Physiological mechanism contributing to efficient use of water in field tomato under different irrigation

An open field experiment was conducted under furrow irrigation with 3 treatments: CK (control), PRD (partial root drying) and RDI (regulated deficit irrigation). The results showed that water potential, water content of the leaf and growth were decreased under PRD and RDI and the plants met stronger water stress under RDI than under PRD regime. The water use efficiency (WUE) based on fruit yield reached to 10.95 kg/m(3) and 15.33 kg/m(3), i.e. 17.1% and 63.9% increase over CK under RDI and PRD, respectively. The transpiration efficiency in RDI was kept at the same level as CK, whereas it was promoted by 32.4% under PRD condition. CAT, SOD and POD activities were more active under RDI and especially under PRD than under CK. Therefore, following conclusions could be made: moderate water stress induced osmotic regulation under PRD conditions, leading to normal water status higher antioxidant enzymes activities, the same level of biomass and lower water use, thus providing some part of mechanism to higher WUE under PRD condition.