Abstract
Napier grass (Pennisetum purpureum) holds significant forage value in many tropical and subtropical regions. To investigate the production adaptability of napier grass in flood-prone areas, napier grass seedlings were selected to conduct a flooding stress experiment. By simulating different flooding durations and depths indoors, we studied the changes in the morphology of napier grass leaves, leaf photosynthetic and chlorophyll fluorescence parameters. The results indicated the occurrence of yellow leaves across all three groups. Specifically, under shallow flooding conditions, the tips of the leaves of napier grass turned yellow. In semi-flooding conditions, the leaves of napier grass yellowed, wilted, developed brown spots, and the stem base exhibited reddish-brown swelling. Under fully flooding conditions, the growth of napier grass was significantly impacted, with partial shedding of leaves and stems, and a mortality rate reaching 60% after 12 days. Both shallow and semi-flooding treatments induced the formation of aerial roots at the base of the stem in napier grass. The photosynthetic parameters Pn, Gs, Ci, and Tr of napier grass showed an overall downward trend under flooding stress. After the experiment, the values Fv/Fo, Fv/Fm, NPQ, and Qp of napier grass under flooding conditions were higher than those in the control group at the same time point, while the other two groups were lower than the control. Based on these findings, we conclude that napier grass exhibits good adaptability in shallow flooding environments, and can survive for 12 days under semi-flooding conditions.