Department of Biology, Queen's University, Kingston, Ontario, Canada.
Plant Physiol. 1973 Feb;51(2):327-31. doi: 10.1104/pp.51.2.327.
The growth of Lemna minor was followed by means of frond number, fresh weight, and dry weight measurements in the presence of various amino acids at a concentration 0.25 mm. Lysine inhibited growth but not to the same extent as threonine and homoserine. Isoleucine was also an inhibitor of growth. In the presence of methionine there was some growth for 2 to 3 days, but by 5 days most of the plants appeared to be dead. When lysine and threonine were added together, there was no growth at all, and the plants were dead after 5 days. This effect of lysine + threonine could be reversed by adding methionine or homoserine to the growth medium.The isolated aspartokinase from Lemna showed inhibition by lysine and higher concentrations of threonine. When these amino acids were added together at low concentrations, there was a concerted inhibition of the aspartokinase. It is suggested that some effects of amino acids on the growth of L. minor can be explained on the basis of a concerted feedback control of aspartokinase.
在 0.25 毫米浓度的各种氨基酸存在下，通过测量浮萍的叶数、鲜重和干重来跟踪浮萍的生长情况。赖氨酸抑制生长，但不如苏氨酸和高丝氨酸那么严重。异亮氨酸也是生长的抑制剂。在蛋氨酸存在的情况下，植物在 2 到 3 天内有一些生长，但到第 5 天，大多数植物似乎已经死亡。当赖氨酸和苏氨酸一起添加时，根本没有生长，植物在 5 天后死亡。这种赖氨酸+苏氨酸的作用可以通过向生长培养基中添加蛋氨酸或高丝氨酸来逆转。从浮萍中分离出的天冬氨酸激酶受到赖氨酸和高浓度苏氨酸的抑制。当这些氨基酸在低浓度下一起添加时，天冬氨酸激酶会协同抑制。因此，一些氨基酸对浮萍生长的影响可以根据天冬氨酸激酶的协同反馈控制来解释。
