多胺对共生条件下丛枝菌根真菌及宿主植物生长发育的影响

为探讨多胺对共生条件下丛枝菌根真菌及其宿主植物生长发育的影响,本研究以丛枝菌根真菌(Gigaspora margarita)为试验材料,通过施用不同浓度的多胺(Polyamine,PA)及其生物合成抑制剂[Methylglyoxal bis(guanylhydrazone),MGBG]处理接种丛枝菌根真菌的葡萄微繁苗,研究共生培养条件下外源多胺及多胺合成抑制剂对丛枝菌根真菌孢子萌发、芽管菌丝及其宿主植物生长发育的影响.试验结果表明,共生培养条件下,一定浓度的外源PA对丛枝菌根真菌及其宿主植物的生长发育具显著促进作用,丛枝菌根真菌孢子数、菌丝长度、侵染率、丛枝丰富度及菌根化葡萄幼苗生长势均显著提高.MGBG则表现较强的抑制作用.且该抑制作用可被外源PA部分解除,证明外源多胺对菌根化葡萄微繁苗生长发育的促进作用是通过活化根系土壤中丛枝菌根真菌,促进微繁苗丛枝菌根共生体的良好发育,最大程度地发挥菌根化效应得以表现的.     

土壤因子对西藏高原草地植物AM真菌的影响

于西藏高原中部地区就土壤因子对草地植物AM真菌的影响进行的研究表明：AM真菌孢子密度与菌根侵染率、菌根侵染强度无相关性；土壤质地对AM真菌孢子密度的影响明显大于土壤类型，壤土、粉砂土中AM真菌对植物根系的侵染率高于砂壤土；土壤pH与植物根围土壤孢子密度、菌根侵染率分别呈显著正相关和正相关，与菌根侵染强度则呈负相关；土壤有机质与AM真菌孢子密度呈负相关，菌根侵染效果则随土壤有机质含量的增加而提高；高磷土壤环境对AM真菌产孢和侵染均具不同程度的抑制作用，其中植物菌根侵染率随土壤有效磷含量的提高而呈显著下降；AM真菌对莎草科植物矮生嵩草、扁穗莎草根系具有良好的侵染效应。     

柑橘砧木和砧穗组合对丛枝菌根发育的影响

倍体体细胞杂种砧木)对丛枝菌根发育的影响。结果表明,柑橘丛枝菌根侵染幅度为 4.88 % ~ 40.52 %,土壤内孢子密度不等,大致在 347 ~ 750 个孢子/kg(干土)内。田间菌根侵染率和孢子密度在不同土层深度的分布以深度 10 ~20 cm 为最高。遗传关系相近的国庆 1 号/枳和国庆 4 号/枳组合间以及红肉脐橙/罗伯逊脐橙 36 号/枳和纽荷尔脐橙/罗伯逊脐橙 36 号/枳间的丛枝菌根发育没有显著差异,与红肉脐橙和纽荷尔脐橙遗传关系远的脐血橙组合,较红肉脐橙和纽荷尔脐橙组合的孢子密度间有极显著差异。红桔 枳的菌根侵染率和土壤孢子密度均最高,且显著高于其他 4 种砧木。盆栽砧木孢子密度与菌根侵染率呈显著正相关性。10 种试材的根围土壤孢子密度与菌根侵染率间呈极显著正相关性。     

砷胁迫条件下接种丛枝菌根真菌对番茄生长和磷吸收的影响

采用盆栽法研究了砷(As)污染条件下(As 0,50,100和200 mg·kg-14个水平)丛枝菌根真菌(AMF)接种对全生育期番茄植株生长及其磷(P)营养的影响。试验中各接种处理均成功侵染,侵染率在11.79%~34.36%之间。砷胁迫显著影响番茄植株的生物量,植株生长过程中各个时期地上部和根系干重均随As添加水平的升高而显著下降。本试验同时发现As 50 mg·kg-1是不接种番茄植株忍受砷毒害的上限,而接种丛枝菌根真菌后,番茄忍受砷毒害的上限上调到100 mg·kg-1;但200 mg·kg-1已达番茄忍受砷毒害的极限。基质中添加砷对番茄植株不同生长时期地上部和根部磷含量有显著影响。除开花期地上部与其不接种处理根部磷含量外,幼苗期和坐果期植株地上部磷含量与根部磷含量均随着砷添加量的增加而呈大致递增趋势。番茄植株生长的各个时期(幼苗期、开花期和坐果期)地上部和根部磷吸收量随砷添加水平的增加呈明显下降趋势。砷污染条件下,接种丛枝菌根在一定程度上促进了植株生长及其对磷的吸收,缓解了砷对植株生长的胁迫。     

外源钙与丛枝菌根真菌协同对玉米生长的影响与土壤改良效应

为了缓解煤炭开采对神东矿区农业生产和地表环境造成的破坏,试验模拟神东矿区干旱缺水特点,以煤炭开采塌陷区退化土壤为供试基质,玉米为供试植物,研究丛枝菌根真菌(每克干土中含63个孢子)和不同浓度的外源钙(5,10,20,40,80mmol/L)协同效应对中度干旱胁迫下苗期玉米生长的影响。结果表明,干旱胁迫下,20mmol/L外源钙与丛枝菌根真菌协同效应最优,玉米质量平均每株可达4.03g,组织含水率和叶色值分别达到91.68%和43.67,玉米植株内氮磷钾累积量显著高于其他处理;同时,玉米根际土壤球囊霉素相关蛋白增加最为明显,总球囊霉素和易提取球囊霉素分别达到4.3和1.6mg/g,根际土壤中有机质含量增加明显。丛枝菌根真菌与外源钙联合作用有利于玉米的生长,缓解了干旱胁迫对苗期玉米生长的影响,接种丛枝菌根真菌对矿区退化土壤具有显著改良效应。     

红壤中丛枝菌根真菌对污泥态铜生物有效性的影响

以玉米为宿主植物 ,研究了不同污泥量 (0、1 %、4% )施入红壤后接种丛枝菌根真菌Acaulosporalaevis、Glomuscaledonium和Glomusmanihotis对菌根侵染率、孢子密度、玉米生长和铜生物有效性的影响。结果表明 ,施用 1 %的污泥可增加接种A laevis的菌根侵染率和孢子密度 ,其玉米地上部和地下部生物量也有显著增加 ,而不接种 (含土著菌根真菌 )、接种G caledonium和G manihotis的菌根侵染率、孢子密度、玉米地上部和地下部生物量却有显著下降 (p<0 0 5 )。施用 1 %的污泥时接种A laevis降低了玉米地上部铜浓度 ,而接种G caledonium和G manihotis却增加了玉米地上部铜浓度 ,另外 ,接种处理增加玉米根部对铜的吸收总量。不同的菌根真菌对重金属的耐受力是不同的 ,只有施入一定的污泥量即在一定污染程度下才能发挥菌根真菌A laevis对污染土壤的修复作用     

不同氮磷比例营养液对AM真菌生长发育的影响

温室条件下,研究不同氮磷比例营养液对丛枝菌根(Arbuscular.mycorrhizae,AM)真菌(Glomus.mosseae)生长发育的影响。结果表明:在一定磷水平条件下增加氮的水平,有利于菌根真菌的生长发育,但超过一定水平则会抑制菌根真菌的生长发育,说明氮水平也会影响菌根真菌的生长发育,这种影响与氮磷比例有关。综合比较菌根长度、根外菌丝量及孢子数三项指标,在20%浓度Hoagland营养液的基础上,将氮磷比例提高到4∶2有利真菌生长。在AM菌剂生产中,通过营养液中氮磷比例的调控能获得较大数量的侵染根段、菌丝及孢子等繁殖体。     

松嫩盐碱草地植物丛枝菌根的初步调查

对松嫩盐碱草地主要植物的丛枝菌根(AM)真菌共生状况进行了初步调查,在观察的9科20种植物中,所有植物均能被AM真菌侵染。在过去认为不被侵染的莎草科、藜科和蓼科植物中,发现球序苔草、碱蓬、灰绿藜、碱地肤、萹蓄蓼和碱蓼有侵染现象。丛枝菌根结构类型以Arum类型(A-型)为主,占75%,少数为Paris类型(P-型),占15%。根际土壤中AM真菌孢子密度范围为0.23～4.71个g-1。在不同质地土壤条件下,根际土壤中AM真菌孢子密度、AM真菌侵染率和侵染强度均有差异,松嫩盐碱草地的壤土比砂壤土更适宜AM真菌的生存。植物根际土壤的pH值和全盐含量对AM真菌侵染和AM真菌均有一定的影响。     

丛枝菌根真菌对镉污染土壤中黑麦草幼苗生长的影响

通过不同浓度的镉污染土壤接种丛枝菌根真菌的黑麦草盆栽试验,研究了丛枝菌根真菌对镉污染条件下黑麦草幼苗生长的影响。结果表明:重度镉污染(Cd2+:180 mg/kg)条件下,Glomus mosseae对黑麦草根系的侵染率仍达到30.23%,对黑麦草的生长有较好的促进作用;丛枝菌根在一定程度上缓解了镉污染对黑麦草株高、根长和生物量积累的抑制;镉污染显著降低黑麦草叶片的叶绿素含量,叶绿素a在重度镉污染时下降幅度最大,不接种丛枝菌根真菌的黑麦草较对照下降37.9%,而接种的黑麦草下降26.7%,接种菌根真菌在中重度镉污染条件下显著提高了黑麦草叶片的叶绿素含量;重度镉污染下接种和不接种的黑麦草根系活力都开始显著下降,但接种植株根系活力下降的幅度小于不接种植株。     

培养基质对丛枝菌根(AM)真菌生长发育的影响

温室条件下,以盆栽培养方法研究不同培养基质对丛枝菌根(Arbuscular Mycorrhizae,AM)真菌Glomus mosseae生长发育的影响。结果表明：不同理化性质的基质对菌根共生体生长发育的影响不同,综合考虑菌根长度、根外菌丝量及孢子数3项指标,以沙土混合物(体积比3∶1)对G. mosseae菌剂的生长发育最为有利。宿主植物菌根长度及根中的可溶性糖浓度与根外孢子数有正相关关系,而宿主植物中磷浓度与菌根真菌的生长发育也有类似的关系。说明培养基质的养分状况、水分状况、通气状况等诸多因素都会影响菌根共生体的建立和发展。宿主植物的菌根长度、根中可溶性糖浓度以及宿主植物磷浓度对菌根真菌的生长发育有显著影响。因此,工厂化AM菌剂生产中,应以沙土混合物(体积比3∶1)为生产G. mosseae菌剂的培养基质。     

Effects of arbuscular mycorrhizal inoculation and phosphorus supply on the growth and nutrient uptake of Kandelia obovata (Sheue,Liu & Yong) seedlings in autoclaved soil

This study evaluated the interactive effect of arbuscular mycorrhizal fungi (AMF) inoculation and exogenous phosphorus supply on soil phosphotases, plant growth, and nutrient uptake of Kandelia obovata (Sheue, Liu & Yong). We aimed to explore the ecophysiological function of AMF in mangrove wetland ecosystems, and to clarify the possible survival mechanism of mangrove species against nutrient deficiency. K. obovata seedlings with or without AMF inoculation (mixed mangrove AMF), were cultivated for six months in autoclaved sediment medium which was supplemented with KH₂PO₄ (0, 15, 30, 60, 120 mg kg−¹). Then the plant growth, nitrogen and phosphorus content, root vitality, AMF colonization and soil phosphatase activity were analyzed. The inoculated AMF successfully infected K. obovata roots, developed intercellular hyphae, arbuscular (Arum-type), and vesicle structures. Arbuscular mycorrhizal fungi colonization ranged from 9.04 to 24.48%, with the highest value observed under 30 and 60 mg kg⁻¹ P treatments. Soil P supply, in the form of KH₂PO₄, significantly promoted the height and biomass of K. obovata, enhanced root vitality and P uptake, while partially inhibiting soil acid (ACP) and alkaline phosphotase (ALP) activities. Without enhancing plant height, the biomass, root vitality and P uptake were further increased when inoculated with AMF, and the reduction on ACP and ALP activities were alleviated. Phosphorus supply resulted in the decrease of leaf N–P ratio in K. obovata, and AMF inoculation strengthened the reduction, thus alleviating P limitation in plant growth. Arbuscular mycorrhizal fungi inoculation and adequate P supply (30 mg kg⁻¹ KH₂PO₄) enhanced root vitality, maintained soil ACP and ALP activities, increased plant N and P uptake, and resulted in greater biomass of K. obovata. Mutualistic symbiosis with AMF could explain the survival strategies of mangrove plants under a stressed environment (waterlogging and nutrient limitation) from a new perspective.     

EXOGENOUS APPLICATION OF POTASSIUM DIHYDROGEN PHOSPHATE CAN ALLEVIATE THE ADVERSE EFFECTS OF SALT STRESS ON SUNFLOWER

A greenhouse experiment was conducted to examine whether foliarly applied potassium + phosphorus (K + P) in the form of monopotassium phosphate (KH₂PO₄) could mitigate the adverse effects of salt stress on sunflower plants. There were two levels of root-applied salt [0 and 150 mM of sodium chloride (NaCl)], and varying levels of KH₂PO₄ [(NS (no spray), WS (spray of water), 5 + 4, 10 + 8, 15 + 12, and 20 + 16 mg g^?1 K + P, pH 6.5] applied foliarly to 18-day old non-stressed and salt stressed sunflower plants. Salt stress adversely affected the growth, yield, photosynthetic capacity, and accumulation of mineral nutrients in the sunflower plants. However, varying levels of foliar applied KH₂PO₄ proved to be effective in improving growth and yield of sunflower under salt stress. The KH₂PO₄ induced growth in sunflower was found to be associated with enhanced photosynthetic capacity, water use efficiency and relative water contents.     

土壤中芦笋生长最大需磷量对接种丛枝菌根真菌的响应特征

Fertilizer application efficiently increases crop yield, but may result in phosphorus（P） accumulation in soil, which increases the risk of aquatic eutrophication. Arbuscular mycorrhizal fungi（AMF） inoculation is a potential method to enhance P uptake by plant and to reduce fertilizer input requirements. However, there has been limited research on how much P application could be reduced by AMF inoculation. In this study, a pot experiment growing asparagus（Asparagus officinalis L.） was designed to investigate the effects of AMF inoculation and six levels of soil Olsen-P（10.4, 17.1, 30.9, 40.0, 62.1, and 95.5 mg kg^-1for P0, P1, P2, P3, P4 and P5treatments, respectively） on root colonization, soil spore density, and the growth and P uptake of asparagus. The highest root colonization and soil spore density were both obtained in the P1treatment（76% and 26.3 spores g^-1 soil, respectively）. Mycorrhizal dependency significantly（P 〈 0.05） decreased with increasing soil Olsen-P. A significant correlation（P 〈 0.01） was observed between mycorrhizal P uptake and root colonization, indicating that AMF contributed to increased P uptake and subsequent plant growth.The quadratic equations of shoot dry weight and soil Olsen-P showed that AMF decreased the P concentration of soil required for maximum plant growth by 14.5% from 67.9 to 59.3 mg Olsen-P kg^-1. Our results suggested that AMF improved P efficiency via increased P uptake and optimal growth by adding AMF to the suitable P fertilization.     

Effects of Phosphorus Additions on Lead,Cadmium, and Zinc Bioavailabilities in a Metal-Contaminated Soil

The use of phosphorus (P) to reduce lead (Pb)bioavailability is being proposed as an alternative to excavationand disposal as a remedial technology for Pb-contaminated soilsin residential areas. The objective of this study was todetermine the influence of P sources and rates andCaCO₃additions on the bioavailabilities of Pb, cadmium (Cd), and zinc(Zn) in a contaminated soil material using plants, a sequentialextraction procedure, and ion activities in equilibrium solutionas indicators. A contaminated soil containing 370 mg kg^-1 Cd, 2800 mg kg^-1 Pb and 29100 mg kg^-1 Zn was amended ina factorial arrangement of CaCO₃ (0 or 2000 mg kg^-1) and P as rock phosphate or KH₂PO₄ at 0:1, 2:1 or 4:1P:Pb mole ratios. A pot study was conducted using sorghum-sudangrass (Sorghum bicolor L. Moench). The addition of P did not influence Pb concentrations in plant tissue and had little effect on Cd concentrations. An interaction between P source and level of P addition was found for Zn concentrations in plant tissue; concentrations increased with increasing amounts of P from KH₂PO₄ anddecreased with increasing amounts of P from rock phosphate. Sequential extraction results suggested a much greater reduction in Pb bioavailability from treatment withKH₂PO₄ than with rock phosphate and that P influencedthe fractionations of Cd and Zn. Activities of Cd²⁺,Pb²⁺, and Zn²⁺ in equilibrium solutions generally weredecreased by rock phosphate and increased by KH₂PO₄. Saturation indices suggested the addition ofKH₂PO₄shifted the soil equilibrium from octavite to hydroxypyromorphite, whereas solid-phase control of Cd²⁺ andZn²⁺ was not influenced by soil amendments. A soluble Psource was more effective in reducing Pb bioavailability thanrock phosphate but had variable effects on Cd and Znbioavailabilities.     

pH对磷钾铝石形成的影响

Effects of column temperature and flow rate on separation of organic acids were studied by determining nine low-molecular-weight organic acids on reversed-phase C18 column using high performace liquid chromatography(HPLC) with a wavelength of UV(ultraviolet)214 nm and a mobile phase of 18 mmol L^-1 KH2PO4 buffer solution (pH2.1).The thermal stabiltiy of organic acids was determined by comparing the recoveries of organic acids in different temperature treatments.The relationships between column temperature,flow rate or solvent pH and retention time were analyzed.At low solvent pH,separatioin efficiency of organic acids was increased by raising the flow rate of the solvent because of lowering the retention time or organic acids.High column temperature was unfavorable for the separation of organic acids.The separating effect can be enhanced through reducing column temperature in organic acid determination due to increasing retention time.High thermal stability of organic acids with low concentrations was observed at temperature of 40℃-45℃,Sensitivity and separation effect of organic acid determination by HPLC were clearly improved by a combination of raising flow rate and lowering column temperature at low solvent pH.     

Comparison of different extractants for the determination of inorganic sulphate in gypsum‐free agricultural soils

Four frequently used extractants (H₂O, 0.1 M NaCl, 0.016 M KH₂PO₄, and 0.5 M NaHCO₃) as well as different extraction conditions have been tested for sulphate extraction from gypsum‐free agricultural soils. Water is the preferable extractant for soils with pH > 6. Two extraction steps have to be carried out for complete extraction (> 95%). A 0.016 M KH₂PO₄ solution was found to be the most efficient extractant for soils with a pH < 6 within a single extraction step. A shaking frequency of 170 min^‐1 and a duration of extraction of 4 hours are the optimized conditions for the sulphate extraction with H₂O and KH₂PO₄ solution.     

丛枝菌根真菌对红三叶草利用不同有机磷源的研究

以红三叶草为材料 ,利用三室隔网培养方法 ,施用不同有机磷源 :植酸钠 (Na -Phytate)、核糖核酸 (RNA)和卵磷脂 (Lecithin) ,研究接种菌根真菌Glmous versiforme对土壤及外加有机磷源的利用效率 ,另设无机磷及不施磷作为对照。结果表明 ,接种菌根真菌能明显增加植株干物重、含磷量和吸磷总量。与各有机磷处理相比 ,无机磷处理前期的生长效应较好 ,施用有机磷各处理在不同生长时期均明显促进了植株生长 ,但不同有机磷源之间没有显著差异。在植株吸磷量上 ,植株生长 7周以前 ,磷酸二氢钾处理高于其它处理 ,而植株生长 10周时 ,植酸钠处理高于磷酸二氢钾处理。接种菌根处理由于丛枝菌根活化了土壤有机磷 ,到植株生长 10周时其吸收有机磷的量已占吸磷总量的 76 .7%。     

Phosphate-induced aggregation kinetics of hematite and goethite nanoparticles

Purpose

The purpose of the present study is to examine the effect of phosphate on the aggregation kinetics of hematite and goethite nanoparticles.

Materials and methods

The dynamic light scattering method was used to study the aggregation kinetics of hematite and goethite nanoparticles.

Results and discussion

Specific adsorption of phosphates could promote aggregation through charge neutralization at low P concentrations, stabilize the nanoparticle suspensions at medium P concentrations, and induce aggregation through charge screening by accompanying cations at high P concentrations. Two critical coagulation concentration (CCC) values were obtained in each system. In NaH₂PO₄, the goethite CCC at low phosphate concentrations was smaller than hematite and vice versa at high phosphate concentrations. Stronger phosphate adsorption by goethite rapidly changed the zeta potential from positive to negative at low phosphate concentrations, and the zeta potential became more negative at high phosphate concentrations. The clusters of hematite nanoparticles induced by phosphate adsorption had an open and looser structure. Solution pH and the phosphate adsorption mechanisms in NaH₂PO₄, KH₂PO₄, and Na₃PO₄ solutions affected zeta potential values and controlled the stability of hematite suspensions during aggregation. High pH and preference for non-protonated inner-sphere complexes in Na₃PO₄ solution decreased the zeta potential of positively charged hematite and promoted aggregation. Activation energies followed the order NaH₂PO₄ > KH₂PO₄ > Na₃PO₄ at low P concentrations. K⁺ was more effective than Na⁺ in promoting hematite aggregation due to the non-classical polarization of cations.

Conclusions

Phosphate can enhance or inhibit the aggregation of hematite and goethite nanoparticles in suspensions by changing surface charge due to specific adsorption onto the particles. The phosphate-induced aggregation of the nanoparticles mainly depended on the initial concentration of phosphate.

     

Ameliorative Effects of Potassium Phosphate on Salt‐Stressed Pepper and Cucumber

Abstract

Bell pepper (Capsicum annuum cv. Urfa Isoto) and cucumber (Cucumis sativus cv. Beith Alpha F1) were grown in pots containing field soil to investigate the effects of supplementary potassium phosphate applied to the root zone of salt‐stressed plants. Treatments were (1) control: soil alone (C); (2) salt treatment: C plus 3.5 g NaCl kg^?1 soil (C + S); and (3) supplementary potassium phosphate: C + S plus supplementary 136 or 272 mg KH₂PO₄ kg^?1 soil (C + S + KP). Plants grown in saline treatment produced less dry matter, fruit yield, and chlorophyll than those in the control. Supplementary 136 or 272 mg KH₂PO₄ kg^?1 soil resulted in increases in dry matter, fruit yield, and chlorophyll concentrations compared to salt‐stressed (C + S) treatment. Membrane permeability in leaf cells (as assessed by electrolyte leakage from leaves) was impaired by NaCl application. Supplementary KH₂PO₄ reduced electrolyte leakage especially at the higher rate. Sodium (Na) concentration in plant tissues increased in leaves and roots in the NaCl treatment. Concentrations of potassium (K) and Phosphorus (P) in leaves were lowered in salt treatment and almost fully restored by supplementary KH₂PO₄ at 272 mg kg^?1 soil. These results clearly show that supplementary KH₂PO₄ can partly mitigate the adverse effects of high salinity on both fruit yield and whole plant biomass in pepper and cucumber plants.     

The nature of humic acid‐apatite interaction products and their availability to plant growth

Abstract

An investigation was conducted to determine the nature of decomposition products resulting from the interaction between humic acid and apatite and assess their availability to plant growth. Interaction analyses were performed by shaking 200 mg apatite with 0 to 800 mg/L HA or FA solutions at pH 5 or 7 for 0 to 12 hr. Phosphorus concentrations were determined in the supernatants by spectrophotometry. The nature of P‐humic acid complexes was determined by ³¹P NMR analysis. Availability of these dissolution products was studied by growing corn plants in aerated hydroponics to which 200 mg apatite and 0 to 800 mg/L HA were added at pH 5 or 7. The results indicated that the rate of dissolution of apatite was parabolic in regression with time, and increased by increasing the amounts of HA or FA applied from 100 to 800 mg/L The dissolution reaction was influenced by pH, because larger amounts of PO₄ ³‐ions were detected at pH 5 than at pH 7. ³¹P NMR spectroscopy indicated the presence of P‐humic acid complexes, previously believed to be humophosphate esters. The PO₄ ^3‐ ion was complexed by HA at pH 7 or above, but PO₄ ^3‐ appeared to be released again as adsorbed and free ions at pH <5.0. Plant performance corresponded with increased PO₄ ^3‐concentrations at pH 5.0. No significant improvement over the control was observed in the growth of corn plants by apatite + HA treatments at pH 7. However, plant growth was increased significantly over the control by apatite + HA treatments at pH 5.0. Better growth performance of corn plants were noticed by apatite + HA than by KH₂PO₄ treatments at pH 5.0.