Table 1. Soluble foliar polyamines in the
current year’s foliage of white
spruce (top) and paper birch (bottom) collected in early June
(pre-heatwave) and late August (post-heatwave) of 2016 and 2017.
Polyamine content is expressed as nmol g-1 DW for
putrescine, spermidine, and spermine. 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.