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1.
The effects of different factors on the embryogenesis and plant regeneration from mature embryos of Russian spring and winter genotypes were studied. Embryogenic callus induction was achieved on MS medium supplemented with different concentrations of 2,4-D (2,4-dichlorophenoxyacetic acid), 2,4,5-T (2,4,5-trichlorophenoxyacetic acid) or Dicamba (3,6-dichloro-o-anisic acid). Although all auxins were able to induce callus from explants with high frequency (98–100%), Dicamba was more effective for the induction of embryogenic callus (21.8–38.3%). Maximum embryogenic callus formation and high number of regenerated plants were observed at 12 mg l−1 of Dicamba. The time exposure to Dicamba (7, 14, 21 and 28 days) had a significant effect on efficiency of somatic embryogenesis. When contact of explants with callus induction medium was increased from 7 to 21 days the rate of somatic embryogenesis and number of regenerated plants per embryogenic callus gradually increased from 13.0 to 38.4% and 3.6 to 8.0%, respectively. Supplement of additional auxins (indoleacetic acid (IAA), indolebutyric acid (IBA), and naphthaleneacetic acid (NAA)) to callus induction medium with Dicamba had a positive effect on the rate of embryogenic callus formation, while the average number of regenerated shoots was not affected. The best rate of somatic embryogenesis was observed at the addition of 0.5 mg l−1 IAA with Dicamba (61.0%). The optimum combination of Dicamba and IAA increased the efficiency of somatic embryogenesis and plant regeneration from seven spring and winter wheat genotypes, thought overall morphogenic capacity was still genotype dependent.  相似文献   

2.
The morphogenic capacity of Digitalis obscura leaf explants cultured in vitro has been studied, noting factors promoting the differentiation of roots, buds and shoots as well as those promoting callus proliferation. Complete plant regeneration was obtained only by first culturing the leaf explants in a medium with NAA and BA to induce formation of buds, and subsequently transferring them to a medium without growth regulators to achieve the further development of shoots.Abbreviations BA benzyladenine - 2,4-D 2,4-dichlorophenoxyacetic acid - IAA indoleacetic acid - NAA naphthaleneacetic acid  相似文献   

3.
Tissue culture techniques were applied for micropropagation of the red alga Kappaphycus alvarezii in order to select the best strain and experimental system for in vitro culture. Five strains were tested: brown (BR), green (GR) and red (RD) tetrasporophytes, brown female gametophyte (BFG), and a strain originating from tetraspore germination (“Edison de Paula”, EP). The effects of three culture media were tested on callus formation, regeneration from explants and from callus in the three tetrasporophytic and EP strains: seawater enriched with half-strength of von Stosch’s (VS 50) and Guillard & Ryther’s (F/2 50) solutions, plus synthetic ASP 12-NTA medium, with or without gelling agent. Explants of the EP strain were treated with glycerol and the phytoregulators indole-3-acetic acid (IAA); 2,4-diclorophenoxyacetic acid (2,4-D); and benzylaminopurine (BA), alone or in combination. The effects of colchicine (0.01%) during 24, 48, 72 hours and 14 days were analyzed in the BFG and EP strains. The EP strain showed the highest percentage of explants forming callus and regeneration from explants in VS 50, indicating its high potential for micropropagation in comparison to the other strains. Regeneration from callus was very rare. Treatments with glycerol and IAA:BA (5:1 mg L−1) stimulated the regeneration from explants. Significant differences were observed in the percentages of regeneration of EP strain explants treated with colchicine for 14 days. Our results indicate that IAA and BA stimulated the regeneration process, and that colchicine produced explants with high potential for regeneration, being useful for improving the micropropagation of K. alvarezii.  相似文献   

4.
Callus was produced on cotyledon, shoot tip, hypocotyl and root explants of twoCorchorus species on several media. Cytokinin was necessary for callus production on cotyledon explants. BothC.olitorius genotypes produced most callus on media with zeatin and either NAA or IAA, and theC.capsularis genotype produced most callus on media with IAA and either zeatin or BA. High frequencies of regenerated shoots were obtained from shoot tip explants of both species, from the apical meristem and from callus. Media with 2.0 mg 1−1 BA were superior for both species, and media with zeatin were equally good forC.capsularis only. More regeneration was obtained for all genotypes after subculture of callus on media with 2.0 mg 1−1 zeatin. Cotyledon callus produced less regeneration, also with differences between genotypes; explants of both genotypes ofC.olitorius produced regeneration on a medium with NAA and zeatin, and theC.capsularis genotype produced regeneration on a medium with IAA and BA. Limited regeneration from root explant callus was obtained forC.capsularis only on medium with BA and IAA. Regeneration was not obtained from hypocotyl callus. Further regeneration of shoots of both species was obtained from secondary callus after subculture, and from nodal segments of regenerated shoots and of seedling shoots cultured on basic MS medium without growth hormones. Roots were produced on about 80% of all shoots after transference to medium with 0.2 mg 1−1 IBA, and rooted plantlets survived and flowered normally after transference to compost.  相似文献   

5.

Taraxacum belorussicum Val. N. Tikhom, a poorly known and obligatory apomictic species, is an attractive plant material for studying the embryological, genetic and molecular mechanisms of apomixis. This work aims to obtain an efficient protocol for Taraxacum belorussicum regeneration. Four types of explants (cotyledons, hypocotyls, meristems and roots) that were taken from 2-weeks-old seedlings were used for in vitro cultures, and a fast and efficient protocol of T. belorussicum regeneration was obtained. Various ½ MS-based media containing IAA (5.71 µM), TDZ (4.54 µM) and PSK (100 nM) were chosen to assess the morphogenetic abilities of selected T. belorussicum explants. Studies on the role of PSK were done in three independent experiments, where the most significant factors were always light and darkness. All explants produced callus by the third day of culture and adventitious shoots after 7 days, although in an asynchronous indirect manner, and with different intensities for all explant types. The most preferred medium culture for hypocotyl, cotyledon and meristem explants was ½ MS?+?TDZ, and ½ MS?+?IAA?+?TDZ?+?PSK for roots which were the only explant sensitive to PSK. A short darkness pretreatment (8 days) in PSK medium was found suitable to enhance organogenesis. Secondary organogenesis was observed for regenerated plants on meristem explants from the ½ MS?+?IAA?+?TDZ?+?PSK medium. A weak somatic embryogenesis was observed for hypocotyl and cotyledon explants from ½ MS?+?IAA?+?TDZ and ½ MS?+?IAA?+?TDZ?+?PSK media. Histological and scanning electron microscope images (SEM) of T. belorussicum confirmed indirect organogenesis and somatic embryogenesis. Plant material treated with aniline blue solution revealed the presence of callose in the cell walls of cotyledon and hypocotyl explants. The presence of extracellular matrix (ECM) and heterogenic structure of callus was also verified by scanning electron microscopy and light microscopy, confirming the high morphogenetic ability of T. belorussicum.

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6.
Summary Methods of plant regeneration from callus and protoplasts of Helianthus giganteus L. are described. Embryogenic callus was obtained from leaf explants and plants were regenerated from these calli on MS media with different combinations of benzyladenine and naphtaleneacetic acid. Leaf protoplasts isolated from in vitro grown plants formed somatic embryos when cultured in agarose solidified droplets of V-KM medium containing benzyladenine and naphtaleneacetic acid. Embryos developed into plantlets on media with reduced auxin contents. Regenerated plants were successfully planted in soil.Abbreviations BA benzyladenine - IAA indoleacetic acid - MS Murashige and Skoog medium - NAA naphtaleneacetic acid - V-KM protoplast culture medium of Binding and Nehls  相似文献   

7.
Hypericum perforatum L. (St. John’s wort) produces a number of phytochemicals having medicinal, anti-microbial, anti-viral and anti-oxidative properties. Plant extracts are generally used for treatment of mild to medium cases of depression. Plant regeneration can be achieved in this species by in vitro culture of a variety of explants. However, there are no reports of regeneration from petal explants. In this report plant regeneration from petal explants of St. John’s wort was evaluated. Petals of various ages were cultured on agarized Murashige and Skoog 1962 (MS) medium supplemented with auxin and cytokinin (kinetin), maintained in the dark and callus and shoot regeneration determined after 28 days. At an auxin to cytokinin ratio of 10:1, callus and shoot formation were induced by all levels of indole-3-acetic acid (IAA), indole-3-butyric acid (IBA) and 1-naphthaleneacetic acid (NAA), while 2,4-dichlorophenoxyacetic acid (2,4-D) induced only callus formation. The optimum level of auxin for shoot regeneration was 1.0 and 0.1 mg/l kinetin, where the regeneration frequency was 100 percent for all three auxins. The highest number of shoots per explant (57.4 and 53.4) was obtained with IAA and IBA, respectively. In the absence of auxin, kinetin levels of 0.1 and 0.25 mg/l induce callus and shoot formation at low frequency but not at lower levels. Callus and shoot formation did not occur in the absence of growth regulators. Petal-derived shoots were successfully rooted on half-strength MS medium without a requirement for exogenous auxin and flowering plants were established under greenhouse conditions. From these results it can be concluded that auxin type is a critical factor for plant regeneration from petal explants of Hypericum perforatum and there is no absolute requirement for high levels of cytokinin.  相似文献   

8.
Enhanced somatic embryogenesis and plant regeneration have been obtained using young leaf bases of naked oat (Avena nuda) as explants by including salicylic acid (SA) and carrot embryogenic callus extracts (CECE) in media. A 5- and 4-fold improvement was achieved in somatic embryogenesis and plant regeneration on the corresponding media supplemented with 0.5 mM SA and CECE as compared to control, respectively. Some physiological and biochemical changes were assayed in both embryogenic callus (EC) and non-embryogenic callus (NEC). The results indicated that superoxide dismutase activity was stimulated and catalases and ascorbate peroxidase activities were inhibited, while the O2 - (superoxide anion) content was reduced and the hydrogen peroxide level was promoted in EC compared with NEC. Reduced malondialdehyde content and relative electrolyte leakage were also detected in EC.  相似文献   

9.
Hypocotyls of cotton (Gossypium hirsutum L.) cultivars cv. YZ-1, Coker 312 and Coker 201 were inoculated on Murashige and Skoog callus induction medium. YZ-1 exhibited a very high regeneration potential, with 81.9 % of the explants inoculated differentiated into embryogenic callus within 8–10 weeks. During the process of callus maintenance (subculture for 1 to 3 years), the total embryos number in Coker 312 and Coker 201 calli dropped sharply, and the percentage of embryo germination decreased. On the contrary, the callus of YZ-1 consistently maintains a high frequency of plant regeneration after long-time subculture. Transgenic kanamycin-resistant calli of Coker 201 partially lost the ability of somatic embryogenesis and plant regeneration. The stress produced by the transformation procedure slightly affected somatic embryogenesis and plant regeneration of YZ-1, which showed minimum loss of plant regeneration ability.  相似文献   

10.
The influence of the source of plant material (greenhouse-grown plants or in vitro shoot cultures), the type of tissue explant (shoot-tip, single-node stem segment, whole leaf, leaf strip or half-leaf section) and growth regulator concentration on shoot regeneration from somatic tissue of Rhododendron laetum × aurigeranum was evaluated. No regeneration response was obtained on explants from greenhouse-grown plants. Adventitious shoots were obtained from callus produced at the basal end of shoot-tip and single-node stem segment explants derived from in vitro-grown shoots cultured on Anderson's medium supplemented with 22.8 M IAA and 73.8 M 2iP. The greatest percentage of adventitious shoot regeneration (77%) was induced on leaf sections cultured in the presence of 22.8 M IAA and 147.6 M 2iP. Plant regeneration was accomplished with minimal callus formation. This technique represents a further step toward gene manipulation of Rhododendron.Abbreviations IAA 1-H-Indole-3-acetic acid - 2iP N-(3-methyl-2-Butenyl)-1H-purin-6 amine  相似文献   

11.
In vitro somatic embryogenesis and regeneration of somatic embryos to whole plants through micropropagules was successfully demonstrated from pigmented uniseriate filamentous callus of Kappaphycus alvarezii (Doty) Doty in axenic cultures. More than 80% of the explants cultured on 1.5% (w/v) agar‐solidified Provasoli enriched seawater (PES) medium showed callus development. The callus induction rate was consistently higher for laboratory‐adapted plants. The excised callus grew well in subcultures and maintained its growth for prolonged periods if transferred to fresh medium in regular intervals. Some subcultured calli (<10%) did undergo transformation and produced densely pigmented spherical or oval‐shaped micropropagules (1–5 mm in diameter) that subsequently developed into young plantlets in liquid PES medium. The micropropagule production was further improved through somatic embryogenesis by a novel method of culturing thin slices of pigmented callus with naphthaleneacetic acid (NAA) or a mixture of NAA and 6‐benzylaminopurine. Transfer of embryogenic callus along with tiny somatic embryos to liquid medium and swirling on orbital shaker facilitated rapid growth and morphogenesis of somatic embryos into micropropagules that grew into whole plants in subsequent cultivation in the sea. The daily growth rate of one tissue cultured plant was monitored for seven generations in field and found to be as high as 1.5–1.8 times over farmed plants. The prolific somatic embryogenesis together with high germination potential of somatic embryos observed in this study offers a promising tool for rapid and mass clonal production of seed stock of Kappaphycus for commercial farming.  相似文献   

12.
Summary Tissue culture methods were developed for reproducible induction and maintenance of embryogenic (E) callus established from developmentally mature embryo explants of bread wheat (Triticum aestivum) and grain sorghum (Sorghum bicolor). Embryogenic callus was obtained by culturing seeds and mature embryos of wheat on Linsmaier and Skoog’s (LS) medium containing 5 or 2 mg/liter 2,4-dichlorophenoxyacetic acid (2,4-D), respectively, and for sorghum mature embryos on LS medium containing 2 mg/1 2,4-D plus 0.5 mg/liter kinetin. Plant regeneration from E callus was achieved for several months and quantified on a fresh-weight basis of E callus. Phenotypically normal plants were regenerated from E callus cultured on LS medium supplemented with 0.1 mg/liter IAA plus 0.5 mg/liter benzyladenine (BA) for wheat and 1.0 mg/liter IAA plus 0.5 mg/1BA for sorghum. Wheat research was funded by the United States Agency for International Development, Washington, DC, cooperative agreement DNA-4137-A-00-4-53-00. Sorghum research was supported by the Gas Research Institute, Chicago, IL, contract 5084-260-0973. Expert technical asistance was provided by Nitschka S. ter Kuile, Barbara J. Ashton, Laurie Osborne, Erin Scott, and Kathleen M. Petersen.  相似文献   

13.
Summary The cv Ringo Rose of hybrid seed geranium (Pelargonium x hortorum Bailey), previously shown to be recalcitrant in culture, produced somatic embryos when cotyledonary explants were cultured on regeneration medium containing thidiazuron (TDZ), forchlorfenuron (CPPU), or a combination of indole-3-acetic acid and N6 benzylaminopurine (IAA+BAP). Amendment of the basal medium with TDZ (0.5 M) was the most effective treatment. Addition of amino acids to the medium promoted the growth of somatic embryos. Retention of the proximal region of the cotyledon was crucial for regeneration, but the removal of the distal 1/3 to 1/2 cotyledon had no significant effect on somatic embryogenesis. Cotyledonary explants formed somatic embryos in higher frequency and much earlier than hypocotyl explants cultured on the same medium. The somatic embryos induced on cotyledonary explants were germinated on basal medium. More than 70% of the somatic embryos were converted into plants and transferred to soilAbbreviations BAP N6-benzylaminopurine - CPPU N-(2-chloro-4-pyridyl)-N'-phenylurea (forchlorfenuron) - IAA indole-3-acetic acid - TDZ N-phenyl-N'-1,2,3,-thiadiazol-5ylurea (thidiazuron)  相似文献   

14.
Somatic embryogenesis in the wild rice species (Oryza perennis) was induced from cultured mature seeds and young inflorescences. Murashige and Skoog's (MS) medium supplemented with 2 mg/l 2,4-D and 0.2 mg/l BAP was used for induction of a compact, white nodular callus and somatic embryos. Plant regeneration occurred with the tranfer of the nodular callus to MS basal medium containing 0.5 mg/l IAA, 0.5 mg/l NAA, 4 mg/l BAP and 500 mg/l casein hydrolysate. The embryogenic nature of the callus from both explants was maintained over 10 subcultures for about 12 months. Plant regeneration with respect to the number of calli plated from the 6th to 10th passage varied from 80% to 60% for young inflorescence derived callus and from 75% to 69.8% for seed-derived callus.Abbreviations MS Murashige and Skoog medium - BAP 6-benzylaminopurine - 2,4-D 2,4-dichlorophenoxyacetic acid - IAA indole-3-acetic acid - NAA naphthalene acetic acid - CH casein hydrolysate  相似文献   

15.
Summary Leaf explants of Sinningia speciosa were cultured in vitro on Murashige and Skoog (MS) basal medium with various growth substances in order to regenerate shoots. On MS medium supplemented with indoleacetic acid (IAA) and kinetin, 80% of the explants produced green callus and 25 to 30 shoots with roots per explant. On MS supplemented with IAA and N6 benzyladenine (BA), 80% of the explants produced green callus and 40 to 50 shoots per explant but lacked roots. After 3–4 mo., these shoots were removed from the initial explants and transferred separately onto MS supplemented with indolebutyric acid for their elongation and successive rooting (3 mo.). Histological studies showed that the callus was associated with mesophyll cell layers, primarily with the spongy parenchyma. The shoots regenerated at the callus surface and were associated with newly differentiated vascular areas. Recurrent regenerations were obtained from leaf explants or apical meristems excised from shoots of the previous subcultures. These explants, as compared to initial cultures, had a high frequency of regeneration and also produced more shoots per explant. Chromosome numbers of root tip cells of the mother plant and of all in vitro-regenerated plants remained constant: 2n=26.  相似文献   

16.
以尾巨桉优良无性系无菌苗茎段为外植体,通过对多种不同浓度生长调节剂组合的优化,进行胚状体诱导研究;并对胚性与非胚性愈伤组织进行形态解剖学观察、相关生理指标检测以及相关基因荧光定量PCR分析,以揭示尾巨桉胚性愈伤组织非胚性化发生的机理,为建立尾巨桉体细胞胚胎再生体系提供参考。结果表明:(1)胚性愈伤组织在MS+0.1mg/L NAA+0.01mg/L TDZ培养基中诱导得到胚状体,外植体经过0.5mol/L蔗糖处理12h有助于胚性愈伤组织产生胚状体,胚状体最高发生率为16.7%。(2)尾巨桉胚性与非胚性愈伤组织石蜡切片观察发现,两者的细胞形态特征存在明显的差异,胚性愈伤组织细胞体积小,排列紧密,表现出典型的胚性细胞特征,而非胚性细胞比较大,排列疏松,细胞呈不规则形状。(3)生理生化指标检测结果表明,非胚性愈伤组织中蛋白质含量、SOD、PPO及CAT活性均显著低于胚性愈伤组织,非胚性愈伤组织中木质素、可溶性糖含量以及PAL和POD活性要高于胚性愈伤组织,二者的反肉桂酸4-单加氧酶基因、淀粉磷酸化酶基因、谷胱甘肽硫转移酶基因、葡萄糖-1-磷酸腺苷酸转移酶基因、葡萄糖六磷酸异构酶基因、分支酸合酶基因以及苯丙氨酸解氨酶基因表达差异也达到显著水平。  相似文献   

17.
Regeneration studies were carried out on four morphotypes ofGracilaria chilensisfound on the coast of Chile (36–41°S). Vegetative explants were obtained from sections of apical and medial origin and were cultured in five media: filtered autoclaved seawater (FAS), Provasoli enriched seawater (PES), PES + indole-3-acetic acid (PIAA), PES + kinetin (PK) and PK + IAA (PKIAA). Mature female gametophyte and tetrasporophyte explants were obtained from sections of medial origin and were cultured in FAS and PES. Bud differentiation and/or callus formation were the morphogenetic responses to the wounding of the explants in all culture media. Plantlet regeneration was obtained from excised buds and calluses cultured separately.  相似文献   

18.
Summary An in vitro propagation system was developed for Echinacea purpurea L. (purple coneflower), a medicinal plant commonly used in the treatment of colds, flu and related ailments. Echinacea seeds were found to be contaminated with systemic fungi and therefore an optimized minimal concentration of Plant Preservation Mixture (PPM) was incorporated in the seed germination medium to recover sterile seedlings. Regeneration was induced on petiole explants from 2-month-old sterile seedlings cultured on medium supplemented with benzylaminopurine (BAP) or thidiazuron (TDZ) in combination with indoleacetic acid (IAA). Two distinct forms of regeneration were identified in cultured petiole explants with histological and morphological observations, viz. the direct formation of somatic embryos on the epidermis and the de novo development of shoots from callus tissues formed in subepidermal cell layers. the results of this study have established a micropropagation system for E. purpurea that will provide sterile plant material for further investigations into medicinally active biochemicals and may facilitate mass production of high-quality E. purpurea plants for the commercial market.  相似文献   

19.
Summary St John’s wort (Hypericum perforatum) is a valuable plant used as a herbal remedy or in phytopharmaceutical drugs to treat a variety of physical ailments. Much research has been performed to study the biochemical production of secondary metabolites of in vitro cultured plants or organs. However, all of these studies have looked at the regeneration of plants from explants in only one genotype. In addition, no study has revealed the mechanism of plant regeneration in H. perforatum, i.e. organogenesis or somatic embryogenesis. We found that different genotypes Helos, Topas, Elixir, and Numi responded similarly to regeneration medium. The regeneration responses (i.e. callus, root, or shool production) of identical explants from different genotypes were similar. However, the source of explant material (leaves, hypocotyls, and roots) from the same genotype had significant effects on the response to media and plant regeneration frequency. Using scanning electron microscopy and light microscopy, the progress of organogenesis and embryogenesis under similar culture conditions was recorded. Root segments were the most responsive explants, producing the maximum number of shoots per explant of all the genotypes.  相似文献   

20.
Summary A rapid and one-step protocol for direct regeneration of shoots from cumin embryo explants has been developed. Embryo explants with shoot meristems were cultured on shoot regeneration medium for 15&#x2013;22 d. After embryo culture, shoots were regenerated from the area adjacent to the region between the cotyledons and embryo axis within 2 wk, without any intermediate callus phase. Shoot proliferation and elongation were achieved on shoot regeneration medium without subculture. Among the different combinations of 6-benzylaminopurine, &#x03B1;-naphthaleneacetic acid (NAA), and indole-3-acetic acid (IAA) tested, 0.8 mgl&#x2212;1 (4.3 &#x03BC;M) NAA in combination with 0.3 mgl&#x2212;1 (1.71 &#x03BC;M) IAA in the B5 medium resulted in the most efficient direct shoot regeneration. No significant difference was detected for the number of regenerated explants when different heterogeneous endemic varieties were compared. This plant regeneration procedure was applicable to different cumin genotypes and regenerated plants were phenotypically normal.  相似文献   

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