Adaptation of the Invasive Plant to Flooding Stress by Hybridization with Native Relatives.

Hybridization is common between invasive and native species and may produce more adaptive hybrids. The hybrid ( × ) of (an invasive species) and (a native species) was found in South China. In this study, , , and × were used as research materials to explore their adaptability to flooding stress. Under flooding stress, the ethylene content and the expression of key enzyme genes related to ethylene synthesis in × and were significantly higher than those in . A large number of adventitious roots and aerenchyma were generated in × and . The contents of reactive oxygen species and malondialdehyde in × and were lower than those in , and the leaves of were the most severely damaged under flooding stress. The results indicate that hybridization catalyzed the tolerance of × to flooding stress, and the responses of × to flooding stress were more similar to that of its native parent. This suggests that hybridization with native relatives is an important way for invasive species to overcome environmental pressure and achieve invasion.