Response of sweet orange cv 'Lane late' to deficit irrigation in two rootstocks. I: water relations, leaf gas exchange and vegetative growth

• Published in: Irrigation science 2008-07, Vol.26 (5), p.415-425
• Main Authors: Pérez-Pérez, J. G, Romero, P, Navarro, J. M, Botía, P
• Format: Article
• Language: English
• Subjects: Agricultural production; Agriculture; Aquatic Pollution; Biomedical and Life Sciences; Carbon dioxide; cell division; Citroncirus webberi; Citrus aurantium var. chrysocarpa; Citrus fruits; Citrus sinensis; Climate Change; Crop science; crops; deficit irrigation; Environment; Evapotranspiration; Fruit trees; Fruits; Gas exchange; Irrigation; leaves; Life Sciences; mandarins; Moisture content; net assimilation rate; oranges; Original Paper; Poncirus trifoliata; roots; rootstocks; seasonal variation; Seasonal variations; Soil water; soil water content; soil water deficit; Soils; Sustainable Development; tree growth; trees; vegetative growth; Waste Water Technology; Water content; Water deficit; Water Industry/Water Technologies; Water Management; Water Pollution Control; Water potential; Water relations; Water stress; xylem water potential
• ISSN: 0342-7188; 1432-1319
• DOI: 10.1007/s00271-008-0106-3

The influence of a deficit-irrigation (DI) strategy on soil-plant water relations and gas exchange activity was analysed during a 3-year period in mature 'Lane late' (Citrus sinensis (L.) Osb.) citrus trees grafted on two different rootstocks, 'Cleopatra' mandarin (Citrus reshni Hort. ex Tanaka ) and 'Carrizo' citrange (C. sinensis L., Osbeck x Poncirus trifoliata L.). Two treatments were applied for each rootstock: a control treatment, irrigated at 100% ETc (crop evapotranspiration) during the entire season, and a DI treatment, irrigated at 100% ETc, except during Phase I (cell division) and Phase III (ripening and harvest) of fruit growth, when complete irrigation cut-off was applied. Under soil water deficit, the seasonal variations of soil water content suggested that 'Cleopatra' mandarin had a better root efficiency for soil water extraction than 'Carrizo' citrange. Moreover, in all years, trees on 'Cleopatra' reached a lower water-stress level (midday xylem water potential values (Ψmd) > -2 MPa), maintaining a better plant water status during the water-stress periods than trees on 'Carrizo' (Ψmd < -2 MPa). Similarly, net CO₂ assimilation rate (A) was higher in trees on 'Cleopatra' during the water-stress periods. In addition, the better plant water status in trees on 'Cleopatra' under DI conditions stimulated a greater vegetative growth compared to trees on 'Carrizo'. From a physiological point of view, 'Cleopatra' mandarin was more tolerant of severe water stress (applied in Phases I and III of fruit growth) than 'Carrizo' citrange.