Growth of and potassium transport in winter wheat and durum wheat as affected by various aluminum exposure times

Effects of various aluminum (AlCl3) concentration and exposure times (6, 12, and 24 h and 3 d) on growth and potassium (K) transport were studied in two wheat species (Triticum aestivum L. cv. Jubilejnaja 50 and Triticum durum Desf, cv. GK Betadur) grown in low salt conditions hydroponically. In longer (3 d) Al exposure times at pH 4.1, the inhibition of root growth appeared at 10 mu M Al3+ treatment in GK Betadur, and at 50 mu M Al3+ treatment in Jubilejnaja 50. Shoot growth was not influenced by Al3+ treatment, except at 100 mu M in 7 d experiments. In 6, 12, and 24 h Al3+ exposure times, at low pH, the K+(Rb-86) influx in roots increased as the Al3+ concentration increased in the outer medium in both species. It also appeared in K+(Rb-86) transport toward the shoots, except by higher Al3+ treatments of GK Betadur seedlings. At the same time, in longer-term (3 d) Al3+ treatments, a striking inhibition were observed in K+(Rb-86) influx and K+ concentration of roots and shoots. The K+ concentration of roots and shoots measured at the end of 24 h Al3+ exposure times was significantly not affected by Al3+ treatment. Durum wheat proved to be more sensitive to the Al toxicity than common winter wheat.