Water status and osmoprotective responses in lettuce (Lactuca sativa var. Capitata L.) grown under conditions of water deficit

Trabajo presentado al XIV International Plant Water Relations Symposium (Simposio Internacional de Relaciones Hídricas en Plantas), celebrado en Madrid (España) del 3 al 5 de octubre de 2018.
Reducing water consumption and enhancing the quality of vegetables is a high priority in agronomy. The aim of this study was to examine how the reduction of water supply affects lettuce water status and osmoprotective responses. When defining plant water relationships, apart from the well-known attributes of transpiration rate and relative water content, here the unfreezable and freezable water content was also determined in lettuces grown under three different regimens of water supply: well-watered (WW); moderate water deficit (MWD); and severe water deficit (SWD). Several approaches were used to assess solute accumulation, including the determination of the total soluble solids (ºBrix) and the decrease in the freezing onset temperature, in cinjunction with changes in the apparent viscosity and density. Short-chain fructooligosaccharides (FOS) and raffinose-oligosaccharides (RFOs) were also analyzed by mass spectometry. The chromatic characteristics and the chlorophyll a/b ratio of the plants were also taken into account as a measure of senescence and the stress-related deterioration of lettuces. Our results indicate that MWD lettuces exhibit moderate net solute accumulation, undergoing fewer changes that resemble senescence and accumulating more short-chain oligosaccharides, all of which may contribute towards water stress tolerenace.
This work was financed by a Spanish National Research Project AGL2017-85291-R (MINECO/AEI/FEDER, UE).