effect of warming and water deficit on the non-structural sugars varations in picea mariana /

Abstract

The aim of the study was to qualify and quantify non-structural carbohydrates (NSC) in stems of black spruce (Picea mariana (Mill.) B.S.P) seedlings. The effects of temperatures and water deficit on the seasonal NSC amount within the stem were also investigated. Weekly secondary growth observations of the stem was correlated to the sugars variations in order to define the most important sugars involved in wood formation in different environmental conditions (water deficit and warmer temperatures). The carbohydrates found in cambium and xylem were mainly composed of sucrose, pinitol, glucose, fructose, raffinose and starch. Water deficit decreased sucrose, while raffinose rose. Temperature had no effect on carbohydrates but amplified the effect of water deficit. Sucrose, pinitol and raffinose were correlated to cambium activity and xylem development, but changes in those carbohydrates quantities only had a little effect on cell development in the stem.