Davenport Romola, James Richard A, Zakrisson-Plogander Anna, Tester Mark, Munns Rana
Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom.
Plant Physiol. 2005 Mar;137(3):807-18. doi: 10.1104/pp.104.057307. Epub 2005 Feb 25.
In many species, salt sensitivity is associated with the accumulation of sodium (Na(+)) in photosynthetic tissues. Na(+) uptake to leaves involves a series of transport steps and so far very few candidate genes have been implicated in the control of these processes. In this study, Na(+) transport was compared in two varieties of durum wheat (Triticum turgidum) L. subsp. durum known to differ in salt tolerance and Na(+) accumulation; the relatively salt tolerant landrace line 149 and the salt sensitive cultivar Tamaroi. Genetic studies indicated that these genotypes differed at two major loci controlling leaf blade Na(+) accumulation (R. Munns, G.J. Rebetzke, S. Husain, R.A. James, R.A. Hare [2003] Aust J Agric Res 54: 627-635). The physiological traits determined by these genetic differences were investigated using measurements of unidirectional (22)Na(+) transport and net Na(+) accumulation. The major differences in Na(+) transport between the genotypes were (1) the rate of transfer from the root to the shoot (xylem loading), which was much lower in the salt tolerant genotype, and (2) the capacity of the leaf sheath to extract and sequester Na(+) as it entered the leaf. The genotypes did not differ significantly in unidirectional root uptake of Na(+) and there was no evidence for recirculation of Na(+) from shoots to roots. It is likely that xylem loading and leaf sheath sequestration are separate genetic traits that interact to control leaf blade Na(+).
在许多物种中，盐敏感性与光合组织中钠（Na⁺）的积累有关。Na⁺进入叶片涉及一系列运输步骤，到目前为止，很少有候选基因参与这些过程的调控。在本研究中，对两个已知耐盐性和Na⁺积累量不同的硬粒小麦（Triticum turgidum）L.亚种硬粒小麦品种进行了Na⁺运输比较；相对耐盐的地方品种系149和盐敏感品种塔马罗伊。遗传研究表明，这些基因型在控制叶片Na⁺积累的两个主要位点上存在差异（R. 芒斯、G.J. 雷贝茨克、S. 侯赛因、R.A. 詹姆斯、R.A. 黑尔[2003]《澳大利亚农业研究杂志》54: 627 - 635）。通过测量单向²²Na⁺运输和净Na⁺积累来研究由这些遗传差异决定的生理特性。基因型之间Na⁺运输的主要差异在于：（1）从根到地上部的转运速率（木质部装载），耐盐基因型的该速率要低得多；（2）叶鞘在Na⁺进入叶片时提取和隔离Na⁺的能力。基因型在Na⁺的单向根吸收方面没有显著差异，也没有证据表明Na⁺从地上部再循环到根部。木质部装载和叶鞘隔离可能是相互作用以控制叶片Na⁺含量的独立遗传性状。
