The components of plant tissue culture media II. Organic additions, osmotic and pH effects, and support systems

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.

Current trends in the embryology of angiosperms.

A highly efficient gene transfer method mediated by Agrobacterium tumefaciens was developed for Group I indica rice, which had been quite recalcitrant in tissue culture and transformation. Freshly isolated immature embryos from plants grown in a greenhouse were inoculated with A. tumefaciens LBA4404 that harbored super-binary vector pTOK233 or pSB134, which had a hygromycin-resistance gene and a GUS gene in the T-DNA. The efficiency of gene transfer varied with the kinds of gelling agents and the basic compositions of co-cultivation media. The highest activity of GUS after co-cultivation was observed when NB medium solidified with agarose was used. For the subsequent cultures, two types of media (modified NB and CC) were chosen to recover hygromycin-resistant cells efficiently. The transformation protocol thus developed worked very well in all of the varieties tested in this study, and the transformation frequency (number of independent hygromycin-resistant and GUS-positive plants per embryo) reached more than 30% in IR8, IR24, IR26, IR36, IR54, IR64, IR72, Xin Qing Ai 1, Nan Jin 11, and Suewon 258. Most of the transformants (T0) were normal in morphology and fertile. Stable integration, expression and inheritance of transgenes were demonstrated by molecular and genetic analysis of transformants in the T0 and T1 generations. For the recovery of multiple independent transgenic events from a single immature embryo, procedures were developed to section the embryo into as many as 30 pieces after non-selective cultures following co-cultivation. Transformants were then obtained from the pieces cultured on the selective media, and, in the highest case, more than seven independent transgenic plants per original embryo (transformation frequency of 738%) were produced. Thus, the efficiency of transformation was remarkably improved.

Improved protocols for transformation of indica rice mediated by Agrobacterium tumefaciens

A highly efficient somatic embryo production and maturation procedure has been developed to regenerate plantlets from cotton (Gossypium hirsutum). This procedure involves the acceleration of differentiation through manipulations of nutrient and microenvironment conditions. Embryogenic calli, initiated from hypocotyls or cotyledonary leaf sections on MS medium containing 0.1 mg/l 2,4 dichlorophenoxyacetic acid, 0.5 mg/l kinetin, and 3% maltose produced globular-stage somatic embryos when transferred to hormone-free MS medium supplemented with high concentrations of nitrate. Subculture of globular embryos on hormone-free MS medium led to the development of torpedo- and cotyledonary-stage at a low frequency (two to four per plate) with the majority of embryos lacking further growth or entering into the dedifferentiation stage. Significant improvement in embryogenesis (two- to threefold) was achieved when calli were cultured on 1/5-strength MS medium irrespective of stress treatment. However, the frequency of globular embryos developing into normal plantlets improved considerably (20–24 per plate) when cultured on filter paper placed on MS medium. In this procedure, about 33% of globular embryos not only developed into the cotyledonary stage but rooted simultaneously, eliminating a separate rooting step. More than 70% of cotyledonary embryos developed into normal plantlets when cultured on full- strength MS medium containing 0.05 mg/l gibberellic acid.

High-frequency somatic embryo production and maturation into normal plants in cotton (Gossypium hirsutum) through metabolic stress.

Interactive effects of genotypes with callus induction and regeneration media combinations on green plantlet regeneration response were studied for three indica rice (Oryza sativa L.) cultivars, IR-72, IR-54 and Karnal Local. Isolated mature-embryos were used to derive scutellar callus and fifteen media combinations involving MS, N6, R2, SK1 and some modifications were tested. Regeneration percentage as well as the shoot-bud induction frequency were influenced by genotype, callus induction medium, regeneration medium, interaction between genotype and the two media (callus induction and regeneration) as well the interaction between the callus induction medium and regeneration medium. Basal media combination of SK1m (callusing) and MS (regeneration) was found to be the best for cv. Karnal Local in which regeneration frequency of 88% and shoot-bud induction of 233% was observed. In IR-72, the highest regeneration frequency of 47.5% and shoot-bud induction frequency of 77% was obtained on MS-MS combination. In IR-54, highest regeneration frequency (25%) was recorded on MMS(N)-MMS(N) combination, whereas, highest frequency of shoot-bud induction (50%) was observed on MMS(S)-MS combination. Although genotype and the composition of the callus induction basal medium were the major determinants of regeneration response, an overall analysis of variation also revealed a significant interaction between the media used for de-differentiation (callusing) and re-differentiation (plantlet regeneration).

Genotype x culture media interaction effects on regeneration response of three indica rice cultivars

High-Frequency Plant Regeneration from Protoplasts of Indica Rice (Oryza sativa L.) Using Maltose

Plant Regeneration from Long-Term Cell Suspension Cultures of Indica Rice (Oryza sativa L. cv. IR43)

Protoplasts were isolated from young inflorescence-derived suspension cultures of a japonica rice cultivar ‘Taipei 177’. The isolated protoplasts which were cultured either in liquid, agar on Sea plaque agarose underwent sustained division. Maximum plating efficiency of 1.06% occurred in a medium containing macroelements of KM, microelements and vitamins of B5, 0.5 % Sea plaque agarose, 1.0 mg/l of 2,4-D, and glucose as an osmotic stabilizer. Green and albino plants were regenerated from the protocalli in MS semisolid medium containing 4 mg/l BAP, 0.5 mg/l NAA and 500 mg/l casein hydrolysate (MS18–2).

G.C. Ghosh Biswas

Papers

High-Frequency Plant Regeneration from Protoplasts of Indica Rice (Oryza sativa L.) Using Maltose

Plant Regeneration from Long-Term Cell Suspension Cultures of Indica Rice (Oryza sativa L. cv. IR43)

Callus Formation and Plant Regeneration from Protoplasts Derived from Suspension Culture of Rice (Oryza sativa L. cv. ‘Taipei 177’)