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EN
The aim of the research was to make a preliminary determination of the effectiveness of the in duc tion of haploids in Capsicum frutescens L. In order to induce androgenesis red and yellow fruit forms of species were used, each bred by the re searchers on their own. The experiment was per formed in October. An ther cultures were conducted according to a modified me - thod developed by Dumas et al. (1981) for C. annuum L. The anthers were laid on CP medium con taining 0.01 mg·dm⁻³ 2.4-D and 0.01 mg·dm⁻³ kinetin, with the addition of 0.5 g·dm⁻³ of activated carbon and 5 mg×dm⁻³ of silvernitrate, solidified with 8 g·dm⁻³ of agar. The cul tures were in cu bated in the dark at 35 deg C for 8 days. Next they were trans ferred to 25 deg C under a 12-hour photoperiod. After 14 days of induction, anthers were trans ferred to R₁ medium supplemented with 0.1 mg·dm⁻³ kinetin. Obtained embryos were subsequently transplanted onto V₃ hormone-free me dium and well growing plants were planted in green houses. The efficiency of androgenesis for both C. frutescens L. forms was relatively low and it did not exceed 5 %. The ploidy level of the result ing plants was determined by flow-cytometric analysis. The regenerants con sisted of about equal numbers of haploids and diploids. Additionally, among plants regenerated from anthers of yellow fruit forms, two mixoploids were observed.
EN
Ionizing radiation (IR) is applied to inactivate the nuclear genome in rainbow trout eggs during induced androgenetic development. However, IR-generated reactive oxygen species (ROS) may affect developmental potential of eggs and reduce the effectiveness of androgenesis. To verify this assumption, androgenetic development of rainbow trout was induced in eggs irradiated with 350 Gy of X-rays. Survival rates, pH of the ovarian fluid and activity of antioxidant enzymes, including SOD, CAT and GPx, were examined in non-irradiated and irradiated eggs originating from four females. Survival rates of androgenetic embryos developing in eggs produced by different females varied from 1% to 57% and these inter-clutch differences were significant. Eggs from female F4, which showed the highest developmental competence for androgenesis, also showed increased activities of SOD, CAT and GPx enzymes. The pH value of the ovarian fluid of each female was over 8 before and after irradiation, therefore it seems that radiation did not affect the ovarian fluid pH. Considering the above-mentioned inter-clutch differences, a strong maternal effect on the effectiveness of androgenesis can be assumed. Eggs with increased activity of antioxidant enzymes before irradiation should be expected to show increased developmental competence for androgenesis.
10
75%
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2015
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tom 96
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nr 1
EN
The androgenetic response of several selected male sterilitymaintainer genotypes of triticale was investigated. Androgenesis induction was obtained in all cultivars, but a large genotypic variation in green plant regeneration was observed. The number of regenerated triticale plants varied from 0.1 to 4.7 green plants per spike, depending on genotype. Spontaneous doubling of chromosomes varied from 14 to 60 % for particular genotypes and, on average, reached the value of 34 % for all genotypes. Fertile DH lines obtained in this study will find practical application in the development of triticale male sterile lines that are desirable in hybrid breeding.
EN
The purpose of this work was to quantify the impact of spontaneous and X-radiation-induced chromosome rearrangements on survival rate of androgenetic rainbow trout (Oncorhynchus mykiss). Various doses of X irradiation (50, 150, 250, 350 Gy) were used for inactivation of nuclear DNA in oocytes. After the irradiation, eggs were inseminated with normal sperm from 4 males derived from a strain characterized by Robertsonian rearrangements and length polymorphism of the Y chromosome. The haploid zygotes were exposed to a high hydrostatic pressure (7000 psi) to duplicate the paternal DNA. Neither Robertsonian chromosome polymorphism nor the Y chromosome morphology impaired the viability of the androgenetic embryos and alevins. Moreover, survival of eyed embryos of the androgenetic rainbow trout increased significantly with increasing doses of oocyte X irradiation. After 6 months of rearing, only specimens from the 250 and 350 Gy variants survived. The number of fingerlings with remnants of the maternal genome in the forms of chromosome fragments was higher in the 250 Gy group. Intraindividual variation of chromosome fragment number was observed, and some individuals exhibited haploid/diploid mosaicism and body malformations. Individuals irradiated with less than 250 Gy died, presumably because of the conflict between intact paternally derived chromosomes and the residues of maternal genome in the form of chromosome fragments.
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