Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
Planta. 1972 Mar;105(1):25-32. doi: 10.1007/BF00385160.
Various nitrogen compounds were tested for their ability to alleviate the reduced nitrogen requirement of soybean cells growing in defined liquid medium containing nitrate as the alternative nitrogen source. Either L-glutamine, L-alanine, putrescine or NH4 (+) satisfied this requirement. Addition of L-glutamate resulted in poor growth. Where growth was stimulated, nitrate reductase (NR) activity increased whereas glutamate dehydrogenase activity in the cells showed no such correlation. In all fresh media which supported rapid growth, NR activity first decreased rapidly to a low value. Subsequent dry weight increases occurred concommitantly with an increase in NR activity. When 2,4-dichlorophenoxyacetic acid was omitted from the medium the growth was slow and the NR activity did not increase. During the first 40 h of incubation in medium containing NH4 (+) plus NO3 (-) the cells produced a growth-enhancing factor(s). This factor(s) was present in the cells and in the medium and eliminated the requirement for reduced nitrogen.
各种氮化合物被测试其缓解在含有硝酸盐作为替代氮源的定义液体培养基中生长的大豆细胞的减少的氮需求的能力。L-谷氨酰胺、L-丙氨酸、腐胺或 NH4 (+) 满足此要求。添加 L-谷氨酸导致生长不良。在刺激生长的地方，硝酸还原酶 (NR) 活性增加，而细胞中的谷氨酸脱氢酶活性则没有这种相关性。在所有支持快速生长的新鲜培养基中，NR 活性首先迅速下降到低值。随后的干重增加与 NR 活性的增加同时发生。当培养基中不含有 2,4-二氯苯氧基乙酸时，生长缓慢，NR 活性不增加。在含有 NH4 (+) 加 NO3 (-) 的培养基中培养的前 40 h 中，细胞产生了一种促进生长的因子。该因子存在于细胞和培养基中，并消除了对还原氮的需求。
