Abstract:To determine the impacts of cutting on the growth and photosynthetic fluorescence characteristics of Potamogeton crispus, apexes of the plant were cut with different cutting intensities(0, 15, 30, 45, 60, 75, 90 and 105 cm) in a pool depth of 1.5 m. Results show that:Cutting significantly affected the growth and recovery of the shoot of P. crispus. The plant height of the control group(0 cm) was maximum and had formed canopy on the surface of water. The group of 15 cm restored on the twentieth day of the experiment. The recovery rates of the groups from 30 cm to 105 cm were 69.67%, 17.78%, 8.83%, 5.33%, 2.28% and 1.90%, respectively; Cutting significantly reduced the biomass of P. crispus. Comparing with the control group, the increment of fresh weight of the cutting groups decreased by 23.71%, 54.90%, 81.19%, 85.82%, 90.72%, 94.07% and 95.10%, respectively. The final biomass of the cutting groups from 15 cm to 105 cm declined to 59.36%, 43.16%, 27.69%, 18.73%, 14.66%, 8.14% and 4.07% of the control group, respectively; Cutting has significantly reduced the quantity of the brood bud and the size of each individual and the fresh weight of P. crispus; Cutting with medium and low intensity did not have obvious impact on the leaves of Fv/Fm of P. crispus, but Fv/Fm of high intensity cutting groups(especially 105 cm) has significant impact. The maximal relative electron transport rate(ETRmax) of the leaves rapid light curves had no significant difference. The groups with medium and low intensity increased slightly while the ETRmax of high intensity cutting groups declined. The experimental results show that cutting had obvious effect on controlling biomass of P. crispus and numbers of brood buds, but medium and low cutting intensity was less obvious.