Schnapp S R, Bressan R A, Hasegawa P M
Center for Plant Environmental Stress Physiology, Purdue University, West Lafayette, Indiana 47907.
Plant Physiol. 1990 Jun;93(2):384-8. doi: 10.1104/pp.93.2.384.
Carbon use efficiencies (gram cell organic dry weight accumulated per gram sugar assimilated from the medium) of unadapted and NaCl-adapted (428 millimolar) cells of tobacco (Nicotiana tabacum L. var Wisconsin 38) were determined to evaluate metabolic costs associated with growth and survival in a saline environment. No net increase in carbon costs was associated with salt adaptation. At low substrate levels, carbon use efficiencies of unadapted and NaCl-adapted cells were not appreciably different (0.495 and 0.422, respectively) and at higher substrate levels carbon use efficiency of NaCl-adapted cells was clearly higher than that of unadapted cells. These results indicate that a homeostasis of metabolic efficiency is established after cells have adapted to NaCl. Altered carbon availability does not cause the reduced cell volume that results from adaptation to NaCl. This does not preclude, however, the possibility that altered intracellular partitioning of carbon affects cell expansion.
测定了未适应盐环境和适应428毫摩尔氯化钠环境的烟草（Nicotiana tabacum L. var Wisconsin 38）细胞的碳利用效率（每克从培养基中同化的糖积累的细胞有机干重克数），以评估在盐环境中与生长和存活相关的代谢成本。盐适应并未导致碳成本的净增加。在低底物水平下，未适应盐环境和适应氯化钠环境的细胞的碳利用效率没有明显差异（分别为0.495和0.422），而在较高底物水平下，适应氯化钠环境的细胞的碳利用效率明显高于未适应盐环境的细胞。这些结果表明，细胞适应氯化钠后建立了代谢效率的稳态。碳可用性的改变不会导致因适应氯化钠而导致的细胞体积减小。然而，这并不排除碳在细胞内分配的改变影响细胞扩张的可能性。
