Does hydraulic lift exist in shallow-rooted species? A quantitative examination with a half-shrub Gutierrezia sarothrae

• Published in: Plant and soil 1993-06, Vol.153 (1), p.11-17
• Main Authors: Wan, C. (Texas Tech Univ., Lubbock, TX (USA). Dept. of Range and Wildlife Management), Sosebee, R.E, McMichael, B.L
• Format: Article
• Language: English
• Subjects: ABSORCION DE AGUA; ABSORPTION D'EAU; AMERICA DEL NORTE; AMERIQUE DU NORD; Animal and plant ecology; Animal, plant and microbial ecology; ARBUSTE; ARBUSTOS; Autoecology; Biological and medical sciences; CLIMA SEMIARIDO; CLIMAT SEMI ARIDE; COMPOSITAE; DROUGHT STRESS; ESTRES DE SEQUIA; EVAPORACION; EVAPORATION; Fundamental and applied biological sciences. Psychology; Gutierrezia sarothrae; Hydraulics; Moisture content; NORTH AMERICA; Plant roots; Plants; Plants and fungi; RACINE; RAICES; Rangeland soils; ROOTS; SEMIARID CLIMATE; SHRUBS; Soil depth; Soil hydraulic properties; Soil water; Soil water content; SOUS SOL; STRESS DU A LA SECHERESSE; SUBSOIL; SUBSUELO; WATER UPTAKE; XEROFITAS; XEROPHYTE; XEROPHYTES
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/BF00010540

Hydraulic lift occurs in some deep-rooted shrub and herbaceous species. In this process, water taken up by deep roots from the moist subsoil is delivered to the drier topsoil where it is later reabsorbed by shallow roots. However, little is known about the existence of hydraulic lift in shallow-rooted xeric species. The objectives of this study were 1) to ascertain whether hydraulic lift exists in Gutierrezia sarothrae (broom snakeweed), a widespread North American desert species with a shallow root system, grown in pot and field conditions and 2) if it does, how much water can be transferred from the subsoil to the 30 cm topsoil during the night. Snakeweed seedlings were transplanted in buried pots allowing the deeper roots to grow into the subsoil 30 cm below the surface. Soil water content inside and outside of the pot was measured seasonally and diurnally with time domain refiectometry technique (TDR). An increase in water content was detected in the pot after the plant was covered for 3 h by an opaque plastic bag during the day, suggesting hydraulic lift from deeper depths and exudation of water into the drier topsoil. Root exudation was also observed on native range sites dominated by snakeweed. Water efflux in the pot was 271 g per plant per night, which was equivalent to 15.3% of the extrapolated, porometer-derived whole-plant daily transpiration. Hydraulic lift observed in Gutierrezia improved water uptake during the day when evaporative demand is high and less water is available in the topsoil. We concluded that hydraulic lift might help snakeweed to alleviate the effect of water stress.