紫花苜蓿、黑麦草和狼尾草对Cu、Pb复合污染土壤修复能力的研究

随着经济和社会的发展,土壤重金属污染对粮食安全及人类的身体健康构成了巨大的威胁,而目前对于土壤重金属污染的治理主要以植物修复为主。为了寻找适宜修复Cu、Pb复合污染土壤的牧草,采用盆栽试验法,将试验的植物设置9组处理:1组对照组(CK),不添加任何重金属盐;4组单一污染,即单一Cu低(Cu1,200 mg×kg-1)、高浓度(Cu2 400 mg×kg-1),单一Pb低(Pb1 300 mg×kg-1)、高浓度(Pb2 800 mg×kg-1);4组Cu、Pb复合污染(Cu1Pb1、Cu1Pb2、Cu2Pb1、Cu_2Pb_2)。通过比较紫花苜蓿(Medicago sativa)、黑麦草(Lolium perenne)、狼尾草(Pennisetum alopecuroides)的适应能力和富集特征,研究了这3种常见牧草植物对受Cu、Pb复合污染土壤的修复效果。结果表明:1)紫花苜蓿地上部和根部生物量均在Pb1处理组时最大,显著高于其他处理组;黑麦草地上部生物量在Cu1Pb1处理组最大,根部生物量在Pb1处理组最大;狼尾草地上部生物量在Cu_2Pb_2处理组最大,根部生物量在Cu2处理组最大。2)Cu单一污染下,狼尾草抗性系数最大;Pb单一污染下,紫花苜蓿抗性系数最大;Cu-Pb复合污染下,狼尾草的抗性系数较大。高浓度Cu处理组3种牧草植物的地上部生物量、根部生物量和抗性系数均呈现:狼尾草黑麦草紫花苜蓿,且狼尾草显著大于黑麦草和紫花苜蓿。3)种植3种牧草植物后,土壤重金属Cu、Pb含量均有所降低。在一定浓度下,土壤Cu-Pb重金属间会相互促进对方在牧草植物中的吸收。4)3种牧草中紫花苜蓿地上部对Cu的富集系数在Cu_2Pb_2处理组最大,达1.61;黑麦草根部对Cu的富集系数在Cu_2Pb_2处理组最大,达3.80;3种牧草地上部和根部对Pb的富集系数只在黑麦草根部的Cu1Pb1处理组时大于1,达1.46。5)黑麦草对Pb的吸收能力较强,且主要积累在根系;紫花苜蓿对Cu-Pb复合污染综合修复效果最好。紫花苜蓿和黑麦草分别在Cu-Pb复合污染和Pb单一污染土壤中对Pb的转运系数大于1,分别为2.72和2.06,反映其对土壤中的Pb具有富集潜力。综合表明,黑麦草对重金属Pb具有较强的耐性,在Pb单一污染土壤的植物修复及尾矿废弃地的植被重建中,可优先作为选择的材料;紫花苜蓿对重金属Cu、Pb均具有较强的耐性,在重金属Cu单一或Cu-Pb复合污染土壤的植物修复及尾矿废弃地的植被重建中,可优先作为选择的材料。     

高CO2浓度和剪叶疏花对水稻‘Y两优2号’ 产量形成的影响

利用稻田FACE(Free Air CO_2 Enrichment)平台,以创造世界高产纪录的超级稻组合‘Y两优2号’为试验材料,CO_2处理设环境CO_2浓度[(382.5±2.0)μmol·mol-1]和高CO_2浓度(增200μmol·mol-1)两个水平,齐穗期源库改变设对照、剪除剑叶(剪1叶)、剪除所有功能叶(剪3叶)以及相间剪除一次枝梗(疏花),研究开放条件下高CO_2浓度对不同源库处理水稻产量及其构成因子的影响。结果表明,对没有进行剪叶疏花处理的水稻(即对照)而言,高CO_2浓度使‘Y两优2号’籽粒产量平均增加12%,这主要与每穗颖花数和结实能力均略有增加有关。高CO_2浓度使剪1叶、剪3叶处理水稻的产量分别增加26%和57%,这主要与饱粒率和所有籽粒平均粒重均大幅增加有关。对齐穗期疏花处理水稻而言,高CO_2浓度导致的产量增幅与对照水稻接近。与对照相比,齐穗期剪1叶、剪3叶处理使水稻籽粒产量分别降低17%和52%,均达极显著水平,这主要与饱粒率和所有籽粒平均粒重均显著下降有关;尽管齐穗期疏花处理使水稻结实能力显著增加,但因每穗颖花数减半,产量大幅下降(-29%)。籽粒最终产量对高CO_2浓度的响应与饱粒率和所有籽粒平均粒重的响应呈显著正相关。以上结果表明,水稻齐穗期人为改变源库比例(特别是剪叶)可以改变籽粒结实能力和最终产量对高CO_2浓度的响应。     

铅、镉胁迫对饲用高粱生长及铅、镉吸收和累积的影响

采用盆栽试验研究了不同浓度的土壤外源重金属Pb,Cd及其复合胁迫对饲用高粱（Sorghum vulgare）生长的影响及其对Pb和Cd的积累能力。结果表明：随着Pb和Cd单一及复合胁迫浓度的增加,饲用高粱株高、生物量呈降低趋势,Pb和Cd含量呈增加趋势,茎鞘Cd含量及Cd累积量高于叶片,叶片Pb含量及Pb累积量高于茎鞘。在复合胁迫下,低、中浓度的Pb和Cd处理表现出相互促进吸收累积,高浓度处理表现出相互抑制吸收累积的特性,饲用高粱对Cd的富集能力远大于Pb。研究结果将为利用饲用高粱修复重金属污染土壤提供理论依据。     

FACE对杂交籼稻汕优63干物质生产与分配的影响

2005--2006年利用我国惟一的农田开放式空气CO2浓度增高（FACE）研究平台,以三系杂交籼稻汕优63为供试材料,设计比大气CO2浓度（对照,370umol．mol^-1）高200umol．mol^-1的FACE处理（570umol．mol^-1）和施N量为125kg·hm^-2（LN）、250kg·hm^-2（NN）处理,研究其对汕优63物质生产与分配的影响。结果表明：（1）两季平均,FACE处理使汕优63移栽-分蘖中期、分蘖中期-拔节期、拔节-抽穗期和抽穗-成熟期干物质生产量分别比对照增加了39％、20％、32％和41％,结果使成熟期生物产量显著增加（＋33％）;（2）与干物质生产量相比,汕优63平均叶面积指数（LAI）和净同化率（NAR）对CO2的响应有相似的季节性变化趋势,但LAI的响应值明显大于NAR;（3）FACE处理使汕优63不同生育时期叶片和稻穗占地上部干重的比例下降,而使茎鞘占地上部干重的比例明显增加;（4）三系杂交籼稻汕优63成熟期生物产量以及不同生育阶段平均LAI、NAR和干物质生产量对FACE的响应与粳稻品种存在明显差异．而干物质分配差异较小。     

Effects of different soil management practices on total P and Olsen-P sediment loss: A field rainfall simulation study

Field rainfall simulations were conducted in 2002 and 2005 to study the effects of different soil management practices on the total phosphorous (TP) and Olsen-P losses by soil erosion and redistribution along a 15 m long slope in Luoyang, Henan province, China. Field plots were set up in 2001 and included the following soil management practices: subsoiling with mulch (SSM), no-till with mulch (NTM), reduced tillage (RT), and a conventional tillage control (CT). The results showed that there were no significant differences in TP and Olsen-P content in the sediment load between different plots after 6 years uniform tillage practices. The enrichment of TP and Olsen-P at the lower slope showed a clear redistribution along the slope. Effects of tillage practices on the temporal pattern of the enrichment ratio (ER) of TP and Olsen-P was not uniform. ER_TP values were initially high and diminished after a short period of time and leveled to the end of the rainfall test in CT and RT plots, but remained ≥ 1. The ER of Olsen-P at the end of rainfall simulation showed a significant difference when compared to the initial stage, 0.78 to 1.60, respectively. However, the temporal loss rate of TP and Olsen-P showed a similar pattern because it was more depending on the sediment loss rate than on the concentration in the sediment. SSM resulted in 96% less TP and Olsen-P erosion loss compared to CT in 2002. Also, SSM showed the highest reduction in TP and Olsen-P loss after 4 years consistent practice. RT reduced TP and Olsen-P loss by 30%, although the runoff reduction was not significant. NTM was the best alternative with respect to TP and Olsen-P conservation, when considering its lower operational costs.     

Frequency of occupation with different simultaneously offered devices by fattening pigs kept in pens with or without straw

The aim of this study was to investigate to what extent different occupational devices (pendular beam, cross of chains or lifting beam) offered simultaneously were used by one or more pigs kept in pens with or without straw during the fattening period. The data were obtained in four fattening periods. In every round four pens with nine animals each were available, two of them had a solid concrete floor and were littered with straw the other two had a partially slatted floor without any straw. At three stages during each fattening period the behaviour of the pigs was video-recorded for 24 h and their use of each occupational tool was analysed second-wise.In both housing systems the cross of chains was used longer for occupation than the other devices. The pendular beam was used least of all. All three devices could have been used by more than one pig at the same time, but the cross of chains was used longer by two to four pigs simultaneously than the others. It was observed that pigs in pens without straw used the cross of chains and the lifting beam significantly (p < 0.05) longer than the pigs in the pens with straw.All three devices are suitable to enrich a housing system without any litter. Especially a cross of chains allows the pigs to perform their explorational behaviour.     

汞在春小麦植株中的富集及转移规律研究

为了明确汞（Hg）在小麦植株中的吸收和转运规律,采用盆栽试验,研究了Hg胁迫下重金属Hg在春小麦中的分布、富集及转移规律。结果表明,Hg迁移速率较慢,Hg胁迫下,根对Hg的富集吸收于春小麦生育期结束还未达到峰值。春小麦吸收的Hg大部分积累在根中,仅极少部分转移至叶和茎,未发现转移至籽粒。小麦根对Hg的富集能力较强,根中Hg积累量与土壤中Hg含量呈显著正相关（R2=0.9499,P〈0.05）;籽粒中Hg含量与土壤中Hg含量无明显相关性。     

蚯蚓对铁的富集转移及对苹果根铁营养影响研究

田间试验在永年县曹庄果园和中国农业大学曲周实验站果园进行,试材为8年生红富士苹果树,在苹果根际用不同价态、不同浓度的铁处理玉米秸秆后接种蚯蚓.试验表明:蚯蚓对铁有很大的富集量,在20 000 mg/kg(试验所用最高浓度)二价铁和三价铁处理的秸秆中可以成活并把秸秆转化为蚯蚓粪,促进根系生长,提高根的质外体铁含量,蚯蚓对二价铁的适应性高于三价铁.蚯蚓可以将有机物料中的铁转移到果树根系内,5 000 mg/kg铁处理增加蚯蚓体内Fe~(2+)含量和根质外体铁含量效果最好,蚯蚓、蚯蚓粪和根中的全铁含量随铁处理浓度的增加而增加.铁显著促进果树根系生长,没有用铁处理秸秆接种蚯蚓的新根量明显少于用铁处理的,两种不同价态的铁都是以5 000 mg/kg的新根量最多.蚯蚓显著促进根系生长,没有接种蚯蚓的处理新根量显著少于接种蚯蚓的处理.     

控制食用菌中重金属富集方法的研究进展

有害重金属含量超标是当前食用菌食品安全的一个突出问题。影响食用菌中重金属富集的因素主要有空气、水质,培养料、食用菌种类、栽培方法、农业化学品的使用等。本文综述了食用菌富集重金属的重要特点和部分已经被阐明机理,以及目前用于控制食用菌中重金属富集的几种方法,旨在引起同行对该问题的重视。     

二色胡枝子总黄酮提取及富集工艺研究

[目的]研究二色胡枝子黄酮的最佳提取工艺与富集参数。[方法]选取分布于内蒙古自治区的二色胡枝子为试验材料,通过单因素试验研究乙醇浓度、料液比、提取时间和提取温度对其总黄酮提取的影响,通过L16（4^4）正交试验确定该黄酮的最佳提取工艺。采用SP700大孔吸附树脂对其进行纯化与富集,通过L9（3^3）正交试验确定该黄酮的最佳富集参数。[结果]二色胡枝子叶中黄酮含量高于茎中黄酮的含量。影响黄酮提取率的因素大小依次为乙醇浓度〉料液比〉温度〉时间。该黄酮的最佳提取工艺为40％乙醇、温度70℃、料液比1：30、时间3．0h。提取率为5．228％。该黄酮的最佳富集参数为进样速度1．5ml／min、80％乙醇洗脱、洗脱速度2．0ml／min。[结论]该研究为进一步开发二色胡枝子资源提供参考依据。