Báo cáo khoa học: Cytogenetic study of diploid and spontaneous triploid oaks, Quercus robur L

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Cytogenetic study of diploid and spontaneous triploid oaks, Quercus robur L...
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Báo cáo khoa học: "Cytogenetic study of diploid and spontaneous triploid oaks, Quercus robur L" Original article Cytogenetic study of diploid and spontaneous triploid oaks, Quercus robur L AK Butorina Department of Genetics and Bioecology Central Research Institute of Forest Genetics and Breeding, Voronezh, RussiaSummary — Data are presented on the cytogenetics of 2 unusually large oak trees found in theVoronezh region of Russia. In both trees, cells with 2n 3x 36 chromosomes were predominant, = =with occasional observations of diploid hypoaneuploid and hyperaneuploid cells. Functionally, thetrees can be considered triploids, although in a strict sense, they are mixoploids. Meiosis in micro-sporogenesis of these trees is very disturbed and, as a consequence, pollen with unbalanced chro-mosome numbers are produced. Correspondingly, the progeny from each tree were very different inmorphological characteristics and cytogenetic constitution. These progeny can be used in genemapping studies and for other basic research purposes. Studies on some diploid oaks reveal thepresence of 2n pollen, formed by parallel spindles in the 2nd meiotic division. Methods for producingadditional oak triploids that have a potential for heterosis are discussed.oak / triploid / mixoploid / meiosis / meiotic mutant / progenyRésumé — Cytogénétique de chênes diploïdes et triploïdes spontanés (Quercus robur L).Des données cytogénétiques relatives à 2 chênes de très grande taille situés dans la région de Vo-ronezh (Russie) sont présentées dans cet article. Des cellules comprenant 2n 3x 36 chromo- = =somes sont prédominantes dans chaque arbre. Des cellules hypoaneuploïdes et hyperaneuploïdesont également été rencontrées. Au plan fonctionnel, les 2 arbres peuvent être considérés comme tri-ploïdes, plus précisément mixoploïdes. La méiose durant la microsporogenèse est très perturbée etproduit des grains de pollen au nombre de chromosomes déséquilibré. Les descendants de cesarbres manifestent des caractéristiques morphologiques et une constitution cytogénétique très va-riables. Ces familles peuvent être utilisées pour des études de cartographie génétique et d’autres re-cherches fondamentales. Des études similaires faites sur des chênes diploïdes mettent en évidencedes grains de pollen à 2n chromosomes formés par des fuseaux parallèles lors de la seconde divi-sion méiotique. Des méthodes de production de chênes triploïdes en vue de générer de l’hétérosissont discutées.chêne/ triploïde / mixoploïde / méiose / mutant méiotique / descendanceINTRODUCTION MATERIALS AND METHODS For the cytological investigations, branches wereThe Voronezh region in south central Rus- taken from each putative triploid and a number ofsia is famous for oak stands producing ex- putative diploid trees at the appropriate samplingcellent quality lumber. Rich Voronezh period for meiotic observations. The brancheschernozem provide optimum edaphic were placed into water vessels and kept in a coldconditions for oak species. Two triploid room. Somatic chromosome counts were madetrees of Quercus robur L were discovered using vegetative buds that were removed fromin the Voronezh region by the scientific re- the branches and placed in a damp penicillin bot- tle under freezing conditions for 1-2 h to inhibitsearchers of the Central Research Insti- spindle fiber formation. The young leaves weretute of Forest Genetics and Breeding, VV then fixed in aceto alcohol.levlev and TI Pletmintseva. The trees were For the study of meiosis in microsporogene-more than 100 years old and differed from sis and the process of development of the maleoaks of a similar age. They were of gigan- gametotype, the flower buds were fixed from thetic height, weak fertility and exhibited stage of green cone up to the flowering.unusual morphological and anatomical All materials were stained in acetohaemotac-features. These characteristics have often silin. The squash techniq ...