NaCl alleviates polyethylene glycol-induced water stress in the halophyte species Atriplex halimus L.
NaCl alleviates polyethylene glycol-induced water stress in the halophyte species Atriplex halimus L.
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DOI：
10.1093/jxb/eri235
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发表时间：
2005-09-01
影响因子：
6.9
通讯作者：
Lutts, S
中科院分区：
文献类型：
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作者：
Martínez, JP;Kinet, JM;Lutts, S
滨藜(Atriplex halimus L.)是一种适应盐分和干旱条件的C-4旱生盐生植物。为了了解低盐水平对幼苗抗旱性的生理影响，将幼苗暴露在含有0%或15%聚乙二醇10000(PEG10 000)的营养液中6d，其中加入或不加入50 mM的氯化钠。在标准的Linsmaier和Skoog(LS)、添加50 mMNaC l的LS培养液或无Na+的培养液中，分别培养50d至0%或15%的不同浓度的PEG5 0%和15%的细胞株，进行类似的实验。氯化钠减轻了聚乙二醇对整个植物和对聚乙二醇敏感的细胞系生长的有害影响，并提高了胁迫组织执行渗透调节(OA)的能力。水分胁迫降低了在高CO2和低O-2水平(A)、气孔导度和蒸腾作用下量化的CO2净同化速率，但NaCl通过其对A值的正向影响而提高了植物的水分利用效率，尤其是在幼叶中。聚乙二醇乙二醇酯可增加心肌细胞内Na+浓度。耐药细胞系积累的Na+浓度高于聚乙二醇敏感细胞系。培养液中完全不含Na+危及两种细胞系在聚乙二醇组中的存活。虽然Na+本身只对光合作用的一小部分有贡献，但在光合作用组织中，Na+诱导了Pro浓度的增加，并刺激了甘氨酸甜菜碱的合成。可溶性糖是油酸的主要贡献者，与单独处理相比，当组织同时暴露于聚乙二醇和氯化钠时，可溶性糖含量增加，这表明Na+可能影响糖的合成和/或转运。
Atriplex halimus L. is a C-4 xero-halophyte species well adapted to salt and drought conditions. To collect information on the physiological impact of low salt levels on their water-stress resistance, seedlings were exposed for 6 d to nutrient solution containing either 0% or 15% polyethylene glycol 10 000 (PEG), in the presence or in the absence of 50 mM NaCl. Similar experiments were performed with one PEG-resistant and one PEG-sensitive selected cell line exposed for 50 d to 0% or 15% PEG on standard Linsmaier and Skoog (LS) medium, on LS medium supplemented with 50 mM NaCl, or on Na+-free medium. NaCl mitigated the deleterious impact of PEG on growth of both whole plants and PEG-sensitive cell lines and improved the ability of stressed tissues to perform osmotic adjustment (OA). Water stress reduced CO2 net assimilation rates quantified in the presence of high CO2 and low O-2 levels (A), stomatal conductance and transpiration, but NaCl improved water use efficiency of PEG-treated plants through its positive effect on A values, especially in young leaves. PEG increased the internal Na+ concentration. The resistant cell line accumulated higher concentration of Na+ than the PEG-sensitive one. The complete absence of Na+ in the medium endangered the survival of both cell lines exposed to PEG. Although Na+ by itself contributed only for a small part to OA, NaCl induced an increase in proline concentration and stimulated the synthesis of glycinebetaine in response to PEG in photosynthetic tissues. Soluble sugars were the main contributors to OA and increased when tissues were simultaneously exposed to PEG and NaCl compared with PEG alone, suggesting that Na+ may influence sugar synthesis and/or translocation.