The Characteristics Of Reproduction Of Three Submerged Macrophyte

Submerged macrophyte plays an important role in lake ecosystems. It is not only a primary producer in the food chain, but also plays a major role in lake nutrient accumulation and circulation, thus, having a great influence on the eutrophication process of lakes. This thesis studies on the reproductive biology of three submerged plants (Potamogeton pectinatus, Potamogeton perfoliatus and Myriophyllum verticillatum) in the Yellow River Hetao irrigation area of Inner Mongolia. The structures of propagation organs of the three submerged macrophyte were observed, and research the seed dormancy and germination of three submerged macrophytes. The shape and distribution of vegetative organ of the three submerged macrophyte were observed, and research the regeneration capacity of shoots. The result shows:(1) The ability of sexual reproduction of three submerged macrophytes is different. The three plants can have a lot of seeds, but we are hard to find the seedling under natural conditions. Their seed coat is very hard and there are have the gas chamber, and these seeds use it to isolation water and air from the outside.(2) Myriophyllum verticillatum seed has a high dormancy rate, but its dormancy is easy to be broken. Various treatments including seed coat scarification, low temperature stratification, applications of KNO3and Gibberellic Acid can significantly increase the germination percentages; Potamogeton pectinatus seed has a deep dormancy. Low temperature stratification and application of Gibberellic Acid can effectively break the seed dormancy, but other treatments had no effect; Potamogeton perfoliatus seed has a deep dormancy. None of the above mentioned treatments can significantly break its dormancy.(3) Myriophyllum verticillatum can use stolons around the mother plant extension growth and the formation of new individuals. Potamogeton pectinatus and Potamogeton perfoliatus have developed underground rhizomes and can rely on these roots extended to more distant places and to formation of new individual, and the Potamogeton pectinatus has more space to expand capacity.(4) The snags of three submerged macrophytes have strong regenerative capacity. Under different treatments the snags of different parts have different survival rate. When snags of Potamogeton plants buried in the mud, its survival rate is very low, but Myriophyllum verticillatum is opposite.(5) Potamogeton pectinatus has more tubers and these tubers can germinate quickly. Then we need to further study on the physiological causes of Potamogeton pectinatus tubers on the dormancy and factor of break dormancy.