Abstract

Soil salinity causes considerable losses of crop productivity. Barley (Hordeum vulgare) is one of the most salt-tolerant Gramineae crops. Previously, we found that net photosynthetic rate (A _n) was kept remarkably higher in the salt-tolerant barley accession OUE812 than in the salt-sensitive accession OUC613 after heading under salt stress due to the low level of salt accumulation in leaves. Here we grew seedlings in Hoagland solution with 100 mM NaCl (salt treatment) or without added NaCl (control), and compared A _n, stomatal conductance (g _s), salt accumulation in leaves, root hydraulic conductance and gene expression of root aquaporins between the accessions under salt stress for a few days. A _n, g _s and root hydraulic conductance of the plants with salt treatment decreased significantly in OUC613 compared to OUE812 with no accession difference in salt accumulation in leaves at 2 days after the onset of treatment (DAT). The reduction in root hydraulic conductance in OUC613 was caused by the reduction of the root hydraulic conductivity (Lp _r). Salt treatment also decreased the transcript levels of some plasma membrane intrinsic aquaporin genes (HvPIPs) in OUC613 and, on the contrary, increased those of some HvPIPs in OUE812, resulting in a large difference between OUC613 and OUE812 in the transcript levels at 2 DAT. The accession difference in HvPIPs expression and thus Lp _r was closely associated with the accession difference in A _n and g _s under the short-term salt stress.

摘要

土壤盐分会严重损害作物的生产力。大麦（Hordeum vulgare）是最耐盐的禾本科作物之一。以前，我们发现，在盐胁迫下抽穗后，耐盐的大麦登录号OUE812的净光合速率（A _n）显着高于盐敏感的登录号OUC613，这是由于叶片中盐分的积累水平较低。在这里，我们在装有100 mM NaCl（盐处理）或不添加NaCl（对照）的Hoagland溶液中生长幼苗，并比较了A _n，气孔导度（g _s），叶片中的盐分累积，根系水力传导率和根水通道蛋白的基因表达。盐胁迫下的种质维持了几天。 与OUE812相比，用盐处理的植物的_{n n}，g _s和根部水力传导率在OUC613中显着降低，并且在开始处理（DAT）后第2天叶片中盐分的积累没有差异。OUC613中根部水力传导率的降低是由根部水力传导率（Lp _r）的降低引起的。盐处理还降低了OUC613中某些质膜内在水通道蛋白基因（HvPIP s）的转录水平，相反，增加了OUE812中某些HvPIP的转录水平，导致OUC613和OUE812在2的转录水平上有很大差异DAT。HvPIP的登录差异s的表达，因此Lp _r与短期盐胁迫下A _n和g _s的种质差异密切相关。