Ward M R, Aslam M, Huffaker R C
Department of Agronomy & Range Science, University of California, Davis 95616, USA.
Plant Physiol. 1986 Jan;80(1):520-4. doi: 10.1104/pp.80.2.520.
The effect of Ca2+ on NO3- assimilation in young barley (Hordeum vulgare L. var CM 72) seedlings in the presence and absence of NaCl was studied. Calcium increased the activity of the NO3- transporter under saline conditions, but had little effect under nonsaline conditions. Calcium decreased the induction period for the NO3- transporter under both saline and nonsaline conditions but had little effect on its apparent Km for NO3- both in the presence and absence of NaCl. The enhancement of NO3- transport by Ca2+ under saline conditions was dependent on the presence of Ca2+ in the uptake solution along with the salt, since Ca2+ had no effect when supplied before or after salinity stress. Although Mn2+ and Mg2+ enhanced NO3- uptake under saline conditions, neither was as effective as Ca2+. In longer studies, increasing the Ca2+ concentration in saline nutrient solutions resulted in increases in NO3- assimilation and seedling growth.
研究了在有和没有NaCl的情况下，Ca2+对年轻大麦（Hordeum vulgare L. var CM 72）幼苗中NO3-同化作用的影响。在盐胁迫条件下，钙增加了NO3-转运体的活性，但在非盐胁迫条件下影响很小。在盐胁迫和非盐胁迫条件下，钙都缩短了NO3-转运体的诱导期，但在有和没有NaCl的情况下，对其NO3-的表观Km影响很小。在盐胁迫条件下，Ca2+对NO3-转运的增强作用取决于吸收溶液中Ca2+与盐的共同存在，因为在盐胁迫之前或之后供应Ca2+均无效果。虽然Mn2+和Mg2+在盐胁迫条件下增强了NO3-的吸收，但两者都不如Ca2+有效。在更长时间的研究中，增加盐胁迫营养液中Ca2+的浓度会导致NO3-同化作用和幼苗生长的增加。
