Responses of physiological activities and lateral root anatomical structure of Cercis glabra to waterlogging stress

Abstract

Cercis glabra is a colour-leaf tree with excellent ornamental value, whereas its physiological and morphological responses to waterlogging stress are still unclear. A potted study was conducted to determine the effects of waterlogging stress on antioxidative enzymes (superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT)), lipid peroxidation (in terms of malondialdehyde (MDA) content), relative electric conductivity, and osmotic substance (free proline) of leaves and aerenchyma, lignification, suberization and Casparian strip of lateral roots of C. glabra. The result showed that the SOD, POD, and CAT activity and free proline content of C. glabra were significantly increased by the different degrees of waterlogging stress compared with the non-waterlogged treatment at 8 and 12 days, and the MDA content and relative electric conductivity of C. glabra leaves were significantly increased under the different degrees of waterlogging stress compared to the non-waterlogged treatment at 16 days, and the degrees of change increased among treatments was ranked as total waterlogged > semi-waterlogged > shallow waterlogged. The lateral roots of C. glabra not only formed developed aerenchyma in the cortex but also formed suberization and Casparian strip in the endodermis under semi-waterlogged treatment at 16 days. These results implied that C. glabra had a certain tolerance to waterlogging stress, which was associated with the increasing antioxidant enzyme activity and osmotic adjustment substance content, and with the formation of aerenchyma, suberization and Casparian strip in the lateral root to adapt to the waterlogged environment.