[The resistance of plants Setaria veridis (L.) Beauv. to the influence of cadmium].

It was shown that cadmium causes a slowdown of green foxtail Setaria veridis (L.) Beauv. shoots; however it had no effect on root growth or accumulation of underground and above-ground biomass. In the analysis of the effect of cadmium on the water regime and photosynthesis of plants, it was found that it had a negative effect on the stomatal-apparatus, which led to a decrease in the transpiration rate and stomatal conductance. It was noted that the water content of tissues, as well as the rate of photosynthesis in the presence of cadmium, reinained at the level of those in'control planrits. A high resistance of green foxtail to the effects of cadmium was established, which is provided with different adaptive mechanisms and anatomical and physiologicdal characteristics associated with its affiliation to the group of C4-plants.

[Setaria viridis tolerance of high zinc concentrations].

The effect of high zinc concentrations on the growth and photosynthetic apparatus of Setaria viridis (L.) Beauv. was investigated under laboratory conditions and a vegetation experiment. The experiments showed that zinc concentrations of 10(-6) to 10(-3) M did not influence seed germination. Moreover, zinc in concentrations of 40 and 80 mg kg(-1) substrate had no significant effect on most of the plant growth parameters. However, higher metal concentrations (160 and 320 mg kg(-1) substrate) inhibited shoot biomass, leaf area, inflorescence length, and biomass. At the same time, parameters such as the content of chlorophyll (a + b), F0, F(v), and the F(v)/F(m) rate were not reduced even in the presence of zinc in the highest concentrations (320 mg kg(-1) substrate). S. viridis tolerance of high zinc concentrations, as well as its capacity to accumulate zinc in roots and shoots, suggests the plant can be used for phytoremediation of zinc polluted soils.

[The effect of cadmium on shoot apical meristems of barley].

We studied the effects of cadmium acetate at various concentrations (200 to 800 mg/kg substrate) on growth and development of shoot apical meristem of the barley plants (Hordeum vulgare L.) under the conditions of vegetative experiment. It was shown that in the presence of increasing cadmium concentrations in the soil substrate, the apex length and number of inflorescence elements decreased and the rate of organogenesis slowed down, thus affecting the spike potential productivity and morphological parameters of barley plants at the flowering phase. It is possible that the negative effect of cadmium on the shoot apical meristem is associated with its influence on division of the apex cells.

[Effect of lead on the photosynthetic apparatus of annual grasses].

The effect of lead (in the form of Pb(CH3COO)2 x 3H2O at concentrations of 200, 400, and 800 mg/kg substrate) on the photosynthetic apparatus of barley (cultivar Dina) and oat (cultivar Falenskii) was studied. Exposure to low concentrations of lead (200 mg/kg) slightly increased the content of chlorophyll in leaves and the rate of photosynthesis. Medium concentrations of lead (400 mg/kg) had no marked effect on the parameters analyzed, whereas high concentrations (800 mg/kg) decreased the area of leaves, the content of green pigments in them, and the rate of photosynthesis.