Abstract: The dry weight, total N, and glutamate oxaloacetate transaminase(GOT) and glutamate pyruvate transaminase(GPT) activities in roots and leaves of wheat seedlings (Triticum aestivum) grown with ammonium sulfate or amino acids (glycine, glutamate or lysine) were studied under sterile sand culture. The results showed that both NH₄⁺-N and amino acid-N could be absorbed by wheat. The total Nof plant fed with NH₄⁺-N was similar to that fed with amino acid-N. The dry weight of plants grown30 days with glycine or glutamate was significantly higher than that of plants grown with NH₄⁺-N or free N. The dry weight of ammonium treatment was similar to that of lysine treatment or free N. NH₄⁺-N in concentration of 0.7 mmol稬^-1 significantly increased GPTactivity of roots, but had no significant effects on leaves or roots treated 6 h in concentration of 35.7 mmol稬^-1 . Different species or concentrations of amino acids had different abilities to increase the GOTor GPTactivity in leaves or roots.

Key words: Triticum aestivum, Amino acid-N, NH₄⁺-N, Transaminase, Sterile culture, Malus hupenhensis, AFOF, antagonistic bacteria, apple replant diseases