Effects of grafting on root growth, anaerobic respiration enzyme activity and aerenchyma of bitter melon under waterlogging stress

A potted study was conducted to determine the effects of grafting on the fresh and dry weights; root activity; pyruvate dehydrogenase (PDC), alcohol dehydrogenase (ADH), and lactate dehydrogenase (LDH) activities; and aerenchyma of bitter melon roots under waterlogging stress. Compared with no waterlogged treatment, the fresh and dry weights of roots and root activity of taproots of the grafted bitter melon had reduced levels below those of the self-rooted bitter melon under waterlogging stress. By contrast, the root activity and PDC, ADH, and LDH activities of adventitious roots of the grafted bitter melon had increased levels higher than those of the self-rooted bitter melon under waterlogging stress. Grafting significantly increased the fresh and dry weights of the roots, root activity, PDC, ADH, and LDH of taproots and adventitious roots of bitter melon and expanded the aerenchyma of adventitious roots under waterlogging stress. These results implied that grafting can improve the tolerance of bitter melon to waterlogging stress by increasing the activity of anaerobic respiration enzymes in the taproots and adventitious roots of bitter melon on the one hand and expanding the aerenchyma of adventitious roots of bitter melon on the other hand.