biologia plantarum

Biologia plantarum 68:22-30, 2024 | DOI: 10.32615/bp.2023.035

Putrescine priming effects on chlorophyll fluorescence, antioxidant enzyme activity, and primary metabolite accumulation in maize seedlings under water deficit

C.C. Toledo¹, A.C.C. Da Silva¹, M.C. Del Peloso¹, M.A. Leite¹, L.A.A. Bressanin², G. EsteveS², P.C. Magalhães³, T.C. De Souza², P.R. Dos Santos-Filho^{1, *}

¹ Federal University of Alfenas - UNIFAL-MG, Biochemistry Departament, Alfenas, MG, 37130-001, Brazil

² Federal University of Alfenas - UNIFAL-MG, Institute of Natural Sciences, Alfenas, MG, 37130-001, Brazil

³ Maize and Sorghum National Research Center, Sete Lagoas, MG, 35701-970, Brazil

This study aimed to evaluate the effect of putrescine priming on the initial growth, chlorophyll fluorescence, primary metabolites accumulation, and antioxidant enzyme activities in two maize hybrids with contrasting drought tolerances. Seeds of Zea mays L. hybrids DKB 390 (drought tolerant) and BRS 1030 (drought sensitive) were primed with putrescine (10 or 100 µM). Paper rolls moistened with distilled water or mannitol (-0.6 MPa) were maintened at 30°C for 7 d. The growth parameters were higher in the DKB hybrid than in the BRS hybrid. Putrescine priming (10 µM) promoted the root growth of BRS at levels similar to those of DKB and improved photochemical and non-photochemical quenching and maximum quantum efficiency of BRS seedlings. Higher levels of reducing sugars were found in DKB seedlings when compared to BRS in both roots and leaves, especially with 100 µM putrescine. Total soluble sugar and starch were lower in the maize roots under water deficit and with 10 µM putrescine for both hybrids. BRS seedlings showed higher starch content in the leaves in the control and 10 µM putrescine treatments. Superoxide dismutase was activated in BRS plants by the priming, especially in the roots, but this effect was not observed for catalase, ascorbate, or guaiacol peroxidase, although the DKB seedlings presented much higher guaiacol peroxidade activity than BRS seedlings in both the roots and shoots. In conclusion, putrescine priming (10 M) improved the morphological and biochemical responses of the drought sensitive maize hybrid BRS.

Keywords: antioxidant enzymes, chlorophyll fluorescence, photochemical quenching, polyamines, sugars.

Received: May 23, 2023; Revised: October 23, 2023; Accepted: October 26, 2023; Published online: April 12, 2024  Show citation