DYNAMICS OF SOLUBLE CARBOHYDRATES IN Ilex paraguariensis PLANTS SUBJECTED TO DROUGHT STRESS

AVICO, EDGARDO H.; ACEVEDO, RAÚL M.; CAPELLARI, PABLO L.; RUIZ, OSCAR A.; SANSBERRO, PEDRO A.

Mar del Plata

Congreso; SAIB - 51 Annual Meeting Argentine Society for Biochemistry and Molecular Biology; 2015

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Soluble sugars are considered as important metabolites in plants under water deficit and carbohydrate storage and it has been traditionally considered a measure of carbon shortage or surplus for growth that reflects the plant carbon source-sink balance. In this sense, the aim of this work was to examine the sugars content in leaves and roots of Ilex paraguariensis plants subjected to progressive soil water deficit. Samples were collected at Ψsoil= ~ -0,04 (field capacity) to -3MPa including a re-watering (RW) treatment. Net CO2 Assimilation (A) was measured with Li-Cor LI-6400. Sugar extraction was performed according to ISO 2103. Glucose (Glu), fructose (Fru) and sucrose (Su) were separated and quantified by HPLC-RI. After 35-day experiment a decreased from 9.8±0.4 to 5.7±0.2 mol CO2 m-2 s-1,when Ψ soil dropped from~ -0.04 to -3MPa, respectively. Therefore, leaf Glu and Fru contents decreased 2 folds respect to the well-watered conditions while Su remained unchanged. At the same time, the content of soluble sugars in roots increased 2-2.5 folds. After 48 hs of irrigation, the levels of Glu and Fru from both organs are similar to the non-stressed condition. Decreasing levels of hexoses concentration in the leaves of stressed-plants could be the result of a lower rate of CO2 fixation due to stomatal closure and / or export to the roots where would contribute to osmotic adjustment.