Husain Shazia, von Caemmerer Susanne, Munns Rana
CSIRO Plant Industry, GPO Box 1600, Canberra, ACT 2601, Australia.
Research School of Biological Sciences, Australian National University, PO Box 475, Canberra, ACT 2601, Australia.
Funct Plant Biol. 2004 Dec;31(11):1115-1126. doi: 10.1071/FP04078.
Wheat genotypes with 5-fold difference in shoot Na concentrations were studied over a salinity range of 1-150 mm NaCl and CaCl of 0.5-10 mm to assess their performance in saline and sodic soils. All genotypes had a maximum shoot Na concentration at 50 mm external NaCl when the supplemental Ca provided an activity of 1 mm or more. Shoot Na concentrations either stayed constant from 50 to 150 mm external NaCl, or decreased in some genotypes at the higher salinity. Calculated rates of root uptake, and root : shoot transport, were at a maximum at 50 mm NaCl in all genotypes, and decreased at higher NaCl in some genotypes, indicating feedback regulation. K showed a pattern inverse to that of Na. Cl uptake and transport rates increased linearly with increasing salinity, and differed little between genotypes. Increasing external Ca concentration reduced the accumulation of Na in the shoot, the effects being greater in the low Na genotypes, and greater as the salinity increased, indicating that the plateau in shoot Na concentration relied on the maintenance of a minimal Ca activity of 1 mm. Increasing external Caconcentration did not reduce the root Na concentration, however, suggesting that Ca influenced the loading of Na in the xylem.
研究了地上部钠浓度相差5倍的小麦基因型，在1-150 mM NaCl和0.5-10 mM CaCl₂的盐度范围内，评估它们在盐渍土和苏打土中的表现。当补充的钙提供1 mM或更高的活性时，所有基因型在外部NaCl浓度为50 mM时地上部钠浓度达到最大值。地上部钠浓度在外部NaCl浓度从50 mM到150 mM时要么保持不变，要么在一些基因型中在较高盐度下降低。计算得出的根系吸收速率和根：茎运输速率在所有基因型中在NaCl浓度为50 mM时最大，在一些基因型中在较高NaCl浓度下降低，表明存在反馈调节。钾的模式与钠相反。氯的吸收和运输速率随盐度增加呈线性增加，基因型之间差异不大。增加外部钙浓度会降低地上部钠的积累，在低钠基因型中影响更大，且随着盐度增加影响更大，这表明地上部钠浓度的平稳期依赖于维持1 mM的最低钙活性。然而，增加外部钙浓度并没有降低根系钠浓度，这表明钙影响了木质部中钠的装载。
