• 关键词：旱柳  Pb  耐性  富集  转运  胁迫响应

• 基金项目：湖南省重点研发计划项目（No.2015SK20043）；湖南省高校创新平台开放基金项目（No.15K147，13K070）；中南林业科技大学引进高层次人才科研启动基金项目（No.0369）；湖南省环境科学重点学科建设基金项目（No.2310006）

• 朱健
• 中南林业科技大学环境科学与工程学院, 长沙 410004

• 王平
• 中南林业科技大学环境科学与工程学院, 长沙 410004

• 夹书珊
• 中南林业科技大学环境科学与工程学院, 长沙 410004

• 李猛
• 中南林业科技大学环境科学与工程学院, 长沙 410004

• 雷明婧
• 中南林业科技大学环境科学与工程学院, 长沙 410004

• 摘要：耐性机理的系统解析对于旱柳在土壤Pb污染控制上的应用具有重要意义. 为了明确旱柳对Pb的耐性机理，通过盆栽试验研究了旱柳对Pb的耐性、富集、转运特征，采用STEM、EDAX、FTIR分析了旱柳对Pb的胁迫响应机制.结果表明：低含量（≤ 600 mg·kg^-1）Pb对旱柳生长有促进作用，高含量（≥ 1000 mg·kg^-1）Pb明显抑制旱柳的生长；旱柳对Pb具有很高的耐性，耐性指数TI（%）可达108.32，属Pb高耐性植物；旱柳对Pb的富集能力较强，富集系数均值可达7.5773，而对Pb的转运能力较弱，转运系数均小于1；低含量Pb胁迫不影响叶绿素的合成，也不会促生丙二醛（MDA），而高含量Pb胁迫明显抑制叶绿素的合成，促使MDA大量生成，导致严重的细胞膜脂过氧化和膜损伤；抗氧化酶（POD、CAT、SOD）及可溶性蛋白能够对低含量Pb胁迫做出积极有效的响应，但无法清除高含量Pb胁迫所产生的毒害；扫描透射电镜（STEM）分析表明，Pb胁迫使根系发黑、萎蔫，茎部破败、堵塞，叶片褶皱、卷曲，破坏气孔结构；傅里叶红外光谱（FTIR）分析表明，Pb胁迫使导致膜脂过氧化和膜损伤的自由羟基增多，而使对Pb具有络合、螯合作用的连生羟基、巯基、羰基数量减少；能谱（EDAX）分析表明，Pb胁迫抑制了Ca、K的吸收，同时干扰其他矿质元素的吸收利用.

• Abstract：Systematic analysis of tolerance mechanism is of high significance for application of Salix matsudana Koidz in lead pollution control in soil. The tolerance, accumulation and translocation characteristics of Salix matsudana Koidz to lead was investigated by a pot test, and the stress response mechanism of Salix matsudana Koidz to lead was analyzed by using STEM, EDAX and FTIR. The obtained results showed that Pb of low content (≤ 600 mg·kg^-1) promoted Salix matsudana Koidz growth, but Pb of high content (≥ 1000 mg·kg^-1) significantly restricted its growth. Salix matsudana Koidz presented much high tolerance to Pb with the tolerance index (%) of 108.32, so it can be regarded as a high Pb tolerance plant. Salix matsudana Koidz presented great ability to accumulate Pb and its average bioconcentration factors (BCF) for Pb could attain 7.5773, but it presented weak ability to translocate Pb and its translocation factors (TF) for Pb were less than 1. Low content Pb stress had no effect on chlorophyll synthesis and also had no promotion in MDA synthesis, but high content Pb stress significantly restricted synthesis of chlorophyll, greatly promoted synthesis of MDA, and caused serious membrane lipid peroxidation and membrane damage. Antioxidase (POD, CAT, SOD) and soluble protein gave positive and effective responses to low content Pb stress, but could not remove toxicity caused by high content Pb stress. The analysis by using STEM indicated that Pb stress leads to roots blackening and wilting, stems broking and blocking, leaves foilding and crimping, and stomata structure destroyed. The FTIR analysis indicated that Pb stress increased free hydroxyl which led to membrane lipid peroxidation and membrane damage and reduced fixed hydroxyl, sulfydryl and carbonyl which could complex and chelate Pb. The EDAX analysis indicated that Pb stress restricted adsorption of Ca and K and interfered adsorption and utility of other mineral elements.

• Key words：Salix matsudana Koidz  Pb  tolerance  accumulation  translocation  stress response

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