Author(s): Yi Min Zhang, Fei Yang, Meng Jie Ma, Yue Xiang Gao, Long Mian Wang, Ming Kong, Yueing Zhu
Linked Author(s): Yimin Zhang
Keywords: Submerged macrophyte, flow velocity, morphological traits, hydrodynamic performance, photo-synthetic fluorescence characteristics
Abstract: Morphological traits (plant height and average biomass), hydrodynamic performance (drag, drag coefficient (Cd) and E-value) and photosynthetic fluorescence characteristics (Fv/Fm and rapid light curves) of various initial densities of four canopy-former species (Hydrilla verticillata, Potamogeton malaianus, Myriophyllum spicatum and Potamogeton crispus) were studied under different flow velocities. The results demonstrated that the largest average plant height and biomass appeared in 0. 05m/s and decreased significantly with increasing flow velocity when the velocity is more than 0. 05m/s (P<0. 05). The drag exerted on plants also increased with increasing velocity (P<0. 05). The value of Cd and E-value of four submerged plants were significantly different (P<0. 05), which presented P. crispus < M. spicatum < P. malaianus < H. verticillata. The Fv/Fm and RLCs in the 0. 05m/s were higher than 0m/s and 0. 1m/s-0. 3m/s had a negative impact on Fv/Fm and RLCs. It was evident from this study that high flow velocity inhibited the normal growth of all four plants, while low velocity did not harm them. M. spicatum was found to possess high adaptability to cope with this mechanical stress, which was the preferred species for the aquatic plant recovery. Moreover, faced with high velocity, the negative effect of water movement on plants could be reduced by increasing initial planting densities
Year: 2017