Young guava plants were grown in a nutrient solution in the presence of 0, 5, 10, 15, 20 and 25 mg L-1 aluminum, with pH being kept at 4.0. After 110 days, the plants were harvested and their content of macronutrients, Cu, Fe, Mn, Zn and Al were determined. Visual toxicity symptoms, developed under 20 and 25 mg L-1 aluminum, were as follows: reduction in height, absence of branching, decrease in diameter of stem dark roots and smaller leaves presenting reddish petiole. Dry matter was also reduced. The macronutrient, Fe, Mn and Zn concentrations in the leaves sampled (third and fourth pairs from the top) were affected by Al rates. The same did occur with the content of elements in the various parts of the plant. Aluminum toxicity affected particularly the content of P, Ca, Mg, Fe, and Mn with approximately 95% of the Al taken up confined to the root system. Lower rates of aluminum promoted growth.
Psidium guajava; nutrient concentration; aluminum toxicity; fruit growing