Showing papers on "Kinetin published in 1993"
TL;DR: In the roots of maize seedlings, Zm-p60.1 was localized to the meristematic cells and may function in vivo to supply the developing maize embryo with active cytokinin.
Abstract: A beta-glucoside encoded by a cloned Zea mays complementary DNA (Zm-p60.1) cleaved the biologically inactive hormone conjugates cytokinin-O-glucosides and kinetin-N3-glucoside, releasing active cytokinin. Tobacco protoplasts that transiently expressed Zm-p60.1 could use the inactive cytokinin glucosides to initiate cell division. The ability of protoplasts to sustain growth in response to cytokinin glucosides persisted indefinitely after the likely disappearance of the expression vector. In the roots of maize seedlings, Zm-p60.1 was localized to the meristematic cells and may function in vivo to supply the developing maize embryo with active cytokinin.
345 citations
TL;DR: In the grain legume Cicer arietinum L. (chickpea), the seed-derived embryo axes deprived of the apical meristem were able to regenerate adventitious shoots on Murashige and Skoog medium supplemented with kinetin, suitable for Agrobacterium-mediated gene transfer by the co-cultivation technique.
Abstract: In the grain legume Cicer arietinum L. (chickpea), the seed-derived embryo axes deprived of the apical meristem were able to regenerate adventitious shoots on Murashige and Skoog (1962) medium supplemented with kinetin. This protocol was suitable for Agrobacterium-mediated gene transfer by the co-cultivation technique. Chickpea transgenic plants showed neomycin phosphotransferase II and s-glucuronidase activities and the presence in their genome of integrated bacterial DNA.
118 citations
TL;DR: The presence of taxol in callus samples was established by high performance liquid chromatography, its biological activity confirmed by a microtubule-stabilizing bioassay and its structure confirmed using one-and two-dimensional 1H and 13C nuclear magnetic resonance spectroscopy.
Abstract: Callus was induced from Taxus baccata cv. Repandens Parsons ex Rehd., T. brevifolia Nutt., T. cuspidata Sieb. & Zucc., and T. x media cvs. Hicksii and Densiformis Rehd. using different concentrations of 2,4-d-(2,4-dichlorophenoxyacetic acid), IBA (indole-3-butyric acid), or NAA α-naphthalene acetic acid in combination with kinetin. All cultures grew slowly following the first subculture, and a majority turned brown and ceased growth within the next six to twelve months. The callus cultures which lived, continued to grow very slowly for one to two years before the growth rate improved. Initiation of roots and shoot primordia-like structures occurred on some cultures maintained in the dark, and 16 h light/8 h dark, respectively. A fast-growing, habituated callus line (CR-1) derived from T. x media Rehd. cv. Hicksii was established from callus initiated in 1986. Supplementing the medium with casein hydrolysate and both fructose and glucose enhanced the growth rate. A great deal of heterogeneity was found among and within the callus, with respect to the amount of taxol produced. The callus exhibited levels of taxol ranging from 0.1 to 13.1 mg kg-1 (0.0001 to 0.0131%) on a dry weight basis. Overall, the older brown-colored callus produced more taxol than the younger pale yellow-colored callus. The presence of taxol in callus samples was established by high performance liquid chromatography, its biological activity confirmed by a microtubule-stabilizing bioassay and its structure confirmed using one-and two-dimensional 1H and 13C nuclear magnetic resonance spectroscopy.
108 citations
TL;DR: Analysis of the effect of different culture media components on growth and production of taxol in developing callus cultures of T. cuspidata found significant increases in taxol yield and growth over basal medium grown calli were observed with some of the modified media.
Abstract: Cell culture of Taxus spp. represents a potential alternative source of taxol and related taxanes used in cancer chemotherapy. We have analyzed the effect of different culture media components on growth and production of taxol in developing callus cultures of T. cuspidata. Several sequential modifications were made to the basal B5 medium, which included addition and/or variation in the concentration of sucrose, B5 organic supplements, gibberellic acid, 36 combinations of 2,4-D/kinetin ratios, media salts and organic supplements, phenylalanine, casein hydrolysate and medium pH. The experiments were conducted during a 55 day-growth period followed by taxane extraction and analysis. Significant increases in taxol yield and growth over basal medium grown calli were observed with some of the modified media.
86 citations
TL;DR: It is shown that BA was required for adventitious shoot formation but its concentration in the medium was not critical, and biotechnology could be used as a means of introducing resistance to cucurbit potyviruses by inserting segments of viral DNA into existing watermelon germplasm without altering the genetic identity of elite lines
Abstract: Adventitious shoots were obtained from watermelon [ Citrullus lanatus (Thunb.) Matsun. & Nakai] cotyledons incubated on a modified Murashige and Skoog medium containing BA. Initial experiments comparing the effects of BA (0, 5, 10, or 20 μM ) and IA4 (0, 0.5, or 5 μM ) demonstrated that BA was required for adventitious shoot formation but its concentration in the medium was not critical. The addition of IAA to medium with BA increased callus production and inhibited shoot formation. However, the percentage of responding explants in the best treatment was 90% for ‘Minilee’, 64% for S86NE, and 50% for ‘Jubilee II’ when explants were prepared from 5-day-old seedlings. Explants from nongerminated embryos or seedlings germinated for 10, 15, or 20 days produced fewer shoots. The effect of several cytokinins on shoot organogenesis was then examined using the optimized protocol. The percentage of explants with shoots and the number of shoots per explant were about two to four times higher when 5 to 10 μM BA was used compared to the most effective kinetin (20 μM ) or thidiazuron (0.1 μM ) concentration. The percentage of explants with shoots and the number of shoots per explant were greater for diploid (57% and 2.2, respectively) than for triploid (22% and 0.6, respectively) or tetraploid (20% and 0.8, respectively) lines. Chemical names used: N -(phenylmethyl)-1 H -purin-6-amine (BA); 6-furfurylaminopurine (kinetin); N -phenylN' -1,2,3-thiadiazol-5-ylurea (thidiazuron); 1 H -indole3-acetic acid (IAA). Potyviruses cause serious disease problems in commercial cucurbit plantings across the United States (Adlerz et al., 1983) and in other production areas of the world. Resistance to viruses such as zucchini yellow mosaic virus (ZYMV) exists in wild germplasm (Provvidenti, 1991); however, the introduction of this germplasm into commercial watermelon cultivars would result in the loss of favorable characteristics and require years of selective breeding to obtain acceptable virus resistant cultivars. Biotechnology could be used as a means of introducing resistance to cucurbit potyviruses by inserting segments of viral DNA (e.g., sense, antisense, coat protein genes, etc.) into existing watermelon germplasm without altering the genetic identity of elite lines. This method has proven successful for obtaining transgenic plants resistant to alfalfa mosaic virus (Loesch-Fries et al., 1987; Turner et al., 1987; Van Dun et al., 1988), cucumber mosaic virus (Chee and Slightom, 1991; Cuozzo et al., 1988; Quemada et al., 1991), potato virus x and y (Hemenway et al., 1988; Hoekema et al., 1989; Kaniewski et al., 1990; for publication 30 Mar. 1992. Accepted for publication 15 Aug. 1992. lorida Agr. Expt. Sta. J. Ser. no. R-02349. This work was supported nt from the State of Florida High Technology and Industry Council Research Grants Program. Seeds were provided by Gary W. Elmstrom, lorida Research and Education Center, Institute of Food and Agriculences, Univ. of Florida, Leesburg, Fla. Use of trade names does not dorsement of the products named nor critism of similar products not d. The cost of publishing this paper was defrayed in part by the paypage charges. Under postal regulations, this paper therefore must be arked advertisement solely to indicate this fact. orate Research Assistant. To whom reprint requests should be ad-
83 citations
TL;DR: A protocol for high-frequency somatic embryogenesis in Cucumis melo L. was developed using 'Male Sterile A147 as a model cultivar and the optimal treatments were tested with 51 other commercial varieties.
Abstract: Additional index words. cantaloupe, melon, muskmelon, cell culture, regeneration Abstract. A protocol for high-frequency somatic embryogenesis in Cucumis melo L. was developed using 'Male Sterile A147 as a model cultivar. Basal halves of quiescent seed cotyledons were cultured on embryo induction (EI) medium containing concentration ranges of the auxin 2,4-D and the cytokinins BA, Bin, TDZ, or 2iP before transfer to embryo development (ED) medium. Medium with 2,4-D at 5 mg·liter -1 and TDZ at 0.1 mg·liter -1 was superior, with 49% of explants responding and an average of 3.3 somatic embryos per explant (6.8 somatic embryos per responding explant). More explants produced embryos when incubated on EI medium for 1 or 2 weeks (30% and 33%) than for 3 or 4 weeks or with no induction. However, 2 weeks was 2.9 times better than 1 week in terms of number of embryos per explant. One week of initial culture in darkness, followed by a 16 hour light/8 hour dark photoperiod, produced more responding explants (26%) than two or more weeks in darkness or no dark period at all; but 1 and 2 weeks of darkness resulted in a similar number of embryos per explant (2.1 and 2.8). Sucrose concentration in EI and ED media had a highly significant effect on embryo induction and development. EI medium with 3% sucrose resulted in more embryogenic explants than EI medium with 1.5% or 6% sucrose. However, treatments with 3% sucrose in EI medium and 3% or 6% sucrose in ED medium produced significantly more embryos per explant (8.5 and 11.9) than other treatments. Treatments did not affect embryo induction directly and regeneration per se but, instead, frequency and efficiency of somatic embryo development. The optimal treatments were tested with 51 other commercial varieties. All varieties underwent somatic embryogenesis, exhibiting a response of 5% to 100% explant response and 0.1-20.2 embryos per explant. Chemical names used: N-(phenylmethyl)-lH-purin-6-amine (benzyladenine or BA); N-(2-furanylmethyl)-lH-purin-6-amine (kinetin or BIN); N-phenyl-N'-1,2,3-thiadiazol-5-ylurea (thidiazuron or TDZ); N-(3-methyl-2-butenyl)-lH-purin-6-amine (2iP); (2,4-dichlorophenoxy) acetic acid (2,4-D).
79 citations
TL;DR: A complete protocol for micropropagation of 4-yr-old plants of the bambooDendrocalamus longispathus is described and more than 85% of the tissue culture-raised plants were successfully transferred to soil.
Abstract: A complete protocol for micropropagation of 4-yr-old plants of the bambooDendrocalamus longispathus is described. Culture initiation was strongly influenced by the nature of the explant and the season. In vitro multiplication was achieved through forced axillary branching. Single node segments from the young lateral branches produced multiple shoots on agar-solidified Murashige and Skoog (MS) medium supplemented with 12µM benzylaminopurine (BAP) and 3µM kinetin. The shoots have been multiplied for 15 passages in liquid and thereafter for over 5 passages on semisolid MS+15µM BAP+1µM indolebutyric acid (IBA)+10% coconut water at a rate of 3.2- and 2.8-fold, every 4 wk, respectively. The nature of the propagule was a critical factor for shoot multiplication and rooting. Seventy-three percent of the shoots rooted on a modified MS medium (major salts reduced to half strength) containing 1µM indoleacetic acid, 1µM IBA, and 68µM coumarin. Through a simple in vitro hardening step, more than 85% of the tissue culture-raised plants were successfully transferred to soil.
79 citations
TL;DR: Addition of 10–25 mM proline with 0.4 mM thioproline and 50 mM potassium enhanced the size of embryogenic callus and significantly enhanced subsequent embryo formation along with higher numbers of cotyledonary embryos.
76 citations
TL;DR: Good results for anthocyanin production in dark-grown calli of Aralia cordata Thunb are obtained on the addition of sucrose as the carbon source and NH4+ and NO3− at a molar ratio of 1:4.
68 citations
TL;DR: Elite trees of Commiphora wightii (Arnott) Bhandari were selected from the wild on the basis of their content of guggul, an oleoresin to micropropagated through forced axillary branching on Murashige and Skoog's medium supplemented with benzyladenine and kinetin to study the shoot proliferating potential of the initial explants in vitro.
Abstract: Elite trees of Commiphora wightii (Arnott) Bhandari were selected from the wild on the basis of their content of guggul, an oleoresin. The selected tree was micropropagated through forced axillary branching on Murashige and Skoog's (MS) medium supplemented with benzyladenine (BA) and kinetin. Highest frequency of shoot formation was achieved on MS medium supplemented with 17.8 μM BA, 18.6 μM kinetin, 100 mg l-1 glutamine, 10 mg l-1 thiamine HCL and 0.3% activated charcoal. Seasonal changes affected the shoot proliferating potential of the initial explants in vitro. Transfer of shoots to a medium containing a lower concentration of BA (1.8 μM) and kinetin (1.9 μM) before rooting markedly stimulated shoot elongation. Shoots could be rooted by treating them with both indoleacetic acid and indolebutryic acid for 24 h in darkness and transferring them to a low-salt basal medium with activated charcoal. After rooting, transfer to a half-strength White's (modified) medium was necessary for further development of the plantlet. Regenerated plantlets were successfully established in soil.
60 citations
TL;DR: 2,4-d was more effective than picloram for inducing embryogenesis from embryonal axes, and sucrose was the best for embryo induction and at 6% sucrose the highest frequency of responding cultures and average number of somatic embryos per explant were obtained.
Abstract: Somatic embryogenesis and plant regeneration were induced from immature embryonal axes and immature cotyledons of peanut (Arachis hypogaea L. fastigata type cv JLM-1). Influence of different auxins, cytokinins and sugars on somatic embryogenesis from immature cotyledon explants was also investigated. Among the different auxins tested, 2,4-dichlorophenoxyacetic acid (2,4-d) was most effective, producing the highest frequency of responding cultures and highest average number of somatic embryos per responding culture, while dicamba, picloram, indolepropionic acid, α-naphthaleneacetic acid, 2,4,4-trichlorophenoxypropionic acid and α-naphthoxyacetic acid were also effective for embryogenesis. Indolebutyric acid, indoleacetic acid, p-chlorophenoxyacetic acid and trichlorophenoxyacetic acid were not beneficial. Among the four cytokinins tested, zeatin slightly enhanced the frequency of somatic embryogenesis, while kinetin, 6-γ-γ-dimethylallylaminopurine and benzyladenine were relatively inhibitory. Among the different carbon sources tested, sucrose was the best for embryo induction and at 6% sucrose the highest frequency of responding cultures and average number of somatic embryos per explant were obtained. For inducing embryogenesis from embryonal axes, 2,4-d was more effective than picloram. Highest plant conversion frequency from somatic embryos was obtained in presence of dicamba or NAA and using cotyledon explants.
TL;DR: Callus originated in microsporangial wall layers and connective tissues of anthers containing uninucleate microspores on Nitsch's or Murashige and Skoog's medium supplemented with growth regulators to induce multiple shoots induced in this anther-derived callus.
Abstract: Callus originated in microsporangial wall layers and connective tissues of anthers containing uninucleate microspores on Nitsch's or Murashige and Skoog's medium supplemented with growth regulators. A higher percentage of cultures (43) produced callus on Nitsch's medium containing 10 μM indole-3-acetic acid + 1 μM 6-benzyladenine. After 13–15 weeks, green nodular structures and prominent roots developed in 25% of the cultures on Murashige and Skoog's medium + 10 μM α-naphthaleneacetic acid + 1 μM kinetin. Multiple shoots were induced in this anther-derived callus when subcultured on Murashige and Skoog's medium augmented with 4.44 μM 6-benzyladenine + 0.53 μM α-naphthaleneacetic acid along with 18.75 μM polyvinylpyrrolidone. The excised shoots formed roots after subculturing on Murashige and Skoog's medium + 4.90 μM indole-3-butyric acid + 18.75 μM polyvinylpyrrolidone, thus developing complete plantlets. Examination of callusing anthers also revealed two- to multi-celled pollen masses with intact exine.
TL;DR: The genetic integrity of clones (based on phenotype assessment) was not affected by the in vitro culture method and up to 14 months of low-maintenance storage conditions, and these in vitro plants will be further tested for genetic stability using biochemical and molecular techniques.
Abstract: An in vitro method for the establishment and storage of over 200 Saccharum spp. hybrid clones was developed that involved only 1 medium for shoot development and multiplication, and no decontamination procedures. Apical buds, from the leaf axils of developing leaves surrounding the apical meristem, were cultured on medium containing the plant growth regulators 6-benzylaminopurine (BAP) and 6-furfurylaminopurine (kinetin), and regenerated multiple shoots. Shoots transferred to medium containing naphthaleneacetic acid (NAA) developed roots. In vitro plants transferred to a medium containing half strength salts and vitamins without plant growth regulators were placed in storage at 18°C. After 12 months of storage plants were transferred to fresh medium and returned to storage. The genetic integrity of clones (based on phenotype assessment) was not affected by the in vitro culture method and up to 14 months of low-maintenance storage conditions. These in vitro plants will be further tested for genetic stability using biochemical and molecular techniques.
TL;DR: 3-Indole-acetic-acid and inositol in the medium increased the degree of unspecific genomic DNA methylation in growing rhizogenic carrot callus tissue in the absence of kinetin, which inhibits root induction at that stage.
Abstract: Rapid genomic DNA variation due to methylation and copy number alteration was observed in carrot root explants 6 h after inoculation and during a 36-h period of exponential callus growth. De novo methylation and amplification of restricted BspNI fragments of low molecular weight occurred before cell cycle activation and should, therefore, be independent of progression through the S-phase of the cell cycle. Growth regulators seemed to influence the amplification pattern indirectly by regulating cell division activity. In exponentially growing callus tissue the copy number of most of the repetitive fragments was dramatically reduced. It is presumed that this reduction in the copy number of repetitive fragments is characteristic of ‘rejuvenilization’. 3-Indole-acetic-acid (IAA) and inositol in the medium increased the degree of unspecific genomic DNA methylation in growing rhizogenic carrot callus tissue in the absence of kinetin, which inhibits root induction at that stage. A possible relation to the induction of rhizogenesis is considered. The observed reduction in number of repetitive restriction fragments and the increase in DNA methylation are gross changes covering the total genome. The results are discussed in relation to the controversy concerning the general biological significance of the methylation and amplification of DNA sequences.
TL;DR: Benzyladenine and thidiazuron had optimum effects at the same concentration with regard to axillary shoot formation but thdiazuron induced a significantly lower number of shoots than benzyladenines.
Abstract: The thidiazolylurea derivative thidiazuron has been reported to be considerably more effective than benzyladenine in promotion of in vitro shoot formation in a number of dicotyledonous species. In the present study, axillary shoots of Miscanthus sinensis (Thunb.) Anderss. ‘Giganteus’ that had been subcultured four times on modified Murashige & Skoog medium with 20μM benzyladenine were transferred to media with benzyladenine, kinetin, isopentenyladenine or thidiazuron at concentrations of 0.01, 0.1, 1, 10, 30 or 100μM and grown over four subcultures. Shoot and root formation stabilized after the first subculture and results from the three subsequent subcultures are presented. The common effects of cytokinins, i.e., promotion of axillary bud growth, inhibition of root formation, reduced stem growth and delay of senescence, were observed for all four cytokinins. In a descending order regarding shoot formation, the four cytokinins at the optimum concentration could be ranked as follows: benzyladenine, thidiazuron, kinetin and isopentenyladenine. Benzyladenine and thidiazuron had optimum effects at the same concentration with regard to axillary shoot formation but thidiazuron induced a significantly lower number of shoots than benzyladenine. The number of roots, shoot size and percentage of chlorotic shoots were also the same for benzyladenine and thidiazuron. When transferring shoots from benzyladenine or thidiazuron medium to rooting medium, shoots previously grown on thidiazuron became taller and formed fewer roots than shoots previously grown on benzyladenine.
TL;DR: Immature inflorescence segments of sugarcane breeding lines were cultured on several versions of MS based media containing various concentrations and combinations of 2,4-D, kinetin, BAP, CH and calcium pantothenate and all of the three genotypes were capable of producing a large quantity of callus.
TL;DR: Embryogenic calluses of sugarcane capable of regenerating green plants after long-term culture were sought and genotypic differences were observed, embryogenesis occurred in all 17ugarcane clones tested.
Abstract: Embryogenic calluses of sugarcane capable of regenerating green plants after long-term culture were sought. The largest quantities of embryogenic calluses were produced on Murashige & Skoog medium, but cultures maintained on Chu N6 medium remained embryogenic and totipotent longer. Both media contained 4.5 μM 2,4-dichlorophenoxyacetic acid (2,4-d). The effect of supplements on somatic embryogenesis was examined. Kinetin (0.5 μM) and 10% (v/v) coconut water in callus initiation medium were inhibitory to subsequent embryogenesis. Embryogenic calluses on N6 medium increased in fresh weight with proline concentration up to 90 mM. Maximum fresh weight was achieved with 5% sucrose. Although genotypic differences were observed, embryogenesis occurred in all 17 sugarcane clones tested. Embryogenic calluses of one cultivar regenerated green plants after 16 months, but suspensions were totipotent for only 8 months. Total number of regenerated plants decreased with time in culture, while the number of pale green plants increased starting after 5 months in culture.
TL;DR: Plants were obtained via somatic embryogenesis in callus derived from in vitro raised leaf and petiole explants of Aconitum heterophyllum Wall using a Murashige-Skoog medium supplemented with either 2,4-dichlorophenoxy acetic acid or kinetin.
Abstract: Plants were obtained via somatic embryogenesis in callus derived from in vitro raised leaf and petiole explants of Aconitum heterophyllum Wall. Callus was induced on a Murashige-Skoog medium supplemented with either 2,4-dichlorophenoxy acetic acid (2,4-d 1 mg l-1) and kinetin (KN 0.5 mg l-1) with coconut water (CW 10% v/v) or naphthalene acetic acid (NAA 5 mg l-1) and benzylaminopurine (BAP 1 mg l-1). Somatic embryos appeared after 2–3 months or 2 subculture passages when 2,4-d or NAA induced source of the callus was transferred to a MS medium containing BAP (1 mg l-1) and NAA (0.1 mg l-1). For successful plantlet formation, the somatic embryos were transferred to a medium containing 1/4 strength MS nutrient with indole-3-butyric acid (IBA 1 mg l-1). Alternatively, the somatic embryos were dipped in a concentrated solution of IBA for 5 min and placed on a hormone free medium. Complete plantlets were formed after 4 weeks and were transferred successfully to soil.
TL;DR: A tissue culture technique for rapid vegetative propagation of mature jackfruit trees using apical bud cultures using Benzyladenine and kinetin supported shoot proliferation and higher concentrations of the cytokinins inhibited bud breaking and favoured callus formation at the explant bases.
Abstract: A tissue culture technique for rapid vegetative propagation of mature jackfruit trees using apical bud cultures has been developed. Shoot-tip cultures were established on MS medium with 5–10 mm explants dissected from terminal buds of new growth from trunk. After initial culture of bud explants, one- to two-node pieces were taken from the microshoots formed and used to proliferate further axillary shoots for multiplying and maintaining shoot cultures. Benzyladenine and kinetin (4.5–9.0 µM), either separately or together, supported shoot proliferation; higher concentrations of the cytokinins inhibited bud breaking and favoured callus formation at the explant bases. Bud explants taken from emerging trunk sprouts invariably produced clumps of multiple shoots, whereas buds obtained from actively growing top branches generally elongated to form a solitary shoot. November to January was the best season for initiation of cultures from field-grown trees. Shoots proliferated at the initial subcultures had mature morphology and were difficult-to-root. Shoots assumed to be juvenile-like developed at the later passages and could be rooted with 60–80% success using 1/2-MS salts and 10 µM of indolebutyric acid or naphthaleneacetic acid. Regenerated plantlets were transferred to the soil and about 50% survived.
TL;DR: Calli obtained by modifying the auxin/cytokinin balance lost their embryogenic potential and those obtained on media with high sucrose or calcium concentrations were mainly composed of embryogenic cells embedded in a mucilaginous matrix, which could be of potential interest for establishing embryogenic cell suspension cultures.
Abstract: The influence of plant growth regulators, sucrose, calcium and various macronutrient media on callus friability and somatic embryogenesis was investigated inHevea brasiliensis Mull. Arg. Friable and embryogenic calli were spontaneously formed in two rubber tree clones (PR 107 and RRIM 600) on the Medium for Hevea (MH), with 3,4-dichlorophenoxyacetic acid (3,4-d), kinetin and sucrose, while compact embryogenic calli were enhanced in three other clones (PB 260, PB 235 and GT1). Callus friability was enhanced in clone PB 260 when the concentration of one growth factor (3,4-d or kinetin) was reduced from 4.5 μLM to 0.45 μM during the first culture, or when high sucrose or calcium levels 351 mM and 12 mM, respectively) were maintained during subcultures. The different macronutrient media did not alter callus texture but only use of MH and Murashige and Skoog (MS) media led to somatic embryogenesis. Friable calli obtained by modifying the auxin/cytokinin balance lost their embryogenic potential. In contrast, those obtained on media with high sucrose or calcium concentrations were mainly composed of embryogenic cells embedded in a mucilaginous matrix. Such calli could be of potential interest for establishing embryogenic cell suspension cultures.
TL;DR: Tissue culture techniques were applied to study the regeneration and growth of bulblets from bulb scale segments of Crinum macowanii Bak.
Abstract: Tissue culture techniques were applied to study the regeneration and growth of bulblets from bulb scale segments ofCrinum macowanii Bak. (bush- or march lily)in vitro. Shoots were induced on twin scales taken from the basal plate region of flowering-size bulbs on Murashige and Skoog (MS)-medium containing 0–20 mg l−1 NAA and BA and a modified MS medium (MMS medium) containing 1.25 mg l−1 ancymidol (A-RestTM), 0.1 mg l−1 NAA and 0.1 mg l−1 kinetin (ANK). Large bulblets could only be initiated on the latter. Subsequently the bulblets of 5 mm or more in diameter were trimmed and split in half, and secondary plantlets were regenerated on MMS-medium containing ANK or MS-medium without any growth regulators which in turn grew into bulblets suitable for splitting within 12–16 weeks. A total of 700–1000 bulblets could be obtained from each initial bulb within 12 months. Anatomical studies showed that the shoots were initiated from the epidermis and hypodermis on the abaxial surface of the meristematic tissue of the basal plate of the bulb scale. This technique is useful for the multiplication and preservation of a genotype, since plantlets regenerated in this manner should be genetically uniform.
TL;DR: Embryogenic callus and adventitious buds were initiated from only two anthers of the hybrid H. annuus ×H.
Abstract: A method of plant regeneration from cotyledons ofHelianthus tuberosus, Helianthus annuus ×Helianthus tuberosus and for the backcross of the interspecific hybrids onH. annuus was developed. Induction of somatic embryogenesis and plantlet regeneration from anther culture of the interspecific hybridsH. annuus ×H. tuberosus is reported. Cotyledons were cultured on Murashige and Skoog basal medium (MS) supplemented with indole-3-acetic acid (IAA) and 6-furfurylaminopurine (kinetin) or N6-benzylaminopurine (BAP). Shoot regeneration occurred on most of the media tested, but the best results were obtained on media with a high concentration of cytokinins (BAP or kinetin: 4 mg l−1) and lower concentration of auxin (IAA: 0.5−1 mg l−1). Embryogenic callus and adventitious buds were initiated from only two anthers of the hybridH. annuus ×H. tuberosus cultured on the MS medium containing BAP (0.2 mg l−1) and 1-naphtalenacetic acid (NAA: 0.1 mg l−1). Prolonged culture of these embryogenic calli and buds on the original medium with successive subculture on MS basal medium without growth regulators resulted in embryo formation and shoot differentiation. The plantlets, after rooting, were established in soil.
TL;DR: The ability of this system to propagate embryos exponentially offers potential for development of new gene transfer systems and application to artificial seed technology.
Abstract: Callus cultures from 300 genotypes of alfalfa (Medicago sativa L.) were initiated from leaf, petiole, and internode explants placed on Blaydes medium containing 10.74 μM α-naphthaleneacetic acid, 11.42 μM indole-3-acetic acid, and 9.29 μM kinetin. Five genotypes produced somatic embryos. Upon transfer of these embryos to growth regulator-free Murashige and Skoog medium with B5 vitamins, new somatic embryos repeatedly formed directly on older somatic embryos without an intervening callus phase in a cycle lasting about 30 days. These cultures have been maintained for two years, during which time their embryogenic capacity has remained stable. New embryogenic cultures could be started repeatedly from these genotypes. The elimination of sugars from the medium could stop recurrent embryogenesis. Glucose, maltose, and fructose stimulated recurrent embryogenesis more effectively than sucrose. Sucrose was superior to lactose, while sorbitol and mannitol did not stimulate recurrent somatic embryogenesis. The absence of nicotinic acid in the medium, as long as sucrose was present, was lethal to embryos of three of the five tested genotypes. The ability of this system to propagate embryos exponentially offers potential for development of new gene transfer systems and application to artificial seed technology.
TL;DR: The ability of various diploid and tetraploid genotypes to undergo prolonged axillary shoot proliferation on medium with 1 µM BA was examined and among the genotypes tested, the number of axillary shoots per explant was greater for ‘Bush Jubilee’ and ‘Jubilee II’ than for “Minilee”, ‘Dixielee’, and the tetraPloid genotype.
Abstract: Shoot-tip explants from 21-day-old aseptically-germinated watermelon seedlings were incubated on solidified MS medium containing test concentrations of benzyladenine (BA) and kinetin (each at 0, 1, 5 or 10 µM), and thidiazuron (TDZ; 0, 0.1, 1 or 5 µM) for 8 weeks. Approximately 1.5x–2.8x more axillary shoots formed at the optimum BA level (1 µM) compared to the best TDZ (0.1 µM) or kinetin (10 µM) concentration. The ability of various diploid and tetraploid genotypes to undergo prolonged axillary shoot proliferation on medium with 1 µM BA was examined. Among the genotypes tested, the number of axillary shoots per explant was greater for ‘Bush Jubilee’ and ‘Jubilee II’ than for ‘Minilee’, ‘Dixielee’, and the tetraploid genotypes. For a majority of the genotypes tested, the number of shoots per explant was low (2.7–4.0) during the first month of culture, peaked (5.3–12.5) at 2 to 3 months, and then declined (3.7–7.7) at 6 months. In contrast, the number of shoots per explant was greatest (11.7) for ‘Bush Jubilee’ during the first month of culture and declined to 7.7 by the sixth subculture. The percentage of rooted shoots varied from 60% to 100% and the percentage of acclimatized plants ranged from 21% to 96% depending on the genotype and the length of time in culture. Using this procedure, 13,200 finished plants could be produced in 3 months from 250 seedlings.
TL;DR: Seed pretreatment with GA3 or kinetin nullified the deleterious effects imposed by irrigation with sea water particularly the high level on photosynthetic14CO2 fixation and inhibited leaf growth by themselves in almost all measurements.
Abstract: The antagonistic effects of some growth regulators [i.e. indol-3-yl-acetic acid (IAA), gibberellic acid (GA3) or kinetin] on stress imposed by sea water on leaf area, pigment and photosynthetic activity in leaves of broad bean plants at different stages of development were investigated. Seed priming with GA3 alleviated either partially or completely the effects induced by the two levels of sea water (10 and 25 %) used on leaf area at all experimental stages. However, IAA, GA3 and kinetin inhibited leaf growth by themselves in almost all measurements. Seed pretreatment with kinetin alleviated the inhibition of pigment production in sea water-irrigated plants. Furthermore, GA3 or kinetin nullified the deleterious effects imposed by irrigation with sea water particularly the high level (25 %) on photosynthetic14CO2 fixation.
TL;DR: When the culture conditions for callus induction in the tissue of Aloe arborescens were examined, callus formation was promoted, but the protein and aloin concentrations, and carboxypeptidase activity in the Aloe callus decreased more than those observed in the sucrose‐containing medium.
Abstract: We examined the culture conditions for callus induction in the tissue of ALoe arborescens. When incubated in the dark at 25°C, for about 30 days callus was induced. The frequency of callus formation was in the order of superior stalk > middle stalk > inferior stalk. No callus was formed in the leaf. When the Murashige-Skoog (MS) basal agar medium was supplemented with 3% sucrose, 0.1-0.5 μM kinetin (a plant growth regulator) and 10-50 μM alpha-naphthalenacetic acid, callus formation occurred at an incidence of 20-52% (mean: 39%). When the MS basal agar medium was supplemented with 3% glucose and 10% Alpha Modification of Eagle's Medium instead of 3% sucrose, callus formation was promoted, but the protein and aloin concentrations, and carboxypeptidase activity in the Aloe callus decreased more than those observed in the sucrose-containing medium
TL;DR: In this paper, plantlets were regenerated from the callus of Iris pallida, an important perfume plant, and the components of the essential oil in the rhizome of regenerated plants were essentially the same as those in natural plants.
Abstract: Plantlets were regenerated from callus of Iris pallida, an important perfume plant. Only the leaf base attached to the rhizome had the ability to generate yellow-colored callus on LS medium supplemented with 1 mg/l 2,4-D and 0.1 mg/l KT in the dark. Yellow calli grew with partial differentiation into white tissue, probably embryogenic, during subculture on the same medium with a 16-h photoperiod. Only yellow-colored calli with the white tissue could differentiate into plantlets after transfer to kinetin- or gibberellin- supplemented LS medium. Regenerated plantlets which grew on the medium without growth regulators were transferred to the soil. After 2 years of cultivation in soil, the regenerated plants flowered and formed rhizomes. The components of the essential oil in the rhizome of regenerated plants were essentially the same as those in natural plants.
TL;DR: Media for induction of somatic embryogenesis from immature cotyledonary tissues of Azadirachta indica (Neem) were determined and Histologic studies confirmed indirect somatics embryogenesis.
Abstract: Media for induction of somatic embryogenesis from immature cotyledonary tissues ofAzadirachta indica (Neem) were determined. Callus was initiated on Murashige and Skoog medium supplemented with 0.5 mg·liter−1 of indol-3 acetic acid, 1.0 mg·liter−1 of 6-benzyl amino purine, and 1000 mg·liter−1 of casein hydrolysate. Effect of kinetin was also studied for embryo induction. Carbohydrate source in the form of sucrose and glucose alone and in combination was tested for embryogenic efficiency. Seventy percent embryos showed germination. Healthy plants were potted in sand and soil. Histologic studies confirmed indirect somatic embryogenesis.
TL;DR: The production of an intracellular secondary metabolite rosmarinic acid (RA) by plant cell suspensions of Anchusa officinalis cultivated with intermittent medium exchange is investigated, with the highest RA concentration ever reported in the Anchusa culture.
Abstract: The production of an intracellular secondary metabolite rosmarinic acid (RA) by plant cell suspensions of Anchusa officinalis cultivated with intermittent medium exchange is investigated. Initially, a two-stage perfusion culture method was employed. After being cultured in the batch mode for ca. 6 days in B5 medium plus 3% sucrose, 1 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D), and 0.1 mg/L kinetin (2,4-D B5 medium), Anchusa culture was cultivated to high cell density by perfusion during the growth stage using a hormone-free Gamborg B5 medium supplemented with 6% sucrose. This was followed by a production stage, in which a complete medium exchange into B5 medium plus 3% sucrose and 0.25 mg/L naphthleneacetic acid (NAA) was conducted. The two-stage perfusion culture had a higher maximum culture RA concentration but a lower RA content per cell than the batch stock culture maintained in the 2,4-D B5 medium. Higher culture RA concentration was due primarily to high cell density. The high packed cell volume, however, seemed to reduce the synergistic effect of NAA on RA synthesis. Subsequently, a single-stage perfusion culture method was investigated. The best result was obtained by growing the culture in the batch mode for ca. 10 days using B5 medium supplemented with 3% sucrose and 0.25 mg/L NAA, followed by perfusing the culture with B5 medium plus 6% sucrose and 0.25 mg/L NAA at a constant perfusion rate of 0.1/day. A maximum cell dry weight of 35 g/L and a RA concentration of almost 4 g/L were achieved. This is the highest RA concentration ever reported in the Anchusa culture. © 1993 John Wiley & Sons, Inc.
TL;DR: The effects of plant growth regulators, light intensity, and end-of-day (EOD) light quality treatments on node and microtuber induction and development and development in yam suggested the involvement of phytochrome in these processes.
Abstract: The effects of plant growth regulators, light intensity, and end-of-day (EOD) light quality treatments on node and microtuber induction (% of cultures with microtubers) and development (fresh weight of microtubers) in yam (Dioscorea alata L. cv. Oriental) cultures were investigated. Nodal segments were excised from plantlets cultured on tuberization medium containing growth regulators and exposed to various light treatments. Absciscic acid (1 μM) stimulated and cytokinins (2.5 μM) inhibited microtuber development from yam nodal segments cultured on Mantell's and Hugo's full-strength tuberization medium under 8-h photoperiods. EOD far-red (FR) light inhibited microtuber induction and development and enhanced node formation. EOD FR light effects were nullified by immediately following the FR treatment with red light. This suggested the involvement of phytochrome in these processes. The lowest light intensity evaluated (12 μmol m−2 s−1) inhibited microtuber, root and shoot production as compared to light intensities of 42, 72 and 102 μmol m−2 s−1. Kinetin (2.5 μm) in half-strength tuberization medium inhibited microtuber induction and development but did not affect node production in the light intensity evaluation.