EFFECTS OF ALUMINUM ON HONEYLOCUST (GLEDITSIA-TRIACANTHOS L) SEEDLINGS IN SOLUTION CULTURE

Honeylocust (Gleditsia triacanthos L.) seedlings were grown in solution culture at pH 4.0 with 50, 150, 600 and 1500 mmol m-3 aluminium. All levels of aluminium reduced the size and weight of roots, shoots and leaves with the exception of root elongation at 50 mmol m-3 Al. Aluminium content of roots was 50 to 100 times that of shoots. With increasing concentration of aluminium, aluminium content of leaves and roots increased exponentially while a linear increase was observed for stems. The nutrient content of seedlings was improved in 50 mmol m-3 where increases in shoot calcium, magnesium, and phosphorus concentrations were observed. Aluminium concentrations greater than 50 mmol m-3 reduced shoot nutrient content. Presence of aluminium increased the root phosphorus and calcium levels but had no effect on potassium and magnesium concentrations. Results show that honeylocust is an aluminium sensitive tree species whose growth may be reduced by high soil Al levels.