Biochemical Characteristics and Elemental Composition Peculiarities of Rheum tataricum L. in Semi-Desert Conditions and of European Garden Rhubarb

Abstract

Biochemical and mineral peculiarities of plants inhabiting desert and semi-desert areas may provide important information about the mechanism of their adaptability and reveal the prospects of their utilization. Rheum tataricum L., known for its high tolerance to drought, salinity, and nutritional deficiency, is the least studied species of wild rhubarb. Using biochemical and ICP-MS analysis, the antioxidant status and mineral composition of R. tataricum were determined. Extremely high levels of antioxidant activity (148–155 mg GAE g−1 d.w.), polyphenols (24.6–25.1 mg GAE g−1 d.w.) and carotenoids (1.94 mg-eq β-carotene g−1 d.w.) were revealed in roots, proline in leaves (71.1 ± 6.2 mg kg−1 d.w.) and malic acid in stems (3.40 ± 0.50 mg g−1 d.w.). Compared to garden rhubarb, R. tataricum demonstrated significant root–leaves translocation of Li, Se, Si, and Mo, known to participate in plant antioxidant defense. Under high levels of Ca, Na, Mg, Fe, Cr and Si in soil, R. tataricum demonstrated the ability to significantly increase the accumulation of these elements in roots, showing a hyperaccumulation ability for Sr. The first broad picture of R. tataricum biochemical and mineral characteristics in semi-desert habitat and its nutritional value indicate the prospects of R. tataricum utilization in plant breeding, medicine, and nutrition.