| To study water ecological amplitude of Phalaris arundinacea based on Rhizomatic Germination and Seeding Growth,8 moisture gradients were set up in the indoor culturing experiment.The water content is separately 2±0.5%,10±0.5%,15±0.5%,20±0.5%,25±0.5%,30±0.5%,40±0.5%(water saturation)and flooding(2cm),determining the germination rate and various physiological indexes and morphological indexes.The result shows that:(1)Drought or excessive saturated soil moisture lowers the germination of Phalaris arundinacea.But it does make the Phalaris arundinacea rhizome more drought-resistance than seeds.The relationship between the height of Phalaris arundinacea and biomass can be described as a exponential function: y = 0.2038e0.0486x(R2 = 0.8032).With the increase of soil water content,they all show the trend of increasing firstly and then decreasing.The leaf length,leaf width,leaf number and leaf area show the tendency of falling after rising firstly with the increase of soil water content.When the soil water content ranges between 10% and 30%,the water content of Phalaris arundinacea remains relatively constant.Phalaris arundinacea can adapt to the stress environment by adjusting the structural features,reducing the size,and decreasing the leaf number and the leaf area.Phalaris arundinacea's Chl,Car and SPAD content rises at first and goes down latter with increased soil water content,on the condition of which,Chl a/b content decreases firstly and then increases;there is no significant difference between Chl a and Car in these groups.After the quantitive analysis on different morphological indexes and physiologic indexes by means of Gaussian model,it turns out that the water ecological amplitude of Phalaris arundinacea is 7.48%~52.20% and 18.99%~40.60% is the optimum.(2)Through culturing experiment with 7 water treatments: C1(10±0.5)%,C2(15±0.5)%,C3(20±0.5)%,C4(25±0.5)%,C5(30±0.5)%,C6(40±0.5,water saturation)% and C7 flooding(2 cm)for 50 days,effect of soil water concent on photosynthetic pigments,leaf Superoxide(SOD)activity,Catalase(CAT)activity,Peroxidase(POD)activity,Malondialdehyde(MDA)and soluble protein content of Phalaris Arundinacea seedlings was studied under water stress.Results show:(1)The SOD activity was higher when the soil moisture content was 20%-35%.When the soil moisture was lower than 20% or higher than 35%,the SOD activity decreased.Experiment 50 days SOD activity was higher than the experiment 25 days.(2)CAT and POD activity were significantly correlated at the 0.01 level,and show the trend of decreased firstly and then increased with the increase of soil water content.(3)The trend of MDA content and SOD activity was opposite,In contrast to the trend of SOD activity,the content of MDA decreased with the increase of soil water content,but when experiment 50 days C7(flooding 2 cm)increased slightly.(4)The connect of soluble protein was higher when the soil moisture content was 20%-40%,the plants with a better growth.In drought or excessive saturated of soil water content,the contents of soluble protein were significantly decreased.All the results indicated that effect of soil water content on photosynthetic pigments,antioxidase,MDA and soluble protein was closely interrelated with water stress level.(3)Phalaris arundinacea plays a very important role in Baishazhou nature reserve as the second dominant species.Phalaris arundinacea has drought resistance,hygrophilous but not resistant to flooding.The distribution range of Phalaris arundinacea altitude is 9.85 ~ 18.11 m,the main elevation range of 12.13 ~ 15.84 m.In addition,the higher the altitude,the better the growth. |
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