Antioxidant status of anoxia‐tolerant and ‐intolerant plant species under anoxia and reaeration

Abstract

The redox potential of the cell, as well as the antioxidant status of the tissue, are considered to be important regulatory constituents in an adaptive response in plants. Here the involvement of active antioxidants ascorbic acid (AA), reduced glutathione (GSH) and α‐ and β‐tocopherols in reactive oxygen species scavenging, and the effect of anoxic stress on their reduction state were studied in 4 anoxia‐tolerant and ‐intolerant plant species: Iris germanica L., Iris pseudacorus L., wheat (Triticum aestivum L. cv. Leningradka) and rice (Oryza sativa L. cv. VNIIR). The initial antioxidant content (both AA and GSH) was higher in the rhizomes of the more anoxia‐tolerant Iris spp., as compared with that of the roots of the cereals. The predominant form of ascorbate was dehydroascorbic acid (DHA) in the cereals and AA in the Iris spp. Imposition of anoxia with subsequent reoxygenation resulted in an overall depletion of the reduced forms of antioxidants. No concurrent increase in oxidised forms (DHA and conjugated glutathione) was observed in anoxic samples. α‐tocopherol content in Iris spp. was in the range 1–2 μg g−1 fresh weight, while β‐tocopherol content was higher in the anoxia‐intolerant I. germanica (7.2 μg g−1 fresh weight) as compared with the tolerant I. pseudacorus (1.5 μg g−1 fresh weight). In I. pseudacorus, a significant decrease in α‐ and β‐tocopherol levels was observed only after long‐term (45 days) anoxia. The results suggested exclusion of AA and GSH from the redox cycling under prolonged anoxia, and a concomitant decrease in the redox state, as well as an anoxia‐induced depletion of α‐ and β‐tocopherols.

A conformational study of hydroxyflavones by vibrational spectroscopy coupled to DFT calculations

“…Phytochemicals are a class of compounds comprising a wide variety of molecules present in plants, including flavonoids which are known to possess significant health-promoting properties, generally related with their capabilities to act as chain-breaking antioxidants or as radical scavengers [1,2]. In fact, oxidative stress occurs upon disruption of the homeostatic balance between free radical generation and the natural antioxidant defence mechanisms (e.g.…”

Phytochemical constituents of Vangueria infausta: their radical scavenging and antimicrobial activities

“…This shows that the steady state conditions are attained after three hours. The structure-activity relationship studies have shown that among other factors, the more the hydroxyl groups in a molecule the higher the antioxidant activity of that molecule 14,15 . Key: NT = Not tested…”

The study of plant adaptation to oxygen deficiency in Saint Petersburg University

“…Wetland species (Iris pseudacorus, rice) produce a smaller amount of ROS and products of LPX under anoxic and post-anoxic stress than nonresistant ones (I. germanica, oats, wheat, Chirkova, Novitskay, and Blokhina, 1998;Blokhina, Fagerstedt, and Chirkova, 1999). Suppression of oxidative damage in hypoxia-resistant plants correlates with activation of antioxidant enzymes: peroxidase (Chirkova, Sokolovskaya, and Khazova, 1973;Chirkova and Sokolovskaya, 1976;Lastochkin, Yemelyanov, and Chirkova, 2000) and superoxide dismutase (Chirkova, Novitskaya, and Blokhina, 1998), accumulation of tocopherols (Chirkova and Gobedzhishvili, 1993;Chirkova, Novitskaya, and Blokhina, 1998;Blokhina et al, 2000), and turnover of ascorbic acid and glutathione (Blokhina et al, 2000). Thus, hypoxia-resistant plants demonstrate resistance to oxidative stress, too.…”