Embryons somatiques de Vitis rupestris et embryons zygotiques de Vitis sp. : morphologie, histologie, histochimie et développement

1990 ◽  
Vol 68 (11) ◽  
pp. 2305-2315 ◽  
Author(s):  
Olivier Faure
Keyword(s):  
Somatic Embryos ◽  
Vascular System ◽  
Root Apex ◽  
Zygotic Embryos ◽  
Vitis Rupestris ◽  
Saturated Atmosphere ◽  
Vitis Sp ◽  
Water Saturated ◽  
Root Apices

The problem of the development of grapevine somatic embryos into plantlets was examined through a morphological, histological, and histochemical comparison of zygotic and somatic embryos. Only 3% of somatic embryos were capable of developing into plantlets. However, 27% of these embryos had shoot and root apices showing a histological pattern similar to that observed in zygotic embryos; other embryos had root apex but no shoot apex. In comparison with zygotic embryos, somatic embryos showed the following characteristics: acquisition of giant, and often teratologic, organs, retention of a high proliferative capacity among superficial cells, starch and tannin accumulation, important suberization and slight lignification of superficial cells, differentiation of tracheids in the vascular system, and preservation of a high embryogenic potential in the absence of exogenous growth regulators. The water-saturated atmosphere to which grapevine somatic embryos were submitted during in vitro culture could be unfavourable to germination. Under these conditions, embryos built impermeable suberized superficial layers. Key words: somatic embryos, zygotic embryos, Vitis sp., histochemistry, development.

Primary vascular patterns in root meristems of Pontederia cordata and their relevance to studies of root development

1980 ◽  
Vol 58 (12) ◽  
pp. 1351-1369 ◽  
Author(s):  
W. A. Charlton
Keyword(s):  
Apical Meristem ◽  
Vascular System ◽  
Root Apex ◽  
Root Apical Meristem ◽  
Vascular Pattern ◽  
Quiescent Centre ◽  
Vascular Differentiation ◽  
Pontederia Cordata ◽  
Distribution Of Components ◽  
Root Apices

There are several files of metaxylem cells in root apices of Pontederia cordata L., each considered to consist of a series of prospective vessels with their ends in contact. Two longitudinally adjacent vessels may be in the same file of cells produced by the root apex or in adjacent files. As the root grows, successive prospective vessels are added to the apical ends of most of the files but not all files are continued. Addition of prospective vessels appears to take place within the "quiescent centre" of the root apical meristem. Where files are not continued there is no immediate readjustment of remaining files. The longitudinal and transverse distribution of components of the vascular system (including protophloem and protoxylem) is discussed in relation to the means by which the pattern of development may be controlled. Rates of production of vessels and the final lengths of the vessels are estimated. The observations and deductions are discussed in relation to other studies of root growth, vascular differentiation, and vascular pattern formation and maintenance.

Synchronous and high frequency germination of interior spruce somatic embryos following partial drying at high relative humidity

1990 ◽  
Vol 68 (5) ◽  
pp. 1086-1090 ◽  
Author(s):  
D. R. Roberts ◽  
B. C. S. Sutton ◽  
B. S. Flinn
Keyword(s):  
Relative Humidity ◽  
Somatic Embryos ◽  
Low Frequency ◽  
High Relative Humidity ◽  
Zygotic Embryos ◽  
Interior Spruce ◽  
Half Strength ◽  
Abnormal Pattern ◽  
Time Required ◽  
Water Saturated

The germination of mature somatic embryos of interior spruce was limited by the low frequency of root emergence. In addition, development was abnormal, since elongation and greening of the hypocotyl and cotyledons preceded root emergence by 1–2 weeks. Pretreatment of the embryos on water-saturated Kim-paks increased the frequency of root emergence but did not alter the abnormal pattern of germination. Somatic embryos do not survive desiccation at room humidity, but partial drying at high humidity promoted germination up to 90%. Furthermore, this treatment decreased the time required for root emergence such that elongation of the root and hypocotyl–cotyledon was synchronized over a period of 5–6 days. This germination closely resembled that of excised zygotic embryos. Drying over a range of humidities indicated that humidities of 81% and lower were lethal to the embryos, whereas germination was enhanced following treatment at humidities greater than 95% relative to untreated controls. The best germination and root elongation occurred on one-half strength basal media containing 2–3.4% sucrose. Of the plantlets derived from treated embryos, 50% survived transfer to soil compared with only 5% of the untreated controls. Key words: conifers, desiccation, germination, high relative humidity, partial drying, somatic embryogenesis, spruce.

scholarly journals Blue sky’s the limit? Somatic embryogenesis as a means of propagating recalcitrant blue spruce (Picea pungens) cultivar Hoopsii

2019 ◽  
Author(s):  
Jordan Demone ◽  
Jingqin Mao ◽  
Shen Wan ◽  
Maryam Nourimand ◽  
Äsbjörn Erik Hansen ◽  
...  
Keyword(s):  
Somatic Embryogenesis ◽  
Somatic Embryos ◽  
Growing Season ◽  
Zygotic Embryos ◽  
Embryo Abortion ◽  
Blue Spruce ◽  
Picea Pungens ◽  
Initiation Frequency ◽  
Propagation Methods

AbstractThe ‘triple-blue’ cultivar of blue spruce (Picea pungens Hoopsii) is notably recalcitrant towards the realm of traditional vegetative propagation methods. Its ability to naturally proliferate is limited by ovule and embryo abortion during the growing season, leading to low viable seed yield. In this study, we established a protocol using somatic embryogenesis (SE) as a means of propagating this popular ornamental cultivar. We collected cones from Hoopsii trees at seven different timepoints throughout the growing season (mid-June to late July in Ottawa (Plant Hardiness Zone 5A)). Female megagametophytes were harvested following each collection and immature zygotic embryos were plated onto induction media. Early somatic embryos began developing from the embryonic tissue (ET) three to five weeks following induction. The highest ET initiation frequency occurred from embryos collected June 20–July 10, suggesting that developmental stage of the embryo was a significant factor in SE induction. The conversion of mature somatic embryos into plantlets (emblings) was completed in eight–ten weeks at a rate of 92.8%. In this study, we demonstrate that in vitro somatic embryogenesis using our optimized protocol is a fast and prolific method for the mass propagation of Hoopsii blue spruce. This is the first report on the production of somatic Hoopsii emblings.

scholarly journals Coconut Tissue Culture: The Indian Initiatives, Experiences and Achievements

CORD ◽  
2017 ◽  
Vol 33 (2) ◽  
pp. 11
Author(s):  
Anitha Karun
Keyword(s):  
Tissue Culture ◽  
Somatic Embryos ◽  
Culture Media ◽  
Zygotic Embryo ◽  
Shoot Meristem ◽  
Direct Organogenesis ◽  
Zygotic Embryos ◽  
Immature Inflorescence ◽  
High Yielding Varieties

Coconut is one of the principal crops of India cultivated in over 35 districts mainly in the southern states. The productivity of the crop is declining in many of the traditionally cultivated regions owing to ageing plantations as well as biotic and abiotic stresses. These plantations are to be replanted with high yielding varieties/hybrids for which adequate quantity of quality planting material is not available. Even though tissue culture research was initiated in many laboratories in the country, the work was eventually phased out in most of the laboratories for want of a repeatable protocol.  At ICAR-CPCRI, coconut tissue culture programs have been continuing for the past three decades. The attempts made include experimentation with different explants viz., immature inflorescence, plumular tissues, mature palm shoot meristem, ovary and anthers and different culture media supplemented with varying levels and types of hormones. Some of the successful protocols developed at the Institute include coconut zygotic embryo culture for collection and exchange of germplasm, cryopreservation and retrieval of zygotic embryos and pollen and plantlet regeneration from plumular tissues. Even though ICAR-CPCRI has succeeded in obtaining plantlets via direct organogenesis from inflorescence explants, the absence of friable calli formation from explants, the low rate of somatic embryo formation, large number of cultures turning to abnormal shoot development, non conversion of somatic embryos into plantlets, and formation of abnormal somatic embryos remain the major bottlenecks. Gene expression studies are being currently undertaken to decipher the molecular basis of in vitro recalcitrance.

scholarly journals Morphoanatomic changes in shoot and root apices of banana Williams (AAA, Musa sp.) cultured on different N6- benzyladenine concentrations

1969 ◽  
Vol 92 (1-2) ◽  
pp. 53-72
Author(s):  
Maribel Ramírez-Villalobos ◽  
Helga Lindorf ◽  
Eva De García
Keyword(s):  
Lateral Roots ◽  
Root Apex ◽  
Transitional Zone ◽  
Root Cap ◽  
Anatomic Structure ◽  
Musa Sp ◽  
Tunica Layer ◽  
Vitro Development ◽  
Root Apices

Structural evidence about the in vitro growth of the shoot apex (SA) and root apex (RA) of banana is for the most part lacking.This paper presents an analysis of the morphoanatomic events that occur in the in vitro development of the SA, RA and explants of banana Williams cultured under different N6-benzyladenine (BA) concentrations. We examined the SA of explants (8 mm X 1.5 mm, shoot tip with part of rhizome) grown on 0, 2.5 and 5 mg /L of BA for 0, 3, 6, 9 and 12 d, and also the first emergent root (1 to 1.5 cm long) from these explants. Samples were sectioned (10 to 12 µm) and stained with safranin-fast green. The SA showed a dome shape with tunica-corpus organization (a single tunica layer). SA diameters were larger for explants growing in BA (93.75 to 142.05 µm) than in those growing without the cytokinin (73.87 to 85.83 µm), except for the diameter on the sixth day (127.84 µm). The noncultured initial explant without culture reached a diameter of 164.78 µm. The SA showed a cambium-like transitional zone in explants cultured with 2.5 mg/L of BA on the ninth day. This concentration also induced the highest number of shoots per explant (2.19) in 35 days. RA growing in media without BA showed protoderm, ground meristem, procambium, initial cells and root cap whereas with BA procambium, fundamental meristem and root cap (compressed) were distinguished. Benzyladenine decreased the number and length of the roots, inhibited the formation of lateral roots, increased the time for root emergence and caused distortion in their anatomic structure.

scholarly journals Somatic Embryogenesis using Immature Zygotic Embryos from Developing Fruits of Papaya (Carica papaya)

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 783E-783
Author(s):  
S.K. Dhir ◽  
U.L. Yadava
Keyword(s):  
Somatic Embryogenesis ◽  
Somatic Embryos ◽  
Carica Papaya ◽  
Induction Medium ◽  
Zygotic Embryos ◽  
Synthetic Seed ◽  
Factors Affecting ◽  
Secondary Embryos ◽  
Potential Use

An efficient protocol has been developed for the in vitro multiplication of papaya (Carica papaya L.) through somatic embryogenesis utilizing immature zgotic embryos. Somatic embryos were initiated on MS basel media supplemented with 5 mg·liter–1 2,4-D, 400 mg·liter–1 glutamine, and 6% sucrose. After culturing for 2 months, 65% of the explants became highly embryogenic. Each explant produced 50 to 80 embryos in 4 months on culture induction medium. Frequency of embryogenesis was increased (75 to 150 somatic embryos on 80% explants) upon supplementing medium with 4% maltose as a carbon source and 100 mg·liter–1 L-asparagine. The embryogenic callus appeared yellow and embryos at different stages of development were well-organized. On regular subculturing, these cultures continued to produce secondary embryos. Following their transfer to the hormone-free medium supplemented with 4% maltose, these embryos germinated. The somatic embryogenesis system is rapid, repetitive, and highly proliferative. Thus, this system may have a potential use in the development of synthetic seed and transgenic papaya plants. Details of important factors affecting somatic embryogenesis will be discussed.

scholarly journals Somatic embryos of Picea abies behave like isolated zygotic embryos in vitro but with greatly reduced physiological vigour

2003 ◽  
Vol 69 (2) ◽  
pp. 176-185 ◽  
Author(s):  
C.H. Bornman ◽  
O.S.P. Dickens ◽  
C.F. van der Merwe ◽  
J. Coetzee ◽  
A.-M. Botha ◽  
...  
Keyword(s):  
Picea Abies ◽  
Somatic Embryos ◽  
Zygotic Embryos

Somatic embryogenesis in tissue cultures of Podophyllum hexandrum

1990 ◽  
Vol 68 (3) ◽  
pp. 487-491 ◽  
Author(s):  
N. Arumugam ◽  
Sant S. Bhojwani
Keyword(s):  
Somatic Embryogenesis ◽  
Somatic Embryos ◽  
Basal Medium ◽  
Podophyllum Hexandrum ◽  
Zygotic Embryos ◽  
Tissue Cultures ◽  
Globular Embryos ◽  
Further Development ◽  
Sucrose Level

In vitro multiplication of Podophyllum hexandrum Royle (Podophyllaceae) via somatic embryogenesis is reported. The callus derived from zygotic embryos on Murashige and Skoog medium containing 2 μM BA and 0.5μM IAA differentiated globular embryos. On this medium the globular embryos continued to multiply but failed to mature. Further development of the embryos occurred if the sucrose level in the basal medium was raised to 6% or the medium was supplemented with 1–10 μM NAA. Light and temperatures higher than 25 °C suppressed embryogenesis. Embryogenic potential of the callus has been maintained for over 20 months through subcultures. The somatic embryos developed into plantlets on the basal medium. Key words: endangered species, podophyllotoxin, Podophyllum, somatic embryogenesis.

scholarly journals Effect of carbon source on morphology and histodifferentiation of Araucaria angustifolia embryogenic cultures

2005 ◽  
Vol 48 (6) ◽  
pp. 895-903 ◽  
Author(s):  
Neusa Steiner ◽  
Felipe do Nascimento Vieira ◽  
Sara Maldonado ◽  
Miguel Pedro Guerra
Keyword(s):  
Carbon Source ◽  
Somatic Embryos ◽  
Zygotic Embryos ◽  
Araucaria Angustifolia ◽  
Embryogenic Cultures ◽  
Important Species ◽  
Induction Rate

The aim of the present work was to establish in vitro conditions for the induction, stabilization and proliferation of embryogenic cultures of A. angustifolia. Pre-cotyledonary staged zygotic embryos inoculated BM medium supplemented with 5 µM 2,4- D, 2 µM BAP and Kin, and 3% maltose or sucrose resulted in 66.7% induction rate. The rate of induction of embryogenic cultures was affected by the carbon source, as well the multiplication and morphology of the embryogenic cultures. Embryogenic cultures maintained in BM medium with maltose presented bipolar morphology. Globular somatic embryos were obtained BM medium with 9% (PEG) and (9%) maltose. These results could establish an in vitro regenerative protocol towards the conservation and improvement of this important species.

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