In vitro regeneration through organogenesis and somatic embryogenesis in pigeon pea [Cajanus cajan (L.) Millsp.] cv. JKR105

In vitro regeneration of pigeon pea through organogenesis and somatic embryogenesis was demonstrated with pigeon pea cv. JKR105. Embryonic axes explants of pigeon pea showed greater regeneration of shoot buds on 2.5 mg L⁻¹ 6-benzylaminopurine (BAP) in the medium, followed by further elongation at lower concentrations. Rooting of shoots was observed on half-strength Murashige and Skoog (MS) medium with 2 % sucrose and 0.5 mg L⁻¹ 3-indolebutyric acid (IBA). On the other hand, the regeneration of globular embryos from cotyledon explant was faster and greater with thidiazuron (TDZ) than BAP with sucrose as carbohydrate source. These globular embryos were maturated on MS medium with abscisic acid (ABA) and finally germinated on half-strength MS medium at lower concentrations of BAP. Comparison of regeneration pathways in pigeon pea cv. JKR105 showed that the turnover of successful establishment of plants achieved through organogenesis was more compared to somatic embryogenesis, despite the production of more embryos than shoot buds.     

In vitro somatic embryogenesis and plant regeneration of cassava

An efficient and reproducible plant regeneration system, initiated in somatic tissues, has been devised for cassava (Manihot esculenta Crantz). Somatic embryogenesis has been induced from shoot tips and immature leaves of in vitro shoot cultures of 15 cassava genotypes. Somatic embryos developed directly on the explants when cultured on a medium containing 4–16 mg/l 2,4-D. Differences were observed with respect to the embryogenic capacity of the explants of different varieties. Secondary embryogenesis has been induced by subculture on solid or liquid induction medium. Long term cultures were established and maintained for up to 18 months by repeated subculture of the proliferating somatic embryos. Plantlets developed from primary and secondary embryos in the presence of 0.1 mg/l BAP, 1mg/l GA₃, and 0.01 mg/l 2,4-D. Regenerated plants were transferred to the field, and were grown to maturity.     

In vitro propagation of reed grass by somatic embryogenesis

A micropropagation system using regeneration via somatic embryogenesis from immature inflorescences has been optimized. This system is proposed for the production of the macrophyte Phragmites australis (Cav.) Trin. for the construction of wetlands used in wastewater purification. Embryogenic calli were produced in florets from inflorescences in the presence of 2,4-dichlorophenoxyacetic acid in the induction media. Up to 28.4% of the calli were embryogenic. Somatic embryos developed into plantlets when transferred to the regeneration medium lacking growth regulators. The addition of myo-inositol to the induction medium resulted in the highest number of plantlets on the regeneration medium. A decrease in the number of plantlets was observed when the embryogenic calli were maintained longer than three months on the induction medium. Plantlets can be further propagated by node culture. Plantlets were successfully acclimatized and developed normally showing no morphological differences when compared to seed-grown plants. This revised version was published online in June 2006 with corrections to the Cover Date.     

In vitro plant regeneration of Arachis correntina (Leguminosae) through somatic embryogenesis and organogenesis

In vitro protocols for plant regeneration of Arachis correntina through both somatic embryogenesis and organogenesis were developed using immature leaves as explants. Morphologically normal somatic embryos were obtained on culture media composed of 20.70 or 41.41 μM picloram (PIC) with the addition of 0.044 μM 6-benzylaminopurine (BA), resulting in a 33 and 24% of conversion into plants, respectively. The source of explants and the developmental stage of the leaves had a marked effect on somatic embryogenesis. The second folded immature leaves from in vitro growing plants were the most responsive producing up to 30% embryogenesis in MS+41.41 μM PIC. Embryos converted into plants after transfer to MS medium devoid of growth regulators and these plants were successfully acclimatised. Adventitious shoots were obtained on culture media supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D) or naphthaleneacetic acid (NAA) with or without 0.044 μM BA, achieving plant regeneration in the induction media. The highest percentage of bud formation was obtained on culture medium composed of␣MS+10.74 μM NAA+0.044 μM BA (12.5%). Roots were formed on all culture media tested. Regenerated plants were transferred to pots and grew well under greenhouse conditions.     

Induction of somatic embryogenesis in gum arabic tree [Acacia senegal (L.) Willd.]

Factors affecting somatic embryogenesis from immature cotyledon of gum arabic tree [Acacia senegal (L.) Willd.] were investigated. Induction of somatic embryogenesis was influenced by plant growth regulator concentrations and addition of amino acids in medium. Best induction of somatic embryogenesis was obtained on MS medium supplemented with 0.45 μM 2, 4-D, 2.32 μM Kin and 15 mM L-glutamine. L-glutamine plays a significant role in the maturation of somatic embryos and most of embryos attained maturity only on L-glutamine (15 mM) containing medium. Maximum percent (75.0 ± 2.5) germination of somatic embryos was recorded on medium containing 0.22 μM BAP.     

In vitro regeneration of Camellia sinensis (L.) O. Kuntze by somatic embryogenesis

Within 3 weeks of culture, excised cotyledon expiants of Camellia sinensis (L.) O. Kuntze produced somatic embryos without intermediate callus when cultured in Murashige and Skoog's basal medium with 30 g^–1 sucrose. In medium without plant growth regulators, up to 60% of the cultures developed somatic embryos. Embryogenic competence was reduced by increasing concentrations of plant growth regulators tested (i.e. kinetin, 6-benzylaminopurine, and indole butyric acid). The somatic embryos developed, grew to maturity without being subcultured within 6–8 weeks. Secondary embryogenesis was not observed. Germination of isolated mature somatic embryos was low in medium without plant growth regulators. Up to 53% and 60% germination occurred when medium impregnated with kinetin at 1.8 mgl^–1 or 1.0 mgl^–1 6-benzylaminopurine were used respectively. Callus was also routinely produced when cotyledons were cultured in MS basal medium with auxins (2,4-dichlorophenoxyacetic acid and indole acetic acid). Callus induction was however, also achieved in plant growth regulator free medium. Indirect somatic embryogenesis was not induced in the present study.Abbreviations K kinetin - BAP 6-benzylaminopurine - IBA indole butyric acid - IAA indole acetic acid - 2,4-D 2,4-dichlorophenoxyacetic acid - NAA Naphthalene acetic acid - Fe-EDTA Ethylenediaminetetra-acetic acid (Ferric monosodium salt)     

In vitro somatic embryogenesis from cell suspension cultures of cowpea [Vigna unguiculata (L.) Walp]

We report, an efficient protocol for plantlet regeneration from the cell suspension cultures of cowpea through somatic embryogenesis. Primary leaf-derived, embryogenic calli initiated in MMS [MS salts (Murashige and Skoog 1962) with B5 (Gamborg et al. 1968) vitamins] medium containing 2,4-Dichlorophenoxyacetic acid (2,4-D), casein hydrolysate (CH), and l-Glutamic acid-5-amide (Gln). Fast-growing embryogenic cell suspensions were established in 0.5 mg l^–1 2,4-D, which resulted in the highest recovery of early stages of somatic embryos in liquid MMS medium. Embryo development was asynchronous and strongly influenced by the 2,4-D concentration. Mature monocotyledonary-stage somatic embryos were induced in liquid B5 medium containing 0.1 mg l^–1 2,4-D, 20 mg l^–1 l-Proline (Pro), 5 M Abscisic acid (ABA), and 2% mannitol. B5 medium was found superior for the maturation of somatic embryos compared to MS and MMS media. The importance of duration (5 d) for effective maturation of somatic embryos is demonstrated. A reduction in the 2,4-D level in suspensions increased the somatic embryo induction and maturation with decreased abnormalities. Sucrose was found to be the best carbon source for callus induction while mannitol for embryo maturation and maltose for embryo germination. Extension of hypocotyls and complete development of plantlet was achieved in half-strength B5 medium supplemented with 3% maltose, 2500 mg l^–1 potassium nitrate, and 0.05 mg l^–1 thidiazuron (TDZ) with 32% regeneration frequency. Field-established plants were morphologically normal and fertile. This regeneration protocol assures a high frequency of embryo induction, maturation, and plantlet conversion.     

In vitro plant regeneration of Aster scaber via somatic embryogenesis

We established an in vitro plant regeneration system via somatic embryogenesis of Aster scaber, an important source of various biologically active phytochemicals. We examined the callus induction and embryogenic capacities of three explants, including leaves, petioles, and roots, on 25 different media containing different combinations of α-naphthalene acetic acid (NAA) and 6-benzyladenine (BA). The optimum concentrations of NAA and BA for the production of embryogenic calli were 5.0 μM and 0.05 μM, respectively. Media containing higher concentrations of auxin and cytokinin (such as 25 μM NAA and 25 μM BA) were suitable for shoot regeneration, especially for leaf-derived calli, which are the most readily available calli and are highly competent. For root induction from regenerated shoots, supplemental auxin and/or cytokinin did not improve rooting, but instead caused unwanted callus induction or retarded growth of regenerated plants. Therefore, plant growth regulator-free medium was preferable for root induction. Normal plants were successfully obtained from calli under the optimized conditions described above. This is the first report of the complete process of in vitro plant regeneration of A. scaber via somatic embryogenesis.     

In vitro axillary shoot proliferation and somatic embryogenesis of yellow pitaya Mediocactus coccineus (Salm-Dyck)

Yellow pitaya (Mediocactus coccineus) seeds were sown on Murashige and Skoog (1962) mineral salt medium. After germination, epicotyls were placed on media enriched with a combination of naphthaleneacetic acid (NAA) (0.05, 0.27 or 0.54 M) and benzyladenine (BA) (2.2 or 4.4 M). The apical tip was excised from half of the shoots and the other half were kept intact. Different values for proliferation rate, shoot length and thickness were observed on each medium. The cotyledons and roots were placed on MS medium supplemented with NAA (2.7 or 5.4 M) and embryogenic calluses were formed. Somatic embryos were induced on these media and then they normally developed on a growth regulator-free medium.Abbreviations BA benzyladenine - MS Murashige and Skoog - NAA -naphthalenacetic acid     

In vitro culture and somatic embryogenesis of four Trifolium species

Callus cultures were induced from hypocotyl sections of Trifolium incarnatum L., T. vesiculosum Savi., T. ambiguum Bieb., and T. repens L. Callus production was the greatest for T. incarnatum and T. ambiguum on Phillips and Collins L2 medium with 0.06 mg/l picloram and 0.1 mg/l 6-benzylaminopurine and for T. vesiculosum and T. repens on Gamborg B5 medium with 1.25 mg/l 2,4-dichlorophenoxyacetic acid (2.4-D), 0.5 mg/l naphthaleneacetic acid (NAA), and 0.5 mg/l 6-furfurylaminopurine (kinetin). Proembryos or somatic embryos were formed in all four species though germination and subsequent plantlet formation only occured in t. incarnatum and T. vesiculosum. Mature plants were obtained via somatic embryogenesis for T. incarnatum. The regenerated plants were fertile and had the normal diploid number of chromosomes (2n = 14).     

RETRACTED ARTICLE: In vitro somatic embryogenesis from immature female flower of Musa AAB cv. Chenichampa and molecular analysis of transcript factors (TFs) during somatic embryogenesis

Plant Cell, Tissue and Organ Culture (PCTOC) - Somatic embryogenesis (SE) is a process where somatic embryos can form differentiated tissues and regenerate into new plants. Efficient SE and liquid...     

Optimisation of somatic embryogenesis in fourteen cultivars of sweet potato [Ipomoea batatas (L.) Lam.]

Culture procedures have been developed to facilitate the induction and maintenance of somatic embryogenic tissues in 14 out of 16 tested cultivars of sweet potato [Ipomoea batatas (L.) Lam]. Both the size of the axillary bud explant and the type of auxin were found to be critical for the successful induction of somatic embryogenesis. Of the five auxins screened 2,4-dichlorophenoxyacetic acid 2,4-D and 2,4,5-trichlorophenoxyacetic acid were the most effective, with use of the latter inducing the production of embryogenic tissues in 7 cultivars which responded poorly or not at all to 2,4-D. Procedures for secondary/cyclic embryogenesis, formation of mature embryos and their conversion to plants are also described. Received: 24 September 1996 / Revision received: 16 December 1996 / Accepted 27 January 1997     

In vitro regeneration in Trifolium. 1. Direct somatic embryogenesis in T. rubens (L.)

The origin and development of zygotic and somatic embryos of Trifolium rubens L. was studied with the aid of paraffin sections and light microscopy. Zygotic embryos were collected, fixed and prepared daily from one to ten days after cross-pollination. Somatic embryos were obtained by plating petiole sections on modified L2 medium with 0.015 mgl^-1 picloram and 0.1 mgl^-1 6-BAP. Cultured petioles were collected and fixed daily from one to 25 days after plating. Two regions in the vascular bundle sheath of cultured petioles gave rise to callus. The first region was adjacent to the phloem fibers and produced friable callus. The second region gave rise to compact callus that was connected to the fascicular cambium. Somatic embryos originated from single cells in the cortex directly without intervening callus formation and from single cells in the friable callus. In addition, embryos arose from meristematic regions in compact callus. Many early stages of embryogenesis (one, two and four-celled stages) were observed in the cortex and friable callus. Zygotic embryogenesis in Trifolium differs from other legumes in that the suspensor is short and has a broad attachment. This arrangement was observed in zygotic embryos of T. rubens and in many somatic embryos. However, a continuum of somatic embryogenesis was observed where some young embryos had a Trifolium suspensor-like arrangement while others were attached to a long narrow suspensor-like structure more characteristic of Medicago.     

Shoot regeneration and somatic embryogenesis from different explants of Brahmi [Bacopa monniera (L.) Wettst.]

The morphogenetic potential of node, internode and leaf explants of Brahmi [Bacopa monniera (L.) Wettst.] was investigated to develop reliable protocols for shoot regeneration and somatic embryogenesis. The explants were excised from shoots raised from axillary buds of nodal explants cultured on Murashige and Skoog (MS) basal medium. Presence of 6-benzylaminopurine (BA) or kinetin influenced the degree of callus formation, from which a large number of shoot buds regenerated. Leaf explants gave the largest number of shoot buds followed by node and internode explants. BA was superior to kinetin; BA at 1.5 – 2.0 mg/l appeared to be optimum for inducing the maximum number of shoot buds. MS + 0.1 mg/l BA + 0.2 mg/l indole-3-acetic acid was the most suitable for shoot elongation. Elongated shoots were rooted on full- or half-strength MS medium with or without 0.5 – 1.0 mg/l indole-3-butyric acid or 0.5 – 1.0 mg/l α-naphthaleneacetic acid. The rooted plants were successfully established in soil. Calli derived from nodal explants cultured on MS medium containing 0.5 mg/l 2,4-dichlorophenoxyacetic acid (2,4-D), when subcultured on MS medium containing 0.1 or 0.5 mg/l BA or 0.2 mg/l 2,4-D + 0.1 or 0.5 mg/l kinetin, developed somatic embryos. The somatic embryos germinated either on the same media or on MS basal medium, and the resulting plantlets were successfully transplanted to soil. Received: 25 September 1996 / Revision received: 23 October 1997 / Accepted: 12 November 1997     

In vitro organogenesis and somatic embryogenesis from leaf explants of Leucosceptrum canum sm.

Plantlets were obtained from leaf explants of a Labiatae tree — Leucosceptrum canum Sm. using plant tissue culture techniques. Two types of calli proliferated from the leaf explants when grown on different media, one of which was amenable to somatic embryogenesis. Differentiation of the embryoids started from the fourth passage of culture and continued up to the seventh passage. The number of embryoids decreased with the age of the callus. The capacity of such embryoids to form entire plantlets was studied using different nutrient mileux. Embryoids formed plantlets on Murashige and Skoog's (MS) medium fortified with benzylaminopurine plus indolebutyric acid. Organogenesis was observed in shoot-buds derived from explants of in vitro regenerated plantlets on MS basal medium supplemented with benzylaminopurine. Culture regenerated plantlets were transferred to MS medium without sucrose and growth hormones; finally transferred to pots containing sterile vermiculite where they are growing.Abbreviations MS Murashige and Skoog's medium - 2,4-D 2,4-dichlorophenoxy acetic acid - NAA naphthaleneacetic acid - IAA indoleacetic acid - IBA indolebutyric acid - Kn kinetin - BAP benzylaminopurine - CW coconut water     

Retraction Note to: In vitro somatic embryogenesis from immature female flower of Musa AAB cv. Chenichampa and molecular analysis of transcript factors (TFs) during somatic embryogenesis

Plant Cell, Tissue and Organ Culture (PCTOC) - This article has been retracted. Please see the retraction notice for more detail: https://doi.org/10.1007/s11240-020-01912-4     

Effect of 2,4-dichlorophenoxyacetic acid concentration on somatic embryogenesis and heritable variation in soybean [Glycine max (L) merr.]

Summary The frequency and quality of embryogenic response from cotyledons of immature zygotic soybean embryos varied with 2,4-dichlorophenoxyacetic acid (2,4-D) concentration in the culture medium. The frequency of variants among progeny of regenerated plants decreased with an increase of 2,4-D concentration. Teratogenic effects on embryo morphology and development were greatest at 22.5μM 2,4-D and decreased with increasing 2,4-D. At the lowest 2,4-D concentration tested, 22.5μM, morphologically abnormal, cotyledonary-stage somatic embryos were produced. Ten percent or less of these embryos converted to plants. Over the nine genotypes tested, 40% of the families derived from plants regenerated under a low 2,4-D concentration manifested heritable variation. In contrast, embryogeny was suppressed at the globular stage by the highest 2,4-D concentration tested, 200μM. Eighty to one-hundred percent of the embryos organized under this latter 2,4-D level converted to plants. Only 3% of the families from the progeny of plants regenerated under a high 2,4-D concentration exhibited heritable variation. This is Journal Paper No. J-14217 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa. Project No. 2974. The mention of a trademark or proprietary product does not constitute a guarantee or warranty of the product by the United States Department of Agriculture or Iowa State University and does not imply its approval to the exclusion of other products that may be suitable. This work was supported, in part, by American Soybean Association grant no. 400-46-73-15-2763.