The role of auxins in somatic embryogenesis of Abies alba

2011 ◽  
Vol 6 (4) ◽  
pp. 587-596 ◽  
Author(s):  
Zuzana Vondráková ◽  
Kateřina Eliášová ◽  
Lucie Fischerová ◽  
Martin Vágner

AbstractThe somatic embryogenesis of conifers is a process susceptible to exogenous phytohormonal treatments. We report the effects of the synthetic auxin 2,4-dichlorophenoxyacetic acid (2,4-D) and the auxin inhibitor p-chlorophenoxyisobutyric acid (PCIB) on the endogenous level of the auxin indole-3-acetic acid (IAA) and on the anatomical composition of early somatic embryos of Abies alba (European silver fir). The embryogenic suspensor mass (ESM) of Abies alba proliferated on a medium supplemented by 2,4-D as well as on an auxin-free medium. The endogenous level of IAA was significantly higher in the ESM cultivated on a medium supplemented by 2,4-D. The decrease in the endogenous level of IAA in the first week of maturation is one of the most important stimuli responsible for the subsequent development of embryos. However, suppression of IAA synthesis by an auxin inhibitor did not stimulate the development of embryos. The maturation of somatic embryos from the globular to the cotyledonary stage occurs when the concentration of endogenous auxin in the ESM (including the embryos) increases. Early somatic embryos proliferating on a medium supplemented by auxin had an increased probability of maturing successfully. Exogenous auxin treatment during maturation did not compensate for the auxin deficiency during proliferation.

2004 ◽  
Vol 52 (2) ◽  
pp. 257 ◽  
Author(s):  
M. Panaia ◽  
T. Senaratna ◽  
K. W. Dixon ◽  
K. Sivasithamparam

Rushes are important understorey species and comprise a significant component of pre-mined ecosystems. Re-establishment of rushes into disturbed sites has often been problematic. Several cytokinins and thidiazuron were investigated for the stimulation of somatic embryogenesis in key members of the Restionaceae. Somatic embryogenesis was observed for Desmocladus flexuosus (R.Br.) B.G.Briggs & L.A.S.Johnson with benzyladenine (BA) at 1, 5 or 15 μM alone and 1 μM 2,4-dichlorophenoxyacetic acid (2,4-D). The response to zeatin (Z) and 2iP-6-γ-γ-dimethyl-allyamino-purine (2iP) was negligible. For Baloskion tetraphyllum (J.J.H. de Labillardiere) B.G.Briggs & L.A.S.Johnson and Lyginia imberbis R.Br., BA, Z and 2iP were ineffective in stimulating any response.Somatic embryogenesis was achieved for B. tetraphyllum on 1/2-strength Murashige Skoog (1/2 MS) + 1 μM 2,4-D, with an estimated 14 000 somatic embryos produced from 1 g of plant material. All somatic embryos converted into plantlets and were successfully transferred to soil.Investigation of thidiazuron (TDZ) at 5 and 10 μM and 1 μM 2,4-D demonstrated that young coleoptiles (5–7 days) of B. tetraphyllum produced significantly more somatic embryos (168-fold more) than did older coleoptiles (>14 days). For D. flexuosus, leaf basal portions produced somatic embryos on 5 and 10 μM TDZ, and 5 μM TDZ + 1 μM 2,4-D. Proliferation of 'secondary somatic embryos' was also successful when somatic embryos were initiated on 10 μM TDZ and transferred to 1/2 MS (~9-fold increase).This study demonstrated variation in response among species of the same family, with D. flexuosus responding to BA and TDZ and B. tetraphyllum responding only to 2,4-D. The protocol investigated has the potential to be commercially viable with over 14 000 somatic embryos produced in 6 weeks for B. tetraphyllum.


1989 ◽  
Vol 19 (2) ◽  
pp. 285-288 ◽  
Author(s):  
S. A. Merkle ◽  
A. T. Wiecko

Tissue cultures were initiated from developing seeds of black locust (Robiniapseudoacacia L.) collected from three trees at weekly intervals from 1 week following anthesis until early fruit maturity. Explants were cultured on media containing 0, 2, or 4 mg/L 2,4-dichlorophenoxyacetic acid and 0 or 0.25 mg/L 6-benzyladenine. Seeds explanted onto hormone-supplemented media remained on these media for 1 or 3 weeks before being placed on hormone-free media, or were maintained on hormone-supplemented media for the entire study. Direct somatic embryogenesis was observed in a single culture, initiated from a seed collected 4 weeks after anthesis and cultured for 1 week on a medium supplemented with 4 mg/L 2,4-dichlorophenoxyacetic acid and 0.25 mg/L 6-benzyladenine before transfer to basal medium. Although it could not be discerned from which part of the explant somatic embryos were derived, secondary embryogenesis continued from the radicles of cotyledonary-stage somatic embryos. Most somatic embryos were well formed, with two distinct cotyledons. Embryos germinated precociously, producing plantlets that were initially weak but later gained vigor and resembled seedlings.


1995 ◽  
Vol 43 (4) ◽  
pp. 385-390 ◽  
Author(s):  
S. Kulothungan ◽  
A. Ganapathi ◽  
A. Shajahan ◽  
K. Kathiravan

Embryogenic callus was induced from seedling leaf explants of cowpea (Vigna unguiculata (L.) Walp. cv. C152 on Murashige and Skoog (MS) medium containing 2.0 mg 1−1 2,4-dichlorophenoxyacetic acid (2,4-D). The maximum frequency of somatic embryogenesis was noticed when this callus was transferred to MS liquid medium supplemented with 2 mg 1−1 2,4-D. Further studies on ontogeny of somatic embryos showed that the cells destined to become somatic embryos divided into spherical or filamentous proembryos. Subsequent divisions in the proembryo led to globular, heart, torpedo-shaped, and cotyledonary-stage somatic embryos. Tiny plantlets were obtained by transferring the cotyledonary-stage somatic embryos to MS liquid medium containing 0.5 mg 1−1 2,4-D.


Author(s):  
T.T.B. Phuong ◽  
V.P. Trung ◽  
N.H. An ◽  
N.D. Tuan ◽  
P.T.T. Nguyen

Background: Dinh Lang [Polyscias fruticosa (L.) Harms] is a medicinal plant widely grown in Vietnam, with proven note-worthy health benefits. However, Dinh Lang’s amounts of triterpenoid saponins could not meet the need of the pharmaceutical industry. Thus, this study’s purpose is to figure out the optimal condition for raising Dinh Lang’s cell biomass, rhizogenesis and somatic embryogenesis to provide materials for bioactive compound productions. Methods: Different 2,4-dichlorophenoxyacetic acid and α-naphthaleneacetic acid concentrations (0.5, 1.0, 1.5 and 2.0 mg/L) were examined to determine the best amount of each plant growth regulator for raising cells’ biomass, rhizogenesis and somatic embryogenesis. In each treatment, two grams of eight-week-old calli were cultured in 50 mL of liquid MS medium. Result: It is demonstrated by the results that liquid MS medium containing 1.5 mg/L α-naphthaleneacetic acid has the capacity of producing the highest numbers of somatic embryos (489 embryos per flask) and rooted cells (259.5 cells per flask), while the fresh weight of cells cultured in the medium given 1.5 mg/L 2,4-dichlorophenoxyacetic acid reached its peak of 5.7 g.


HortScience ◽  
1992 ◽  
Vol 27 (1) ◽  
pp. 63-65 ◽  
Author(s):  
Les Frey ◽  
Yehoshua Saranga ◽  
Jules Janick

Somatic embryogenesis was induced from internodal callus of `Scania', `Improved White Sim', and `Sandra' carnation (Dianthus caryophyllus L.). The optimum protocol for the induction of somatic embryogenesis included initiation of callus in liquid basal Murashige and Skoog medium supplemented with 3.0 μm 2,4-D followed by transfer to liquid basal medium lacking 2,4-D for embryo development. Somatic embryos originated from single cells and early embryonic development proceeded conventionally (i.e., via globular, heart-shaped, and torpedo stages), but clearly developed apical or root meristems were not always formed. A few embryos developed into seedlings and were acclimatized to ex vitro conditions. Chemical name used: 2,4-dichlorophenoxyacetic acid (2,4-D).


2016 ◽  
Vol 11 (1) ◽  
pp. 55-60 ◽  
Author(s):  
Guomin Shi ◽  
Lina Yang ◽  
Tao He

AbstractA protocol is described for plant regeneration from protoplasts of Gentiana straminea Maxim. via somatic embryogenesis. Protoplasts were isolated from embryogenic calli in an enzyme solution composed of 2% Cellulase Onozuka R-10, 0.5% Macerozyme R-10, 0.5% Hemicellulase, and 0.5 M sorbitol with a yield of 3.0 × 106 protoplasts per gram of fresh weight. Liquid, solid-liquid double layer (sLD) and agar-pool (aPL) culture systems were used for protoplast culture. The aPL culture was the only method that produced embryogenic, regenerative calli. With aPL culture, the highest frequencies of protoplast cell division and colony formation were 39.6% and 16.9%, respectively, on MS medium supplemented with 2 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.5 mg/L N6-benzylaminopurine (BA). Microcalli were transferred to solid MS medium containing a reduced concentration of 2,4-D (0.5 mg/L) to promote the formation of embryogenic calli. Somatic embryos developed into plantlets on MS medium supplemented with 2 mg/L BA at a rate of 43.7%.


2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Premananda Das

Somatic embryogenesis was achieved in four leguminous tree species, that is, Acacia catechu, Acacia arabica, Hardwickia binata, and Dalbergia sissoo using immature zygotic embryos as explants on Murashige and Skoog (MS) medium supplemented with 0.25–1.0 mg/l Kn (kinetin) and 2.0–3.0 mg/l 2,4-D (2,4-dichlorophenoxyacetic acid) or NAA (1-napthaleneacetic acid) and 3% sucrose. MS medium containing 2.0 mg/l 2,4-D and 1.0–1.5 mg/l Kn was noted to be most effective in inducing friable embryogenic callus (FEC); the number of somatic embryos per culture varied in MS medium supplemented with 1.0–2.0 mg/l 2,4-D or NAA and 0.25–1.5 mg/l kinetin. The maximum number of somatic embryos was obtained in MS medium containing 1.5–2.0 mg/l 2,4-D or NAA and 1.0–1.5 mg/l kinetin; proliferation of embryogenic calli was enhanced in cultures having 1.0–2.0 mg/l 2,4-D, 1.0–1.5 mg/l kinetin, and 400–600 mg/l L-Proline. The somatic embryos in various shapes and sizes after the first subculture on MS medium supplemented with 0.1 mg/l IAA and 0.25 mg/l BA; developed shoots and rooted in strength MS medium supplemented with 0.1 mg/l IBA or IAA. The somatic embryo-derived plantlets were transferred to the field after being hardened in the climate-controlled hardening chamber.


HortScience ◽  
1995 ◽  
Vol 30 (6) ◽  
pp. 1295-1297 ◽  
Author(s):  
Carol Gonsalves ◽  
Baodi Xue ◽  
Dennis Gonsalves

Six summer squash (Cucurbita pepo L.) cultivars were regenerated via somatic embryogenesis using cotyledons excised from germinated or nongerminated seeds. Genotypes included were zucchini, commercial F1 hybrids, `President', `Seneca Zucchini', `Jade'; the noncommercial inbred line `Caserta Inbred 557311'; and two yellow squash hybrids `Dixie' and `Seneca Butterbar'. Somatic embryogenesis was initiated in induction medium containing 22.62 μm 2, 4-D, and embryos were germinated in maturation medium containing 0.27 μm NAA and 0.23 μm kinetin. Plants were elongated and rooted on basal medium without hormones. All media contained carbenicillin at 500 mg·liter–1. Sixty-one percent of the `Seneca Butterbar' cotyledons produced somatic embryos when kept on induction medium for 10 weeks. Overall, 7% of the initial explants produced plantlets, and regeneration efficiency was calculated as 0.3 plantlets per initial explant. The relative production of plants from cotyledons that were kept on induction medium for different time periods were determined for `Caserta Inbred 557311' and `Seneca Zucchini'. All cotyledons produced somatic embryos after 11 to 17 weeks on induction medium. However, plantlet production was optimal with explants kept on induction medium for 13 weeks for `Seneca Zucchini' and for 15 weeks for `Caserta Inbred 557311', producing an average of 4.5 and 9.3 plants per explant, respectively, from 90% to 70% of the explants. We recovered plants from all six cultivars; thus, our regeneration protocol may be applicable to other genotypes. The high percentage of regenerants obtained indicates that the regeneration method is efficient enough to be adapted successfully to squash transformation experiments. Chemical names used: α-carboxybenzylpenicillin (carbenicillin); 2,4-dichlorophenoxyacetic acid (2,4-D); 6-furfurylaminopurine (kinetin); α-napthaleneacetic acid (NAA).


HortScience ◽  
1990 ◽  
Vol 25 (7) ◽  
pp. 792-793 ◽  
Author(s):  
Paula P. Chee

A simple procedure for regeneration of cucumber plants (Cucumis sativus L. cv. Poinsett 76) from cotyledon and hypocotyl explants has been developed. Somatic embryogenesis was induced on Murashige and Skoog (MS) salts and vitamins medium supplemented with 2,4-D at 2.0 mg·liter-1 and kinetin at 0.5 mg·liter-1. Development of embryos was accomplished on MS medium with NAA at 1.0 mg·liter-1 and kinetin at 0.5 mg·liter-1. Eighty-five percent of the mature somatic embryos formed showed a typical bipolar structure. All developed into morphologically normal plantlets when transferred to MS medium containing no growth regulators. Chemical name used: 2,4-dichlorophenoxyacetic acid (2,4-D).


2001 ◽  
Vol 44 (3) ◽  
pp. 247-255 ◽  
Author(s):  
Juliana A. Fernando ◽  
Murilo Melo ◽  
Marli K. M. Soares ◽  
Beatriz Appezzato-da-Glória

Mature zygotic embryos of Carica papaya L. ‘Sunrise Solo’ were used as explants for embryogenesis induction. The explants were inoculated on Murashige and Skoog culture medium supplemented with 2 mg.L-1 2,4-dichlorophenoxyacetic acid and incubated in darkness at 25+2°C. Histological analysis of callogenesis and somatic embryogenesis indicated occurrence of direct and indirect somatic embryogenesis development. Direct somatic embryo formation was observed from hypocotyledonary epidermic cells only from explant 18 days after inoculation. Somatic embryos formed indirectly were originated from embryogenic superficial cells of pre-embryonic complexes located on peripherical and on internal cell layers of callus 49 days after inoculation. Diverse morphological differences including disformed embryos were observed among the somatic embryos.


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