Abstract: | In Ochroma pyramidale (Cav. ex Lam.) Urb., photon-saturated photosynthetic capacity (P
Nmax) was 13 mol(CO2) m–2 s–1. Average stomatal conductance (g
s) and water-use efficiency (WUE) were greater at high irradiance, about 260 mmol(H2O) m–2 s–1 and 2.15 g(C) kg–1(H2O), respectively. In the dark, g
s values were about 30% of maximum g
s. Leaf nutrient contents on a leaf area basis were 131, 15, 36, 21, and 12 mmol m–2 for N, P, K, Ca, and Mg, respectively. Ochroma also accumulated a greater amount of soluble saccharides than starch, 128 versus 90 g kg–1 (DM). The availability of N and Mg, but not P, Ca, or K, may limit photosynthetic rates of Ochroma in this site. |