Knowledge of the specificity of accumulation of 137Cs and 90Sr by plants and limits of accumulation by plant fruits plays a key role at breeding of vegetable crops, which make demand for ecological safety of the product. The article is concerned with the study of varietal sources of spinach (Spinacia oleracea L.) aimed at development of ecological safety product on the territory polluted by radionuclides.The specificity of accumulation of radionuclides 137Cs and 90Sr was studied in 54 varieties of spinach at industrial contaminated and polluted lands. Experimental tests were conducted in the Moscow and Bryansk regions in 2012 and 2014. The absolute value of radionuclide 90Sr was higher than absolute value of radionuclide 137Cs in all studied zones. It was found that the hazard rate of 90Sr is higher because the level of pollution of product reaches up to 76% from maximum permissible concentration (MPC), while the level of product pollution by 137Cs is 26,4% from MPC. The spinach genotype differentiation for 90Sr in the most environments is lower than differentiation for 137Cs. The histograms of distribution 90Sr and 137Cs showed that samples amount in the groups of accumulation for both radionuclides are equal. Statistically significant data for radionuclides 137Cs and 90Sr in spinach were not obtained. The evaluation of spinach for low content of radionuclides should be conducted separately for each radionuclide on various backgrounds.

Spinach is an economically important vegetable crop widely cultivated and consumed worldwide. This early ripening leafy vegetable is rich in bioactive components, fiber, micro and macro elements, vitamins, and has high antioxidant activity. Results of numerous studies on the effects of spinach on human health confirm its beneficial effect. The species S. oleracea L. is cultivated commercially. The ancestor of cultivated spinach is S. turkestanica Iljin, which has a breeding potential for different economically valuable traits. Its biochemical composition has been studied extremely little. The present article offers a comparative evaluation of the biochemical profile and antioxidant activity of cultivated and wild spinach species. The material for the study was a representative sample of 48 collection accessions of spinach from the N.I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR). The accessions were grown in 2019 and 2020 in the open ground of the Pushkin and Pavlovsk Laboratories of VIR. The antioxidant activity was studied spectrophotometrically by the DPPH assay of free radical scavenging at a wavelength of 515 nm. A significant similarity of the two species in most biochemical parameters was revealed, which confirms their phylogenetic relationship. Significant differences were found in the content of phenolic elements, which determine the elevated values of antioxidant and antiradical activity of S. turkestanica. The article presents correlation matrices of species biochemical composition, describes general trends, negative relationships and conjugated factors. The identified promising accessions of both cultivated and wild spinach are recommended for breeding for increased content of phenolic compounds, ascorbic acid and antioxidant activity. The result of the study helps to reveal the potential of the crop as a valuable source of bioactive components and high antioxidant activity.

Hormonal regulation is considered to be a unique mechanism controlling growth and development of living organism. The review discusses the correlations between pant hormonal status of non-accumulators and hyper-accumulators of Se with the accumulation levels of this microelement. The phenomenon of stimulation and redistribution of selenium as a result of phytohormone treatment, the peculiarities of phytohormones effect among different species and cultivars, and influence of plant sexualization on selenium accumulation are described in article. Data of hormonal regulation of selenium level for spinach, garlic, perennial onion, Brassica chinenesis and Valeriana officialis are presented in the review.