The Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan.
Plant Physiol. 1974 Feb;53(2):319-22. doi: 10.1104/pp.53.2.319.
Analyses of free amino acids in poplar (Populus gelrica) were carried out throughout a year to see the effect of low temperature on a system regulating amino acid metabolism in the tree. The results indicated that during the wintering phase arginine was the major amino acid both in bark and xylem, particularly in xylem, and that at the time of budding and growing glutamine and glutamate became dominant. Changes in the relative levels of glutamine (plus glutamate) and arginine to the total amino acids of the alpha-ketoglutarate family indicated the presence of a regulatory system annually controlling the synthesis between glutamine (plus glutamate) and arginine. The system appeared to be governed and sensitized by low temperatures. Neither a transition of the synthesis from arginine to glutamine (plus glutamate) nor budding occurred in the poplars which spent the winter months in a greenhouse.
对杨树（Populus gelrica）中的游离氨基酸进行了一整年的分析，以观察低温对树木中调节氨基酸代谢的系统的影响。结果表明，在冬季休眠期，精氨酸是树皮和木质部中主要的氨基酸，特别是在木质部中，而在萌芽和生长时期，谷氨酰胺和谷氨酸成为优势氨基酸。谷氨酰胺（谷氨酸）和精氨酸相对于α-酮戊二酸族总氨基酸的相对水平的变化表明存在一个调节系统，每年控制着谷氨酰胺（谷氨酸）和精氨酸之间的合成。该系统似乎受到低温的控制和敏化。在温室中度过冬季的杨树中，既没有从精氨酸到谷氨酰胺（谷氨酸）的合成转变，也没有萌芽。
