[Effect of soil moisture on water potential gradients in the soil-plant-atmosphere continuum (SPAC) of apple orchards in the Loess Plateau, Northwest China].

The variations of water potential gradients through the soil-plant-atmosphere continuum (SPAC) are of great significance to reveal the responses of plant water use to environmental changes. We conducted a continuous experiment to monitor the potentials in the near-canopy atmosphere (Ψ), soil (Ψ) and plant xylems (Ψ) during the growing season in an apple orchard located in the Loess Plateau. The results showed that the average Ψ during the growing season ranged from -0.

Response of sap flow rate of apple trees to environmental factors in Loess Platea of Western Shanxi Province, China.

To clarify the effects of environmental factors on transpiration process of apple trees in rain-fed ecosystem, the dynamics of sap flow in apple trees from Loess Plateau area in western Shanxi Province of China were monitored using the thermal diffusion technique. Meanwhile, environmental factors including meteorological elements and soil moisture content were measured. The results showed that both net solar radiation (R) and atmospheric vapor deficit (VPD) were closely correlated with sap flow rate (J), as the main ones among all the measured environmental factors.