Hydraulic redistribution in three Amazonian trees

摘要: About half of the Amazon rainforest is subject to seasonal droughts 3 months or more. Despite this drought, several studies have shown that these forests, under a strongly climate, do not exhibit significant water stress during dry season. In addition deep soil uptake, another contributing explanation for absence plant drought process hydraulic redistribution; nocturnal transfer by roots from moist regions profile. Here, we present data on patterns moisture and sap flow in three dimorphic-rooted species Tapajos Forest, Amazonia, which demonstrate both upward (hydraulic lift) downward redistribution. We measured lateral tap our study over 2-year period using heat ratio method, sap-flow technique allows bi-directional measurement flow. On certain nights season, reverse acropetal (i.e.,in direction soil) positive basipetal (toward plant) Coussarea racemosa (caferana), Manilkara huberi (macaranduba) Protium robustum (breu) were observed, pattern consistent with redistribution lift). With onset heavy rains, reversed, continuous night-time root roots, indicating movement wet top deeper soils (downward redistribution). Both trees within rainfall exclusion plot (Seca Floresta) more limited extent control plot. Although has traditionally been associated arid environments, findings now suggest it important ameliorating improving rain infiltration Amazonian rainforests. This broad implications understanding modeling ecosystem forest function biome.