Differential response of plant transpiration to uptake of rainwater-recharged soil water for dominant tree species in the semiarid Loess Plateau

Abstract. Establishing whether uptake of rainwater-recharged soil water (RRS) can increase plant transpiration in response to rainfall pulses requires an investigation evaluate adaptability, especially water-limited regions where rainwater is the only replenishable source. In this study, sources from RRS and three layers, predawn leaf potential (Ψpd), midday (Ψm), gradient (Ψpd−Ψm), were analyzed for two dominant tree species, Hippophae rhamnoides subsp. sinensis Populus tomentosa, pure mixed plantations during growing period (June–September). Mixed afforestation significantly enhanced Ψpd−Ψm, proportion (RUP), relative daily normalized sap flow (SFR) reduced source deep layer (100–200 cm) both species (P<0.05). plantations, large Ψpd−Ψm was consistent with high SFR H. small low P. tomentosa pulses. Therefore, exhibited anisohydric isohydric behavior, respectively, former more sensitive than tomentosa. Furthermore, affected by RUP influenced However, plantation. These results indicate that influence on these different rainfall-pulse-sensitive plants. This study provides insights into suitable plantation selection management considering link between regions.