© 1991 Heron Publishing—Victoria, Canada
Clonal variation in amino acid contents of roots, stems, and leaves of aspen (Populus tremuloides Michx.) as influenced by diurnal drought stress
David H. Griffin, Michail Schaedle, Paul D. Manion and Michael DeVit
Department of Environmental and Forest Biology, College of Environmental Science and Forestry, Syracuse, NY 13210, USA / Received July 19, 1990
Summary
Three aspen (Populus tremuloides Michx.) clones were grown hydroponically in growth chambers and subjected daily to 6 h of drought stress by exposing the
roots to air. Relative to that of unstressed control plants, growth of the drought-stressed plants was severely reduced, but
the leaves remained green and healthy. Amino acid concentrations varied among clones and organs. Drought stress caused both
organ-specific and clone-specific changes in amino acid concentrations. Among organs, succulent stems usually had the highest
concentrations of amino acids in both control and drought-stressed plants. Glutamate, glutamine, asparagine, arginine, and
an unidentified amino acid were usually the major amino acids in all organs, except root tips where γ-aminobutyrate replaced
arginine as one of the most abundant amino acids. Proline was a minor constituent in both control and drought-stressed plants.
Comparison of the results of the present study with those of earlier studies with the same aspen clones indicates that the
method of inducing drought stress affects the responses observed.
