Antioxidant defense system response in groundnut under waterlogging and recovery conditions

Abstract:

Waterlogging ranks among the most damaging abiotic stresses for groundnut, yet antioxidant recovery kinetics after water withdrawal remain poorly documented. This research examined enzymatic and non-enzymatic antioxidant responses of groundnut (Arachis hypogaea cv. Giza 6) under 2, 4, and 6 days of waterlogging followed by 2 and 4 days of recovery at Alexandria College of Agriculture, Egypt, during 2023. SOD, CAT, and APX activities peaked at 4 days of waterlogging (SOD: 112.4 U/mg, CAT: 51.8 µmol/min/mg) before declining at 6 days. MDA increased steadily from 6.8 to 31.4 nmol/g FW over 6 days. During recovery, enzyme activities returned toward baseline within 4 days though full recovery was incomplete. These results indicate that the 4-day threshold marks a turning point beyond which oxidative damage exceeds defense capacity.