Figure 1

Seasonal changes in overnight dark-adapted maximum photochemical efficiency of photosystem II (Fv/Fm) in 1-year-old shoots in seedlings (closed circles) and the ratio of the budbreak-commenced seedlings to the total (open circles) of Abies sachalinensis (a), and minimum temperature (Tmin) (closed circles) and integrated photosynthetic photon flux density during the morning from sunrise to noon (PPFDint) (open bars) of the previous day to the Fv/Fm measurement (b). Values are means ± standard error (SE) of n = 5–7 for Fv/Fm.