Effects Of Soil Moisture Stress On The Growth And Eco-physiology Of Arundo Donax Seedlings

Study on characteristics of drought resistance Arundo donax under different soil moisture conditions based on the reed seedlings indoor pot experiment,different soil moisture gradient to study the morphology,growth and physiological indexes.To explore the character of drought tolerance A.donax under different soil moisture conditions,which is of great significance to the restoration of degraded ecosystems.On the basis of indoor simulation test,and the correlation analysis in grey mathematical theory in different period of reed seedling morphology and growth and physiological indexes of data analysis,the study reached the following conclusions:(1)In the early and middle stage,soil water stress had significant effects on A.donax plant height(p<0.05),and the leaf length,leaf area and leaf width effect was not significant(p>0.05);and at the end of the experiment,soil moisture conditions on A.donax plant height,leaf length,leaf area and leaf width plays an extremely significant effect(p<0.01),when soil water stress is small,A.donax grows better,reached the highest level in the 35% groups(p<0.01).Analysis of the relationship between soil moisture and A.donax morphological indexes through comparison,found at the end of the experiment,the soil moisture gradient reaches 35% ~ 40%,morphological indexes to achieve the best level of A.donax.Plant height is one of the most sensitive indexes of soil water stress at this time.(2)The stress gradient under different soil moisture conditions,A.donax leaf chlorophyll a(Chl a),chlorophyll b(Chl b),carotenoid(Car)and chlorophyll a+b(Chl a+b)content with the test time,variation showed first increased and then decreased,reached the maximum at the beginning of test period in the 45% group,and in late 35% in the test group of more than 45% groups.In the early stage of the experiment,the effect of water stress on each reed biomass was not significantly(p>0.05),and in the middle and late stage,biomass growth is better in the 20%~40%group,35% groups of biomass moisture conditions reached the maximum value,the difference reached significant level(p<0.05).(3)With the increase of stress time,the root activity of each A.donax decline,with the higher level of stress drop is more obvious(p<0.01);malondialdehyde(MDA),proline(Pro)and soluble protein(SP)content increased with the stress time prolonged showed a rising trend;A.donax antioxidant enzyme activity of superoxide dismutase(SOD),peroxidase(POD),catalase(CAT)stress in the early and mid rise,and in the later period of decline(p<0.01)(4)A.donax morphological indicators of resistant to drought stress related order:plant height > leaf area > leaf number > aboveground biomass > leaf length >,underground biomass > leaf width > growth rate > root-shoot ratio;physiological indexes of stress resistance related order: Chl a+b>Chl a>Chl b>SP>SOD>MDA>POD>Pro>CAT>Root activity>Car.Although the reed plant height,SP,Chl a+b,Chl a,Chl b content correlation degree is greater than 0.9,but not on these indexes A.donax to adapt to water stress through regulating the metabolism of habitat,but its function to improve its resilience to maintain its normal growth.