Effect of Boric Acid Application on Antioxidant Enzymes Activity and Gene Expression in Safflower (Carthamus tinctorius L.) Cultivars

Abstract

Boron is one of the most important micronutrients for plants. Plants may suffer from deficiency or with boron toxicity. Boron plays a role in significant physiological and biochemical events in plants such as synthesis of the cell wall, membrane integrity, antioxidation, transport of photosynthesis products to other organs of the plant. The enzyme activities of ascorbate peroxidase (APX), catalase (CAT), glutathione reductase (GR) and superoxide dismutase (SOD) in three different safflower cultivars (Balcı, Dinçer and Remzibey) subjected to different boric acid concentrations (0, 5, 10, 15 mM) were measured spectrophotometrically, and the changes in the expression levels of the genes that encode these enzymes were obtained by quantitative RT-qPCR. When both the spectrophotometric measurements and the mRNA values were evaluated together, both the activity and mRNA values of APX and GR enzymes were found to be the highest in the Dinçer cultivar among the varieties treated with 15 mM boric acid, while the lowest values of these enzymes were determined in the Remzibey cultivar. According to the RT-qPCR results, the lowest SOD and CAT values were determined in Remzibey. The Dinçer cultivar was found to have the highest antioxidant capacity (APX, GR) to cope with oxidative stress caused by boric acid application at high concentrations. The sensitive Remzibey cultivar was found to have the lowest antioxidant capacity to cope with such oxidative stress. Balcı was found to be closer to Dinçer than to Remzibey in terms of boron tolerance. As a result, the boron-sensitive cultivar had low antioxidant activity. HIGHLIGHTS• In this study, three safflower cultivar (Balcı, Dinçer, Remzibey) were used.• Four different concentrations of boric acid (0, 5, 10, 15 mM) were applied to the plants.• SOD, CAT, APX, GR activities of plant samples were investigated by spectrophotometric method and expression levels of these enzymes by RT-qPCR.• The Remzibey variety was found to have the lowest antioxidant capacity to deal with oxidative stress compared to other varieties.

Effects of Foliar Boron Application on Physiological and Antioxidants Responses in Highbush Blueberry (Vaccinium corymbosum L.) Cultivars

“…SOD activity plays a crucial role in plants under stress conditions, serving as an indicator of oxidative stress [ 13 ]. In boron-toxicity-tolerant plants like Carthamus tinctorius (safflower), low SOD activity was observed at high B concentrations [ 41 ], which is similar to the findings of this study. A similar behavior was observed in woody citrange orange species, when excess B resulted in decreased SOD activity and reduced activity of other antioxidant enzymes [ 42 , 43 ].…”