|
|
|
| Stem sap flow of Itea yunnanensis at different habitats in karst region |
| Yang Rui，Xiao Weiping, Yu Lifei |
| College of Forestry, Guizhou University, 550025, Guiyang, China |
|
|
|
|
Abstract Itea yunnanensis at different habitats were taken as the study object in karst region. By using thermal dissipation proble (TDP) measurement method, under the same conditions such as similar crown and climatic factors which determine crown transpiration, the stem sap flow velocity of Itea yunnanensis was measured to reveal the rules of water variation at different habitats in karst region. By observing the fluid flow of Itea yunnanensis on three consecutive sunny days after rain, results revealed that the stem sap flow velocity varied consistently in one day in different habitats, stone face, gully and soil surface. Probably the peak was irregular-shaped curve, and the trend occurred that the sap flow velocity was high in daylight while low at night, and it reached climax during 10:00 to 14:00. The fluid flow velocity of Itea yunnanensis varied in different habitat types. The highest variation was in the stone face, followed by soil surface, gully had no obvious variation, which reflected three different water heterogeneity in karst region. The average sap flow fluid of three habitats were given as follows: stone face＞gully＞soil surface, and all increased over time with increased overall coefficient of variation. It can be concluded that water transmission capacity and water use efficiency in stone face was stronger than other habitats, and the soil surface was the weakest.
|
|
Received: 26 October 2010
|
|
|
|
|
|
|
