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Ide spermatozoa were genetically inactivated using ultraviolet (UV) irradiation. The highest survival of haploid embryos was noted in the group treated with UV for 5 min (dose 1920 J m-2). High-temperature shock influenced the suppression of the second polar body in ide oocytes. The highest survival rate of diploid gynogenotes (below 10%) was observed in groups shocked at 12 min after egg insemination for 3 min. Eggs shocked later in time exhibited lower survival rates.
The aim of the present research were histological analysis of regenerating structures through in vitro gynogenesis from unfertilized ovules of sugar beet (Beta vulgaris L.). The process of shoot regeneration using a novel two stage method combines the preculture in liquid medium with the culture on solid medium. The highest number of explants that formed shoots (60%) was observed on medium supplemented with BAP, sucrose and gerlite, and as regards carbohydrates used in the medium most of explants forming shoots (42%) and the largest total number of shoots (110) was observed for glucose. To accurately determine the course of shoot formation, histological analyses were performed. Careful histologic evaluation of regenerating structures revealed the presence of numerous meristematic centres. In some meristems formation of specialized tissues and organs was observed, including epidermis, apical meristem, leaf primordia and tracheal elements. The analyses showed that the regeneration of the new structures from sugar beet ovules occurred both through organogenesis as well as somatic embryogenesis since the presence of somatic embryos in the globular stage or torpedo stage were observed.
Bream, Abramis brama (L.), eggs fertilized with genetically inactivated sperm (UV irradiation dose of 1920 J m-2) were exposed to thermal cold shock to produce meiotic gynogenotes. The shock was applied at one-minute intervals from 1 to 10 min after egg insemination. The temperature of the shock was 2.0 ± 0.1°C, and its duration was 45 min. The water temperature prior to the shock was 20.0°C. Eggs fertilized with genetically inactivated sperm (putative haploids) exhibited retarded and abnormal development. The yield of gynogenesis was relatively low, except for the group to which the shock was applied 1 min after fertilization (about 30% in comparison with the controls). Ninety fish from the control and gynogenetic groups were reared for ten months. The survival of the gynogenetic bream was twofold lower than that of the controls. The gynogenotes were highly variable in size and exhibited some morphological abnormalities. The sex ratios in the control groups were close to 1:1, whereas all the gynogenotes were female.
A three-step procedure was adopted for the induction of gynogenesis in two cultivars of mulberry (Morus alba L.). This includes in vitro flowering, inflorescence segment culture and isolated ovary culture. In the third step, that is, isolated ovary culture, the cultured ovaries burst and an embryo emerged from the ovary. The present paper investigates the ontogeny of the developing gynogenic embryo. The study confirmed that the gynogenic embryo emerged from the egg cell. Before the onset of division of the egg, all other cells of the embryo sac degenerated in the majority of ovules, but in exceptional cases the polar nuclei will be retained along with the dividing egg cell. The presence of the gynogenic embryo along with free-nuclear autonomous endosperm is the most important feature of the present investigation. Autonomous endosperm is formed from either the polar nuclei or secondary nucleus. In both cultivars used for the experiment, the percentage of ovaries showing proembryo induction during inflorescence segment culture is much higher than that of ovaries producing gynogenic plants during isolated ovary culture. This suggests the degeneration of some gynogenic embryos during the initial stages of induction.
The effects of heat (40 °C, 1.5 min) and cold (2-4 °C, 60 min) shocks applied within 2nd, 8th, 15, and 30th minute after fertilization on the results of gynogenetic reproduction of common carp were compared. The sperm was inactivated using ultraviolet radiation. The temperature of fertilization and incubation of eggs was 22 °C. Greater numbers of larvae were obtained in the case of the heat shocks (0.3-3.4% of the incubated eggs) than of the cold ones (0-0.4%).
Induced gynogenesis as potential tool for detection of receive deleterious mutations carriers salmonids fishery . 8 rainbow trout females were tripped and the eggs were subjected to induced gynogenesis procedure. Approximately half of 3 female’s progeny showed type of malformations occasionally observed in rainbow trout stock kept in Rutki Station. The case study describes the potential usefulness of gynogenesis as breeding test to reveal carriers of harmful recessive alleles.
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