Chromosome Numbers and Karyotype Analysis of 9 Species in Hydrocharitaceae AUeviatory Effect of Exogenous Glutathione (GSH) on Hydrocharis dubia Toxicated by Zn2+ Physiological studies on poisoning effects of Cd on Hydrocharis asiatica through inhibition of Pi Toxic effect of cadmium on Hydrocharis dubia co-composting of aniseed marc, filter mud