Along with specific adaptive reactions, universal defense reactions, in particular activation of antioxidant system, are of great importance for plant survival under cold conditions. We have studied a relationship among the content of low-molecular-weight protective compounds with antioxidant properties (proline, soluble carbohydrates, flavonoids), the activity of antioxidant enzymes (superoxide dismutase, catalase, and guaiacol peroxidase) in seedlings of winter wheat, rye and triticale, and frost resistance of etiolated seedlings and adult plants at tillering stage. It was found that there was a fairly close correlation between the frost resistance of seedlings and adult cereal plants (r = 0,78). It was shown that a pronounced relationship between individual indicators of antioxidant system functioning in unhardened seedlings and their frost resistance was not found. After 6-day hardening of seedlings at 2-4°C, there was a high correlation between the total indicator of the enzymatic antioxidant system (the sum of normalized indicators of superoxide dismutase, peroxidase, and catalase activity) and their frost resistance (r = 0,86), but the correlation coefficient of this index with frost resistance of plants in tillering phase was significantly lower (r = 0,47). At the same time, a high correlation was found between the content of low-molecular-weight protectors in hardened seedlings and frost resistance of tillering adult plants (r = 0.89). The closest correlation was observed between the integral normalized indicator, comprising the sum of normalized values of antioxidant enzymes activity and the content of low-molecular-weight protectors in hardened seedlings, and frost resistance of seedlings (r = 0,94) and plants in tillering phase (r = 0,89). A presence of specific features in the functioning of antioxidant system during cold adaptation of cereal seedlings was established. Rye is characterized by a high content of low-molecular-weight protective compounds; at the same time, increased activity of antioxidant enzymes - superoxide dismutase and catalase - was noted in wheat seedlings. In triticale, depending on the genotype, the values of both enzymatic antioxidant activity and the content of low-molecular-weight protectors varied.
Different toxicities of nanoscale titanium dioxide particles in the roots and leaves of wheat seedlings