Dynamics of some mineral nutrients and heavy metals in decomposing forest litter

The dynamics of three major mineral nutrients (K, Ca, Mg) and six heavy metals (Fe, Mn, Zn, Cu, Pb and Cd) were studied in decomposing natural, unpolluted litter in two forest types: Scots pine needle litter in a pure Scots pine forest and oak‐hornbeam leaf litter in a mixed oak‐hornbeam stand. Of the mineral nutrients, only K in the oak‐hornbeam system showed a significant decrease in concentration during the course of litter decomposition. For Ca and Mg in both systems and for K in the Scots pine system no clear relation between concentration and accumulated litter‐mass loss was observed. On the other hand, for Fe, Zn, Pb and Cd at both sites, as well as for Mn in the oak‐hornbeam stand and Cu in the Scots pine stand highly significant positive relations were found between heavy metal concentrations and accumulated mass loss. A decrease in concentration was noted only in the case of Mn in the Scots pine system. No clear pattern was found for Cu in the oak‐hornbeam stand. Concentrations of heavy metals in the decomposing litter reached levels at or above those reported to retard decomposition in other studies. At the oak‐hornbeam stand increased also the absolute amounts of Fe, Zn, Pb and Cd.     

铜、镉、铅、锌对4种豆科植物种子萌发的影响

筛选和研究适合当地气候与土壤条件的重金属耐性植物,是对重金属污染土壤进行植物修复的前提.以蒸馏水为对照,采用培养皿法研究了Cu2+、Cd2+、pb2+和Zn2+单一重金属对4种豆科植物种子萌发和幼苗生长的影响.结果表明,随着Cu2+、Cd2+、pb2+和Zn2+浓度的增大,红豆草(Onobrychis viciaefolia Scop.)、白三叶(Tri folium repens L.)、柠条(Caragana Korshinskii Kom.)、胡枝子(Lespedeza bicolor Turcz.)的发芽率、发芽势呈不同程度的降低趋势;但在Cu2+＜300 mg/L处理下,红豆草种子的发芽率并没受到明显抑制,反而有不同程度地促进;在Cd2+处理下,25 mg/L浓度对柠条种子萌发促进作用最为显著,柠条种子发芽率与对照相比达到显著性差异水平(p＜0.05);Pb2+对柠条和胡枝子种子的发芽率种子的发芽表现为“低促高抑”.Cu2+、Cd2+、pb2+和Zn2+对4种植物根系生长均表现出强烈的抑制作用.随着Cu2+、Cd2+、pb2+和Zn2+离子浓度的增大,红豆草、白三叶、柠条和胡枝子种子萌发后形成幼苗的根长和苗长都呈降低趋势,对4种植物均表现为随着浓度增加,抑制作用越明显.     

硅对镉和锌复合胁迫下水稻幼苗生长及重金属吸收的影响

通过盆栽试验研究了镉(Cd)、锌(Zn)复合胁迫下,外源施加不同浓度的硅(0,1.5,2.0,2.5 mmoL/kg)对水稻幼苗生物量及地上部和地下部Cd和Zn含量的影响.结果表明,无论是在Cd和Zn单一或者复合污染条件下,不同浓度的硅处理均能显著提高水稻幼苗地上部和根系的生物量,其中以硅浓度为1.5 mmol/kg时...     

The genetic architecture of zinc and iron content in maize grains as revealed by QTL mapping and meta-analysis

Micronutrient malnutrition, especially zinc (Zn) and iron (Fe) deficiency in diets, has aroused worldwide attention. Biofortification of food crops has been considered as a promising approach for alleviating this deficiency. Quantitative trait locus (QTL) analysis was performed to dissect the genetic mechanism of Zn and Fe content in maize grains using a total of 218 F_2:3 families derived from a cross between inbred lines 178 and P53. Meta-analysis was used to integrate genetic maps and detect Meta-QTL (MQTL) across several independent QTL researches for traits related to Zn or Fe content. Five significant QTLs and 10 MQTLs were detected. Two informative genomic regions, bins 2.07 and 2.08, showed a great importance for Zn and Fe content QTLs. The correlation between Zn and Fe level in maize grains was proposed by MQTLs as 8 of the 10 involved both traits. The results of this study suggest that QTL mapping and meta-analysis is an effective approach to understand the genetic basis of Zn and Fe accumulation in maize grains.     

重碳酸氢根对水稻根区重要有机酸分布的影响与水稻品种耐缺Zn关系的研究

选用缺Zn敏感水稻品种IR26和耐缺Zn水稻品种IR8192-31-2，采用营养液培养方法，研究了缺Zn敏感和耐性水稻品种根生长和根区主要有机酸分布受HCO-3影响的差异。在低锌浓度下，HCO-3严重抑制敏感品种根系生长，而对耐性品种影响很小；苹果酸在敏感品种根区的分布情况是伸长区>分生区>根毛区,而在耐性品种根区的分布情况是伸长区     

锌铬复合污染对水稻不同生育期土壤酶活性的影响

通过盆栽试验,研究了锌铬复合污染对水稻(Oryza sativaL.)不同生育期土壤酶活性的影响。结果表明,锌铬复合污染对水稻生长有抑制作用,随土壤中锌铬浓度的增加,不同生育期水稻生物量均呈下降的趋势,而根冠比呈一定的升高趋势,差异极显著(P<0.01)。在锌铬污染下,土壤过氧化氢酶活性随土壤中锌铬浓度增大而降低。与对照相比,在水稻分蘖期、孕穗期及灌浆结实期土壤过氧化氢酶活性的最小值分别降低了34.17%、23.02%和4.89%;除在灌浆结实期锌与铬浓度互作间的差异不显著外,其他生育期的锌浓度间、铬浓度间及锌与铬浓度互作间的差异均极显著(P<0.01)。在水稻分蘖期,土壤脲酶活性、转化酶活性随土壤锌铬浓度的增加而降低,但在孕穗期及灌浆结实期则升高,其差异均极显著(P<0.01)。线性回归及偏相关分析表明,在水稻不同生育期,土壤过氧化氢酶活性与土壤中锌、铬浓度均有极显著的线性回归关系,并呈显著或极显著负相关关系,这说明锌铬复合污染对土壤过氧化氢酶活性可能产生协同或加和的抑制效应。土壤脲酶活性在水稻灌浆结实期与土壤中锌浓度有极显著的线性回归关系,偏相关系数为0.7253**;土壤转化酶活性在水稻分蘖期、灌浆结实期与土壤中铬浓度均有极显著的线性回归关系,偏相关系数分别为-0.7426**、0.8056**,这说明锌铬复合污染对土壤脲酶活性及转化酶活性未产生复合效应。     

Fe对龙葵幼苗Zn毒害耐受性的影响

本研究以龙葵为试验材料,采用水培方法分析了补充Fe对龙葵幼苗Zn毒害耐受性的影响。结果表明,补充200μmol.L 1Fe-EDTA提高了龙葵幼苗对Zn毒害的耐受性。400μmol.L 1ZnCl2处理导致龙葵幼苗株高、根长和叶绿素含量显著减少,并引起H2O2的积累。补充Fe后,植株生长状况得到明显改善,SOD、CAT和APX基因的表达和酶的活性显著提高。同时RT-PCR结果显示,补充Fe后,FeSOD2和CAT1基因的表达明显升高。这些结果表明,Zn毒害对龙葵幼苗生长发育的影响很大程度上可能是由于Zn毒害引起的缺Fe导致的;Zn毒害条件下补充Fe可以通过提高FeSOD2和CAT1基因的表达,提高抗氧化酶的活性,降低ROS的水平,降低植株的氧化伤害。本研究为进一步研究植物响应Zn毒害的生理分子机理,以及植物修复技术的实际应用提供了理论基础。     

螯合剂对铅锌尾矿改良基质上蓖麻幼苗生长和铅锌积累的影响

采用盆栽试验,以铅锌尾矿与对照土壤按1∶1的质量比例混合为培养基质,研究了单独添加乙二胺四乙酸二钠盐(EDTA-Na2)和氨三乙酸(NTA)以及复合添加对蓖麻幼苗生长和重金属积累的影响。结果表明:添加螯合剂后蓖麻生物量和根系形态参数均显著下降。其中,根系形态参数中根尖数下降最明显,与对照相比差异极显著(p<0.01)。各螯合处理蓖麻叶绿素a、b和叶绿素a+b与对照相比均显著下降(p<0.05),且叶绿素b较叶绿素a下降幅度略大。蓖麻叶片中三种抗氧化酶活性均随螯合处理中EDTA添加量的增加先上升后下降。添加螯合剂使蓖麻各部位Pb、Zn含量明显增加,且Pb的增幅较Zn大。螯合剂添加显著提高蓖麻对Pb、Zn的积累能力,其中对Pb的积累能力大于Zn。添加螯合剂明显促进了Pb、Zn从根部向地上部的转移,转移系数在添加EDTA和NTA各3 mmol kg-1处理中达最大值。蓖麻对Pb和Zn有较强的耐性和积累能力,可用于铅锌尾矿废弃地植物修复的进一步研究。     

旱改水对砂姜黑土中锌含量的影响研究

本文用连续分级浸提法,研究了旱改水对砂姜黑土中锌的含量、赋存形态和有效性的影响。砂姜黑土中的锌绝大部分以残留态存在,晶态铁结合态约占１０％,其余形态锌一般小于＃％。这些形态锌可以分为三类;一类为土壤锌的强度因子,即代换态锌,另一类是土壤锌的容量因子,即有机态、无定形铁结合态的晶形铁结合态锌;第三类为残留态 有效态锌主要来自代换态。旱改水后,晶形铁结合态锌向有机态和无定形铁结合态锌转化,使得土壤中锌