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Due to the environment pollution by cadmium (Cd) near industrial metallurgic factories and the widespread use of phosphorus fertilizers, the problem of toxic Cd effect on plants is well discussed by many authors, but the phytotoxicity of Cd under iron (Fe) deficiency stress has not been sufficiently studied. The aim of the work was to study comprehensively the effect of Cd under Fe deficiency conditions on physiological, biochemical, and anatomical parameters of rice varieties, to identify varietal differences in plant response to the effect of double stress. Relative resistance and sensitivity to the joint effect of Cd and Fe deficiency stress rice varieties have been identified. Double stress decreased a linear growth and biomass accumulation of roots and shoots (by 36-50% and 33-46% and 32-56% and 32-48%, accordingly), content of photosynthetic pigments (Chla, Chlb, and carotenoids by 36-51%, 32-47%, and 64-78%, accordingly), and relative water content (by 18-26%). Proline content increased by 28-103% in all rice varieties, but to a lesser extent in sensitive varieties. The thickness of the lower and upper epidermis and the diameter of vascular bundles of leaves decreased by 18-50%, 46-60%, and 13-48%, accordingly. The thickness of the root endodermis and exodermis and diameter of the central cylinder mainly decreased. The thickness of the exodermis increased slightly by 7%, and the diameter of the central cylinder remained at the control level in resistant Madina variety while in sensitive Chapsari variety, these indicators decreased significantly by 50 and 45%, accordingly. Thus, the aggravation of adverse effect of Cd under Fe deficiency conditions and the varietal specificity of plants’ response to double stress were shown. It creates the need for further study of these rice varieties using Fe to identify mechanisms for reducing the toxic effect of Cd on plants as well as the study of Fe and Cd transporter genes at the molecular level.

The article presents results of determining the content of proteins and amino acids in seeds of Kazakhstani soybean varieties. Soybean, being a high-protein crop, contains from 30 to 50% protein. The advantage of soybean protein among other plant proteins is the optimal ratio of amino acids. These are, first of all, essential amino acids, the main source of which are animal proteins. Soy protein, when consumed at the recommended dose, most fully satisfies the daily intake of essential amino acids of an adult. It is important to identify varieties with the highest protein content and essential amino acids. In this study, protein determination was carried out by the Bradford (1976) spectrophotometric method. The amino acid content was determined by high-performance liquid chromatography. The objects of the study were domestic soybean varieties: «Lastochka», «Almaty» and «Vita» from the collection of LLP «Kazakh Research Institute of Agriculture and Plant growing», Almalybak v., Almaty region, Republic of Kazakhstan. According to the results obtained, the Lastochka variety has the highest content of protein, and also the amino acid composition of the «Lastochka» variety differs by existing of essential amino acids, which makes it possible to recommend it both for food and in the production of biologically active additives.