G. Vengadesan

Bio: G. Vengadesan is an academic researcher from Bharathidasan University. The author has contributed to research in topics: Murashige and Skoog medium & Callus. The author has an hindex of 12, co-authored 16 publications receiving 355 citations.

In vitro organogenesis and plant formation in Acacia sinuata

Abstract: In vitro morphogenesis via organogenesis was achieved from callus cultures derived from hypocotyl explants of Acacia sinuata on MS (Murashige and Skoog, 1962) medium. Calli were induced from hypocotyl explants excised from 7-day-old seedlings on MS medium containing 3% sucrose, 0.8% agar, 6.78 μM 2,4-dichlorophenoxyacetic acid and 2.22 μM 6-benzylaminopurine. Regeneration of adventitious buds from callus was achieved when they were cultured on MS medium supplemented with 10% coconut water, 13.2 μM 6-benzylaminopurine and 3.42 μM indoleacetic acid. Addition of gibberellic acid (1.73 μM) favored shoot elongation. Regenerated shoots produced prominent roots when transferred to half strength MS medium supplemented with 7.36 μM indolebutyric acid. Rooted plantlets, thus developed were hardened and successfully established in the soil. This protocol yielded an average of 20 plants per hypocotyl explant over a period of 4 months.

High frequency plant regeneration via somatic embryogenesis in cell suspension cultures of cowpea, Vigna unguiculata (L.) Walp.

Abstract: Embryogenic callus was induced from primary leaves of Vigna unguiculata (L.) Walp. in MS medium (Murashige and Skoog, 1962) containing 2,4-dichlorophenoxyacetic acid (2,4-D). Greenish-white, friable embryogenic calluses were used to establish suspension cultures. A shaking speed of 90 rpm and 0.4 ml packed cell volume per 25 ml medium were found to be optimal for maintaining suspension cultures. Globular, heart-shaped and torpedo-shaped embryos were developed in suspension culture containing 4.52 μM 2,4-D. Maturation of cotyledonary-stage somatic embryos was achieved on 0.05 μM 2,4-D, 5 μM abscisic acid and 3% mannitol. Twenty-two percent of the embryos were converted into plants and survived; survival in the field was 8–10%.

In vitro propagation of Acacia sinuata (Lour.) Merr. via cotyledonary nodes

Abstract: Acacia sinuata is a valuable multipurpose tree in Southern India. The tree is over exploited, but its regeneration rate in natural habitat is low. Therefore, it is important to study if it can be regenerated through in vitro micro-propagation. Cotyledonary node and shoot-tip explants excised from 15 day-old in vitro grown seedlings were used to initiate cultures. Maximum number of shoots was induced from cotyledonary node explants on Murashige and Skoog's (MS) medium containing6.66 µM 6-benzylamino purine (BAP) and 4.65µM kinetin (Kn). Subculturing was done in the fresh medium of same composition. The number of shoots formed was comparatively greater in the first subculture. Maximum shoot elongation was achieved (5.5 cm)when subcultured on MS medium supplemented with 1.75 µMgibberellic acid (GA3). In vitro regenerated shoots produced roots when transferred to half strength MS medium supplemented with 7.36 µM indolebutyric acid (IBA). From each cotyledonarynode 30 shoots were obtained within 90 days after two subcultures. The success rate of establishing the rooted plantlets in the field was 55%.

Current trends in the embryology of angiosperms.

Abstract: Introduction. 1. Male Gametogenesis Development and Structure of Sperm D. Southworth, S.C. Russell. 2. Sperm and Generative Cell Isolation and Manipulation D. Southworth. 3. Pollen Germination and Pollen Tube Growth Tip Growth Mechanism in Sexual Plant Reproduction A. Moscatelli, M. Cresti. 4. Female Gametogenesis Ontogenesis of the Embryo Sac and Female Gametes S.D. Russell. 5. Embryo Sac Isolation and Manipulation D.D. Cass, J.D. Laurie. 6. In Vivo Fertilization T.B. Batygina, V.E. Vasilyeva. 7. In Vitro Fertilization E. Kranz. 8. Sexual Incompatibility F. Cruz-Garcia, B.A. MacClure. 9. Zygotic Embryogenesis Structural Aspects R. Czapik, R. Izmailow. 10. Zygotic Embryogenesis Hormonal Control of Embryo Development B. Fischer-Iglesias, G. Neuhaus. 11. Zygotic Embryogenesis: Developmental Genetics The Formation of an Embryo from a Fertilized Egg K. Schrick, T. Laux. 12. Somatic Embryogenesis T.A. Thorpe, C. Stasolla. 13. Synthetic Seeds of Asparagus officinalis L. K. Mamiya, et al. 14. Endosperm Development P.W. Becraft, et al. 15. Seed Maturation, Germination, and Dormancy A.B. Downie. 16. Gametophytic Apomixis A Successful Mutation of the Female Gametogenesis Y. Savidan. 17. Parthenocarpy State of the Art A. Spena, G.L. Rotino. 18. Androgenesis in Brassica A Model System to Study the Initiation of Plant Embryogenesis J.B.M. Custers, et al. 19. Androgenesis in Cereals S.K. Datta. 20. In Vitro Gynogenesis S.S. Bhojwani, T.D. Thomas. 21. Inheritance of Cytoplasmic Traits -- Embryological Perspectives T. Kuroiwa, et al. Subject Index.

Genetic transformation of cowpea (Vigna unguiculata L.) and stable transmission of the transgenes to progeny

Abstract: Cowpeas are nutritious grains that provide the main source of protein, highly digestible energy and vitamins to some of the world's poorest people. The demand for cowpeas is high but yields remain critically low, largely because of insect pests. Cowpea germplasm contains little or no resistance to major insect pests and a gene technology approach to adding insect protection traits is now a high priority. We have adapted features of several legume and other transformation systems and reproducibly obtained transgenic cowpeas that obey Mendelian rules in transmitting the transgene to their progeny. Critical parameters in this transformation system include the choice of cotyledonary nodes from developing or mature seeds as explants and a tissue culture medium devoid of auxins in the early stages, but including the cytokinin BAP at low levels during shoot initiation and elongation. Addition of thiol-compounds during infection and co-culture with Agrobacterium and the choice of the bar gene for selection with phosphinothricin were also important. Transgenic cowpeas that transmit the transgenes to their progeny can be recovered at a rate of one fertile plant per thousand explants. These results pave the way for the introduction of new traits into cowpea and the first genes to be trialled will include those with potential to protect against insect pests.

Hardwood tree biotechnology

Abstract: Due to the commercial importance of some conifer species, advances in conifer biotechnology often appear to overshadow equally significant advances in the biotechnology of angiosperm forest trees. However, progress with some hardwood forest trees has been just as promising as that made with conifers, and in some areas, has surpassed conifer biotechnology, particularly in the past few years. Until relatively recently, progress with in vitro propagation and gene transfer in hardwood forest trees was confined primarily to the genus Populus. Similarly, compared to other hardwood species, the greatest progress has been made both in the areas of genomics and modification of wood quality traits in this genus. However, the advances in in vitro propagation, in general, and somatic embryogenesis, in particular, have brought mass clonal propagation of other top commercial hardwood trees, in particular Eucalyptus, closer to reality and gene transfer systems have been reported for a number of them. While by far the most extensive application of genomic tools, including genomic sequencing, expressed sequence tags, transcript profiling and molecular markers, has also been made with Populus, these tools are now being applied to wider range of hardwood species. Just as with conifers, potential biotechnology applications for hardwood forest species include development of trees with faster growth, altered wood quality, and insect and disease resistance. In addition, some hardwood species are being manipulated for such non-traditional uses as phytoremediation. Given these advances and the worldwide importance of the products derived from them, it is likely that in vitro propagated and transgenic hardwood forest trees will have just as great an impact on commercial forestry and our environment as the top coniferous species.