Effects Of Soil Water Content On Rhizomatic Germination,Seedin Ggrowth And Physiology Of Triarrhena Lutarioriparia L.Liu.

We used Triarrhena lularioriparia L.Liu which is typical beach wetland plant of Poyang Lake as research object,to study the changes of germination and seedling growth under different soil water content,and the physiological response of Triarrhena lularioriparia L.Liu seedlings to drought stress.(1)Indoor pot control experiment was used to monitor the rhizome germination and seedling growth under different water conditions.Studies have shown that both the rhizome germination and seedling growth are affected by the soil water content.Drought inhibited the germination of rhizomes.The stronger the drought was,the lower the germination rate was,and the water saturation also inhibited the germination to a certain extent.The highest germination rate was 40% soil moisture content.The growth index of Triarrhena lularioriparia L.Liu seedlings(plant height,aboveground biomass,leaf length,leaf width,leaf area,leaf number)showed a trend of increased first then decreased with increasing soil moisture content.(2)The seedling germination(germination rate),growth(plant height,leaf area,aboveground biomass)and photosynthetic pigment index(chlorophyll a,chlorophyll b,chlorophyll a+b,relative chlorophyll,carotenoids)could be imitated by quadratic equations,analyzed quantitatively the relationship between germination,seedling growth,photosynthetic pigments and soil water content of Triarrhena lularioriparia L.Liu.It was determined that the water ecological amplitude of Triarrhena lularioriparia was 7.2%—60.68%,and the optimum moisture ecological amplitude was 22.31%— 40.60%.(3)The physiological indexes of Triarrhena lularioriparia L.Liu seedlings changed with the changes of soil water content under different water stress.SOD content increased first then decreased with increasing soil water content in the middle and later stages of the experiment,it was higher between 30% and 50% soil water content.POD content decreased with increasing soil water content in the middle stage,and increased first then decreased in later stage,it was higher between 5% and 20% soil water content.The stronger the water stress,the lower CAT content in the middle stage,but in the later stage,each group showed an upward trend.The stronger the drought stress,the higher MDA content.The soluble protein content was higher under mild water stress.Proline content decreased with the increase of soil water content.Root activity values of all groups were higher in the early stage,but each group rapidly decreased in later stage,root activity value was higher under the condition of mild drought stress and moisture saturation.All the above indexes were higher in the indoor water control group than in the field control group.