Thu, Aug 18, 2022: 9:15 AM-9:30 AM
518B
Background/Question/MethodsIn this study, we measured the P50, the negative pressure inducing 50% loss of hydraulic conductivity in the xylem ducts (lethal threshold in conifers), in two tree species with high ecological and economic value in Quebec: white spruce and black spruce. We compared the P50 of these species at the seedling, sapling and adult stages.
Results/ConclusionsWe observed that white spruce and black spruce had generally similar P50. Also, the P50 of spruce saplings was more negative than that of mature spruce. However, there was an interaction between species and ontogenic stage; in white spruce, the P50 was more negative for the sapling stage than for the mature stage, whereas in black spruce the P50 of the two stages did not differ. And the mature white spruce reached P50 at less negative pressures compared to mature black spruce. We conclude that the vulnerability to cavitation of spruce trees increased between the sapling and mature stages, particularly in white spruce, which becomes more vulnerable to cavitation than black spruce in the mature stage.
Results/ConclusionsWe observed that white spruce and black spruce had generally similar P50. Also, the P50 of spruce saplings was more negative than that of mature spruce. However, there was an interaction between species and ontogenic stage; in white spruce, the P50 was more negative for the sapling stage than for the mature stage, whereas in black spruce the P50 of the two stages did not differ. And the mature white spruce reached P50 at less negative pressures compared to mature black spruce. We conclude that the vulnerability to cavitation of spruce trees increased between the sapling and mature stages, particularly in white spruce, which becomes more vulnerable to cavitation than black spruce in the mature stage.