cultures exhibiting the same morphology as described previously. Furthermore, following DNA extraction, amplification and sequencing of the EF1-α gene of the re-isolated fungi, all sequences were 100% identical to those obtained for the original isolates, thus fulfilling Koch’s postulates. To our knowledge, this is the first report of Fusarium wilt of statice. Further work is required to establish the host range of this potentially new forma specialis.
A. Harten - One of the best experts on this subject based on the ideXlab platform.
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Efficient in vitro regeneration of leek (Allium ampeloprasum L.) via Flower Stalk segments
Plant Cell Reports, 1995Co-Authors: B.c.h.j. Silvertand, Evert Jacobsen, J. Mazereeuw, P. Lavrijsen, A. HartenAbstract:A new simple, efficient and rapid in vitro method for mass clonal propagation of leek ( Allium ampeloprasum L.) plants, using small (5 mm) Flower Stalk (peduncle) explants, was established. Adventitious shoots were produced from single subepidermal cells. A wide variation in the percentage of regenerating explants and number of regenerated shoots per explant between individual plants within one cultivar was observed. The concentration of the growth regulators 6-benzylaminopurine and α-naphthalene-acetic acid influenced the percentage of regenerating explants and the average number of regenerated shoots per explant. A combination of 10 mg.l^−1 6-benzylaminopurine and 10 mg.l^−1 α-naphthalene-acetic acid, resulted in a maximum percentage of regenerating explants and a high average number of regenerated shoots per explant. The percentage of regenerating explants and the average number of regenerated shoots per explant decreased with increasing Flower Stalk length (age). The basal explants gave both the highest percentage of regenerating explants and average number of regenerated shoots per explant. An average of 300 shoots per Flower Stalk was obtained for all plants, making this new in vitro method a powerful tool in hybrid leek breeding.