Showing papers on "Kinetin published in 2003"
TL;DR: The results are a clear indication that O-glucosylation of cis-zeatin is a natural metabolic process in maize and serves as a precursor to the active trans-isomer or has any other unique function.
Abstract: trans-Zeatin is a major and ubiquitous cytokinin in higher plants. cis-Zeatin has traditionally been viewed as an adjunct with low activity and rare occurrence. Recent reports of cis-zeatin and its derivatives as the predominant cytokinin components in some plant tissues may call for a different perspective on cis-isomers. The existence of a maize (Zea mays) gene (cisZOG1) encoding an O-glucosyltransferase specific to cis-zeatin (R.C. Martin, M.C. Mok, J.E. Habben, D.W.S. Mok [2001] Proc Natl Acad Sci USA 98: 5922-5926) lends further support to this view. Results described here include the isolation of a second maize cisZOG gene, differential expression of cisZOG1 and cisZOG2, and identification of substantial amounts of cis-isomers in maize tissues. The open reading frame of cisZOG2 has 98.3% identity to cisZOG1 at the nucleotide level and 97.8% at the amino acid level. The upstream regions contain common and unique segments. The recombinant enzymes have similar properties, K(m) values of 46 and 96 microM, respectively, for cis-zeatin and a pH optimum of 7.5. Other cytokinins, including N(6)-(delta(2)-isopentenyl)adenine, trans-zeatin, benzyladenine, kinetin, and thidiazuron inhibited the reaction. Expression of cisZOG1 was high in maize roots and kernels, whereas cisZOG2 expression was high in roots but low in kernels. cis-Zeatin, cis-zeatin riboside, and their O-glucosides were detected in all maize tissues, with immature kernels containing very high levels of the O-glucoside of cis-zeatin riboside. The results are a clear indication that O-glucosylation of cis-zeatin is a natural metabolic process in maize. Whether cis-zeatin serves as a precursor to the active trans-isomer or has any other unique function remains to be demonstrated.
150 citations
TL;DR: The highest number of shoots was induced by adding BA at concentration 11.0 μM, then by 4.4 μM BA, in both cultivars, and `Kosui' was more susceptible to hyperhydricity compared with `Hosui'.
Abstract: This study was made to clarify the effects of cytokinin type and their concentrations on shoot proliferation and hyperhydricity in in vitro Pyrus pyrifolia N. (`Hosui' and `Kosui') shoots. The shoots were subcultured in a woody plant medium supplemented with 0.5 μM 3-indolyl-butyric acid, 3% (w/v) sorbitol, 0.8% (w/v) agar, and with cytokinins kinetin, 6-benzylaminopurine (BA), N-(2-chloro-4-pyridyl)-N9-phenylurea (CPPU), 1-phenyl-3-(1,2,3-thiadiazol-5-yl) urea (TDZ) added at concentrations 0.44, 4.40, 11.0 and 44.0 μM. The highest number of shoots was induced by adding BA at concentration 11.0 μM, then by 4.4 μM BA, in both cultivars. TDZ and CPPU caused greater hyperhydricity in cultured explants than BA and kinetin. `Kosui' was more susceptible to hyperhydricity compared with `Hosui'.
149 citations
TL;DR: The hypothesis that the male development is controlled in concert by multiple hormones is supported and a potential method for generating maintainable male sterility in plants by using existing agrochemicals is suggested to reduce the expense of seed production for existing hybrid crops and provide a method to produce hybrid varieties of traditionally non-hybrid crops.
Abstract: Numerous plant hormones interact during plant growth and development Elucidating the role of these various hormones on particular tissue types or developmental stages has been difficult with exogenous applications or constitutive expression studies Therefore, we used tissue-specific promoters expressing CKX1 and gai, genes involved in oxidative cytokinin degradation and gibberellin (GA) signal transduction, respectively, to study the roles of cytokinin and GA in male organ development Accumulation of CKX1 in reproductive tissues of transgenic maize (Zea mays) resulted in male-sterile plants The male development of these plants was restored by applications of kinetin and thidiazuron Similarly, expression of gai specifically in anthers and pollen of tobacco (Nicotiana tabacum) and Arabidopsis resulted in the abortion of these respective tissues The gai-induced male-sterile phenotype exhibited by the transgenic plants was reversible by exogenous applications of kinetin Our results provide molecular evidence of the involvement of cytokinin and GA in male development and support the hypothesis that the male development is controlled in concert by multiple hormones These studies also suggest a potential method for generating maintainable male sterility in plants by using existing agrochemicals that would reduce the expense of seed production for existing hybrid crops and provide a method to produce hybrid varieties of traditionally non-hybrid crops
128 citations
TL;DR: In this procedure, about 33% of globular embryos not only developed into the cotyledonary stage but rooted simultaneously, eliminating a separate rooting step, and significant improvement in embryogenesis was achieved.
Abstract: A highly efficient somatic embryo production and maturation procedure has been developed to regenerate plantlets from cotton (Gossypium hirsutum). This procedure involves the acceleration of differentiation through manipulations of nutrient and microenvironment conditions. Embryogenic calli, initiated from hypocotyls or cotyledonary leaf sections on MS medium containing 0.1 mg/l 2,4 dichlorophenoxyacetic acid, 0.5 mg/l kinetin, and 3% maltose produced globular-stage somatic embryos when transferred to hormone-free MS medium supplemented with high concentrations of nitrate. Subculture of globular embryos on hormone-free MS medium led to the development of torpedo- and cotyledonary-stage at a low frequency (two to four per plate) with the majority of embryos lacking further growth or entering into the dedifferentiation stage. Significant improvement in embryogenesis (two- to threefold) was achieved when calli were cultured on 1/5-strength MS medium irrespective of stress treatment. However, the frequency of globular embryos developing into normal plantlets improved considerably (20–24 per plate) when cultured on filter paper placed on MS medium. In this procedure, about 33% of globular embryos not only developed into the cotyledonary stage but rooted simultaneously, eliminating a separate rooting step. More than 70% of cotyledonary embryos developed into normal plantlets when cultured on full- strength MS medium containing 0.05 mg/l gibberellic acid.
127 citations
TL;DR: A reproducible system for efficient direct somatic embryogenesis from leaf and internodal explants of Paulownia elongata was developed and the survival and germination rates of encapsulated embryos increased following storage at 4°C, which could be useful for the rapid clonal propagation and dissemination of synthetic seed material.
Abstract: We have developed a reproducible system for efficient direct somatic embryogenesis from leaf and internodal explants of Paulownia elongata. The somatic embryos obtained were subsequently encapsulated as single embryos to produce synthetic seeds. Several plant growth regulators [6-benzylaminopurine, indole-3-acetic acid, α-naphthaleneacetic acid, kinetin and thidiazuron (TDZ)] alone or in combination were tested for their capacity to induce somatic embryogenesis. The highest induction frequencies of somatic embryos were obtained on Murashige and Skoog (MS) medium supplemented with 3% sucrose, 0.6% Phytagel, 500 mg l-1 casein hydrolysate and 10 mg l-1 TDZ (medium MS10). Somatic embryos were induced from leaf (69.8%) and internode (58.5%) explants on MS10 medium after 7 days. Subsequent withdrawal of TDZ from the induction medium resulted in the maturation and growth of the embryos into plantlets on MS basal media. The maturation frequency of somatic embryos from leaf and internodal explants was 50.8% and 45.8%, respectively. Subculturing of mature embryos led to their germination on the same medium with a germination frequency of 50.1% and 29.8% from leaf and internode explants, respectively. Somatic embryos obtained directly on leaf explants were used for encapsulation in liquid MS medium containing different concentrations of sodium alginate with a 30-min exposure to 50 mM CaCl2. A 3% sodium alginate concentration provided a uniform encapsulation of the embryos with survival and germination frequencies of 73.7% and 53.3%, respectively. Storage at 4°C for 30 days or 60 days significantly reduced the survival and complete germination frequencies of both encapsulated and non-encapsulated embryos relative to those of non-stored somatic embryos. However, the survival and germination rates of encapsulated embryos increased following storage at 4°C. After 30 days or 60 days of storage, the survival rates of encapsulated embryos were 67.8% and 53.5% and the germination frequencies were 43.2% and 32.4%, respectively. These systems could be useful for the rapid clonal propagation and dissemination of synthetic seed material of Paulownia elongata.
124 citations
TL;DR: Single medium-based efficient protocols for large-scale multiplication of the rare woody aromatic medicinal plant Rotula aquatica Lour by means of axillary bud multiplication and indirect organogenesis were established using Murashige and Skoog medium to make the protocol economically advantageous.
Abstract: Single medium-based efficient protocols for large-scale multiplication of the rare woody aromatic medicinal plant Rotula aquatica Lour. by means of axillary bud multiplication and indirect organogenesis were established using Murashige and Skoog (MS) medium. There were no significant differences with respect to the induction of shoots per node or callus and roots per shoot on media prepared either with tap water and commercial sugar or those prepared with double distilled water and tissue culture-grade sucrose. The most effective medium for axillary bud proliferation was MS medium fortified with 1.0 mg l–1 N6-benzylaminopurine (BAP) and 0.5 mg l–1 indole-3-butyric acid (IBA), on which shoots were induced at the rate of 15 per node. The excision of node segments from the in vitro-derived shoots and their subsequent culture on medium supplemented with same concentrations of BAP and IBA facilitated enhanced axillary bud proliferation. Callus that developed from the lower cut end of the node explants induced shoots during subculture on half-strength MS medium with 1.0 mg l–1 BAP and 0.5 mg l–1 kinetin. The shoots developed rooted best on half-strength MS medium supplemented with 0.5 mg l–1 naphthaleneacetic acid (NAA). Rooted shoots, following acclimation in the greenhouse, were successfully transferred to field conditions, and 80% of the plantlets survived. When the basal ends of shoots harvested from multiplication medium were dipped in an NAA (0.5 mg l–1) solution for 25 days, a mean of 5.6 roots per shoot developed; the transfer to small pots facilitated the survival of 75% of the rooted shoots. Ex vitro rooting by direct transfer of the shoots from the multiplication medium to the greenhouse resulted in a 65% survival. Commercial sugar and tap water and ex vitro rooting make the protocol economically advantageous. About 750 plantlets were procured in a 3-month period starting from a single node explant.
119 citations
TL;DR: The regeneration protocol developed in this study provides a basis for germplasm conservation and for further investigation of medicinally active constituents of A. judaica.
Abstract: An in vitro propagation system for Artemisia judaica L., a traditional Egyptian medicinal plant, has been developed. De novo shoot organogenesis was induced by culturing etiolated hypocotyls and intact seedlings on medium supplemented with thidiazuron [N-phenyl-N'-(1,2,3-thidiazol-yl) urea] via callusing at the cotyledonary notch region. Up to 16 shoots formed per seedling cultured on a medium containing 1 micro mol l(-1) thidiazuron for an optimal duration of exposure of 20 days. Regenerated shoots formed roots when subcultured onto a medium containing 1 micromol l(-1) indole-3-butyric acid. The regeneration protocol developed in this study provides a basis for germplasm conservation and for further investigation of medicinally active constituents of A. judaica.
114 citations
TL;DR: The pretreatment with indole-3-acetic acid, gibberellic acid and kinetin, each ranging from 0.1 to 10 µM, in restoring the metabolic alterations imposed by NaCl salinity was investigated in mung bean and the three phytohormones used were able to overcome to variable extents the adverse effects of stress imposed byNaCl solution.
Abstract: Application of NaCl (electrical conductivity 4.0 mS cm−1) resulted in about 52, 50 and 55 % reduction in total nitrogen contents in mung bean [Vigna radiata (L.) Wilczek] leaf, root and nodule, respectively. In nodule, nitrogenase activity was reduced by about 84 % under stress as compared with the control set. Glutamine synthetase activity was reduced by about 31, 16 and 23 %, glutamate oxoglutarate aminotransferase activity was reduced by 78, 57 and 42 % and glutamate dehydrogenase activity was reduced by 9, 8 and 42 % in leaf, root and nodule, respectively, under salt stress. The pretreatment with indole-3-acetic acid, gibberellic acid and kinetin, each ranging from 0.1 to 10 µM, in restoring the metabolic alterations imposed by NaCl salinity was investigated in mung bean. The three phytohormones used were able to overcome to variable extents the adverse effects of stress imposed by NaCl solution.
109 citations
TL;DR: The study demonstrated a dedifferentiated callogenic propagation route via adventitious shoot development in T. indica, which could be useful for large scale multiplication of this endangered medicinal plant.
Abstract: An efficient protocol has been developed for rapid mass propagation of Tylophora indica from leaf derived callus. Optimal callus was developed from leaf explants on Murashige and Skoog (MS) basal medium supplemented with 10 μ 2,4,5-T. Adventitious shoots were regenerated (85%) from the surface of the callus on MS medium supplemented with 5 μM Kinetin. Individual elongated shoots were rooted on half-strength MS medium containing 0.5 μM IBA. Regenerated plantlets with well developed shoots and roots were successfully transferred to soil. The study demonstrated a dedifferentiated callogenic propagation route via adventitious shoot development in T. indica, which could be useful for large scale multiplication of this endangered medicinal plant.
99 citations
TL;DR: An improved system for routinely developing transgenic plum plants (Prunus domestica L.) through the use of Agrobacterium tumefaciens is described, the production of non-transformed "escapes" has been virtually eliminated, and rates of plant establishment in the greenhouse have been dramatically improved.
Abstract: We describe here an improved system for routinely developing transgenic plum plants (Prunus domestica L.) through the use of Agrobacterium tumefaciens. The production of non-transformed "escapes" has been virtually eliminated, and rates of plant establishment in the greenhouse have been dramatically improved. The system is based on the regeneration of shoots from hypocotyls extracted from mature seed. The shoot regeneration medium is Murashige and Skoog (MS) salts and vitamins supplemented with 7.5 microM thidiazuron and 0.25 microM indole-butyric acid. Transferring the explants after co-cultivation to shoot regeneration medium containing 80 mg l(-1) of kanamycin and 300 mg l(-1) of Timentin reduced the total number of regenerated shoots without affecting the transformation rate. Transformation rates using the described system averaged 1.2% of the hypocotyl slices producing transgenic plants, with a range of 0-4.2%. The transgenic shoots rooted at a rate of 90% on half-strength MS salts and vitamins supplemented with 5 microM alpha-naphthaleneacetic acid and 0.01 microM kinetin. Plantlets were transferred to a greenhouse directly from culture tubes with a 90% average survival.
97 citations
TL;DR: Explants, callus, and suspension cultures derived from a range of explant sources and seedling ages were exposed to variations in the culture medium and changes to the culture environment and none of the treatments tested were successful in promoting plantlet regeneration.
Abstract: Hemp (Cannabis sativa L.) is cultivated in many parts of the world for ils fiber, oil, and seed. The development of new hemp cultivars with improved traits could be facilitated through the application of biotechnological strategies. The purpose of this study was to investigate the propagation of hemp in tissue culture and to establish a protocol for Agrobacterium-mediated transformation for foreign gene introduction. Stem and leaf segments from seedlings of four hemp varieties were placed on Murashige and Skoog medium with Gamborg B5 vitamins (MB) supplemented with 5 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 1 μM kinetin, 3% sucrose, and 8 gl−1 agar. Large masses of callus were produced within 4 wk for all cultivars. Suspension cultures were established in MB medium containing 2.5 μM 2,4-D. To promote embryogenesis or organogenesis, explants, callus, and suspension cultures derived from a range of explant sources and seedling ages were exposed to variations in the culture medium and changes to the culture environment. None of the treatments tested were successful in promoting plantlet regeneration. Suspension cells were transformed with Agrobacterium tumefaciens strain EHA101 carrying the binary vector pNOV3635 with a gene encoding phosphomannose isomerase (PMI). Transformed callus was selected on medium containing 1–2% mannose. A chlorophenol red assay was used to confirm that the PMI gene was expressed. Polymerase chain reaction and Southern hybridization detected the presence of the PMI gene. Copy number in different lines ranged from one to four.
TL;DR: Application of this micropropagation protocol for Saussurea obvallata (DC.) Edgew has the potential to substantially reduce the pressure on natural populations.
Abstract: This is the first report of a micropropagation protocol for Saussurea obvallata (DC.) Edgew. (Asteraceae), a rare, threatened and near-endemic medicinal herb of the Indian Himalayan region. Multiple shoots were formed from epicotyle explants on Murashige and Skoog (MS) medium supplemented with 1.0 µM kinetin and 0.25 µM α-naphthaleneacetic acid. A maximum of five shoots were obtained from one explant in a 75-day culture period. The effect of subsequent subcultures on shoot formation was also studied. After 100% in vitro rooting was obtained in half-strength MS supplemented with 2.5 µM Indole-3-butyric acid, the plantlets were transferred to ex vitro conditions. Following a 15-day in vitro rooting period and 12 days of ex vitro acclimatization, 66.7% of the plantlets had established in the field. Application of this protocol has the potential to substantially reduce the pressure on natural populations
TL;DR: An efficient and reproducible protocol for the regeneration of shoots at high frequency was developed by using explants derived from the axillary meristems from the cotyledonary nodes of in vitro-germinated seedlings of chickpea.
Abstract: An efficient and reproducible protocol for the regeneration of shoots at high frequency was developed by using explants derived from the axillary meristems from the cotyledonary nodes of in vitro-germinated seedlings of chickpea (Cicer arietinum L.). Culture conditions for various stages of adventitious shoot regeneration including the induction, elongation, and rooting of the elongated shoots were optimized. The medium for synchronous induction of multiple shoot buds consisted of Murashige and Skoog basal medium (MS) with low concentrations of thidiazuron (TDZ), 2-isopentenyladenine (2-iP), and kinetin. Exclusion of TDZ and lowering the concentration of 2-iP and kinetin in the elongation medium resulted in faster and enhanced frequency of elongated shoots. Cultivation of the stunted shoots on MS with giberellic acid (GA3) increased the number of elongated shoots from the responding explants. pH of the medium played a very crucial role in the regeneration of multiple shoot buds from the explants derived from cotyledonary nodes. A novel rooting system was developed by placing the elongated shoot on a filter paper bridge immersed in liquid rooting medium that resulted in rooting frequency of up to 90%. A comprehensive protocol for successful transplantation of the in vitro-produced plants is reported. This method will be very useful for the genetic manipulation of chickpea for its agronomic improvement.
TL;DR: Direct plant regeneration from flowering plant-derived lamina explants of Anthurium andraeanum Hort was established on modified Murashige and Skoog medium and Cultivar Tinora Red was more regenerative than Senator in terms of number of shoots per explant.
Abstract: Direct plant regeneration from flowering plant-derived lamina explants of Anthurium andraeanum Hort. cultivars Tinora Red and Senator was established on modified Murashige and Skoog (MS) medium. Cultivar difference, stage of source lamina and the position of explant in lamina, medium pH, and type of growth regulators significantly influenced direct plant regeneration. Explants from young brown lamina were superior to young green lamina. The half-strength MS medium containing 1.11 μM N6-benzyladenine (BA), 1.14 μM indole-3-acetic acid, and 0.46 μM kinetin at pH 5.5 was most effective for induction of shoot formation. Explants from the proximal end of the source lamina gave rise to a higher number of shoots compared to the mid and distal regions. Cultivar Tinora Red was more regenerative than Senator in terms of number of shoots per explant. The use of a lower BA concentration (0.44 μM) was essential for callus-free shoot multiplication during subculture. Regenerated shoots could be induced to form roots on half-strength MS medium supplemented with 0.54 μM α-naphthaleneacetic acid and 0.93 μM kinetin. More than 300 plantlets of each eultivar were harvested from a single source lamina within 200 d of culture. Most plantlets (95%) survived after acclimation in soil.
TL;DR: Callus induction was observed from hypocotyl, root, and cotyledonary leaf segments, grown on Murashige and Skoog medium supplemented with various concentrations and combinations of 2, 4-dichlorophenoxyacetic acid (2,4-D) and kinetin (KN).
Abstract: Callus induction was observed from hypocotyl, root, and cotyledonary leaf segments, grown on Murashige and Skoog (MS) medium supplemented with various concentrations and combinations of 2,4-dichlorophenoxyacetic acid (2,4-D) and kinetin (KN). Maximum callusing (100%) was obtained from root and cotyledonary leaf segments grown on MS medium supplemented with a combination of 2 mg l−1 (9.1 μM) 2,4-D and 0.2 mg l−1 (0.9 μM) KN. The calluses, when subcultured in the same medium, showed profuse callusing. However, these calluses remained recalcitrant to regenerate regardless of the quality and combinations of plant growth regulators in the nutrient pool. When hypocotyl segments were used as explants, callus induction was noticed in 91% of cultures which showed shoot regeneration on MS medium supplemented with 2 mg l−1 2,4-D and 0.2 mg l−1 KN. These shoots were transferred to fresh medium containing various concentrations and combinations of 6-benzyladenine (BA) and N6-(2-isopentenyl)adenosine (2-iP). Maximum shoot multiplication was observed after 60 d of the second subculture on MS medium containing 2 mg l−1 (8.9 μM) BA. These shoots were rooted best (87%) on MS medium containing 2 mg l−1 (9.9 μM) indole-3-butyric acid (IBA). The plantlets were transferred to the field after acclimatization and showed 60% survival.
TL;DR: The usefulness of this system for further studies on the genetic transformation of pigeonpea has been demonstrated in biolistics-mediated gene transfer by using nptII and uidA as marker genes, where 50% of the selected plants showed gene integration and expression.
Abstract: A protocol for efficient plant regeneration from leaf explants of pigeonpea [Cajanus cajan (L.) Millsp.] was developed for the production of transgenic plants. Leaf explants from 4- to 5-day-old in vitro raised seedlings were most efficient in producing multiple adventitious shoots in 90% of the explants on shoot induction medium [Murashige and Skoog (MS) medium +5.0 μM benzyladenine +5.0 μM kinetin]. Shoot buds originated from the petiolar cut end of the explants and elongated rapidly on medium containing 0.58 μM gibberellic acid. Over 80% of the elongated shoots rooted well on MS medium containing 11.42 μM indole-3-acetic acid and were transplanted with 100% success. The procedure reported here is very simple, efficient and reproducible, and is applicable across diverse genotypes of pigeonpea. The usefulness of this system for further studies on the genetic transformation of pigeonpea has been demonstrated in biolistics-mediated gene transfer by using nptII and uidA as marker genes, where 50% of the selected plants showed gene integration and expression.
TL;DR: These studies provide a baseline for propagation, conservation, and genetic manipulation of elite pineapple germplasms.
Abstract: Axillary and terminal buds from suckers of Ananas comosus cv. Phuket were established on Murashige and Tucker-based (MT) medium with 2.0 mgl−1 (9.8 μM) indolebutyric acid, 2.0 mgl−1 (10.74 μM) naphthaleneacetic acid, and 2.0 mgl−1 (9.29 μM) kinetin, followed by multiplication on Murashige and Skoog-based (MS) medium containing 2.0 mgl−1 (8.87 μM) benzyladenine (BA) to provide a continuous supply of axenic shoots. Leaves, excised from such cultured shoots, produced adventitious shoots from their bases when these explants were cultured on MS medium containing 0.5 mgl−1 (2.26 μM) 2,4-dichlorophenoxyacetic acid (2,4-D) and 2.0 mgl−1 (8.87 μM) BA. Embryogenic callus was produced when leaf explants were cultured on MS medium with 3.0 mgl−1 (12.42 μM) 4-amino-3,5,6-trichloropicolinic acid (picloram). Somatic embryos developed into shoots following transfer of embryogenic tissues to MS medium with 1.0 mgl−1 (4.44 μM) BA. Cell suspensions, initiated by transfer of embryogenic callus to liquid MS medium with 1.0 mgl−1 (4.14 μM) picloram or 1.0 mgl−1 (4.52 μM) 2,4-D, also regenerated shoots by somatic embryogenesis, on transfer of cells to semisolid MS medium with 1.0 mgl−1 (4.44 μM) BA. All regenerated shoots rooted on growth regulator-free MS medium, prior to ex vitro acclimation and transfer to the glasshouse. These studies provide a baseline for propagation, conservation, and genetic manipulation of elite pineapple germplasms.
TL;DR: A test of 68 new initiations tracked closely for 4 months demonstrated that at least 80% of the cultures lost did not grow after transfer to the multiplication media, suggesting that many new Initiations abort during the initiation process.
Abstract: Loblolly pine (Pinus taeda L.) culture initiation was improved by the addition of abscisic acid (ABA) (3.7 µM), silver nitrate (20 µM), and guanosine 3′,5′-cyclic monophosphate, 8-bromo-, sodium salt (10 µM) to the medium and by raising cytokinin levels in the presence of 50 mg/l activated carbon (AC). Basal medium contained modified 1/2-P6 salts, 50 mg/l AC, Cu and Zn added to compensate for adsorption by AC, 1.5% maltose, 2% myo-inositol, 500 mg/l casamino acids, 450 mg/l glutamine, 2 mg/l α-naphthaleneacetic acid (NAA), 0.55 mg/l 6-benzylaminopurine (BA), 0.53 mg/l kinetin, and 2 g/l Gelrite. Across 32 open-pollinated families initiation ranged from 0 to 53.4%, with an average of 17.9%. Further optimization of cytokinins to 0.63 mg/l BA and 0.61 mg/l kinetin along with the removal of ABA maintained initiation at 18.2% across 19 families. Survival of 2001 new initiations was tracked for 4–6 months. Survival averaged 28.8%. A test of 68 new initiations tracked closely for 4 months demonstrated that at least 80% of the cultures lost did not grow after transfer to the multiplication media, suggesting that many new initiations abort during the initiation process.
Journal Article•
TL;DR: Ethanol and chloroform extractives of stem, leaf and stem calli were effective in preventing tonic convulsions induced by transcorneal electroshock.
Abstract: Callus cultures from stem of O. sanctum were induced on slightly modified Murashige and Skoog's (MS) medium and supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D, 1-2 ppm) and kinetin (kn, 1 ppm). Different extractives of stem, leaf and stem callus of O. sanctum were tested for anticonvulsant activity against standard drug phenytoin using maximal electroshock (MES) model. Ethanol and chloroform extractives of stem, leaf and stem calli were effective in preventing tonic convulsions induced by transcorneal electroshock.
TL;DR: Results suggest that kinetin has effective free radical-scavenging activity in vitro and antithrombotic activity in vivo and may be a potential therapeutic agent for arterial thrombosis, but its toxicity must be further assessed.
TL;DR: DSCKX1 appears to play an important role on cytokinin metabolism and the related developmental programmes in orchid, as cloned by mRNA differential display from shoot apices of Dendrobium Sonia cultured in the presence of BA.
Abstract: Cytokinin oxidase plays an important role in the cytokinin regulatory processes We have cloned a novel putative cytokinin oxidase, DSCKX1 (Dendrobium Sonia cytokinin oxidase), by mRNA differential display from shoot apices of Dendrobium Sonia cultured in the presence of BA The DSCKX1 gene appears to have three alternative splicing forms and its expression of DSCKX1 was induced in a tissue-specific manner by cytokinins In transgenic orchid plants overexpressing DSCKX1, the elevated level of cytokinin oxidase activity was accompanied by a reduction of cytokinin content These plants exhibited slow shoot growth with numerous and long roots in vitro Their calli also showed decreased capability of shoot formation Conversly, antisense transgenic plants showed rapid proliferation of shoots and inhibition of root growth combined with a higher endogenous cytokinin content than wild-type plants Thus DSCKX1 appears to play an important role on cytokinin metabolism and the related developmental programmes in orchid
TL;DR: Sage (Salvia officinalis L.) calli were established by culturing internodal segments, excised from aseptic seedlings, on MS basal medium gellied with agar and supplemented with 0.05 mg/L dichlorophenoxyacetic acid, and calli cultures showed the highest specific accumulation of the total phenolics, with rosmarinic acid representing 94-97%.
TL;DR: Multiple shoots were induced from shoot tips and nodal segments of a 12-year-old tree of Cinnamomum camphora on Woody Plant Medium (WPM) supplemented with BA and kinetin to produce a large number of harvestable shoots.
Abstract: Multiple shoots were induced from shoot tips and nodal segments of a 12-year-old tree of Cinnamomum camphora on Woody Plant Medium (WPM) supplemented with BA and kinetin. The nodal segments from the in vitro developed plantlets could be induced again to produce a large number of harvestable shoots. Harvested shoots were rooted in vitro in WPM supplemented with activated charcoal (AC) and IBA. The plantlets were transferred to thermocol cups after which they were replanted into polybags and then to field. These plants survived with over 90% success under field conditions and exhibited vigorous growth. This system could be utilized for large-scale multiplication of C. camphora by tissue culture.
TL;DR: Direct and callus mediated embryogenesis (embryogenic calli with embryos) was induced in Calypso and Green Long cultivars respectively on B5 medium supplemented with 2,4-dichlorophenoxyacetic Acid and α-naphthaleneacetic acid.
TL;DR: Callus cultures of six Genista species were established with the objective to produce isoflavones of phytoestrogenic activity and in vitro cultures had lower contents of genistein esters than the herbs—possible causes are discussed.
TL;DR: Rapid clonal propagation and encapsulation of in vitro-formed bulbs of Ipsea malabarica and its reintroduction to the natural habitat were accomplished and this threatened endemic orchid stands to benefit greatly from the established protocol and will hopefully curtail the threat of extinction.
Abstract: Rapid clonal propagation and encapsulation of in vitro-formed bulbs of Ipsea malabarica (Reichb. f.) J. D. Hook., an endemic and endangered orchid of the Western Ghats of Kerala, and its reintroduction to the natural habitat were accomplished. Rhizome segments of Ipsea cultured on half-strength Murashige and Skoog (MS) medium supplemented with 6.97 μM kinetin induced the highest number of shoots, at the rate of four shoots per explant within 50 d. Transfer of the isolated shoots increased the rate of shoot multiplication to more than 10 shoots. Subsequent culture enhanced the number of shoots. No decline of shoot multiplication was observed up to the 10th subculture. Shoots developed bulbs during culture which developed into rhizomes. Sucrose at 6–8% reduced the time for the development of bulbs and rhizomes. Roots were developed from the base of the developed shoots as well as from the bulbs. Isolation and culture of bulbs also developed 5–10 shoots within 50 d. Encapsulated in vitro-formed bulbs cultured either on hormone-free halfstrength MS or 6.97 μM kinetin-supplemented medium facilitated 100% conversion. As a step to conservation in situ, 50 plantlets were reintroduced into their natural habitat, i.e. at Vellarimala (at 1300 m height) of the Western Ghats of Kerala, and flowered normally. Development of more than 40 000 plantlets starting from a single explant is possible within 250 d. This threatened endemic orchid stands to benefit greatly from the established protocol and will hopefully curtail the threat of extinction.
TL;DR: Androgenic haploids of the neem tree (Azadirachta indica A. Juss.) were produced by anther culture at the early- to late-uninucleate stage of pollen via callusing, and of the plants that regenerated from anther callus 60% were haploid,20% were diploid and 20% were aneuploid.
Abstract: Androgenic haploids of the neem tree (Azadirachta indica A. Juss.) were produced by anther culture at the early- to late-uninucleate stage of pollen. Haploid formation occurred via callusing. The best medium for inducing callusing in the anther cultures was Murashige and Skoog's basal medium (MS) (9% sucrose) supplemented with 1 μM 2,4-D, 1 μM NAA and 5 μM BAP, while anther callus multiplied best on MS medium supplemented with 1 μM 2,4-D and 10 μM Kn. These calli differentiated shoots when transferred to a medium containing BAP; 5 μM BAP was optimum for young calli (75% cultures differentiated shoots), but older calli showed the best regeneration with 7.5 μM BAP. Shoots elongated at a lower concentration of BAP—0.5 μM. These shoots were multiplied by forced axillary branching and rooted in vitro. The plants were subsequently established in soil. Of the plants that regenerated from anther callus 60% were haploid, 20% were diploid and 20% were aneuploid.
TL;DR: Frequency of plant regeneration and number of regenerants dramatically increased with an optimal amount of copper (2 μM) in the MS medium and well-developed plantlets were transferred to the field where 100% survival and normal seed setting was noted.
Abstract: A highly efficient protocol for callus induction and plant regeneration in Sorghum bicolor was developed by varying the concentrations of copper (0.1, 0.3, 0.5, 0.7, 1, 1.5, 2.5 μM) in Murashige and Skoog (MS) medium. The mature embryos of Sorghum bicolor were cultured on MS medium containing 2,4-dichlorophenoxyacetic acid (9μM), kinetin (2.3 μM), and 3% (w/v) sucrose for embryogenic callus induction. Plant regeneration from this callus occurred on MS medium containing kinetin (9.2 μM) and indole-3-acetic acid (2.85 μM). A much greater response was noted on these media with higher levels of copper. Frequency of plant regeneration and number of regenerants dramatically increased with an optimal amount of copper (2 μM) in the MS medium. Rooting of the regenerated shoots readily occurred on half-strength MS medium supplemented with α-naphthaleneacetic acid (10.7 μM) and 3% (w/v) sucrose. Well-developed plantlets were transferred to the field where 100% survival and normal seed setting was noted.
TL;DR: Camptothecin(s) production was examined in callus cultures derived from cotyledons of Nothapodytes foetida (Weigh) Sleumer in relation to the media composition.
Abstract: Camptothecin(s) production was examined in callus cultures derived from cotyledons of Nothapodytes foetida (Weigh) Sleumer. The calluses were grown on various combinations of Murashige and Skoog's basal media supplemented with auxins 2,4-dichlorophenoxyacetic acid (2,4-D), 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), a-napthalene acetic acid (NAA) and indole-3-acetic acid (IAA) with 6-benzyl aminopurine (BA)/kinetin in different concentrations. The presence of camptothecin (CPT) and 9-methoxycamptothecin (9-OMeCPT) were analyzed by HPLC in relation to the media composition. Hyper production of CPT(1.306% on dry wt. basis) was observed with a combination of 2,4-D with BA and 2,4,5-T and NAA in 1-month-old callus.
TL;DR: A protocol has been developed for somatic embryogenesis and plant regeneration of sisal and Histological observations showed a distinct multicellular origin for most of the somatic embryos as they developed from epidermal, sub-epidermal and inside callus cells, while a few of them originated from a superficial callus cell.
Abstract: A protocol has been developed for somatic embryogenesis and plant regeneration of sisal (Agave sisalana Perr. ex. Engelm). Embryogenic callus cultures were initiated from young shoots raised in vitro from the stem portion of the bulbil on medium supplemented with 1–2 mg l-1 kinetin (KN) and 0.2–0.5 mg l-1 α-naphthaleneacetic acid plus KN or 1–1.5 mg l-1 benzylaminopurine (BAP) or 0.25–0.5 mg l-1 2,4-dichlorophenoxyacetic acid plus BAP or 0.5–1.0 mg l-1 KN. Embryos at various developmental stages (globular-, heart- or torpedo-shaped) produced mature and germinating embryos on being transferred to a new medium containing 0–0.25 mg l-1 KN. After 28 days, a maximum of 76% germinated embryos was obtained on a medium supplemented with 0.1 mg l-1 KN. The capacity for embryogenesis remained constant in the callus upon subculturing on the same medium for more than 48 months. Histological observations showed a distinct multicellular origin for most of the somatic embryos as they developed from epidermal, sub-epidermal and inside callus cells, while a few of them originated from a superficial callus cell. Plantlets regenerated from embryos were transferred to the field where their survival rate was 100%.