Response Of The Plants In The Karst Rocky Desertification Control Areas To Drought Stress

Based on the national Twelfth Five-Year Plan Period science andtechnology support program project“Karst plateau velly rockydesertification comprehensive treatment technology anddemonstration”(2011BAC09B01),surveyed the growth characteristicsof plants in demonstration sample plot,selected1year old LoniceraJaponica Thunb,Juglans regia L.,Zanthoxylum bungeanum Maxim, Rosaroxburghii Tratt to test with morphology,physiological andbiochemical indexes(soil water content,leaf relative water content,chlorophyll content,relative electrical conductivity,SOD activity,POD activity,CAT activity,MDA content,proline content)characteristics under water stress.The main conclusions are asfollows:1．Drought effects the morphology of plants.In the early dayson drought stress，the morphology of plants change little；duringthe7day to the14day stage,the leaves began to lose water and wilteven to be yellowing and the leaves of Juglans regia and Rosaroxburghii wilted obviously；during last7days of water stress，the leaves of Juglans regia and Rosa roxburghii wilted seriously，began to dried-up and fall off,the leaves of Zanthoxylum bungeanumand Lonicera Japonica wilted seriously，they had relative later changes.2．Soil water content changed obviously under drought stress.During the early7days stage the soil water of Juglans regia contentwent down rapidly，at the21th day stage，the decline soil waterof four plants content changes little between different plans，the soil water of Zanthoxylum bungeanum is little higher than otherplants.The decline of water content in leaves of Zanthoxylumbungeanum was small，Lonicera Japonica and Juglans regia as second，the decline of water content in leaves of Rosa roxburghii ishighest.3．Under drought stress，chlorophyll content of four kinds ofplants changes different with the extension of stress.In the first14days of drought stress，the chlorophyll content of Zanthoxylumbungeanum Maxim and Lonicera Japonica increase with the intensityof drought stress，but chlorophyll content of Juglans regia and Rosaroxburghii decrease,drought stress promoted the synthesis ofchlorophyll of Zanthoxylum bungeanum and Lonicera Japonica，andinhibited the chlorophyll synthesis of Juglans regia and Rosaroxburghii.At the21day stage of stress，the chlorophyll contentof Zanthoxylum bungeanum and Lonicera Japonica started to decline，Rosa roxburghii have a rising and then decreased，Juglans regiahas declined. 4．Under drought stress, the SOD activity of Zanthoxylumbungeanum, Lonicera Japonica, Juglans regia leaves decreased afterthe first rise, Rosa roxburghii SOD activity showed decreases afterthe first rise; the POD activity of Zanthoxylum bungeanum, LoniceraJaponica, Juglans regia leaves increased first and then decreased,the POD activity of Rosa roxburghii increased with the droughtstress intensity; the CAT activity of Lonicera Japonica and Juglansregia changed alike, which is to increase first and then decrease,the CAT activity of Rosa roxburghii decreasing with the droughtstress intensity,and the CAT activity of Zanthoxylum bungeanumshowed decrease first and then increase. Under continuing droughtZanthoxylum bungeanum SOD activity was positively correlated withPOD,significantly correlation with CAT(P<0.05), POD and CAT weresignificantly correlated(P<0.05); Juglans regia SOD and PODactivity was significantly correlated (P<0.01),and a positivecorrelation with CAT,positive correlation between POD and CAT;Zanthoxylum bungeanum SOD activity and POD activity wassignificantly associated(P<0.01),negatively correlated with CATactivity;Rosa roxburghii SOD activity and POD activity wassignificantly correlated(P<0.01),and CAT was a significantcorrelation(P<0.01),POD and CAT was a significant correlation.5．Four leaves relative conductivity were rising with droughtstress intensity increases. Lonicera Japonica changed fastest,Rosa roxburghii relatively minimal changes, Zanthoxylum bungeanumand Juglans regia in between. MDA content changed inconsistent of four plants, MDA content of Zanthoxylum bungeanum showed anincrease in first seven days and14-21days,declined in other twostages.Lonicera Japonica increased MDA continuous accumulationwith drought stress and reached the maximum at the28day.Rosaroxburghii increased first and then decreased in the drought dress.Juglans regia increased the maximum at21day and then decreased.Proline content increased with intensity increasing of drought，Lonicera Japonica increased slowly and Zanthoxylum bungeanumincreasing trend is most intense.6．Combined with plant morphology, using mathematical analysisto evaluate the index of four plants，the result showed that theorder of the strengths of four kinds of plants were：Zanthoxylumbungeanum> Lonicera Japonica> Rosa roxburghii> Juglans regia.