GROWTH AND PHYSIOLOGICAL ATTRIBUTES OF Cordia trichotoma SEEDLINGS IN RESPONSE TO FERTILIZATION WITH PHOSPHORUS AND POTASSIUM

The cultivation of native tree species of economic and environmental interest, such as Cordia trichotoma, still depends on nutritional information. This study aimed to identify the effect of phosphorus (P) and potassium (K) application on the growth and photosynthetic activity of seedlings of Cordia trichotoma. In a greenhouse, ten treatments were tested considering three levels of P (150, 300, and 450 mg dm-3), three of K (50, 100, and 150 mg dm-3) and a control sample (with no fertilization). Pots filled with Red Argisol were used. At 180 days after prick, the following variables were evaluated: shoot height, stem diameter, area dry matter, root dry weight, leaf area, chlorophyll a fluorescence and photosynthetic pigments. The supplementation with P and K promoted increased growth and photosynthetic capacity of the seedlings. The treatment with 450 mg dm-3 of P and 50 mg dm-3 of K provided the highest growth and the best use of the light energy by the photosystem II (Fv/Fm = 0.76), as well as lower energy loss index (Fo = 172.5). It is recommended the application of 450 mg dm-3 of P and 50 mg dm-3 of K, with the aim at higher growth and photosynthetic rate of seedlings of C. trichotoma.