IMPACT ON THE SOIL BACTERIAL COMMUNITIES BY THE HERBICIDES USED BY THE Lotus tenuis PROMOTION

AVICO E.; ACEVEDO R. M.; CAPELLARI P. ; RUIZ O.A.; SAANSBERRO P.

MAR DEL PLATA

Congreso; CONGRESO 2015 SAIB; 2015

Sociedad Argentina de Bioquímica y Biología Molecular

Soluble sugars are considered asimportant metabolites in plants under water deficit and carbohydratestorageandit hasbeentraditionallyconsideredameasure of carbon shortage or surplus forgrowth that reflects the plant carbon source-sink balance. In this sense, theaim of this work wasto examinethe sugars contentin leaves and roots ofIlex paraguariensisplants subjected toprogressive soil water deficit.Samples were collectedat Ψsoil= ~ -0,04(fieldcapacity) to -3MPa including a re-watering (RW) treatment. Net CO2 Assimilation (A) wasmeasured with Li-Cor LI-6400.Sugarextraction was performed according to ISO2103.Glucose (Glu), fructose (Fru) and sucrose (Su) were separated and quantifiedbyHPLC-RI.After 35-day experiment A decreased from 9.8±0.4to 5.7±0.2 molCO2 m-2s-1, when Ψsoildropped from~ -0.04 to -3MPa, respectively.Therefore, leaf Glu and Frucontentsdecreased 2 foldsrespect to the well-watered conditions while Su remained unchanged.At the same time, the content of soluble sugarsin roots increased 2-2.5 folds.After48 hs of irrigation, the levels of Glu and Frufrom both organs are similar tothe non-stressed condition.Decreasing levels of hexoses concentration in theleaves of stressed-plants could be the result of a lower rate of CO2fixation due to stomatal closure and / or export to the roots where wouldcontribute to osmotic adjustment.