Figure legends
Figure 1. Foliar amino acid content in the current year’s foliage of white spruce in June (pre-heatwave) and late August (post-heatwave) of 2016 and 2017. Amino acid content is expressed as nmol g-1 DW for aspartic acid (a), glutamic acid (b), glutamine (c), serine (d), alanine (e), proline (f), GABA (γ-aminobutyric acid, g), valine (h), methionine (i), isoleucine (j), tryptophan (k), phenylalanine (l), cysteine (m), ornithine (n), and histidine (o). Data are mean (n = 5-8) ± SE. Letters indicate statistical differences (p ≤ 0.05) among treatment groups on a given date based on Tukey’s HSD post hoc test.
Figure 2. Foliar amino acid content in paper birch foliage in early June (pre-heatwave) and late August (post-heatwave) of 2016 and 2017. Amino acid content is expressed as nmol g-1 DW for glutamic acid (a), serine (b), glycine (c), alanine (d), proline (e), GABA (γ-aminobutyric acid, f), valine (g), isoleucine (h), leucine (i), tryptophan (j), phenylalanine (k), cysteine (l), and ornithine (m). Data are mean (n = 5-8) ± SE. Letters indicate statistical differences (p ≤ 0.05) among treatment groups on a given date based on Tukey’s HSD post hoc test.
Figure 3. Foliar total soluble proteins (TSP), chlorophylla +b , total N, and total C expressed as percent change from control values in white spruce (left column) and paper birch (right column). Data was collected in early June (pre-heatwave) and late August (post-heatwave) of 2016 and 2017. Data are mean (n = 5-8) ± SE. Letters indicate statistical differences (p ≤ 0.05) among treatment groups on a given date using the actual data values based on Tukey’s HSD post hoc test. No Data was collected for total N and C in June of 2016.
Figure 4. Simple soluble sugars in the current year’s foliage of white spruce in early June (pre-heatwave) and late August (post-heatwave) of 2016 and 2017. Values are expressed as a percent of the control. Data are mean (n = 4-8) ± SE. Letters indicate statistical differences (p ≤ 0.05) among treatment groups on a given date based on Tukey’s HSD post hoc test. Asterisks indicate quantities below the detection limit.
Figure 5. Simple soluble sugars in the foliage of paper birch in early June (pre-heatwave) and late August (post-heatwave) of 2016 and 2017. Values are expressed as a percent of the control. Data are mean (n = 4-8) ± SE. Letters indicate statistical differences (p ≤ 0.05) among treatment groups on a given date based on Tukey’s HSD post hoc test. Asterisks indicate quantities below the detection limit.
Figure 6. Foliar inorganic ions and P concentration in white spruce (left column) and paper birch (right column) in early June (pre-heatwave) and late August (post-heatwave) of 2016 and 2017. Values are expressed as a percent of the control values for 5% PCA soluble calcium (Ca), potassium (K), magnesium (Mg), manganese (Mn), iron (Fe), and phosphorus (P). Data are mean (n = 4-8). Letters indicate statistical differences (p ≤ 0.05) among treatment groups on a given date based on Tukey’s HSD post hoc test.