Quantification of Individual and Interactive Effects of Some Antioxidants on Drought Tolerance in Cuminum cyminum L

Abstract

Abstract There are complex inter- and intra-relations between antioxidants and plant drought tolerance (biomass; DT); Therefore, commonly used techniques, including correlation analysis, is inadequate to describe the relationship between antioxidants and DT. This study aimed to quantify the individual and interactive effects of six antioxidants on cumin DT using a non-linear multiple regression. Field experiments were conducted at two sites in Iran, in 2020. Treatments were the factorial split plot arrangement of magnetic water (conventional and magnetized waters), deficit irrigation (providing 100%, 70%, and 40% of water requirement), and superabsorbent (0, 100 and 200 kg. ha − 1), leading to a wide range of alterations in traits. For comparison purposes, the dataset was normalized. The results showed that SOD and CAT had a decreasing effect on DT; however, anthocyanins slightly alleviated their negative impacts, as anthocyanins, SOD - CAT interaction synergistically promoted DT. Carotenoids did not favor DT individually; however, DT was promoted by carotenoids SOD and carotenoids_anthocyanins_POD interactions. In terms of effecting DT, the antioxidants were ranked from highest to lowest as POD (sum of individual and interactive effects = 2.267), anthocyanins (1.738), carotenoids (1.203), proline (0.613), SOD (-1.75) and CAT (-2.048). The predicted optimal activities/concentrations of antioxidants, obtained by maximizing the regression function, led to 12% increase in DT, which could be used for breeding purposes.