Growth and Gas Exchange of Cnidoscolus quercifolius Fertilized With Potassium and Under Water Deficit

This study aimed to investigate the gas exchange, growth and biomass production of Cnidoscolus quecifolius fertilized with potassium and submited to different water conditions. The experiment was conducted in a completely randomized design, with 4 replications and two plants per experimental unit, with treatments arranged in factorial scheme 3 × 4, corresponding to three levels of potassium (0 (control), 97.5 and 195 mg dm-3 K) and four levels of water (100% (control), 75%, 50% and 25% of pot capacity). Growth (height, shoot diameter, leaf area, and dry mass) and physiogical parameters (water potencial (Ψw), stomatal conductance (gs), transpiration rate (E), net photosynthesis (A), CO2 intercelular concentration (Ci), carboxylation efficiency (A/Ci), and intrinsic water use efficiency (A/E). Increase in potassium promoted rise in Ψw, gs, E, and A. However, it not influenced the growth parameters, except roots dry mass. Reduction in water levels reduced Ψw, gs, E and A, growth and dry matter production of plants. It is recommended that the substrate moisture level of 75% of the pot capacity in the early growth stages of faveleira seedlings.