Effects Of Light On The Growth Of Vallisneria Natans Under Changing Hydrological Conditions In Poyang Lake

In order to fully elucidate the natural growth and response of typical submerged macrophytes in different hydrological processes of Poyang Lake.First,through the indoor artificial simulation of the effects of different light intensity(800lx?1000lx?5000lx?10000lx and 12000lx)on morphological indexes(Plant height,biomass and tillers),Photosynthesis markers(chlorophyll content a + b concentration,chlorophyll content a / b,total chlorophyll content)?Antioxidant system Molecular markers(SOD,POD,CAT and MDA content)of submerged macrophytes Vallisneria.Secondly,through the field investigation of Poyang Lake and the collection of typical butterfly lake hydrological data in Wucheng Nature Reserve,the typical hydrological years of Poyang Lake were simulated,and the change rule and transparency of water intensity influences,to determine the morphological markers respectively(plant height,biomass and tiller number),physiological and biochemical markers material(chlorophyll content,SOD,POD,CAT content).demonstrate the growth process and suitable mechanism of Vallisneria in different hydrological conditions.(1)The response of the physiological and biochemical indexes to the simulated light intensity of the submerged seedlings of submerged plants was found to be in the optimal state of the growth of the seedlings in the light intensity of about 5000 lx.The effect of relatively high or low light on the seedling of Vallisneria was significant.Among the 800 lx and 1000 lx low light conditions,the growth indexes of Vallisneria were worse than those of other groups,and some of them showed senescence and death.(2)In the perennial hydrological year and the low water hydrological year,the growth period of 5 and 6 months(light intensity: 8.05 klx ~ 13.47klx).In the retention of water hydrological year,the wet period after July(light intensity: 2.04 klx below),bitter grass plant height is negative growth.It was also found that,as the light became weaker,Vallisneria biomass was more distributed on the ground.The activity of antioxidant enzymes showed an increasing trend in perennial hydrography,while in the period of water retention,the activity of antioxidant enzymes showed a sudden drop in July.In addition,the activity of POD and CAT in the two antioxidant enzymes also found a sudden increase in the year of dry water.The comprehensive analysis of IBR shows that the higher water level in the water retention period contributes the most to the comprehensive effect of the biomedical markers of Vallisneria,and the influence of the lower water level can not be neglected.(3)The correlation analysis showed that there was a significant positive correlation between SOD activity,POD activity and CAT activity.From the relationship betweenmorphological and physiological indexes,there was a negative correlation between plant height increment and SOD activity,POD activity and CAT activity.