Genetic Manipulations with Plant Material

Mankind, throughout history, has strived to improve his food sources. By means of slow and empirical selections, it has been possible to greatly increase both quantity and quality of plant crops. This procedure has brought the most useful cereals to a state of refinement that seems to be difficult to further improve by the same methodology. Indeed, natural sexual mechanisms were always used to cross closely related sexually and genetically compatible organisms; the selection procedure consisted of isolating the most promi sing progenies. Obviously, by this way, plants could only share preexisting genetic pools. On the other hand, the last decade has seen drastic modifi cations of the experimental plant sciences, with the appearance of new technological possibilities. Because of this profound reshaping of our experimental ap proaches, other means can now be realistically envisaged in order to achieve similar or even higher goals. It is, for instance, possible to attempt completing sexual crosses (where both male and female gametes bring together the genetic informations necessary for growth and development of the offspring) by parasexual means by which novel genetic informa tions could possibly be added to the heritage •. At the limit, such genetic manipulations could enable man to create plants capable of producing new substances characteris tic of unrelated plants or, more generally, of other living or ganisms. Even if these possibilities might appear quite remote, the interest of Scientists has been awaken and, indeed, several at tempts to such genetic manipulations have already been made.

Contenu
Analysis of Microbial Genome Structure.- The Mechanism of Competence for DNA Uptake and Transformation.- Integrated and Free State of Plasmids.- F-Prime Manipulations of Possible Interest to Plant Biologists.- Interallelic Complementation in the Study of Gene Action.- Principles of Genetic Regulation in Lower and Higher Plants.- The Enzymology of Nitrogen Fixation.- The Physiology and Genetics of Nitrogen Fixation.- Molecular Biology of the Genus Agrobacterium.- Crown Gall: A Model for Tumor Research and Genetic Engineering.- The Role of Plasmids in Crown Gall Formation by A. Tumefaciens.- Genetic Mechanisms in Differentiation and Development.- Plant Cell Cultures: Present and Projected Applications for Studies in Cell Metabolism.- Plant Cell Cultures: Present and Projected Applications for Studies in Genetics.- Heterogeneous Associations of Cells Formed in vitro.- Plant Regeneration and Chromosome Stability in Tissue Cultures.- Single Cell Culture of an Haploid Cell: The Microspore.- Plant Protoplasts as Genetic Systems.- Induction of Auxotrophic Mutations in Plants.- In vitro Selection for Mutants of Higher Plants.- Isozymes and a Strategy for Their Utilization in Plant Genetics: Genetic and Epigenetic Control.- Isozymes and a Strategy for Their Utilization in Plant Genetics: Isozymes as a Tool in Plant Genetics.- Physico-Chemical Aspects of Chromatin and Chromosome Structure.- Isolation and Gradient Analysis of DNA.- Use of Molecular Sieving on Agarose Gels to Study DNA Uptake by Chlamydomonas Reinhardi.- Molecular Hybridization and Its Application to RNA Tumor Virus Research.- DNA-Hybridization Studies of the Fate of Bacterial DNA in Plants.- Fate of Exogenous DNA in Plants.- DNA Mediated Genetic Correction of Thiamineless Arabidopsis Thaliana.- Uptake of DNA and Bacteriophage into Pollen and Genetic Manipulation.- Theoretical and Comparative Aspects of Bacteriophage Transfer and Expression in Eukaryotic Cells in Culture.- Studies on the Use of Transducing Bacteriophages as Vectors for the Transfer of Foreign Genes to Higher Plants.- Communications.- A vvr Mutation That Enhances the Transformation Frequency by Intergenetic CNA in B. subtilis.- Studies on Protease Sensitive Transfecting DNA of Bacillus Phage.- Genetic Control of D.Amino Acid Metabolism in Gram-Negative Bacteria.- Regulation of Development in Fission Yeast.- In Vitro Growth and Polyphenol Production by Tissue Cultures of Datura and Cassia.- Properties of 5-Bromodeoxyuridine-Resistant Lines of Higher Plant Cells in Liquid Cultures.- Respiration and Nitrogen Nutrition of Carrot Callus Cultures.- Quantitative Mutagenesis in Soybean Suspension Cultures....- Protoplast Isolation from Leaves of C3, C4 and C.A.M. Plants and Biochemical Activities.- Anther Derived Plants from Digitalis Purpurea.- Mutations Obtained from Anther Derived Plants of Hyoscyamus Niger.- Ribonucleic Acid Synthesis in Plants.- Fate of Homologous DNA in Seedlings of Matthiola Incama.- DNA Synthesis and Bacterial Contamination in Plants.- Mitochondrial Nucleic Acids from Parthenocissus Tricuspidata Cells.- Involvement of Nucleic Acids and Microtubules in Ciliogenesis: Implications for Cytoplasmic Inheritance.- Methyl 4-Chloroindolyl-3-Acetate in Pea and Barley.- Evidence for a Proposed Function of DNA as Transducer Acting at the Cell Surface.- Genome Activation During Seed Germination.- Participants.