[Cytogenetic effects in Koeleria gracilis Pers. populations from the Semipalatinsk proving ground].

The proliferative activity and the frequency of cytogenetic disturbances in apical meristem of coleoptile sprouts at germination of seeds collected from crested hairgrass populations inhabiting contrast in level of radioactive contamination sites of the Semipalatinsk test site (Kazakhstan) are studied. Sampling of biological material and soil was carrying out during three years (2005-2007). The absorbed dose to critical organs of crested hairgrass vary depending on a site from 2.8 up to 262.2 mGy/year. A sognificant correlation between the frequency of cytogenetic disturbances in apical meristem and dose absorbed in crested hairgrass critical organs is found. Devere aberrations such as single and double bridges make the main contribution to spectrum of structural mutations as well as lagging chromosomes. In spite of the fact that the crested hairgrass populations have occupied the sites with a high level of radioactive contamination for a long time, the data analysis fails to reveal radio-adaptation effect.

[Regulatory radiation risks' for the population and natural objects within the Semipalatinsk Test Site].

Advisability of using risks as indicators for estimating radiation impacts on environmental objects and humans has been jusified. Results are presented from identification of dose burdens distribution to various cohorts of the population living within the Semipalatinsk Test Site (STS) and consuming contaminated farm products. Parameters of dose burden distributions are estimated for areas of livestock grazing and the most contaminated sectors within these areas. Dose distributions to meadow plants for the above areas have been found. Regulatory radiation risks for the STS population and meadow ecosystem components have been calculated. Based on the parameters estimated, levels of radiation exposure of the population and herbaceous plants have been compared.

[Polarization of prompt and delayed fluorescence of photosystem II]. / Poliarizatsiia bystroi i zamedlennoi fluorestsentsii fotosistemy II.

Prompt and delayed fluorescence polarization of the oriented samples of synchronous. Chlorella vulgaris culture is investigated. Two main components with different polarization are revealed in the prompt and delayed fluorescence, however its ratio depends on the emission nature. The delayed fluorescence polarization ratio indicates that the reaction center pigment of PS-II dipole transition moment is in the photosynthetic membrane plane. The heterogeneity of variable and delayed PS-II fluorescence emission can be explained by the existence of two components: one of them is related to pigment-protein complex of PS-II (PPC-II) structurally and migrationally connected with LH-complex (alpha-component), but the other one--to PPC-II setting apart from the main LH-complex bulk (beta-component).

[Spectral anisotropy of chloroplasts, subchloroplast particles and pigment-protein complexes]. / Spektral'naia anizotropiia khloroplastov, subkhloroplastnykh chastits i pigment-belkovykh kompleksov.

Anisotropic properties of pea chloroplasts, subchloroplast fragments (photosystem 1 particles and pigment-protein complexes) and the blue-green algae oriented in polyacrylamide gel were investigated. It was shown that linear dichroism spectra of chloroplasts are the superposition of the corresponding spectra for the main light harvesting complex (HMLC) and P 700 chlorophyll a--protein complex (CP 1). Anisotropic properties of the photosystem 1 particles and blue-green algae are mainly caused by CP 1 anisotropy. Qy-transition moments tend to perpendicular orientation to the membrane plane for the Chl. b 649, Chl. a 660 and parallel orientation--for Chl. b 654, Chl. a 682. The degree of Qy-transition moments parallel orientation is higher for the longwave forms (Chl. a 690, Chl. a 702, Chl. a 712), than for the shortwave ones and coincides with this degree for the reaction centre pigment P 700 transition moment. It is suggested that the specific orientation of the pigment-protein complexes in the chloroplast membrane is important for the regulation of the spillover between two photosystems.