Taking‘ Jingzhoubendisigua’ and‘ Xiangshuai No.5’ as experimental material，this paper studied
the effect of waterlogging stress on the morphology of luffa and balsam pear seedlings，adventitious root anatomical
structure and barrier structure. The results showed that the plant height，number of leaves and fresh weight of luffa
seedling were not significantly different with that of the contrast under waterlogging stress for 12 days. Only after
16 days，those figures were remarkably lower than that of the contrast. But the plant height，number of leaves and
fresh weight of balsam pear seedling were significantly lower than that of the contrast under waterlogging stress for
4 days. The diameter of flooding stem（cotyledons below 1 cm）of luffa seedlings was significantly thicker than
that of the contrast after under waterlogging stress for 8 days. While，there was no significant differences between
balsam pear seedlings and the contrast. After under waterlogging stress for 16 days，there were well developed
aerenchyma in adventitious roots of luffa seedlings，but balsam pear seedlings had not formed aerenchyma yet.
After flooding，the endodermis（at 20 mm）of luffa seedlings adventitious roots appeared inner barrier structure，
while that of balsam pear seedlings appeared higher at 40 mm. This indicated that the main reason for luffa
seedlings more tolerant to waterlogging than balsam pear seedlings was the developed aerenchyma and the inner
barrier structure at 20-40 mm in adventitious roots of luffa seedlings.