AQUATIC FLORA AND ASSEMBLAGE CHARACTERISTICS OF SUBMERGED MACROPHYTES IN FIVE LAKES OF THE CENTRAL YUNNAN PROVINCE

Aquatic plants in 5plateau lakes of the central Yunnan Province were investigated during the dry and wet seasons.Altogether 80species belonging to 33families and 64genera were recorded.Among them were 39wetland plants,19emergent,12submerged,7floating and 3floating-leaved ones.The flora was found to be diverse in its geographical characteristic.Cosmopolitan was the main floristic elements.There were 22tropical(account for 34.4%of the total genera)and 20temperate genera(account for 31.7%of the total genera),indicating the subtropical characteristics of the flora.In the assemblage of submerged macrophytes,Potamogeton pectinatus,an pollution-tolerant species,was the dominant species in Lake Dianchi,Lake Xingyunhu,Lake Qiluhu.Meanwhile,the submerged macrophytes associations in these three eutrophic lakes were relative simple,with monodominant association such as Potamogeton pectinatus association and Potamogeton malaianus association.Environmental analyses demonstrated that the water depth,Secchi depth and total nitrogen of sediment were the important factors influencing the submerged macrophyte assemblages in these lakes.