Showing papers in "Plant Cell Tissue and Organ Culture in 1990"
TL;DR: Thidiazuron (TDZ), a substituted urea with cytokinin activity, was significantly more effective than benzyladenine (BA) at inducing organogenesis from detached Rubus cotyledons and leaves.
Abstract: Thidiazuron (TDZ), a substituted urea with cytokinin activity, was significantly more effective than benzyladenine (BA) at inducing organogenesis from detached Rubus cotyledons and leaves. The optimal TDZ concentration for organogenesis from cotyledons and leaves was 5–10 µM and 5–20 µM, respectively; however, shoot organogenesis occurred at TDZ concentrations of 0.5–5.0 µM. Light fluence rates from 0–81 µmol m-2 s-1 of continuous fluorescent light did not affect the percentage of organogenesis from cotyledons. Two weeks of continuous dark did not enhance the percentage of regeneration from leaf explants. Kanamycin, an antibiotic used to screen for transformation, severely reduced cotyledon growth and regeneration at concentrations as low as 10 mgl-1, and completely inhibited shoot organogenesis at 50 mgl-1.
156 citations
TL;DR: In this article, the authors used paclobutrazol in the rooting medium of Chrysanthemum x morifolium to reduce the wilting of plantlets.
Abstract: Plantlets of Chrysanthemum x morifolium were grown from nodal sections in cellulose plugs which were saturated with liquid rooting medium. Inclusion of 0.5–4.0 mg l−1 paclobutrazol in the rooting medium led to a reduction in wilting when plantlets were transferred to compost and exposed to an atmosphere of reduced humidity. Smaller stomatal apertures, increased epicuticular wax, whortened stems and thickened roots were observed and may each have contributed to this reduction in wilting. Paclobutrazol treatments also increased chlorophyll concentration per unit area of leaf. Gibberellic acid had the reverse effect to that of paclobutrazol on most of the characters which were investigated.
108 citations
TL;DR: In vitro tissue cultures of coconut palm showed marked differences in their growth response according to the age of the medium used and the associated variations in 2,4-D concentrations.
Abstract: The rate of adsorption of 2,4-dichlorophenoxyacetic acid (2,4-D) by activated charcoal (AC) from liquid and semi-solid tissue culture media was determined using 2-[14C]-2′,4′-D. In liquid medium 99.5% of the added 2,4-D (10-4 M) was adsorbed by AC (2.5 gl-1) within 5 days of preparation of the medium. Higher 2,4-D levels of reduced AC concentrations increased the level of available 2,4-D in the medium and extended the period necessary for the level of 2,4-D in the medium to become stabilized. In semi-solid medium the rate of adsorption of 2,4-D by AC was considerably reduced. A stable ratio of gel/2,4-D:AC/2,4-D was only reached after 10 to 20 days, depending on the 2,4-D concentration used. Low pH levels and maintenance of the medium at higher temperatures (20–30°C) accelerated the adsorption of 2,4-D by AC. In vitro tissue cultures of coconut palm showed marked differences in their growth response according to the age of the medium used and the associated variations in 2,4-D concentrations.
106 citations
TL;DR: Axillary buds excised from aseptic shoot cultures of mulberry were encapsulated in an alginate matrix under non-aseptic conditions and addition of a fungicides prevents contamination of the bud and increased survival of the buds when sown in soil.
Abstract: Axillary buds excised from aseptic shoot cultures of mulberry were encapsulated in an alginate matrix under non-aseptic conditions. Addition of a fungicide to the alginate beads prevents contamination of the bud and increased survival of the buds when sown in soil.
85 citations
TL;DR: A period of four days preincubation at 25 °C on a medium containing mannitol was found to be superior to those pretreatments requiring incubation at 4 °C, and the yield of green plants was improved by orienting anthers ‘flat’ on the medium duringMannitol preincubsation, and reducing the number of anothers cultured per dish.
Abstract: A period of four days preincubation at 25 °C on a medium containing mannitol was found to be superior to those pretreatments requiring incubation at 4 °C. In addition, the yield of green plants was improved by orienting anthers 'flat' on the medium during mannitol preincubation, and reducing the number of anthers cultured per dish.
83 citations
TL;DR: A method for rapid and highly effective plant micropropagation from vegetative meristems was established for Aloe barbadensis Mill and high morphogenetic ability was maintained by transferring explants (after 60 days) on media containing 0.2 μM 6-benzylaminopurine.
Abstract: A method for rapid and highly effective plant micropropagation from vegetative meristems was established for Aloe barbadensis Mill. Plant micropropagation was achieved culturing apices on medium containing 1.1 μM 2,4-dichlorophenoxyacetic acid and 2.3 μM kinetin for 15–30 days. High morphogenetic ability was maintained by transferring explants (after 60 days) on media containing 0.11 μM 2,4-dichlorophenoxyacetic acid and 2.2 μM 6-benzylaminopurine.
83 citations
TL;DR: Cytological analysis of regenerated plants showed normal diploid chromosome number in their root tips, and incorporation of different antibiotics such as carbenicillin, cefotaxime and streptomycin sulfate enhanced plant differentiation from somatic embryos.
Abstract: Cultured caryopses of finger millet (Eleusine coracana GAERTN) produced callus from shoot apices or mesocotyls depending upon the concentration of picloram and combination of cytokinins in MS basal medium. On subsequent subcultures, numerous somatic embryos differentiated from the callus on MS medium supplemented with picloram and kinetin. The embryos germinated into complete plants on medium devoid of phytohormones. When different carbohydrates were tested, basal medium containing glucose and sucrose produced the highest frequency of germinating somatic embryos. Supplementation of MS basal medium with a variety of aminoacids, osmotic agents and growth supplements had an adverse effect on the germination of embryos. Incorporation of different antibiotics such as carbenicillin, cefotaxime and streptomycin sulfate enhanced plant differentiation from somatic embryos. Cytological analysis of regenerated plants showed normal diploid chromosome number in their root tips.
81 citations
TL;DR: Adventitious shoots were regenerated from leaf and stem explants of eleven chrysanthemum cultivars and generally, stemExplants were superior to leaf explants.
Abstract: Adventitious shoots were regenerated from leaf and stem explants of eleven chrysanthemum cultivars. The optimum medium for both explant types contained Murashige & Skoog basal medium supplemented with 5 μM 6-benzylaminopurine and 5 μM α-napthaleneacetic acid. Generally, stem explants were superior to leaf explants. There were large cultivar differences in shoot regeneration frequency with three cultivars failing to respond over a wide range of hormone combinations. Shoots on stem explants appeared mainly to originate from cortical cells which rapidly divided and ruptured the epidermis. Regenerated shoots could be easily rooted, transferred to glasshouse conditions, and grown to flowering. All regenerated plants had the same morphological characteristics compared to plants derived from nodes.
81 citations
TL;DR: The modified MS medium containing lesser amounts of potassium nitrate and ammonium nitrate than those of the original MS media was optimal for the production of plantlets from rhizomes of C. kanran without addition of auxin and cytokinin.
Abstract: Growth of Cymbidium kanran rhizome was enhanced by higher NAA:BAP ratios in modified Murashige & Skoog (MS) media. Only vegetative shoots resulted from rhizomes cultured in vitro when lower NAA:BAP ratios were used. The rhizomes were induced from the axils of leaves when shoots were explanted to medium containing higher concentrations of NAA. Root formation of C. kanran was inhibited by the addition of either auxin or cytokinin to the culture media. Differentiation of the rhizomes into plantlets occurred when the concentrations of ammonium nitrate and potassium nitrate in MS medium wewe reduced. The modified MS medium containing lesser amounts of potassium nitrate and ammonium nitrate than those of the original MS media, and was optimal for the production of plantlets from rhizomes of C. kanran without addition of auxin and cytokinin.
80 citations
TL;DR: No critical differences were found in potential for callusing, embryogenesis or regeneration, and genotypic differences were observed in pigment production, embryogenic callus formation, shoot differentiation, and in maintenance of regeneration capacity.
Abstract: A procedure was established for the induction of regenerable calli from immature inflorescence segments of high-tannin cultivars of sorghum (Sorghum bicolor (L.) Moench). Murashige & Skoog's medium with several components altered was utilized for inducing, maintaining, and regenerating the cultures. Embryogenic calli formed at a frequency of 8–70% depending on the genotype. During a ten-month period, 3600 plants were regenerated from eight genotypes tested. Among the developmental stages of immature inflorescence tested (from differentiation of secondary branch primordia to floret formation) no critical differences were found in potential for callusing, embryogenesis or regeneration. Genotypic differences were observed in pigment production, embryogenic callus formation, shoot differentiation, and in maintenance of regeneration capacity.
79 citations
TL;DR: Histological examinations confirmed the embryogenic nature of the immature embryo cultures and revealed that somatic embryos originated from the meristematic areas near the callus surface, indicating a clear effect of embryo size on somatic embryogenesis.
Abstract: Conditions were defined for plant regeneration via somatic embryogenesis in pea, using explants from immature zygotic embryos or from shoot apices. For the induction of somatic embryos, an auxin (picloram or 2,4-dichlorophenoxyacetic acid) was required. Embryogenic callus originated from embryonic axis tissue of immature embryos and from the axillary-bud region and the plumula of shoot apices. A clear effect of embryo size on somatic embryogenesis was shown. There were differences in frequency of somatic embryogenesis among the five genotypes used in the study. Additions of BA to auxin-containing medium reduced embryo production. Histological examinations confirmed the embryogenic nature of the immature embryo cultures and revealed that somatic embryos originated from the meristematic areas near the callus surface.
TL;DR: In vitro- and ex vitro-rooted microcuttings of Acer rubrum L. ‘Red Sunset’, Betula nigra L., and Malux x- domestica Borkh ‘McIntosh’ were distinguished by several important anatomical and morphological properties which continued to regulate both root system and whole plant quality in later stages of production.
Abstract: In vitro- and ex vitro-rooted microcuttings of Acer rubrum L. ‘Red Sunset’, Betula nigra L., and Malux x- domestica Borkh ‘McIntosh’ were distinguished by several important anatomical and morphological properties which continued to regulate both root system and whole plant quality in later stages of production. In vitro microcuttings formed adventitious roots in greater number and more quickly than ex vitro microcuttings. Roots produced in vitro were characterized by extremely enlarged cortical cells and, consequently, had a much greater diameter than ex vitro roots. However, the vascular system of in vitro roots was underdeveloped (primary vascular tissues only) as compared to ex vitro roots, which produced vascular cambium and secondary growth during the same early stage of production. At least 50% of the post-transplant in vitro adventitious roots either died immediately, or temporarily persisted during acclimatization without producing any further growth. For the surviving in vitro-produced roots, the cortex partially collapsed after transplant, and new root extensions with ex vitro-like structure were produced. Only then did the in vitro portion of the root begin to form secondary vascular tissues. Shoots from in vitro treatments continued to grow vigorously during adventitious root initiation and during acclimatization, so that the plants were significantly taller and had a greater shoot area than those receiving comparable ex vitro rooting treatment. In vitro rooting led to a horizontal root morphology which continued to distinguish these treatments from ex vitro rooted plants during later stages of production, when anatomical differences in the roots could no longer be detected.
TL;DR: The effectiveness of several different cytokinins at enhancing Malus and Rubus organogenesis was related to the shoot proliferation activity of the cytokinin and to treatment-induced variation in leaf and petiole size.
Abstract: Shoot regeneration from Rubus leaves was obtained on a medium containing MS salts, vitamins and sugars, Staba vitamins, casein hydrolysate (100 mg l−1) and 10 μM thidiazuron. Shoot regeneration from Malus leaves was obtained on N6 rice anther medium with 5 μM thidiazuron. In vitro pretreatment of source shoots with either colchicine or thidiazuron enhanced the organogenic potential of detached leaves of two Rubus hybrids. The response to colchicine was quadratic and occurred at non-mutagenic concentrations (75–250 μM). The response to thidiazuron was exponential between 0 and 5 μM. When applied as a pretreatment, the effectiveness of several different cytokinins (benzyladenine, thidiazuron, zeatin) at enhancing Malus and Rubus organogenesis was related to the shoot proliferation activity of the cytokinin and to treatment-induced variation in leaf and petiole size.
TL;DR: Out of 6-benzyl aminopurine (BAP), kinetin (KIN), N (Δ−2 isopentyl) adenine (2iP) andAdenine sulphate (AS), only BAP and KIN were found to be more effective in enhancing the frequency of shoot regeneration.
Abstract: Conditions for plant regeneration from excised cotyledons of Vigna radiata were studied. Complete plant developed from the uncallused proximal ends of cotyledons on Murashige & Skoog's (MS), Gamborg's (B5) and ‘C’ (MS salts + B5 vitamins) basal media. The basal medium ‘C’ was found to be best for plant regeneration. Regeneration frequency, however, varied with genotype, size, orientation and age of explant and the different plant growth regulators combination in the medium. Addition of cytokinins induced callusing at the proximal ends of cotyledons followed by multiple shoot formation. Out of 6-benzyl aminopurine (BAP), kinetin (KIN), N (Δ−2 isopentyl) adenine (2iP) and adenine sulphate (AS), only BAP and KIN were found to be more effective in enhancing the frequency of shoot regeneration. BAP at 1×10-1M induced maximum (60%) shoot regeneration whereas maximum number of shoots (8 to 9 shoots) per explant was observed with 5×10-6M BAP. Cotyledons excised from two-day old seedlings were most regenerative. The regenerative response of cotyledons decreased when sliced into two equal parts either longitudinally or transversely. Callusing and organogenic differentiation occured only if the petiolar end of cotyledons was in contact with medium. None of the tested treatments were effective in inducing shoot bud differentiation from subcultured callus. Well developed shoots rooted when incubated on half strength MS, MS and MS basal medium supplemented with IAA (5×10-6M). The rooted plants were transferred to pots and later established in the field with 60% success.
TL;DR: In order to improve the production of the cytotoxic lignan podophyllotoxin, seven precursors from the phenylpropanoid-routing and one related compound were fed to cell suspension cultures derived from the rhizomes of Podophyllum hexandrum Royle, with maximally a 12.8 fold increase in content.
Abstract: In order to improve the production of the cytotoxic lignan podophyllotoxin, seven precursors from the phenylpropanoid-routing and one related compound were fed to cell suspension cultures derived from the rhizomes of Podophyllum hexandrum Royle. These cell cultures were able to convert only coniferin into podophyllotoxin, maximally a 12.8 fold increase in content was found. Permeabilization using isopropanol, in combination with coniferin as a substrate, did not result in an extra increase in podophyllotoxin accumulation. Concentrations of isopropanol exceeding 0.5% (v/v) were found to be rather toxic for suspension growth cells of P. hexandrum. When coniferin was fed in presence of such isopropanol concentrations, β-glucosidase activity was still present, resulting in the formation of the aglucon coniferyl alcohol. In addition, podophyllotoxin was released into the medium under these permeabilization conditions. Entrapment of P. hexandrum cells in calcium-alginate as such or in combination with the feeding of biosynthetic precursors, did not improve the podophyllotoxin production. Cell-free medium from suspension cultures at later growth stages incubated with coniferin, resulted in the synthesis of the lignan pinoresinol.
TL;DR: Research on the application of tissue culture techniques to the micropropagation of cork oak, a forest species of ecological and industrial importance in the Mediterranean area, finds that media with low concentrations of ions are more suitable for growth and proliferation of explants than other media richer in salts.
Abstract: This paper describes research on the application of tissue culture techniques to the micropropagation of cork oak (Quercus suber L.), a forest species of ecological and industrial importance in the Mediterranean area. Apical buds and nodal stem segments were employed as initial explants. Their origins were young seedlings, stump sprouts and sprouts formed on cuttings collected from old trees.
TL;DR: Callus and suspension cultures adapted to various concentrations of NaCl or mannitol were developed from the cultivated potato Solanum tuberosum cv and non-electrolytes were found to be the main contributors to the decrease is osmotic potential in both callus and suspended cultures.
Abstract: Callus and suspension cultures adapted to various concentrations of NaCl or mannitol were developed from the cultivated potato Solanum tuberosum cv. Desire. Growth of the calli was less inhibited by mannitol than by iso-osmotic concentrations of NaCl. Reduction of growth by both NaCl and mannitol was considerably lower in osmotically adapted calli than in non-adapted ones. Salt-adapted suspension cultures that grew in the medium to which they had been originally adapted had a shorter lag in growth as well as a shorter time required to achieve the maximum growth, as compared with non-adapted cells. Suspension cultures adapted to NaCl concentrations higher than 150 mM were obtained only after preadaptation to osmotic stress. Adaptation of these cells was found to be stable. Accumulation of Na+ was lower and level of K+ was more stable in osmotically adapted than in non-adapted calli, when both were exposed to salt. Potassium level in NaCl-adapted calli exposed to saline medium was lower than that in non-adapted calli in standard medium. The maximum of Cl− and Na+ accumulation was reached at higher external salt concentration in salt-adapted than in non-adapted suspension cultures. In both callus and suspension cultures, Cl− accumulated more than Na+. Potassium level decreased more in non-adapted than in NaCl-adapted suspension cultures. The decrease of osmotic potential in osmotically adapted calli exposed to mannitol and in salt-adapted calli and suspension cultures exposed to salt was correlated to the increase of the external concentration. Such a correlation was not found in osmotically adapted calli exposed to salt. Non-electrolytes were found to be the main contributors to the decrease is osmotic potential in both callus and suspension cultures.
TL;DR: Temperature had a strong effect on the induction of dormancy of bulblets generated on scale explants of Lilium speciosum Thunb.
Abstract: We have studied the effect of various in-vitro conditions on dormancy of bulblets generated on scale explants of Lilium speciosum Thunb. cv. ‘Rubrum’ nr. 10. The bulblets were harvested after 11 weeks of culture. Dormancy was measured by determining the percent emergence in soil of viable, non-cold-treated bulblets. A study of the physical conditions showed that temperature had a strong effect on the induction of dormancy (15°C induced hardly any dormancy; 25°C induced a high level of dormancy), whereas short or long day and light or dark had no effect. Of the medium components, a low concentration of sucrose (1 gl−1 or less) or a high concentration of gibberellic acid (1 mg 1−1) reduced the level of dormancy. Application of various concentrations of abscisic acid, 6-benzylaminopurine, α-naphthaleneacetic acid, indole-3-acetic acid, 2,3,5-triiodobenzoic acid or a Murashige and Skoog macro- and microelement mixture did not affect the dormancy status.
TL;DR: Green calli regenerated large numbers of green plants after more than four years and were totipotent after 19 months in newly initiated sugarcane callus cultures.
Abstract: Long-term regeneration of sugarcane (Saccharum spp. hybrid and Saccharum spontaneum L.) callus cultures was achieved by selection of green callus on MS agar medium containing 0.5 mgl-1 picloram or 2,4-D. Newly initiated sugarcane callus cultures were a complex mixture of different tissue types including white, nonregenerative and green, regenerative tissues. The proportion of the tissue types changed as a function of time in culture, genotype, and amount and kind of auxin. Green callus on picloram media always regenerated green plants. Nine hybrids and ten wild relatives of sugarcane produced green calli on picloram media whereas only three hybrids were grown as green calli on 2,4-D media in long-term culture. Green calli were inoculated into liquid MS medium with 0.5 mgl-1 picloram for suspension culture. These cultures were totipotent after 19 months. For routine culture, we initiated callus cultures on modified MS medium with 3 mgl-1 2,4-D, then in two to three weeks we subcultured callus on MS medium with 0.5 mgl-1 picloram and selected for green callus. Green calli regenerated large numbers of green plants after more than four years.
TL;DR: Haploid plants have been obtained from unpollinated ovules of onion cultured in vitro as here reported for the first time, and it was shown that 3 embryos out of 7 regenerated haploid plants (8 chromosomes) were regenerated.
Abstract: Haploid plants have been obtained from unpollinated ovules of onion cultured in vitro as here reported for the first time. Callus was not formed at any step of the process and the young developing embryos sprouted by splitting the ovules. From a total of about 26000 cultured ovules, 13 embryos were obtained and 7 of them developed into plants. Cytological observation of root apexes showed that 3 embryos out of 7 regenerated haploid plants (8 chromosomes). The yield of embryo induction was quite low (0.28% the best treatment) so further experiments are in progress to increase it.
TL;DR: The results indicate that CO2 enrichment for the plantlet in vitro at a relatively high PPF would promote photosynthesis and hence the growth of chlorophyllous shoots/plantlets in vitro and that the plantlets in vivo would make photoautotrophic growth under environmental conditions favorable for photosynthesis.
Abstract: The photosynthetic characteristics of the Cymbidium plantlet in vitro cultured on Hyponex-agar medium with 2% sucrose were determined based on the measurements of CO2 concentration inside and outside of the culture vessels. The CO2 measurements were made with a gas chromatograph at a PPF (photosynthetic photon flux) of 35, 102 and 226 μmol m-2 s-1, a chamber air temperature of 15, 25 and 35°C and a CO2 concentration outside the vessel of approximately 350, 1100 and 3000 ppm. The net photosynthetic rates were determined on individual plantlets and were expressed on a dry weight basis. The steady-state CO2 concentration during the photoperiod was lower inside the vessel than outside the vessel at any PPF greater than 35 μmol m-2s-1 and at any chamber air temperature. The photosynthetic response curves relating the net photosynthetic rate, PPF, and CO2 concentration in the vessel and chamber air temperature were similar to those for Cymbidium plants grown outside and other C3 plants grown outside under shade. The results indicate that CO2 enrichment for the plantlets in vitro at a relatively high PPF would promote photosynthesis and hence the growth of chlorophyllous shoots/plantlets in vitro and that the plantlets in vitro would make photoautotrophic growth under environmental conditions favorable for photosynthesis.
TL;DR: Regeneration in six inbred lines or F1 hybrids of Cucumis sativus was achieved on Murashige & Skoog's medium containing various concentrations of 2,4-D/ BA, NAA/BA, N AA/Z or NAA-K at frequencies of 15–65%, predominantly by the formation of somatic embryos.
Abstract: Regeneration in six inbred lines or F1 hybrids of Cucumis sativus was achieved on Murashige & Skoog's medium containing various concentrations of 2,4-D/BA, NAA/BA, NAA/Z or NAA/K. The range of regeneration frequency for cotyledon, leaf and petiole explants was 0–38, 0–75 and 14–96%, respectively, after 6–8 weeks in culture. Only one subculture of calli to growth regulator-free medium was required for regeneration. Preincubation of explants in the dark for 2–3 weeks was essential to achieve optimal regeneration. Highest frequency of plantlet formation occurred with petiole explants incubated on NAA/BA (5.0/2.5 μM), NAA/Z (5.0/5.0 μM) or 2,4-D/BA (5.0/5.0 μM). Approximately 80% of these plantlets survived after transplanting to greenhouse soil, and they flowered and set fruit. The F1 hybrid, Endeavor, gave the highest regeneration frequency of 91% on 2,4-D/BA at 5.0/5.0 μM. Formation of somatic embryos was observed on 2,4-D/BA, while organogenesis and embryogenesis both were evident on NAA/BA and NAA/Z. Cotyledonary explants yielded the lowest frequency (ca. 7%) of plantlet formation in this study. Plantlets of C. sativus var. hardwickii and an F1 hybrid of C. sativus x C. s. var hardwickii were regenerated on NAA/Z and NAA/K at frequencies of 15–65%, predominantly by the formation of somatic embryos. Shoots were obtained from cotyledon and leaf explants of C. metuliferus on IAA/BA (7.5/5.0 μM) and from leaf and petiole explants of C. melo on NAA/BA (5.0/2.5 μM), but plantlets were recovered only in C. melo.
TL;DR: Multiple shoots were obtained from nodal and shoot tip segments of 10 to 15-day-old seedlings of Syzygium cuminii L. on Murashige & Skoog revised medium supplemented with 6-benzyladenine and regenerated plantlets have been acclimatized and successfully transferred into the soil.
Abstract: Multiple shoots were obtained from nodal and shoot tip segments of 10 to 15-day-old seedlings of Syzygium cuminii L. on Murashige & Skoog (MS) revised medium supplemented with 6-benzyladenine (BA) (0.23–8.90 μM) singly or in combination with α-naphthaleneacetic acid (NAA), indole-3-acetic acid (IAA) or indole-3-butyric acid (IBA). Excised shoots were placed for root induction on MS medium containing NAA and/or IBA and then transferred to MS basal medium to form complete plantlets. The regenerated plantlets have been acclimatized and successfully transferred into the soil.
TL;DR: The atmosphere of the culture vessel is an important factor for successful somatic embryogenesis in Hevea brasiliensis and inhibition of ethylene action by the adding of silver nitrate to the medium enhanced significantly embryo production.
Abstract: The atmosphere of the culture vessel is an important factor for successful somatic embryogenesis in Hevea brasiliensis (Mull. Arg.). Considerable release of carbon dioxide and ethylene occurred during the development of calli. By avoiding the accumulation of gas, unconfined conditions were the most favourable for inducing somatic embryogenesis. Trapping of ethylene was as favourable for calli development and for somatic embryogenesis as unconfined conditions. Inhibition of ethylene synthesis by the adding of aminooxyacetic acid to the medium, also favoured the embryogenic process, and inhibition of ethylene action by the adding of silver nitrate to the medium enhanced significantly embryo production.
TL;DR: Cytokinins and auxin were found to be essential for development of bud explants and microsurgery of the apical bud combined with ethylene pretreatment increased both sprouting and corm production.
Abstract: Means to increase the reproductive capacity of Crocus sativus L., in vitro, are described. Cytokinins and auxin were found to be essential for development of bud explants. Ethylene and ethaphon pretreatments inhibited leaf development but induced corm production. Microsurgery of the apical bud combined with ethylene pretreatment increased both sprouting and corm production.
TL;DR: Populations of embryos were induced to germinate at a rate of over 90% under specific temperature, desiccation and age conditions, and in general, embryos thirty-five days old had the highest germination rates as compared to younger or older ones.
Abstract: Germination was readily induced in recalcitrant microspore-derived embryos of Brassica napus ‘Topas’ when they were exposed to a period of chilling (9–12 days at 4°C) or partial desiccation (rapid or slow air drying) prior to germination. In general, embryos thirty-five days old had the highest germination rates as compared to younger or older ones. Populations of embryos were induced to germinate at a rate of over 90% under specific temperature, desiccation and age conditions. Comparisons to an embryogenic B. napus winter line, F346, are made.
TL;DR: A transformation system was established for red raspberry, blackberry and blackberry x raspberry hybrids, utilizing the binary vector system of Agrobacterium tumefaciens, which confirmed that this marker gene had been transferred into Rubus.
Abstract: A transformation system was established for red raspberry, blackberry and blackberry x raspberry hybrids, utilizing the binary vector system of Agrobacterium tumefaciens. Leaf discs or internodal stem segments were inoculated with Agrobacterium strain LBA4404 containing the binary vectors PBI121.X, which has the β-glucuronidase (GUS) marker gene, or Bin 19, which has the neomycin phosphotransferase II (NPT II) gene. Regenerants were produced on media containing MS salts, 20 gl-1 sucrose, 7 gl-1 agar, 100 mgl-1 inositol, 0.5 mgl-1 nicotinic acid, 0.5 mgl-1 pyridoxine-HCl, 0.1 mgl-1 thiamine, and either 0.1 mgl-1 IBA and 2 mgl-1 BAP for leaf discs, or 0.2 mgl-1 BAP and 0.2 mgl-1 2,4-D for stem segments. Kanamycin sulphate, which was used as a selective agent for the NPT II gene, inhibited organogenesis at 50 mgl-1 and was therefore unsuitable for use as a selectable marker gene in Rubus. All regenerants were assayed utilizing the fluorogenic assay procedure to determine if the GUS gene had been transferred into the material and could therefore cleave the substrate 4-methyl-umbelliferyl-β-D-glucuronide. Seven GUS-positive plantlets were obtained which confirmed that this marker gene had been transferred into Rubus. A ‘dot blot’ assay was carried out on GUS-positive plant material to establish if the NPT II gene had also been transferred to the plant material.
TL;DR: Somatic embryogenesis and plantlet regeneration were achieved from immature and mature zygotic Camellia japonica embryos cultured on Murashige & Skoog's mineral medium without growth regulators or with various combinations of IBA and BAR.
Abstract: Somatic embryogenesis and plantlet regeneration were achieved from immature and mature zygoticCamellia japonica embryos cultured on Murashige & Skoog's mineral medium without growth regulators or with various combinations of IBA and BAR The dependence of embryogenesis rates on growth regulator levels was not clear, though high concentrations such as 4 mg 1-1BAP plus 2 mg 1-1IBA were definitely inhibitory. BAP at 1 or 2 mg 1-1 did appear to determine the formation of ‘bud-like embryos’. By far the most responsive initial explants were immature embryonic axes collected in September, 94% of which produced somatic embryos as against only 20% for embryonic axes from mature seeds collected in October. Cotyledon explants were also embryogenic. Somatic embryos differentiating directly on the hypocotyl of the embryonic axes or the surface of cotyledons passed through typical stages of embryogenesis. Indirect somatic embryogenesis via callus was also evident. Embryogenic potential was maintained by secondary embryogenesis through the successive generations of embryos.
TL;DR: It is concluded that the extraction of plumbagin from Drosera plants is not commercially feasible.
Abstract: The rapid clonal multiplication of two species of South African Drosera is described. Levels of plumbagin, (5-hydroxy-2-methyl-1,4-naphthoquinone) from in vivo and in vitro grown plants are compared to those present in Plumbago roots. P. auriculata Lam. roots contained more than twice as much plumbagin as in vivo grown D. capensis L. plants which in turn contained more than twice as much as comparable plants of D. natalensis Diels. It is concluded that the extraction of plumbagin from Drosera plants is not commercially feasible.
TL;DR: These effects indicated a superior water uptake by the roots in Sorbarods, which was attributed to an increase in number of roots, a reduction in the damage they sustained during transplantation and improved contact between roots and substrate.
Abstract: Plantlets of Chrysanthemum × morifolium were grown in vitro either in cellulose plugs (Sorbarods) that were saturated with liquid culture medium or on agar-solidified medium. After transplantation and exposure to an atmosphere of reduced humidity, plantlets in Sorbarods wilted less but transpired more water than plantlets taken bare-rooted from agar. These effects indicated a superior water uptake by the roots in Sorbarods, which was attributed to an increase in number of roots, a reduction in the damage they sustained during transplantation and improved contact between roots and substrate. Various potential advantages in the use of Sorbarods in conjunction with liquid medium are discussed