铅锌矿区分离丛枝菌根真菌对万寿菊生长与吸镉的影响

盆栽试验研究了土壤不同施Cd水平(0、20、50 mg kg-1)下,接种矿区污染土壤中丛枝菌根真菌对万寿菊根系侵染率、植株生物量及Cd吸收与分配的影响。结果表明:接种丛枝菌根真菌显著提高了Cd胁迫下万寿菊的根系侵染率和植株生物量;随着施Cd水平提高,各处理植株Cd浓度和Cd吸收量显著增加。各施Cd水平下万寿菊地上部Cd吸收量远远高于根系Cd吸收量,尤其在20 mg kg-1施Cd水平下,接种处理地上部Cd吸收量是根系的3.90倍,对照处理地上部Cd吸收量是根系的2.33倍;同一施Cd水平下接种处理地上部Cd吸收量要显著高于对照。总体上,试验条件下污染土壤中分离的丛枝菌根真菌促进了万寿菊对土壤中Cd的吸收,并增加了Cd向地上部分的运转,表现出植物提取的应用潜力。     

接种菌根真菌影响青菜中铅镉的累积和迁移

Heavy metal(HM) contamination in soils is an environmental issue worldwide that threatens the quality and safety of crops and human health. A greenhouse experiment was carried out to investigate the growth, mycorrhizal colonization, and Pb and Cd accumulation of pakchoi(Brassica chinensis L. cv. Suzhou) in response to inoculation with three arbuscular mycorrhizal(AM) fungi(AMF), Funneliformis mosseae, Glomus versiforme, and Rhizophagus intraradices, aimed at exploring how AMF inoculation affected safe crop production by altering plant-soil interaction. The symbiotic relationship was well established between pakchoi and three AMF inocula even under Pb or Cd stress, where the colonization rates in the roots ranged from 24.5% to 38.5%. Compared with the non-inoculated plants, the shoot biomass of the inoculated plants increased by 8.7%–22.1% and 9.2%–24.3% in Pb and Cd addition treatments, respectively. Both glomalin-related soil protein(GRSP) and polyphosphate concentrations reduced as Pb or Cd concentration increased. Arbuscular mycorrhizal fungi inoculation significantly enhanced total absorbed Pb and Cd(except for a few samples) and increased the distribution ratio(root/shoot) in pakchoi at each Pb or Cd addition level. However, the three inocula significantly decreased Pb concentration in pakchoi shoots by 20.6%–67.5% in Pb addition treatments, and significantly reduced Cd concentration in the shoots of pakchoi in the Cd addition treatments(14.3%–54.1%), compared to the non-inoculated plants.Concentrations of Pb and Cd in the shoots of inoculated pakchois were all below the allowable limits of Chinese Food Safety Standard.The translocation factor of Pb or Cd increased significantly with increasing Pb or Cd addition levels, while there was no significant difference among the three AMF inocula at each metal addition level. Meanwhile, compared with the non-inoculated plants, AMF inocula significantly increased soil p H, electrical conductivity, and Pb or Cd concentrations in soil organic matter in the soils at the highest Pb or Cd dose after harvest of pakchoi, whereas the proportion of bioavailable Pb or Cd fraction declined in the AMF inoculated soil. Our study provided the first evidence that AM fungi colonized the roots of pakchoi and indicated the potential application of AMF in the safe production of vegetables in Pb or Cd contaminated soils.     

锌镉超富集植物滇苦菜中碳酸酐酶对镉的响应

A number of higher plants are able to hyperaccumulate cadmium(Cd). However, it is unknown whether cadmium(Cd) plays a biological functional role in the carbonic anhydrase(CA) of hyperaccumulators. A hydroponic experiment was conducted to explore the potentially physiological function of Cd in CA and the accumulation and tolerance of Cd in the Zn/Cd hyperaccumulator Picris divaricata Vant. P. divaricata was exposed to nutrient solutions with six Cd concentrations(0, 5, 10, 25, 50 and 75 μmol L~(-1)). After 12 d, plants were harvested for the analysis of plant biomass, Cd concentration and CA activity. The Cd concentrations in plant increased with the increasing Cd in nutrient solution, reaching 640 and 3 100 mg kg~(-1) in shoot and root, respectively, at the 75 μmol L~(-1) Cd treatment. Meanwhile, plant growth was enhanced by the Cd treatments at 5–25 μmol L~(-1), but it was significantly inhibited when the plants were exposed to solutions with higher Cd concerntrations(50 and 75 μmol L~(-1)). Exposure to Cd significantly increased the CA activity in P. divaricata, which reached a maximum value of 21.27 U mg~(-1) proteins at the 25 μmol L~(-1)Cd treatment, and the CA activity and shoot Cd concentration were positively correlated at solutions Cd of ≤ 25 μmol L~(-1). Moreover, two protein bands appeared on the denatured gel electrophoresis of purified CA, indicating that P. divaricata may have CA isomers with their respective molecular weights at around 60 and 55 k Da, at least one of which is Cd-bound. In addition, trace amounts of Cd in purified CA significantly increased with the supplied Cd concentration in nutrient solution(5–25 μmol L~(-1)). The results suggested that Cd may play a biological role by enhancing the activities and forming the active Cd-specific CA in the hyperaccumulator P. divaricata.     

深色有隔内生真菌柱孢顶囊壳对玉米幼苗生长、光合作用及耐铅能力的影响

Dark septate endophytic (DSE) fungi are ubiquitous and cosmopolitan,and occur widely in association with plants in heavy metal stress environment.However,little is known about the effect of inoculation with DSE fungi on the host plant under heavy metal stress.In this study,Gaeumannomyces cylindrosporus,which was isolated from Pb-Zn mine tailings in China and had been proven to have high Pb tolerance,was inoculated onto the roots of maize (Zea mays L.) seedlings to study the effect of DSE on plant growth,photosynthesis,and the translocation and accumulation of Pb in plant under stress of different Pb concentrations.The growth indicators (height,basal diameter,root length,and biomass) of maize were detected.Chlorophyll content,photosynthetic characteristics (net photosynthetic rate,transpiration rate,stomatal conductance,and intercellular CO2 concentration),and chlorophyll fluorescence parameters in leaves of the inoculated and non-inoculated maize were also determined.Inoculation with G.cylindrosporus significantly increased height,basal diameter,root length,and biomass of maize seedlings under Pb stress.Colonization of G.cylindrosporus improved the efficiency of photosynthesis and altered the translocation and accumulation of Pb in the plants.Although inoculation with G.cylindrosporus increased Pb accumulation in host plants in comparison to non-inoculated plants,the translocation factor of Pb in plant body was significantly decreased.The results indicated that Pb was accumulated mainly in the root system of maize and the phytotoxicity of Pb to the aerial part of the plant was alleviated.The improvement of efficiency of photosynthesis and the decrease of translocation factor of Pb,caused by DSE fungal colonization,were efficient strategies to improve Pb tolerance of host plants.     

植物对镉毒害的形态和生理响应研究进展

Cadmium (Cd) contamination has posed an increasing challenge to environmental quality and food security.In recent years,phytoremediation has been particularly scrutinized because it is cost-effective and environmentally friendly,especially the use of metal-hyperaccumulating plants to extract or mine heavy metals from polluted soils.Under Cd stress,responses of hyperaccumulator and non-hyperaccumulator plants differ in morphological responses and physiological processes such as photosynthesis and respiration,uptake,transport,and assimilation of minerals and nitrogen,and water uptake and transport,which contribute to their ability to accumulate and detoxify Cd.This review aims to provide a brief overview of the recent progresses in the differential responses of hyperaccumulator and non-accumulator plants to Cd toxicity in terms of growth and physiological processes.Such information might be useful in developing phytoremediation technology for contaminated soils.     

丛枝菌根真菌对镉胁迫下黑麦草光合生理的响应

为探究镉(Cd)胁迫下丛枝菌根(AM)真菌对黑麦草(Lolium perenne)光合生理的影响,盆栽条件下以Cd浓度为0、5、15和30 mg·kg-1分别对黑麦草接种AM真菌摩西斗管囊霉(FM)、变形球囊霉(GV)、混合处理(FM+GV)以及不接种对照(NM)共16个处理。结果表明,Cd降低了AM真菌侵染;接种AM真菌则提高了黑麦草株高、叶绿素含量、荧光参数、地上部和根系氮(N)、Cd含量,增强光合作用,显著提高植物体内生理活性。在Cd浓度为30 mg·kg-1水平下,FM+GV处理的菌根侵染率最大,为42.7%,与NM相比,FM+GV处理的黑麦草叶片叶绿素含量、地上部和根系N含量分别提高26.2%、70.6%和85.3%;株高和地上干重分别提高34.1%和18.8%;PSⅡ最大光化学效率和PSⅡ潜在活性分别提高4.9%和19.7%;净光合速率、蒸腾速率和气孔导度分别增加19.8%、28.3%和14.7%;超氧化物歧化酶、过氧化物酶活性、可溶性蛋白含量分别是NM的1.3、1.5和1.8倍,丙二醛含量相较NM下降50.0%。土壤中Cd浓度与植株地上部和根内的Cd含量呈显著正相关,FM+GV处理的黑麦草地上部和根系Cd含量分别达到88.1和606.7 mg·kg-1。总体来看,FM+GV处理增加黑麦草光合生理抗性、吸收固持Cd能力的效果最为显著。     

丛枝菌根真菌(Glomus mosseae)对玉米吸镉的影响

盆栽试验研究了不同培养条件(土壤与河沙)下,3种施Cd水平(0、5、50 mg kg-1)对菌根玉米生长、根系侵染率及重金属Cd吸收的影响。结果表明:施Cd水平显著影响玉米吸Cd能力。随Cd浓度增加,各处理根系与地上部分Cd浓度和吸收量显著增加,各施Cd水平下玉米根系Cd浓度和吸收量远远高于地上部分。不同培养条件下,各处理也表现出明显的差异。以河沙为培养基质,接种菌根真菌显著增加玉米的生物量及根系侵染率;在高Cd水平下,接种处理玉米根系中的Cd浓度和吸收量较对照显著增加,但地上部分的Cd浓度和吸收量却相应降低。以土壤为培养基质,随施Cd水平提高,植株吸Cd量增加,但接种处理植株根部与地上部Cd浓度均显著低于对照。试验表明,丛枝菌根真菌Glomus mosseae可减少重金属Cd向玉米植株地上部的运输,将更多的Cd固持在菌根之中,这可能是菌根减轻宿主植物Cd毒害的一个重要机制。     

丛枝菌根真菌对镉胁迫下芦竹生长、光合特性和矿质营养的影响

为揭示丛枝菌根真菌(Arbuscular mycorrhizal fungi,AMF)对芦竹耐镉(Cd)胁迫的作用及其机理,采用大棚盆栽试验,利用丛枝菌根真菌(AMF)摩西管柄囊霉(Funneliformis mosseae,FM)、根内根孢囊霉(Rhizophagus intraradices,RI)、地表球囊霉(Glomus versiforme,GV)进行接种试验,研究了在Cd胁迫下接种AMF对芦竹生长、光合特性、矿质营养的影响。结果表明:AMF能够显著改善Cd胁迫下芦竹的生长状况,与对照相比,接种处理芦竹的株高增加19.09%～27.98%,叶长增加12.18%～31.06%,叶绿素相对含量SPAD值增加8.55%～9.36%,地上和根系生物量分别增加20.08%～31.41%、12.24%～24.12%,最大净光合速率增加7.08%～32.12%,芦竹根系全磷含量增加30.26%～46.05%。接种处理后芦竹地上Cd含量介于68～105.97 mg/kg,显著高于对照处理(42.20mg/kg),根系Cd含量介于110.67～221.47 mg/kg,显著高于对照处理(46....     

丛枝菌根真菌对烤烟生长及产值的影响

为有效评价菌根化苗在烤烟生产中的应用,对比研究了菌根化苗和常规生产烟苗不同生长期的农艺性状和主要经济性状。结果表明,菌根化烟苗根冠比均显著大于常规育苗组,株高、根长、茎围小于常规生产烟苗;移栽30 d的菌根化烟苗株高、茎围均小于常规育苗组;移栽60 d接种Gm.02和Gm.03的烟株株高大于常规生产烟苗,接种Gm.01和Gm.02的烟株茎围大于常规育苗组;移栽90 d的3种菌根化苗株高、茎围均大于常规育苗组。菌根化烟苗最大叶长在整个生育期内均小于常规生产烟苗;菌根化烟苗移栽30 d最大叶宽均小于常规育苗组,移栽60 d接种Gm.01菌根化烟株大于常规育苗组,移栽90 d,接种Gm.01和Gm.03菌根化烟株大于常规育苗组。菌根化苗均能提高烤烟产量、上等烟比例、均价及产值,但是不同的菌剂作用效果不同。     

玉米铬毒性研究：氧化损伤、渗透调节物质积累、抗氧化防御以及铬的吸收

Agricultural production systems are immensely exposed to different environmental stresses in which heavy metal stress receives serious concerns. This study was conducted to explore the deleterious effects of different chromium(Cr) stress levels, i.e., 0, 30, 6090, 120, and 150 μmol L-1, on two maize genotypes, Wandan 13 and Runnong 35. Both genotypes were evaluated by measuring their growth and yield characteristics, Cr accumulation in different plant tissues, alterations in osmolyte accumulation, generation o reactive oxygen species(ROS), and anti-oxidative enzyme activity to scavenge ROS. The results showed that Cr stress decreased the leaf area, cob formation, 100-grain weight, shoot fresh biomass, and yield formation, while Cr accumulation in different maize tissues was found in the order of roots leaves stem seeds in both genotypes. The increased Cr toxicity resulted in higher free proline soluble sugars and total phenolic contents, and lower soluble protein contents. However, enhanced lipid peroxidation was noticed in the forms of malondialdehyde, hydrogen peroxide(H2O2) and thiobarbituric acid reactive substance accumulation, and electrolyte leakage. The hyperactivity of superoxide dismutase, peroxidase, catalase, ascorbate peroxidase, especially glutathione peroxidase and glutathione reductase indicated that these anti-oxidative enzymes had a central role in protecting maize from Cr toxicity, especially for Wandan 13. Moreover, higher uptake and less translocation of Cr contents into the grains of Wandan 13 implied its importance as a potential candidate against soil Cr pollution.     

伊朗Zanjan城市尾矿土壤中入侵植物的抗氧化能力和金属积累情况

Tailings of a Pb and Zn mine as a metal-contaminated area (Zone 1) with two pioneer plant species, Peganum harmala and Zygophyllum fabago, were investigated and compared with a non-contaminated area (Zone 2) in the vicinity. Total concentrations of Pb, Zn, and Cu in the soil of Zone 1 were 1 416, 2 217, and 426 mg kg-1 , respectively, and all exceeded their ranges in the normal soils. The soil pH was in the neutral range and most of the physical and chemical characteristics of the soils from both zones were almost similar. The species Z. fabago accumulated higher Cu and Zn in its aerial part and roots than the normal plants. On the other hand, their concentrations did not reach the criteria that the species could be considered as a metal hyperaccumulator. The species P. harmala did not absorb metals in its roots; accordingly, the accumulation factor values of these metals were lower than 1. The contents of chlorophyll, biomass, malondialdehyde, and dityrosine in these two species did not vary significantly between the two zones studied. In Zone 1, leaf vacuoles of Z. fabago stored 35.6% and 43.2% of the total leaf Cu and Zn, respectively. However, in this species, the levels of phytochelatins (PCs) and glutathione (GSH) and antioxidant enzyme activities were significantly higher in Zone 1 than in Zone 2. In conclusion, metal exclusion in P. harmala and metal accumulation in Z. fabago were the basic strategies in the two studied pioneer species growing on the metal-contaminated zone. In response to metal stress, elevation in antioxidant enzyme activities, increases in the PCs and GSH levels in the aerial parts, and metal storage within vacuoles counteracted each other in the invasion mechanism of Z. fabago.     

伊乐藻对CuCd污染底泥修复的应用研究

在自然条件下,采用人工模拟水缸培养方法,研究了湖泊底泥不同Cu、Cd处理对沉水植物伊乐藻生长、叶绿素含量以及Cu、Cd吸收和积累的影响。结果表明,较低浓度Cu刺激伊乐藻的生长（生物量、叶绿素）,高浓度抑制伊乐藻的生长;随着Cd处理浓度的增加,伊乐藻的生物量、叶绿素含量均一直降低,在底泥Cd含量为168．69mg·kg^-1 DW（含背景值）时,植株出现死亡。随着Cu处理浓度的增加,伊乐藻体内的Cu含量一直增加,在底泥cu含量为414mg·kg^-1DW（含背景值）时,根部、叶部的富集系数均达到最大（0．21和0．17）;伊乐藻体内的Cd含量随Cd处理浓度的增加先增后减,底泥Cd含量为88．69mg·kg^-1 DW时,根部、叶部的富集系数均达到最大（0．07和0．09）。以上结果说明,伊乐藻对Cu、Cd具有很强的耐受性,可以作为原位修复Cu和Cd污染底泥的植物种类应用。     

在积累镉油菜后茬种植白菜可否减少其对镉的吸收?

Rapeseed (Brassica campestris L.), a Cd-accumulating crop, is effective in reducing plant-available Cd from soil. A pot experiment was conducted to test the hypothesis that the Cd uptake by Chinese cabbage (Brassica pekinensis Rupr.) grown in rotation with rapeseed would be reduced due to the efficient removal of bioavailable Cd from soil solution by the rapeseed crops. The Cd removal by shoot for the rapeseed cultivar Zhucang Huazi ranged from 0.24% to 0.99% in natural Cd-contaminated soil (soil A) and from 0.63% to 1.23% in artificial Cd-contaminated soil (soil B) during the growth period of 4–7 weeks; whereas that for the rapeseed cultivar Chuanyou II-93 ranged from 0.25% to 0.66% and from 0.38% to 1.02%, respectively. Chinese cabbage grown in the pots with soil A for five weeks after harvesting rapeseed exhibited a significantly lower Cd concentration compared to that grown in the control pots (uncropped with rapeseed). However, the rotation of rapeseed did not lower the Cd concentration of Chinese cabbage on soil B. Although an increase of Cd uptake was observed in the rapeseed cultivars with growth time, and the decrease of soil NH 4 OAc-extractable Cd was found only in the natural rather than artificial Cd-contaminated soil.     

硅对Cd胁迫下黄瓜苗期光合及抗氧化酶系统的影响

为了解石灰性土壤硅对Cd胁迫下黄瓜苗期叶片的光合特性和抗氧化酶系统及对实际土壤Cd毒害植物的防治,研究了硅介入下Cd污染土壤中黄瓜苗期的叶片净光合速率(P_n)、气孔导度(G_s)、蒸腾速率(T_r)、胞间CO_2(C_i)等光合作用指标,叶绿素含量,丙二醛(MDA)、超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)等抗氧化酶系统等相关参数。结果表明:与空白相比较,单施Cd处理下,P_n、G_s、T_r和叶绿素含量下降,Ci提高。硅介入后,能明显提高P_n、G_s、T_r和叶绿素总量,降低C_i含量。当C_d含量为5mg/kg时,硅施加量100~200mg/kg情况下,与空白相比,P_n、G_s、T_r和叶绿素上升,C_i下降,但100mg/kg与200mg/kg的硅处理差异不明显,300mg/kg的硅添加量效果最好。对于抗氧化酶系统,与空白相比较,土壤Cd含量为3~5mg/kg时,3类抗氧化酶的活性均受到显著抑制,200~300mg/kg硅的引入可明显提高SOD、POD、CAT活性,降低MDA值。可见,硅的引入可明显改善Cd胁迫下黄瓜叶片的光合特性和抗氧化酶系统。施用少量硅肥在石灰性土壤中对缓解植物Cd毒害具有一定的应用前景。     

Cd胁迫对5种植物体内Cd积累及根际土壤特性的影响

以大豆、棉花、曼陀罗、蓖麻和玉米为供试材料,采用土柱栽培试验,探讨Cd胁迫后,5种植物根系活力与各器官间cd含量的差异,以及5种植物根际土壤酶活性与根际土壤营养含量对Cd胁迫的反应.结果表明:(1)5种受污染的植物体Cd富集量超出对照不受污染的植物体达3～7倍之多,但都未达富集临界值100 mg/kg.(2)不同植物不同器官Cd运转积累部位不同,以根冠比衡量,蓖麻、玉米、棉花R/S大于1,称作根优势植物;大豆、曼陀罗R/S小于1,称作冠优势植物;棉花R/S近于1,称作冠根均衡植物.5种植物吸收富集最强的前3位植物(大豆、玉米、棉花)都是人工驯化的栽培植物,其吸肥能力强于野生植物的,这种吸肥能力与吸Cd能力是否呈正相关关系,吸肥能力的差异是否可以作为污染土壤利用改良的依据值得进一步研究.(3)大豆、曼陀罗茎秆中Cd含量均较根、叶、籽实中的高,考虑到大豆是粮食作物,同时其根部Cd含量仅次子茎的,而曼陀罗作为一种杂草,其地上部Cd转移系数大于1.0,因此,比较供试5种植物,应优先选择曼陀罗用于Cd污染区域的土壤净化.(4)Cd胁迫(5 mg/kg)提高了5种植物根系还原TTC强度,抑制了大豆和蓖麻根际土壤多种酶活性,而促进了曼陀罗和玉米根际土壤多种酶活性以及棉花根际土壤脲酶、蔗糖酶和碱性磷酸酶活性;比较5种酶活性,碱性磷酸酶活性对Cd反应较不敏感,脲酶和蔗糖酶活性对Cd反应较敏感,多酚氧化酶和过氩化氯酶活性对CA的敏感程度因不同植物而异.结果还表明Cd胁迫不同程度地提高了供试5种植物根际土壤营养含量.(5)研究为有效开展Cd污染土壤的植物修复资源提供理论依据.