Figure 2.

Light-response curves for ETR_R and C_i/C_a (a–f) as well as A_S and g_s measured at 2000 μmol m⁻² s⁻¹ photosynthetic photon flux (PPFD; g–l) for three fern species at 25 °C and 75% (open symbols, data from [3]) and 50% (closed symbols) relative humidity. A_S and g_s indicate the net photosynthetic rate and stomatal conductance, respectively, from steady-state light response; ETR_R indicates electron transport rate from rapid light response; C_i and C_a indicate intercellular and atmospheric CO₂ concentration, respectively. Squares, circles, and triangles indicate cultivated under 100%, 50%, and 10% sunlight, respectively. Data are mean ± SE.