Toxicity of aluminium to pinapple (Ananas comosus) grown on acid sands of Cross River State, Nigeria
A solution culture experiment was carried out in April, 2003 at Calabar using two cultivars of pineapple suckers (Ananas Comosus) smooth Cayenne, and Queen to assess the Al toxicity to pineapple solution culture, consider the Al up-take, and attendant Al symptoms, together with shoot and roots growth. The treatment consisted of three levels of Al concentrations 0, 0, 0.35 and 0.070mmol dm-3, combined with four levels of ionic strength produced by diluting a complete nutrient solution to relative concentration of 1.0, 0.5, 0.25 and 0.12. The phosphorus (P) ion concentration of each solution was adjusted to 0.1mmol dm-1. The pH of the solution was maintained at 4.5 0.3. The results showed that shoot and root growth decreased significantly under the Al treatments. The observed lateral roots of AI stressed plant of the two varieties was significant (P<0.05). The roots were thicker, shorter and fewer in number. Smooth Cayenne responded more to Al-stress than Queen Cultivar and the effect was significant given equal experimental treatments. The younger leaves of Al-stressed plants were small curled along the margin and frequently Chlorotic. The effect was less pronounced in Queen than in smooth Cayenne. Leaf analysis of Pineapple suckers showed reduction in Ca and P and increased AI value for plants exposed to excess of soluble AI. When the Al-concentration solution was made constant, the growth of suckers in both varieties was significantly reduced with dilution of the nutrient solution. All roots of Al-stressed pineapple suckers changed from a milky to a brown colour within a few weeks due to excessive concentration of solution Al.
Global Journal of Environmental Sciences Vol. 6 (1) 2007: pp. 15-20