Study On The Relationship Between Variation Of Stem Diameter And Sap Flow About Ligustrun Lucidum

Dendrometer and TDP (Thermal Dissipation Sapwood Flow Velocity Probe) were applied to study the relationgship between stem diameter variation and sap flow fluctuation of Ligustrun lucidum .The main suggestions are showed as follow.(1) When the weather was sunny or cloudy, the growth variation of the stem diameter was contraction-expansion– growth, it has relationship between the indexs of the stem diameter and meteorological factors.The rainfull had great influence to the diameter of stem, the diameter dewindles as the rainfull increases.Therefore the rainfull was the main meteorological factor to the variation of the stem diameter.(2) The growth curve of stem presents a"s"-type.Between June to August, the plants grows better by controlling the water as the plants needs(3) In sunny or cloudy day, the sap flow revealed a single-peak curve.It responds rapidly to the change of the meteorological factors.In rainy day, the sap flow reduces suddenly when the weather begins to rain, and then it goes back normal at last.(4) In the growing period, the rates of sap flow increased grandually.The rates of sap flow at April is higher than it was in May, because the leaves bagan to fall.In September, the rates of sap flow keeps the high level for the leaves did not fall in Autunm.(5) The stem diameter and the sap flow the relationship were inversely, and related which could all precipitates the status of the plant.The stem diameter showed the growing conditions of plants in a long time, the sap flow showed the activities of vitalmovement of plants immediately.(6) In sunny day, the stem diameter and the sap flow respondeds clearly to the change of the meteorological factors.In cloudy day, the sap flow respondeds to the change of the meteorological factors immediately.The stem diameter showed that the air temperature is the main meteorological factor at the early days of the growing period, and the photosynthetically active radiation became the main meteorological factor at the later period of the growing period.(7) The diurnal variation of sap flow of each branches revealed a single-peak curve.There existed significant correlations between the stem sap flow of bough and branch #1 ( r = 0.837) , branch #2 ( r = 0.364) , and branch #3 ( r = 0.761).Compare the peak height of each branches, it is known that the peak height of the bough significantly is greater than other branches which is conformed to the actual flow from the bough to branches.The average sap flow rate for branches and the diameter of branches shows that the smaller the diameter of branches is, the weaker the adaptability of environment could be.