Effects of waterlogging on growth, biomass and antioxidant enzymes on upper ground and roots of two peony cultivars

Tree peony (Paeonia suffruticosa Andr.) is a perennial deciduous shrub with ornamental and medicinal value.Waterlogging stress is an agricultural problem for peony in Jiangnan of China.This study investigated the growth, biomass, cell membrane permeability and antioxidant enzymes of two P. suffruticosa cultivars 'Feng Dan Bai (FDB)' and 'MingXing (MX)'.The response of roots and upper ground to different levels of waterlogging stress in two peony cultivars was also evaluated.Results showed that mild waterlogging stress (MWS) and severe waterlogging stress (SWS) significantly decreased the increment of seedling height, diameter and biomass of leaves.The root biomass increased in FDB but no significant changes in MX.Moreover, cell membrane permeability of leaves and roots also increased, while the chlorophyll content of leaves decreased.Antioxidant enzyme activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) of leaves and roots all increased, along with a gradual increase in malondialdehyde (MDA).Of this two cultivars, the root system of FDB is more susceptible to waterlogging than the upper ground, and the root system can improve the resistance to waterlogging by increasing the root system biomass, Peony adapted to the waterlogging environment by changing its external form.