| 摘要: |
| 【目的】研究铅（Pb）对日本枥木三樱椒（以下简称三樱椒）生理生长的影响，揭示三樱椒对Pb的吸收特征。【方法】选用三樱椒作为试验材料，在供试土壤（Pb本底含量为41 mg/kg）中添加Pb，使土壤中的Pb含量分别为41（CK），291,541,791,1 041,1 541,2 041,2 541,3 041和3 541 mg/kg，测定三樱椒的植株高度、单株干物质量、CAT、POD、SOD、MDA、净光合速率（Pn）及根、茎、叶、果实中Pb含量等指标。对植株高度、单株干物质量与土壤Pb含量的关系建立分段函数；依据CAT、POD、SOD、MDA、Pn 5个指标随土壤Pb含量的变化，对土壤污染程度进行分类；同时对CAT、POD、SOD、MDA、Pn 5个指标与土壤Pb含量进行直接相关和综合相关分析。 【结果】1）三樱椒植株高度和单株干物质量随土壤中Pb含量的增加而明显下降，特别是当土壤Pb含量大于1 200 mg/kg时下降更显著； Pb含量在1 200 mg/kg以下对三樱椒生长的影响不明显。2）三樱椒植株CAT、POD、SOD、MDA、Pn5个生理指标随土壤Pb含量的增加先上升，而后呈下降趋势；土壤Pb含量对POD和SOD的影响最大，其次是CAT，对MDA和Pn的影响相对较小，与5个生理指标的综合相关系数为r=0.992，具有极显著性（P=0.01）；聚类分析和判别分析结果，也很好地反映了土壤Pb不同含量对5个生理指标的综合影响不同。3）三樱椒根系、茎、叶、果实等各部位以及单株Pb含量，均随土壤Pb含量的增加而增加，但峰值点不同。当土壤Pb含量在541 mg/kg时，Pb转移系数最高，之后随土壤Pb含量增加而逐渐减小。随土壤中Pb含量的增加，根部Pb含量增加幅度较大；茎和叶中Pb含量也相对稍增大，增加幅度较小；果实中Pb含量基本稳定，变化幅度最小。说明根部是Pb吸收的主要部位。【结论】三樱椒的生长生理指标随土壤Pb胁迫的增强均受到一定程度的影响。三樱椒根、茎、叶均可富集土壤中的Pb，其中根部是最主要的Pb吸收部位，果实受影响较小。在土壤Pb含量为541 mg/kg时，Pb转移系数达最高，表明三樱椒可以改良土壤Pb污染。 |
| 关键词: 三樱椒 Pb含量 生长生理 Pb富集 |
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| 基金项目:河南省科技厅科技攻关项目(0524050006)；南阳市科技局项目(2005PT019)；南阳师范学院项目（nytc200529） |
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| Physiological growth and lead (Pb) enrichment of Three Cherry Pepper under lead stress |
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| Abstract: |
| 【Objective】This research revealed the physiological growth and Pb absorption and accumulation of Three Cherry Pepper from Tochigi,Japan.【Method】Lead were added to the culture soil with different concentrations (291,541,791,1 041,1 541,2 041,2 541,3 041 and 3 541 mg/kg) (the background was 41 mg/kg),and the physiological indicators,including height and biomass of plants,activities of CAT,POD,SOD,MDA content,net photosynthetic rate (Pn),accumulation of Pb in different tissues (roots,stems,leaves and fruits) were measured.Piecewise function describing changes of plant height and dry matter along with soil Pb content was established.Soil pollution degrees were classified based on activities of CAT,POD,SOD,MDA and Pn.Direct and comprehensive correlation analysis between CAT,POD,SOD,MDA,Pn and Pb content was conducted as well.【Result】(1) The average height and individual biomass of pepper significantly decreased as the increase of Pb concentration,especially when the concentration of Pb was more than 1 200 mg/kg.(2) The contents of CAT,POD,SOD,MDA and Pn in seedlings increased firstly then decreased with the increase of Pb concentration.Pb had the greatest impact on POD and SOD,followed by CAT,MDA and Pn.The relevant coefficient of Pb to the five physiological indicators was 0.992 with extreme significant difference (P=0.01).Cluster and discriminant analysis also revealed the differences.(3) The contents of Pb in roots,stems,leaves and fruits all increased as the increase of Pb concentration with different accumulation peaks.The transfer coefficient of Pb was highest when Pb concentration was 541 mg/kg,then decreased as the increase of Pb concentration.The contents of Pb in roots increased faster than stems,leaves and fruits,indicating that roots were the major tissue for Pb absorption.【Conclusion】The physiological indicators of Three Cherry Pepper were affected by Pb concentrations.Pb enriched in roots,stems,leaves of Three Cherry Pepper,which can be used to reduce soil lead contamination.The highest Pb transfer coefficient occurred when the Pb concentration was 541 mg/kg. |
| Key words: Three Cherry Pepper Pb concentration physiology growth enrichment of Pb |
