Research On Sap Flow Velocity Of Red Fuji Apple Trees Grown In The Loess Plateau

The plantation area of apple trees expands increasingly recently in the west of china, while this area is short of water. In water shortage areas, it is especially important to manage water use of fruit trees effectively. Therefore, in order to guide the irrigation at right time, suitable amount and proper place and provide a theoretical basis and the technical guidance, it is important to understand transpiration process and mechanism of water uptake and use in the apple tree.In this thesis, the present status and existing problems of water transport mechanisms and sap velocity of apple were analysed firstly. From April to October in 2007, experiments were conducted in Baoji demonstration apple orchard located at Dashaao, Fengxiang, Baoji, Shanxi province to investigate the sap flow velocity change in different condition of apple trees grown in Loess Plateau with common management and analysis the effecting factor. The same experiment was conducted at Mata farm located at Huangling Shanxi province.The main results are as follow:(1) The trend of the sap flow velocity along the radius below the cambium in sapwood is decreasing to the heartwood as a single tree. The velocity of the position 12 mm under the cambium is 0.6 to 0.7 of velocity at 5 mm, while the velocity at 32 mm is only 0.2 of velocity at 5 mm.(2) The trunk sap flow velocity behaves a single-peak curve in sunny days, the sap flow velocity begins ascending at 6:30-7:00 from April to August, the velocity can be more than 4 to 5 cm/h and reaches peak at 12:30-14:30. In this period, the velocity keep more than 45 to 57 cm/h, maximum is 64.6 cm/h. the velocity get the lowest at 22:00 and keep it to the next morning. In this period, there is almost no big sap flow, the trunk sap flow velocity behaves a more-peak curve in the cloudy day, and the peak velocity is low.(3) In the main growing season of apple, the change of sap flow velocity is the same with the solar radition, and the peak of solar radiaton is get earlier than the peak of sap flow velocity. The solar radition has a direct effect on the sap flow velocity.There is a combined impact caused by solar radiation, air temperature and RH on the resistance of stoma,then effects the change of the sap flow velocity of the apple trees. In the same condition, soil moisture deficit excessively would lead the sap flow lower...