人参与胡萝卜原生质体PEG融合和电融合研究的比较

由于人参与胡萝卜的双亲的核基因和胞质基因都可能参与融合事件，发生核基因和胞质基因重组，产生大量多样化的遗传变异个体，以期获得新的种质资源。以人参和胡萝卜原生质体为实验材料，筛选出适宜人参胡萝卜悬浮细胞原生质体PEG融合的PEG质量分数为50％，CaCe．2H,．O浓度为2mmol／L，PH值为10。适合人参与胡萝卜叶肉原生质体融合的电融合参数为AC强度40／cm、AC作用时间为40s，DC强度为1000V、作用时间50tzs，脉冲4次，循环2次。     

二倍体马铃薯体细胞电融合参数的优化

以有性杂交不亲和的抗虫、抗晚疫病的野生二倍体马铃薯Solanum pinnatisecta(2 n=2x=24)和抗晚疫病的二倍体材料DY4-5-10(2n=2x=24)的无菌苗叶片为原生质体来源,进行了电融合的研究,以优化马铃薯高效融合的参数。研究结果表明:其最佳的电融合参数为预融合电压1.0×105V/m,时间60 s,脉冲强度1.8×106V/m,脉冲宽幅20μs,脉冲次数1次。其有效融合率为28.89%,破损率为13.33%。     

Synthesis of hydrophilic copolyesters and the characterization of their moisture-related cooling properties

A series of copolyesters (Co-PETs) containing poly(ethylene glycol) (PEG), 5-sodiumsulfodimethyl isophthalate (DMS), and dimethyl isophthalate (DMI) were synthesized via the conventional two-step melt-polycondensation method. The synthesized Co-PETs were characterized by ¹H-NMR spectroscopy, FT-IR spectroscopy, differential scanning calorimeter (DSC), and thermogravimetric analyzer (TGA). The DSC results showed that the melting temperature (T _m) and the heats of fusion (ΔH _m) of Co-PETs decreased with increasing the DMS content in Co-PET, while the inclusion of PEG did not affect their thermal properties significantly. The water absorption and the water contact angle of the Co-PET films were found to be significantly affected by the DMS content rather than PEG content. The moisture-related cooling properties of the fabric samples made of Co-PET 5 as well as PET were evaluated by using liquid moisture management tester (MMT) and Q _max measurements. The MMT and Q _max results indicated that Co-PET 5 fabric containing DMS 1.0 mol% and PEG 10.0 wt% in Co-PET seemed to be a good candidate for the fabric having durable cooling effects.     

Improved procedures for the isolation and culture of protoplasts fromSolanum etuberosum

An efficient and convenient procedure for the isolation of protoplasts fromSolanum etuberosum is described. Excised leaves of plants grownin vitro were preconditioned for 3 days in the dark at 4 C. A 16 h enzyme digestion followed with purification by flotation in Babcock bottles produced a mean yield of 12.5 × 10⁶ protoplasts/g fresh weight. Protoplast viability as judged by morphology at the time of isolation was 89%. Liquid preculture for 1 day at 1 × 10⁶ protoplasts/ml was used prior to plating at 1 × 10⁵ protoplasts/ml and gave a mean survival of protoplasts of 43% after 8 days in culture.     

Improvement of mechanical and electrical properties of poly(ethylene glycol) and cyanoresin based polymer electrolytes

Ionic conductivity and mechanical properties of a mixed polymer matrix consisting of poly(ethylene glycol) (PEG) and cyanoresin type M (CRM) with various lithium salts and plasticizer were examined. The CRM used was a copolymer of cyanoethyl pullulan and cyanoethyl poly(vinyl alcohol) with a molar ratio of 1:1, mixed plasticizer was ethylene carbonate (EC) and propylene carbonate (PC) at a volume ratio of 1:1. The conductive behavior of polymer electrolytes in the temperature range of 298∼338 K was investigated. The PEG/LiClO₄ complexes exhibited the highest ionic conductivity of ∼10⁻⁵ S/cm at 25°C with the salt concentration of 1.5 M. In addition, the plasticized PEG/LiClO₄ complexes exhibited improvement of ionic conductivity. However, their complexes showed decreased mechanical properties. The improvement of ionic conductivity and mechanical properties could be obtained from the polymer electrolytes by using CRM. The highest ionic conductivity of PEG/CRM/LiClO₄/(EC-PC) was 5.33×10⁻⁴ S/cm at 25°C.     

Compressive viscoelastic properties of softwood kraft lignin-based flexible polyurethane foams

Softwood kraft lignin (SKL)-based water-blown flexible polyurethane foams were prepared using SKL as a crosslinking agent and a hard segment polyol. Polyethylene glycol (PEG) as a soft segment diol and 2,4-toluene diisocyanate (TDI) were used. While increasing hard segment content caused the increase in crosslink density in foams, the foams became more and more viscous with increasing hard segment content due to the distinctive phase heterogeneity in foams. In this case, the contributiveness of the filler-like behaviors of separated hard segments always overtook the crosslinking effects derived from SKL in terms of overall viscoelasticity, thus the resultant viscometric properties such as tanδ _max and hysteresis loss increased as hard segment content increased. Furthermore, increasing M _n,PEG caused the severer microphase separation and intensified the filler effects in foams, thus the foams became more viscous with increasing M _n,PEG. The 25 % and 65 % CFD values and Young’s moduli of foams increased with increasing hard segment content due to the increase in crosslink density for foams, and the properties also increased with increasing foam density. Most of foams showed the support factors in the range of 2–3, which are suitable values for cushioning use. Even though the microscopic deformation behaviors in foams are irrelevant to foam density, the cyclic compressive tests showed that the higher foam density possess the better shape recovery performances.     

播期和密度对春小麦品种新春26号生长及产量的影响

为确定新疆主栽春小麦品种新春26号的最佳播种时期和种植密度,采用两因素裂区试验,设4月5日、4月18日和5月2日3个播种时间,以及350万、400万、450万、500万和550万株·hm-2 5个种植密度,分析了播期和种植密度对小麦群体性状、产量及其构成因素的影响。结果表明,在相同种植密度下,随着播期的推后,小麦各生育时期群体茎数、干物质积累量、叶面积指数均显著降低;播期对千粒重的影响不显著,而早播(4月5日)小麦的穗数、穗粒数和产量显著高于晚播(5月2日)小麦。种植密度对小麦各生育时期群体性状也均有显著影响,种植密度过高或过低均不利于小麦群体发育及产量形成,适宜的种植密度可以改善小麦群体结构,进而提高产量。播期和密度互作对小麦整个生育期生长发育的影响均显著。总体来看,在本试验条件下,春小麦品种新春26号应适当早播,最佳播种时间和种植密度分别为4月5日和450万株·hm-2。     

种植密度对不同熟期玉米品种子粒含水率和产量的影响

2019～2020年以陕单 650(中熟)和东单 60(晚熟)为材料,设置 4个种植密度 6.0×10⁴、 7.5×10⁴、 9.0×10⁴和10.5×10⁴株/hm²,研究密度对玉米产量及子粒含水率的影响。结果表明,增密可以提高不同熟期玉米品种的产量,陕单 650在密度为 9.0×10⁴株/hm²时最优产量为 18 083.5 kg/hm²,东单 60在密度 7.5×10⁴株/hm²时最优产量为17 472.9 kg/hm²。两个品种粒重及子粒含水率随密度的增大而减小,陕单 650达到最大灌浆速率的天数、平均灌浆速率较东单 60均早 4 d和高 0.06 g/d;陕单 650和东单 60子粒平均脱水速率为 0.98%/d和 0.93%/d,陕单 650在生理成熟 4 d后子粒含水率迅速降至 25%。当密度为 9.0×104株/hm²时,陕单 650的叶片干物质转运率明显高于东单 60。通过适度增密提高产量、缩短生育期降低子粒水分的技术途径,协同实现陕西春玉米密植高产机械子粒收获生产。     

玉米CLC家族基因差异表达及其与NO3-、Cl-吸收之间的关系

通过对CLC基因家族7个基因的蛋白序列比对,发现他们具有比较高的同源性,在玉米苗期用KNO3、Na Cl、PEG对其进行处理,分别在处理1、4、8、16、24、36 h后检测其体内NO3-、Cl-的浓度,同时取上述几个时间段处理的玉米根和叶,用q PCR检测CLC家族基因的表达量,研究玉米硝态氮吸收与CLC基因表达量之间的关系。结果表明,综合玉米中NO3-、Cl-的变化与CLC家族基因表达量的变化,明确在KNO3、Na Cl、PEG处理下CLC家族基因表达量变化的规律,BT066984.1、GQ412103.1、NM001176231.1和NM001136935.2这4个基因对硝酸盐的响应明显,很可能具有运输硝酸盐的作用。     

Graft copolymerization of acrylamide onto rayon by chemical and radiation methods

The inherent properties of rayon fibre have been changed with additional properties through graft copolymerization of acrylamide, AAm, by chemical method using ceric ammonium nitrate/nitric acid, (CAN/HNO₃), as a redox initiator and γ-radiation induced mutual method. Reaction conditions such as monomer and initiator concentration, liquor ratio, temperature and time of reaction, amount of radiation dose have been optimized with respect to percentage of grafting. Maximum percentage of grafting (Pg), (40 %) using CAN/HNO₃ was obtained at [CAN]=31.92×10^?3 moles/l, [HNO₃]=79.36×10^?2 moles/l, [AAm]=14.07×10² moles/l in 20 ml of H₂O at 45 °C within 120 min while in case of radiation induced method, maximum Pg (30 %) was obtained at higher monomer concentration (28.14×10^?2 moles/l) and time (180 min) in 10 ml of H₂O at room temperature with total dose exposure of 11.178 kGy. The graft copolymers were characterized by FTIR, thermogravimetric and scanning electron micrographic analysis. Swelling behaviour in water, methanol, ethanol, acetone and DMF and dyeing and flame retarding properties of rayon fibre and grafted rayon fibre were investigated. Percent dye uptake (71.8 %) was found to be higher than that observed for the pristine fibre (57.4 %) and the grafted fibre after post phosphorylation reaction showed excellent flame retarding properties.     

立体匀播和密度对冬小麦光合、干物质积累分配及产量的影响

为给小麦立体匀播栽培推广提供理论依据,选用小麦品种新冬22号和新冬46号为供试材料,采用裂区设计,主区种植方式设立体匀播和常规条播2个处理,副区种植密度设150万株·hm~(-2)(D_(150))、225万株·hm~(-2)(D_(225))、300万株·hm~(-2)(D_(300))和375万株·hm~(-2)(D_(375))4个处理,研究了种植方式和密度对冬小麦光合、干物质积累与分配、产量及其构成因素的影响。结果表明,与常规条播比较,立体匀播方式下小麦群体生育后期中、下部叶的LAI、SPAD值和净光合速率显著提高;植株重、干物质转运量、干物质转运效率和干物质转运对籽粒产量贡献率增大,而植株成熟期营养器官干物质分配率降低;随着种植密度增大,茎鞘干物质分配率上升,叶片干物质分配率减小,而颖壳及穗轴、籽粒干物质分配率则无显著变化。与常规条播相比,立体匀播方式下新冬22号和新冬46号主茎穗粒重平均降低7.95%和4.43%,而分蘖穗粒重平均提高11.54%和5.06%,穗数显著提高(17.31%和17.68%),产量提高6.40%和9.84%,以D_(225)处理产量最高;穗粒数分别降低2.23%和1.71%,千粒重分别降低4.38%和4.54%。由此可知,立体匀播方式提高了小麦群体生育后期中、下部叶片叶面积指数和净光合速率,增大了植株干物质积累量,促进了营养器官干物质向分蘖穗籽粒中转运,并主要通过增加群体穗数和分蘖穗穗粒重提高产量;最佳的种植密度为225万株·hm~(-2)。     

Water vapor transport parameters of a cast wheat gluten film

Understanding the mode of transport of water vapor through the film is important for improving the moisture barrier properties of wheat gluten (WG) films. Effective permeability (P_eff), solubility (S_eff), and diffusion (D_eff) coefficients of a hydrophilic cast WG film were determined at 25°C within the relative humidity (RH) range of 0–84% (with a 9–13% RH gradient between upstream and downstream water vapor flux). P_eff, S_eff, and D_eff increased substantially as the RH gradient moved upwards in the RH spectrum. P_eff increased by four orders of magnitude from the lowest RH condition of 0–11% (3.8×10⁻¹¹ g·m/m²·s·Pa) to the highest RH condition of 75–84% (4.1×10⁻⁷ g·m/m²·s·Pa). A moisture sorption isotherm of the film at 25°C was constructed. Both the Guggenheim–Anderson–DeBoer (GAB) and the Kuhn moisture sorption isotherm models showed a good fit to the experimental adsorption data. Testing of WG films at the expected conditions of actual use is necessary to quantify the water vapor permeation through the films.     

Isolation and Culture of Pollen Tetrad Protoplasts from <Emphasis Type="Italic">Solanum tuberosum</Emphasis>

Pollen protoplasts provide a sexual and haploid system for haploid production, cell fusion and mutation studies used in plant improvement. Due to the multiploidy, heterozygosity, and often self-incompatibility in tetraploid genotypes, haploid potatoes are desirable for breeding schemes via ploidy manipulations. In this study, two tetraploid varieties and two dihaploid lines of potato were used for pollen tetrad protoplast isolation and culture. The meiotic tetrad buds were first pre-treated at 5 °C for 0–12 days, then the tetrads were transferred into enzyme solutions containing different concentrations of snailase (0.5–1.5%), 0.3 M osmolites (sucrose, mannitol, glucose or sorbitol), 1.0% Cellulose, 0.5% Hemicellulase, 0.5% Pectolyase, 0.3% Sucrose, 3 mM 2-(N-Morpholino) ethane sulfonic acid, 1% polyvinyl pyrrolidone, 0.01% casein hydrolysate and K₃ medium compositions. Among the four donor materials, tetraploid cv. Gannongshu No. 3 (‘GNS No.3’) showed the greatest protoplast yield (74.6 ± 2.4%). In this variety, most of the tetrad protoplasts regenerated a cell wall and continued cell divisions were observed when they were inoculated in K₃ basic medium supplemented with (0.5–1.0) mg/L 2,4-D + (0.1–0.5) mg/L KT + 0.4 mg/L 6-BA +800 mg/L glutamine +100 mg/L serine. ‘GNS No.3’ also showed the greatest first division frequency (21.6 ± 1.5%) and sustained division to form multicellular structures. The study findings suggested that cultured tetrad pollen protoplasts could reverse the gametophytic developmental pattern programmed in vivo to a sporophytic pathway leading to multicellular microspore-derived colonies.     

Development of nanofibrous membranes with far-infrared radiation and their antimicrobial properties

This study investigated the incorporation of nanoscale germanium (Ge) and silicon dioxide (SiO₂) particles into poly(vinyl alcohol) (PVA) nanofibers with the aim of developing nanostructures with far-infrared radiation effects and antimicrobial properties for biomedical applications. Composite fibers containing Ge and SiO₂ were fabricated at various concentrations of Ge and/or SiO₂ using electrospinning and layered on polypropylene nonwoven. The morphological properties of the nanocomposite fibers were characterized using a field-emission scanning electron microscope and a transmission electron microscope. The far-infrared emissivity and emissive power of the nanocomposite fibers were examined in the wavelength range of 5-20 μm at 37 °C. The antibacterial properties were quantitatively assessed by measuring the bacterial reductions of Staphylococcus aureus, Klebsiella pneumoniae, and Escherichia coli. Multi-component composite fibers electrospun from 11 wt% PVA solutions containing 0.5 wt% Ge and 1 wt% SiO₂ nanoparticles exhibited a far-infrared emissivity of 0.891 and an emissive power of 3.44·102 W m^?2 with a web area density of 5.55 g m^?2. The same system exhibited a 99.9 % bacterial reduction against both Staphylococcus aureus and Escherichia coli, and showed a 34.8 % reduction of Klebsiella pneumoniae. These results demonstrate that PVA nanofibrous membranes containing Ge and SiO₂ have potential in medical and healthcare applications such as wound healing dressings, skin care masks, and medical textile products.     

氮密互作对淮北砂姜黑土区冬小麦冠层光合特性和产量的影响

为筛选出适合淮北平原砂姜黑土区小麦稳产高产栽培的氮密配置,在大田条件下以安农0711(AN0711)和烟农19(YN19)为试验材料,采用裂区设计,设置150×10~4、210×10~4、270×10~4和330×10~4株·hm~(-2)4个种植密度(分别用D1～D4代表),以及135、180、225和270 kg·hm~(-2)4个施氮水平(分别用N1～N4代表),分析了氮密互作对冬小麦冠层结构、光合特性和籽粒产量的影响。结果表明,氮密互作可改善小麦冠层结构,显著影响冠层光合特性。旗叶净光合速率和叶绿素相对含量随着种植密度的增加而降低,而随着施氮量的增加而增加,但施氮量超过225 kg·hm~(-2)时变化均不显著。随着种植密度和施氮量的增加,叶面积指数和冠层截获光合有效辐射显著提高,且在孕穗期和开花期均以D4N4处理最大,灌浆中期均以D3N3处理最大。氮密对籽粒产量有显著的互作效应。在D3N3处理下AN0711和YN19的冠层光合能力和籽粒产量均最高,其中产量分别达到7 866.67和7 400.00 kg·hm~(-2)。在本试验条件下,适宜的种植密度和施氮量分别为270×10~4株·hm~(-2)和225 kg·hm~(-2)。     

Improvement of growth and gymnemic acid production by altering the macro elements concentration and nitrogen source supply in cell suspension cultures of Gymnema sylvestre R. Br

Gymnema sylvestre is an important medicinal plant which bears bioactive compound namely gymnemic acids. The present work deals with optimization of cell suspension culture system of G. sylvestre for the production of biomass and gymnemic acid and we investigated effects of macro elements (NH₄NO₃, KNO₃, CaCl₂, MgSO₄ and KH₂PO₄ - 0.0, 0.5, 1.0, 1.5 and 2.0× strength) and nitrogen source [NH₄⁺/NO₃⁻ ratio of: 0.00/18.80, 7.19/18.80, 14.38/18.80, 21.57/18.80, 28.75/18.80, 14.38/0.00, 14.38/9.40, 14.38/18.80, 14.38/28.20 and 14.38/37.60 (mM)] of Murashige and Skoog medium on accumulation of biomass and gymnemic acid content. The highest accumulation of biomass (165.00 g l⁻¹ FW and 15.42 g l⁻¹ DW) was recorded in the medium with 0.5× concentration of NH₄NO₃ and the highest production of gymnemic acid content was recorded in the medium with 2.0× KH₂PO₄ (11.32 mg g⁻¹ DW). The NH₄⁺/NO₃⁻ ratio also influenced cell growth and gymnemic acid production; both parameters were greater when the NO₃⁻ concentration was higher than that of NH₄⁺. Maximum biomass growth (159.72 g l⁻¹ of FW and 14.95 g l⁻¹ of DW) was achieved at an NH₄⁺/NO₃⁻ ratio of 7.19/18.80, and gymnemic acid production was also greatest at the same concentration of NH₄⁺/NO₃⁻ ratio (11.35 mg g⁻¹ DW).     

Effects of passages through a suitable host of the fungus, Metarhizium anisopliae,on the virulence of acaricide- susceptible and resistant strains of the tick,Rhipicephalus microplus

The aim of this work was to assess the virulence of strain M379 of the fungus, Metarhizium anisopliae (Metchnikoff) Sorokin (Hypocreales: Clavicipitaceae) after different passages through a suitable host and at different concentrations for the control of both acaricide-susceptible and resistant strains of the tick, Rhipicephalus (formerly Boophilus) microplus Canestrini (Ixodida: Ixodidae) in vitro. The highest value of LC₅₀ for the susceptible strain corresponded to zero passage with 7.68 × 10⁷ conidia/ml followed by the fourth passage with 2.68 × 10⁷, which reduced 2.87-fold the lethal concentration. When comparing LC50 values of the fourth vs. the seventh passage (2.59 × 10⁵ conidia/ml), the lethal concentration was reduced 103.47-fold by the seventh passage. In addition, in the resistant strain the LC₅₀ highest value corresponded to zero passage with 4.95 × 10⁷ conidia/ml followed by the fourth passage with 7.86 × 10⁶, which reduced 6.30-fold the lethal concentration. When comparing LC₅₀ values of the fourth vs. the seventh passage (1.04 × 10⁵ conidia/ml) in the resistant strain, the lethal concentration was reduced 75.58-fold by the seventh passage. These results suggest that the number of passages on M. anisopliae through a suitable host increased its virulence on both R microplus strains. When comparing LC₅₀ of the zero passage through a suitable host of both acaricide-susceptible and resistant strains, the highest LC₅₀ values corresponded to the susceptible strain with 7.68 × 10⁷ conidia/ml followed by the resistant one with 4.95 × 10⁷, showing that on the resistant strain the lethal concentration is reduced by 1.55-fold. When comparing the fourth passage, the highest values of LC₅₀ corresponded to the susceptible strain with 2.68 × 10⁷ conidia/ml followed by the resistant one with 7.86 × 10⁶ conidia/ml, showing for the resistant strain a 3.41-fold reduced lethal concentration. Moreover, when comparing the seventh passages, the highest values of LC₅₀ corresponded to the susceptible strain with 2.59 × 10⁵ followed by the resistant with 1.04 × 10⁵ conidia/ml, revealing for the resistant strain a 2.49-fold reduced lethal concentration. These results suggest that the resistant strain needs a lower concentration of conidia than the susceptible strain. In this case, the acaricide-resistant strain is more susceptible to M. anisopliae of zero- and seven-passage strains.     

Generation of Internal-Image Functional Aptamers of Okadaic Acid via Magnetic-Bead SELEX

Okadaic acid (OA) is produced by Dinophysis and Prorocentrum dinoflagellates and primarily accumulates in bivalves, and this toxin has harmful effects on consumers and operators. In this work, we first report the use of aptamers as novel non-toxic probes capable of binding to a monoclonal antibody against OA (OA-mAb). Aptamers that mimic the OA toxin with high affinity and selectivity were generated by the magnetic bead-assisted systematic evolution of ligands by exponential enrichment (SELEX) strategy. After 12 selection rounds, cloning, sequencing and enzyme-linked immunosorbent assay (ELISA) analysis, four candidate aptamers (O24, O31, O39, O40) were selected that showed high affinity and specificity for OA-mAb. The affinity constants of O24, O31, O39 and O40 were 8.3 × 10⁸ M⁻¹, 1.47 × 10⁹ M⁻¹, 1.23 × 10⁹ M⁻¹ and 1.05 × 10⁹ M⁻¹, respectively. Indirect competitive ELISA was employed to determine the internal-image function of the aptamers. The results reveal that O31 has a similar competitive function as free OA toxin, whereas the other three aptamers did not bear the necessary internal-image function. Based on the derivation of the curvilinear equation for OA/O31, the equation that defined the relationship between the OA toxin content and O31 was Y = 2.185X − 1.78. The IC₅₀ of O31 was 3.39 ng·mL⁻¹, which was close to the value predicted by the OA ELISA (IC₅₀ = 4.4 ng·mL⁻¹); the IC₁₀ was 0.33 ng·mL⁻¹. The above data provides strong evidence that internal-image functional aptamers could be applicable as novel probes in a non-toxic assay.     

Preparation and characterization of porous carbon based nanocomposite for supercapacitor

Porous nanocomposites are prepared by electrospinning blended polyacrylonitrile, copper acetate and mutiwalled carbon nanotube in N, N-dimethylformamide. The electrospun nanofiber webs are oxidatively stabilized and then carbonized resulting in composite carbon nanofibers. The study reveals that composite nanofibers with relatively smooth surface morphology are successfully prepared. X-ray diffraction is used to confirm the presence of Cu in carbon nanofibers. The carbon nanofibers with CNTs have better thermal stability and higher electrical conductivity. The Brunauer-Emmett-Teller analysis reveals that C/Cu/CNTs nanocomposites with mesopores possess larger specific surface area and narrower pore size distribution than that of C/Cu nanofibers. The electrochemical properties are investigated by cyclic voltammetry and galvanostatic charge-discharge tests. The nanocomposite with 0.5 wt.% CNT loading exhibits an energy density of 2 Whkg^?1, power density of 1916 Wkg^?1, a specific capacitance of about 225 Fg^?1 at a current density of 2 Ag^?1 and its capacitance decreased to 78 % of its initial value after 3,000 cycles.     

Efficacy and effects on yield of different fungicides for control of wet bubble disease of mushroom caused by the mycoparasite Mycogone perniciosa

Carbendazim, iprodione, prochloraz-Mn, thiabendazole and thiophanate-methyl were tested in vitro and in vivo for their effect on Mycogone perniciosa, the mycoparasite that causes wet bubble disease of white button mushroom. In vitro experiments showed that prochloraz-Mn (ED₅₀ = 0.006–0.064 μg ml⁻¹) and carbendazim (ED₅₀ = 0.031–0.097 μg ml⁻¹) were the most effective fungicides for inhibiting the mycelial growth of M. perniciosa, while iprodione (ED₅₀ = 1.90–3.80 μg ml⁻¹) was the least effective. The resistance factors calculated for the five fungicides were between 1.4 and 2. The results obtained suggest that there is very little risk that M. perniciosa will develop resistance to the fungicides assayed. The in vivo efficacy of fungicides for control of wet bubble was studied in two mushroom cropping experiments, which were artificially infected with two doses of M. perniciosa, 10⁶ and 10⁷ spores m⁻², respectively. There was, in the low dose inoculum experiment, a very high degree of effectiveness (96.5–100.0%) with all the fungicides assayed. However, iprodione performed poorly (20.5–24.4%) compared with the other fungicides (88.7–100.0%) in the high concentration inoculum experiment. The most effective treatments for controlling wet bubble did not improve the biological efficiency of Agaricus bisporus.