Silicon stimulated bioactive and physiological metabolisms of purple corn (Zea mays indentata L.) under deficit and well-watered conditions

Purple corn (PC) is known to be rich in many bioactive and polyphenolic compounds and these compounds’ role in developing tolerance to unfavorable conditions is a matter of curiosity nowadays. We performed series of experiments to highlight the possible beneficial effects of Si priming [0, 0.75, 1.5, 3 and 6 mM] on PC’s A (photosynthesis rate), E (transpiration rate), WUE (water use efficiency), SPAD, LN (leaf number), SL (seedling length), SW (seedling weight), proline, MDA (malondialdehyde), TAC (total anthocyanin content), TAA (total antioxidant activity), TPC (total phenolic content), Chl A-B (chlorophyll A-B) and carotenoids both under deficit and well-watered conditions. There was a 1-week period between each trait sampling. Among all Si treatments, 1.5 mM (TAC, WUE, MDA) was the most effective under drought while effects of 0.75 mM (A, E, TPC, MDA) were mostly remarkable under well-watered conditions. 6 mM silicon priming triggered the mechanism of drought tolerance of PC by increasing proline and TAA levels while it decreased MDA concentrations. Maximum WUE was obtained from 1.5 mM Si, and the highest carotenoid level was obtained from 3 mM Si treatment under drought. Drought stress made the growth parameters decrease although Si primed seedlings were stronger than the non-primed ones (0.75, 3 mM). Silicon had enhancive effects on TAC, carotenoids, WUE and proline concentrations under well-watered conditions as well. According to our results, Si priming had remarkable effects on drought tolerance and also had beneficial effects under well-watered conditions; hence may be an alternative approach to prevent water waste in the possible PC breeding areas.