Comparison of Morphological and Anatomical Characteristics of Taxus chinensis var. mairei Seedlings Root under Waterlogging Stress in Different Substrates

Four different ratios of river sand, ceramic pellets, vermiculite and perlite (1:1), and field soil were selected as thesubstrates in this experiment, and four gradient levels of root waterlogging, half waterlogging, full waterloggingand normal were set to investigate the effects of different gradients of waterlogging stress on the root morphologyof Taxus chinensis var. mairei seedlings under different substrates. In this study, the root anatomical structure ofTaxus chinensis var. mairei under different waterlogging stress was observed by the paraffin section method. Theroots of T. chinensis var. mairei were diarch, with no pith and resin canals. There was a large number of tannins inthe pericycle of the aerial adventitious roots of seedlings adapted to waterlogging. Also, the endodermis hasobvious casparian strip thickening, and there were 4-5 layers of large parenchymatous cells in the close to theinner side of the pericycle in the vascular cylinder, which could increase the storage capacity, and transport capacity of the root. Under the treatment of root waterlogging stress, the development of plant roots in the mixedsubstrate of vermiculite and, perlite was the earliest. Under half waterlogging stress, T. chinensis var. mairei seedlings treated with various substrates all could better adapt to the environment of waterlogging stress. Under thestress of fully waterlogging, the roots of seedlings planted in river sand substrate developed secondary growth.