Chromosome Numbers and Karyotype Analysis of 9 Species in Hydrocharitaceae Influences of temperature and light intensity on the growth and pollutant removal by Hydrilla verticillata Effects of exogenous calcium on resistance of Hydrilla verticillata (L. f.) Royle to cadmium stress STUDIES ON PRODUCTIVITY OF HYDRILLA VERTICILLATA ROYLE Influence of silts on growth and development of Hydrilla verticillata’s seedling in silt waters Karyotype Analysis of Hydrilla Ultrastructural Study of Leaf Cells Damaged from Hg2+ and Cd2+ Pollution in Hydrilla verticillata Effects of arsenic speciations on contents of main organic acids in Hydrilla verticillata and Potamogeton malaianus Physiological effects of ammonia-nitrogen concentrations on Hydrilla verticillata Effects of Low CO2 on Photosynthetic Characteristics of Ottelia alismoides and Hydrilla verticillata The Ontogeny of Hydrilla verticillata (L.f.) Royle Influence of different sediment nutrients on growth and photosynthesis fluorescence characteristics of Hydrilla verticillata (L.f)Royle Influence of Cd2+ or Cu2+ stress on the growth and photosynthetic fluorescence characteristics of Hydrilla verticillata