四种草本植物对铅锌尾矿土壤重金属的抗性与吸收特性研究

盆栽试验的结果表明,高羊茅、早熟禾、黑麦草和紫花苜蓿在铅锌尾矿土壤或处理的尾矿土壤上都能生长,但在处理土壤上生长的植物长势明显优于对照,其中紫花苜蓿的生物量所受影响比其他几种草本植物更大,说明其重金属抗性低于其他几种植物.单位面积上4种植物体内重金属含量均为Zn>Pb>Cu>Cd,但每种植物对Cd、Pb、Zn和Cu的吸收浓度和分布均不相同,一般为根系浓度大于茎叶.加入改良剂和有机肥(菜枯)使生长在铅锌尾矿污染土壤上的4种草本植物生物量显著增加,植物体中的Cd、Pb和Zn元素浓度下降,但Cu元素浓度反而上升,结果单位面积上4种草本植物吸收各重金属元素的量均有所增加,可见利用改良措施与草本植物相结合的方法来修复重金属污染土壤具有可行性.     

多年生黑麦草对覆土作用下铜尾矿的修复

选用耐性强的草坪草进行铜尾矿的植物修复,对尾矿的复垦和重金属污染的治理有十分重要的作用。因此,本研究通过盆栽试验,研究了多年生黑麦草(Lolium perenne)对不同比例的铜尾矿基质的修复效果,具体分析了多年生黑麦草的生长状况、土壤理化性质、土壤酶活性、土壤全铜和有效态的含量以及多年生黑麦草体内铜的含量与分布。结果表明,多年生黑麦草在铜尾矿基质中能较好生长,无严重伤害。多年生黑麦草显著改善了铜尾矿基质的营养和土壤酶活性,与不种植黑麦草组比,种植多年生黑麦草组中有机质、全氮、全磷、全钾含量平均增加了55.5%、 44.1%、 30.0%和24.9%;蔗糖酶、脲酶、磷酸酶和过氧化氢酶活性平均增加了24.8%、 20.5%、 11.4%和14.2%,均存在显著差异(P0.05)。同时,多年生黑麦草的生长和吸收作用促进了土壤铜的活化,这种活化与吸收过程共同降低了土壤铜含量,平均降幅达到12.2%,推动了铜尾矿基质的修复进程。该试验为进一步利用多年生黑麦草修复现场铜尾矿提供了思路和方法,也为其他植物对重金属尾矿的修复提供了参考和借鉴。     

江西省矿山尾矿(砂)综合利用研究现状

江西省是我国资源大省,矿山尾矿(砂)的综合利用,是当前矿业开发面临的紧迫问题。本文在前人研究成果的基础上,结合近年来我省国土资源厅开展的尾矿调研成果,论述了江西省尾矿(砂)综合利用的研究现状,总结了我省尾矿(砂)综合利用取得的主要成果、存在的主要问题,并提出了相应的对策与建议。     

铅锌尾矿区优势草本植物体内铅及氮、磷、钾含量变化特征

通过对铅锌尾矿区9种优势草本植物不同生长时期铅及氮、磷、钾含量分布特征及其相关性研究,结果表明,1)植物地上部氮、磷、钾含量均高于地下部,并随着生长时期的延长呈下降趋势; 2)在3个生长时期,9种优势草本植物均未表现出超富集铅的能力,但华中蹄盖蕨地下部能够囤积大量铅,最高含量和累积量分别达到15 542.1 mg/kg和41.81 mg/株; 3)除生长后期植物地上部氮、钾含量与铅含量存在显著的正相关关系(0.750^*和0.773^*)外,植物氮、磷、钾含量与铅含量在3个生长时期均未表现出显著的相关关系; 4)在植物生长前期,其地上部铅含量与地下部铅含量以及与生长旺盛期和生长后期的地上部或地下部铅含量均不存在显著的相关关系,而在生长旺盛期和生长后期,同一时期地上部和地下部铅含量之间以及不同时期地上部与地下部铅含量之间均存在显著或极显著的相关关系。     

祁连山东麓高寒草甸不同退化程度草地土壤种子库特征研究

通过野外调查和种子萌发法对东祁连山高寒草甸4种不同退化程度草地(未退化,ND;轻度退化,LD;中度退化,MD;重度退化,HD)土壤种子库进行了比较研究。结果表明:4种退化程度草地种子密度大小为:轻度退化草地>未退化草地>中度退化草地>重度退化草地;未退化草地共发现了6种植物,主要为十字花科(Cruciferae)和毛茛科(Ranunculaceae)植物;轻度退化草地共发现了9种植物,主要为禾本科(Gramineae)、菊科(Compositae)和豆科(Leguminosae)植物;中度退化草地共发现了5种植物,主要为车前科(Plantaginaceae)植物;重度退化草地共发现了5种植物,主要为禾本科(Gramineae)植物;对于土壤种子库的物种多样性,轻度退化草地最有利于维持和保护该地区物种多样性,未退化草地和轻度退化草地显著优于中度退化草地和重度退化草地;总体来看,4种退化程度草地种子库种子与地面植被物种相似性均较低。     

可鲁克湖—托素湖保护区4种盐生植物生态化学计量特征

盐生植物是柴达木盆地高寒湿地的重要组成部分,对维护高原地区生态安全有着不可或缺的角色,选取可鲁克湖-托素湖自然护区内的柽柳(Tamarix chinensis)、盐爪爪(Kalidium foliatum)、芦苇(Phragmites australis)和白刺(Nitraria tangutorum)4种典型盐生植物群落为研究对象,分析不同植物及不同营养器官中C,N,P的生态化学计量特征。研究结果表明：4种植物不同器官的C,N,P含量存在明显的种间差异,4种盐生植物叶片的C∶N(19.29)略低于全球植物叶片的平均水平(22.50)、4种盐生植物叶片的C∶P(274.81)高于全球植物叶片C∶P平均水平(232.00),根系的C∶N,C∶P均高于全球水平。4种盐生植物具有较高的固碳优势和养分利用策略,有较强的碳同化能力。柽柳和芦苇两种植物生长主要受N元素限制,盐爪爪和白刺两种植物生长主要受P元素限制,表现出可鲁克湖—托素湖湿地自然保护区内不同植物对于营养元素的分配利用各有不同。     

四种草本植物生长性状和根性状对磷添加的响应策略

采用盆栽种植方式,对低浓度有机磷(20 mg/kg)、低浓度无机磷(20 mg/kg)和高浓度无机磷(200 mg/kg)水平下石竹、冰草、苜蓿和沙葱的生长、根形态和生理性状指标进行测定,探究内蒙古草原四种草本共存植物的磷适应策略。结果表明：与低磷环境相比,高磷环境下四种植物均具有更高的地上部生物量、氮和磷累积量、根生物量,根冠比(除沙葱外)均较低;细根植物(石竹和冰草)的总根长在低浓度有机磷环境最长,粗根植物(苜蓿和沙葱)则在高浓度无机磷环境最长,四种植物的总根长均在低浓度无机磷环境最短;四种草本植物的比根长均在低浓度有机磷环境最高,在低浓度无机磷环境最低,且细根植物的比根长显著高于粗根植物;四种植物中,沙葱具有最高的根系有机酸含量(比其他三种植物高约39倍)和酸性磷酸酶活性(高约52倍)以及最低的根呼吸速率(低约7倍),苜蓿则具有最高的平均根性状变异度。总体来看,细根植物主要是通过增加比根长和总根长,粗根植物主要通过提高根系有机酸和酸性磷酸酶活性(如沙葱)或增大根性状变异度(如苜蓿)来适应低磷环境。     

南亚热带景观湖泊水生植物筛选研究(Ⅱ)——用综合评价指标体系筛选水生植物CSCD

为了提高景观湖泊水生植物开发利用的有效性,2019年从前期研究的47种景观湖泊水生植物中选择21种,采用AHP方法构建评价指标体系,通过分析比较,对其综合利用价值进行排序,以此作为科学选择植物的依据。结果表明:挺水植物对筛选的总体目标贡献率依次为:挺水植物>浮水植物>沉水植物;挺水植物中的芦苇(Phragmites communis)、蒲苇(Cortaderia selloana)等10种植物,浮水植物中的芡实(Euryale ferox)和萍蓬草(Nuphar pumilum),沉水植物中的金鱼藻(Ceratophyllum de⁃mersum)和狐尾藻(Myriophyllum verticillatum)均具有较高的综合利用价值。参试的21种水生植物的综合利用价值排序与传统园林绿化造景、生态修复等所使用的植物有一定差异,实际应用时应根据主要用途和植物的综合利用价值进行优化组合,以释放其最大效益。     

科尔沁草原主要草地植物传播生物学简析

本研究论述了科尔沁草原主要草地植物的传播生物学特性.在141种植物中,44种以种子作为传播体,97种以果实作为传播体;传播体重量< 0.1 mg的植物12种,重量0.1～0.999 9 mg的植物61种,重量1～9.999 9 mg的植物55种,重量10～99.999 9 mg的植物12种,重量100～999.999 9 mg的植物1种;具有典型聚合传播体的植物4种;具有典型多态传播体的植物1种;传播体具附属物的植物66种(占总数的46%),其中19种带冠毛,10种带绢毛或丝毛,15种带芒或刚毛,6种带翅,6种带钩或刺,10种带其他附属物(花柱、花萼、结块和喙等).在124种植物中,11种植物(7种蒿属植物、2种车前、百里香1种和野亚麻1种)种子具有粘液,其种子或果实的干重＜1 mg.已发现23种植物具有明显的植冠种子库(植冠种子库种子达到总结种量的5%).8种植物植冠种子库种子超过结种量的30%,7种植物达到结种量的20%～30%,8种植物少于结种量的20%.具有植冠种子库的植物以菊科(尤其蒿属)、禾本科和藜科植物为多.具有较强或相对较强沙生适应性的植物多数具有植冠种子库.探讨了传播体类型和重量、利于(或阻滞)传播的传播体特征、传播体多态性与传播适应的多面性、延缓传播与植冠种子库等方面的问题.     

沙棘-桑树人工混交林对铁尾矿土壤的改良效益分析

通过测定与调查铁尾矿区营建沙棘-桑树人工混交林的土壤理化性质、养分含量及分布,评价人工混交林对铁尾矿区土壤改良的作用。与新尾矿区土壤相比,沙棘-桑树混交林下尾矿土壤容重与毛管孔隙度分别减小5.85%、5.04个百分点,空气孔隙度和自然含水量分别增加了10.97、1.35个百分点,混交林下尾矿土壤0～40 cm土层的平均相对含水量比新尾矿土壤增加12.90个百分点,表明混交林植物根系的生长促使原来致密的尾矿砂土的物理性质得到有效改善。混交林对尾矿碱性土壤的改良作用明显,且桑树的改良作用优于沙棘。混交林下尾矿土壤中的有机质含量增加,为对照新尾矿土壤的7.22倍,有机质含量随土层加深而递减,且均有一定的表聚性,主要分布在0～20 cm土层;但混交林下尾矿土壤中的有机质含量仍然较低,仅是该区域对照山地天然灌丛土壤的17.15%。混交林下尾矿土壤速效态大量元素的含量依次为速效P>速效K>碱解N,全量为K>P>N,其中沙棘根系周围土壤中的全N、全P、全K含量高于桑树,而桑树根系周围土壤中的全Ca和全Mg平均含量略高于沙棘。依据上述结果认为,沙棘-桑树人工混交林可有效改良铁尾矿土壤的理化性质,增加土壤养分含量。     

Knowledge,attitude, and practices on usage,disposal, and effect of plastic bags on sheep and goats

The objective of this study was to evaluate knowledge, attitudes, and practices of people in the Nairobi and Kajiado Counties, Kenya, on the usage, disposal, and effect of plastic waste on sheep and goats (shoats). A semi-structured questionnaire was used to collect data from 384 respondents in four communities in the two counties. Most of the people irrespective of their age, occupation, and educational status used plastic bags of some type on a daily basis. A high proportion of the respondents (37.0%, 142) used plastic bags because of the low cost. Approximately, 79.1% (304) disposed used plastic bags in open dumps. A total of 147 (38.3%) households kept shoats. Out of these, 38.1% (56) purchased feed and also allowed their animals to roam. Most of them (45.3%, 174) thought that lack of feed for the animals was the main reason why shoats roam and scavenge at refuse dump sites and road sides. A large proportion of the respondents (44.5%, 143) mentioned death of animals as the ultimate consequence of ingestion of waste plastic bags. Though, the respondents were aware that indiscriminate disposal of used plastic bags could result in death of the animals from which they derive their livelihoods, they nevertheless continued with the practice. There is a need for a paradigm shift in the way and manner plastic bags are used and disposed.     

Effects of sire growth potential, growing-finishing strategy, and time on feed on performance, composition, and efficiency of steers.

Beef production systems that increase use of unharvested forages and use animals with greater potential for gain affect age and size of animals placed on a finishing regimen. This experiment was conducted to evaluate effects of genetic potential for gain, age at the start of a finishing period, and time on feed on composition, quantity, and quality of beef produced and efficiency of production during finishing. Crossbred cows were bred by AI to Charolais or Line 1 Hereford bulls that represented potentially high (HG) or moderate growth (MG) rates, respectively, to produce spring- or fall-born calves. Steer calves from these matings were placed on an individually fed finishing diet at three ages (A). Spring-born steers were started at 6 or 18 mo of age (A6 and A18), and fall-born steers were started at 12 mo of age (A12). Slaughter times (T) were at 0, 90, 180, and 270 d for A6; 68, 136, and 204 d for A12; and 0, 45, 90, and 135 d for A18. Data collected on each animal included feed intake, growth, chemical composition of the complete body and carcass, and quantitative and qualitative assessment of the meat produced. Four steers of each sire group were slaughtered in each of the 11 A-T treatment groups, and the experiment was repeated for 2 yr in the A12 groups and 3 yr in the A6 and A18 groups (n = 237). Steers sired by HG bulls were larger and produced larger carcasses and more carcass protein than MG-sired steers (S, P < .05 or .01). Steers sired by MG bulls were fatter, had higher quality grades, and accumulated fat at a faster rate than HG-sired steers, and this effect was greater in older steers (G and GA, P < .05 or .01). Sire growth potential did not affect gain, intake, live weight efficiency, tenderness, or taste panel scores (P > .2). Steers sired by HG bulls were more efficient at producing carcass weight and carcass protein at A12 and A18 than were MG-sired steers. At the end of the finishing period, older (A18), HG-sired steers were too large with insufficient fat by current industry standards, and younger (A6), MG-sired steers were too small. Our conclusions are that both HG- and MG-sired steers can produce acceptable carcasses for current market standards with comparable efficiencies of live-weight gain, but the growing and finishing strategy must be adapted to the genotype.     

Effect of feeding corn naturally contaminated with aflatoxin on feed efficiency, on physiologic, immunologic, and pathologic changes, and on tissue residues in steers

Two of 3 groups of Holstein-Friesian steers (groups II and III; n = 5 each) were fed a ration containing corn naturally contaminated with 800 ng of aflatoxin/g. The other group of steers (group I; n = 5) was fed a ration containing noncontaminated corn. The respective rations were fed for 17.5 weeks, except the ration given to group III; the latter's first diet (contaminated with aflatoxin) was changed to a noncontaminated diet after 15 weeks, continuing for the remaining 2.5 weeks. All steers were killed and tissues and fluids were obtained for aflatoxin analysis. Although aflatoxin B1 and M1 could be detected in blood and urine at several sampling times during the experimental period in groups II and III steers (given the diets containing aflatoxin), there appeared to be no effects on body weight gains and immune phenomena, such as lymphoblastogenesis and antibody production, but there was a waning of the delayed cutaneous hypersensitivity in steers given aflatoxin-contaminated diets. In group III animals (diet was changed to noncontaminated ration at 15 weeks), aflatoxin B1 and M1 disappeared from urine before they were slaughtered. All tissues and fluids, except the rumen contents from these group III steers, were void of detectable aflatoxins B1 and M1 at necropsy. The concentrations of aflatoxin B1 in the rumen content of the latter steers were low. All tissues collected at necropsy from the group II steers fed the aflatoxin diet throughout the 17.5 weeks had detectable aflatoxins B1 or M1 present.     

葡萄糖、果糖、聚乙烯醇及牛磺酸对山羊精液保存的影响

以Androhep稀释液为山羊精液液态保存基础稀释液,研究了葡萄糖和果糖,聚乙烯醇(PVA)含量,及牛磺酸的添加量对5℃保存山羊精液的影响.结果发现,Androhep稀释液中以只含葡萄糖保存效果最好,PVA的量以0.5%为最佳,牛磺酸添加21 mmol/L时保存6 d精子的活力和质膜完整率最高.     

发酵乳中SOD、CAT、GSH-Px、GST活性的变化

10份鲜牛乳98℃煮沸5min后,用乳酸菌发酵制作酸乳。测定了发酵前后乳中SOD、CAT、GSH-Px、GST的变化。发酵前4种酶的活性分别为:45.68±7.81、1.46±1.78、156.67±37.51(GSH-PX活力单位),65.81±25.47;发酵后各酶的活性分别为73.47±5.27、0.44±0.50、0、5.42±3.25。发酵乳SOD活性升高60%多,CAT降低近73%,GST降低近92%,GSH-Px活性全部丧失(P<0.01)。