Research Of The Effect On Hydrophytes Growth Under Oxygen Stress

The gaseous metabolisms of aquatic plants were a series of complicated processes. Plants will develop aerenchyma to maintain their metabolism activity when they were under hypoxia circumstance. So it is important to research the pathway of oxygen obtaining and using. Our research choose five hydrophytes: Paragmites australis, Typha orientalis, Potamogeton distinctus, Ceratophyllum demersum and Lemna minor as experimental materials to analyze dissolved oxygen, organic acid of nutrient solution, plant biomass and survival rate. Our results are as follows:1. The dissolved oxygen increased in daytime because of photosynthesis and decreased in night, so the hydrophytes had an increased diurnal variation both in aerobic and hypoxia nutrient solution. The dissolved oxygen of aerobic solution had a rising gorwth period variation for Paragmites australis, Typha orientalis, Potamogeton distinctus and Ceratophyllum demersum in regular concentration; Paragmites australis and Lemna minor had a decreasing gorwth period variation and a rising variation for the rest species in 1/2 concentration solution; Ceratophyllum demersum decreased roughly whereas the other species had an increasing trends in 1/4 concentration solution. Paragmites australis, Potamogeton distinctus and Ceratophyllum demersum had downtrends in regular concentration solution while all the species had an increasing trend in 1/2 and 1/4 concentration solution with hypoxia treatment.2. Water temperature had a significant effect on dissolved oxygen so that there was a positive correlation between dissolved oxygen and water temperature.3. The organic acid increased both in aerobic and hypoxia nutrient solution and there were no significant differences between two oxygen types.4. The biomass of hydrophytes were higher in aerobic solution and the biomass in 1/2 concentration nutrient solution was the highest.5. Different plant had a different survival rate in nutrient solution with different oxygen treatment. The survival rate in aerobic solution was higher than that in hypoxia solution and the survival rate of emerged plants were bigger than floating-leaved and submerged plants.