Abstract

Pineapple (Ananas comosus (L.) Merrill.) contains many nutrients and enzyme. It is mostly grown on strongly acid soils in Taiwan. In strongly acid soils, aluminum (Al) is biotoxic and may inhibit growth of crops. This study is to evaluate the effects of different Al concentration in hydroponic solutions on the nutrient uptakes in the roots, stems and leaves of four important Taiwan Ananas comosus (L.) Merrill. (Cayenne, Tainung No.6, Tainung No.13 and Tainung No.17). Cayenne is known as the Al resistance, however, Tainung No.6, Tainung No.13 and Tainung No.17 are Al sensitivity. After cultivating for four weeks, the contents of nutrients in different parts of Cayenne would increase when the Al concentration in the hydroponic solution was increased. However, the nutrient uptake in different parts of the other three cultivars would decrease with increase Al concentration, indicating that the nutrient uptake was inhibited, especially that of Ca and Mg. Our experiments indicate that increases in the uptake of Ca and Mg are important to the reduction of Al toxicity when Cayenne is treated with high Al concentration. If Al concentration was increased, Tainung No.6, Tainung No.13 and Tainung No.17 would reduce their uptake of Ca and Mg which might be one of the reasons for the damage of their root apices.

Key words: Acid soil, aluminum (Al), Ananas comosus (L.) Merrill., nutrient uptake, root apices.