Interactive effect of simulated acid rain, calcium silicate, and γ-aminobutyric acid on physiological processes in corn and wheat

Abstract

The effect of calcium silicate, γ-aminobutyric acid (GABA), and their mixture on the adaptation of wheat and corn to simulated acid rain has been evaluated in the pot experiments. Acid rain was simulated by watering twice with distilled water acidified with sulfuric acid to pH = 2. Test plants were grown in a plant growth chamber under controlled conditions of temperature, illumination and relative humidity for 18 days. The physiological state of the test plants was assessed by characteristics of growth (shoot height, root length, dry weight of shoots and roots), the content of photosynthetic pigments, flavonoids, and proline in leaves. For the corn, the content of anthocyanins in shoots and roots was also evaluated. In parallel, the physical and chemical characteristics of the soil (pH, electrical conductivity, redox potential, content of soluble carbonates, and nitrates) were determined.It was established that simulated acid rain inhibited the growth and accumulation of photosynthetic pigments in the leaves of wheat and corn. The content of protective metabolites (proline, flavonoids, and anthocyanins) increased. Wheat showed greater sensitivity to the inhibiting effect of acidification compared to corn. The application of CaSiO3 was more effective than GABA in restoring pH value and HCO3- concentration in soil, while the application of GABA more effectively promoted the accumulation of NO3- anions in soil. Combining CaSiO3 with GABA was the most effective in restoring soil physical and chemical properties altered by simulated acidification and stimulating the growth and photosynthesis in the test-plants. Thus, the mixture of CaSiO3 with GABA is promising for further studies of the possibility of its application to mitigate the negative impact of acid depositions on vegetation and soil.