The manipulation of temperature to synchronise flushing patterns in two strains of the cultivated mushroom Agaricus bisporus

The majority of mushroom (Agaricus bisporus) strains are grown commercially at approximately 16°C throughout the cropping period and show a distinct flushing pattern, with the picking period of each flush lasting several days. Experiments were done to determine whether the picking periods could be reduced by improved synchronisation of growth within flushes by raising the air temperature by several degrees at defined stages of sporophore development (cap diameters of 1, 2 or 3 cm) until the harvest of mature fruitbodies. Two strains of A. bisporus were used, D649 a smooth white strain and D676 an off-white type. High-quality mushrooms of similar size and maturity were harvested from all three treatments in fewer picking days than when grown continuously at 16°C. The highest degree of synchronisation was achieved with both strains when exposed to elevated temperatures at the 1-cm stage with no significant effect on total yield.     

Some factors affecting the growth rate of sporophores of the cultivated mushroom

The growth of sporophores of mushroom (Agaricus bisporus) was studied using the Gompertz growth curve, and the parameters of the curve were found to vary appreciably between experiments.Three factors were identified which are associated with an increase in growth rate. These are (i) the earliness of initiation of the sporophore, (ii) the removal of adjacent sporophores, and (iii) a decrease in the number of sporophores initiated.It is suggested that the growth rate of sporophores is dependent on the substrate density in the mycelium, and also that the initiation process might be less efficient than the growth process. The implications of these findings for a mathematical modelling approach to mushroom crop growth are discussed.     

Fungicides for the control of Mycogone perniciosa (Magn.), the cause of wet bubble on the cultivated mushroom

Two formulations of chlorothalonil (as Daconil 2787) were compared for their activity against Mycogone perniciosa Magn. on the cultivated mushroom Agaricus bisporus (Lange) Imbach. At the same does rates, the flowable formulation was more toxic than the wettable powder to both pathogen and host, but more marketable mushrooms were obtained from diseased plots treated with the flowable formulation at each dose rate (1.0, 0.5 and 0.1 g ai m^?2). Levels of disease control were related to dose rates, making it impracticable to lessen toxicity to mushrooms by reducing the dose rate. Fluotrimazole was less active than chlorothalonil against M. perniciosa and was more toxic to mushrooms.     

Effects of temperature and hydrogen peroxide on mycelial growth of eight Pleurotus strains

Effective use of hydrogen peroxide as a chemical sterilant in mushroom production and selection of cultivable mushroom strains for tropical conditions require knowledge of the genetic diversity in the tolerance of the strains to hydrogen peroxide and to high temperatures. Therefore, three experiments were conducted to examine the sensitivity of Pleurotus mycelium to temperature and hydrogen peroxide. In Experiment 1, eight Pleurotus strains, which included two Pleurotus sajor-caju strains, three Pleurotus ostreatus strains, Pleurotus salmoneo stramineus, Pleurotus cornicopae and Pleurotus eryngii were cultured aseptically on agar at 25, 30 and or 35 °C. In Experiment 2, the eight strains were cultured aseptically on agar at six hydrogen peroxide concentrations (0–0.1%, v/v) at 27 °C. In Experiment 3, P. sajor-caju strain 1, a fast growing strain, was cultured non-asceptically at six hydrogen peroxide concentrations (0–0.1%, v/v) at 27 °C. In Experiment 1, mycelial growth was maximal at 25–30 °C, whereas a temperature of 35 °C was detrimental to mycelial growth except in one strain. At the highest temperature tested (35 °C), the relative mycelial growth rate (% of maximum) ranged from 6 to 91%, indicating marked differences in tolerance of the strains to high temperature. In Experiment 2, the mycelial growth rate in all strains increased when hydrogen peroxide was increased from 0 to 0.001% (v/v), and then decreased with further increments in hydrogen peroxide concentration. The strains differed markedly in sensitivity to hydrogen peroxide. The hydrogen peroxide concentration associated with 50% reduction in maximum mycelial growth rate due to toxicity (EC₅₀) ranged from 0.009 to 0.045% (v/v). It was noted that P. sajor-caju strain 1 which was the most tolerant strain to high temperature was also the most tolerant to high hydrogen peroxide concentration. In Experiment 3, involving non-aseptic culture of P. sajor-caju strain 1, bacterial growth was observed at concentrations ≤0.016%, whilst the upper hydrogen peroxide concentration limit for fungal growth was 0.025% (v/v). The highest hydrogen peroxide concentrations 0.016% (v/v) and 0.025% (v/v) in which bacteria and fungi, respectively, were observed to grow were within the concentration range 0.009–0.028% (v/v) that was found in Experiment 2 to cause a 50% reduction in mycelia growth in six of the eight Pleurotus strains tested. Use of hydrogen peroxide as a chemical sterilant in conjunction with strains highly tolerant of its toxicity offers a very cheap method of producing spawn as well as the mushrooms, and opens up opportunities for poor rural people.     

Effect of the duration of composting on the amount of compost produced and the yield of mushrooms

Prolonging duration of composting, especially of Stage II (peak-heating), increased loss of material, reduced bulk density and resulted in a lower weight of compost prepared per tonne of original straw,Yield of mushrooms (Agaricus bisporus) per tonne of prepared compost was unaffected by prolonging Stage II, but was reduced when expressed per unit area, per tonne of compost filled, or per tonne of original straw, because of loss of materials and reduced bulk density.Fruit bodies of a weed mould, Coprinus sp., were more numerous during mushroom cropping on composts which had been prepared with the shortest Stage II, but there was no correlation between occurrence of Coprinus sp. and the yield of mushrooms per tonne of prepared compost.A basis is proposed for comparing composts prepared by a wide variety of methods.     

Influence of the depth of the casing layer and the harvesting time on changes of the water content of the casing layer and the substrate caused by the first flush of mushrooms

The water extracted from casing layer and substrate by the fruit bodies of the first flush of a mushroom culture (Agaricus bisporus) was investigated. In cultures with a 5-cm casing layer, 33–34% of the water in the sporophores came from the casing, and the remainder from the substrate. In cultures with thin casing layers (3–3.5 cm), only 14–15% of the water came from the casing. Fruit bodies from thin layers contained less water than the ones from thicker layers. Fruit bodies from thick casing layers (6 cm) and harvested early took 36–37% of their water from the casing. Mushrooms from the late harvest (caps fully open) took 40–51% of their water from the casing layer and contained more water than early-harvested ones. The sporophores of the first flush extracted more water (g per g substrate) from the top third of the substrate than from the lower layers.     

丁香蘑菇野生菌株的生物学特性及驯化栽培

以采自内蒙古鄂尔多斯市乌审旗丁香蘑菇野生菌株为试材,采用单因素试验和正交实验,研究了其生物学特性及驯化栽培条件,以达到野生丁香蘑菇驯化栽培出菇的目的。结果表明:单因素试验中温度25℃、pH 6、碳源蔗糖、氮源酵母粉、生长因子蘑菇汁,无机盐为硫酸镁,有机物固体培养基为麦粒+牛粪是最佳条件;正交实验表明,4种因子对丁香蘑菇菌株影响程度不同,生长因子>氮源>碳源>无机盐,各因素之间存在显著性差异;出菇栽培试验,分别将草炭土(主料)与羊粪、牛粪、发酵料、草木灰等按3∶1配比,菌丝生长时最适温度20～25℃,pH 6.5～7.5,出菇时最适温度17.5～22.0℃,湿度90%～95%。     

香蕉黑星病菌形态与生物学特性

为更好地了解香蕉黑星病和指导病害防治,对该病病原菌Macrophomamusae的形态作了系统描述并详细测定了该菌的生物学特性。生物学特性研究表明,在PDA平板上,香蕉黑星病菌在10～35℃均能生长,适宜生长温度为20～30℃,最适生长温度是28℃,PDA、PSA和V8培养基上生长较好,病原菌在pH3～10均能生长,pH4～8生长较好,pH7生长最佳,马铃薯琼脂培养基中添加不同的糖对病原菌生长有不同的影响,其中以蔗糖、果糖、葡萄糖最好,淀粉和乳糖最差,PDA培养基中添加2%的不同的氮源对病原菌生长有抑制作用,在添加氯化铵的PDA上不能生长,光照对病原菌的生长有明显促进作用,振荡培养对病原菌生长的促进作用不明显,病原菌的致死温度为55℃10min。分生孢子在蒸馏水中萌发缓慢,Ca2+有促进孢子萌发的作用,其中10mmol/LCa2+对孢子萌发的促进作用最为明显。     

杀菌剂对蘑菇疣孢霉病的防治效果比较

通过在菇房中11种杀菌剂对蘑菇疣孢霉病防治效果和对双孢蘑菇生长影响试验,结果表明,11种杀菌剂对蘑菇疣孢霉病防治效果和对双孢蘑菇生长影响有明显差异,其中特克多45%悬浮剂500倍液无论是覆土处理或转潮时喷雾覆土处理,均对疣孢霉病有较好的防治效果,防治效率分别达93.7%和89.1%,且对双孢蘑菇菌丝生长和子实体发育无不良影响.其它杀菌剂综合表现均不理想.     

Cytokinins in two cultivated edible mushrooms

Various endogenous cytokinins were extracted and their amounts bioassayed in Agaricus bisporus and Pleurotus sajor-caju. The fruit bodies of both fungi contained zeatin and zeatin riboside, while 2 iP and zeatin ribotide were not detectable. However, their amounts varied in 2 groups of fungi and it is presumed that they may have a bearing on the onset of senescence in mushrooms.     

利用秀珍菇菇渣栽培双孢蘑菇的试验

将秀珍菇菇渣处理后以不同比例用于栽培双孢蘑菇,结果表明:经过简单处理的菇渣栽培双孢蘑菇,与常规配方相比,具有菌丝生长快,产量高、成本低等优点,并且随着菌渣比例的增加菌丝生长速度有增加的趋势.其中在培养基培养料中加入30%秀珍菇菇渣栽培双孢蘑菇,生物学效率达到63%,比常规栽培料高出10%,说明菇渣用于双孢蘑菇生产是可行并有良好效果的.     

一株野生花脸香蘑的生物学特性及其栽培

从采集自云南省临沧市的野生子实体上分离纯化获得菌株YAASM4210,采用形态学法结合ITS序列分子法鉴定为花脸香蘑(Lepista sordida)。对该菌株生物学特性进行研究并对其栽培料进行筛选。试验结果表明:该菌株菌丝生长的最适温度、培养基pH、光照条件、碳源和氮源分别为25℃、6.0~7.0、黑纸包裹、可溶性淀粉和蛋白胨。该菌株在4号配方培养料(40%新鲜牛粪,20%草坪粉,20%米糠,18%木屑,1%蔗糖和1%石膏)上生长优于其它参试培养料:菌丝萌发(2d)、封口(12d)、满袋(40d)以及子实体的采收(9d)均用时最短,头潮菇产量最高(每袋21.1g),但覆土后出菇时间(42d)最长。相对于野生子实体,人工栽培子实体菌盖的紫色减弱,采收后紫色消失较快。     

Influence of temperature and bark injuries on the development of Phytophthora cactorum and P. Citrophthora on peach trees

The effect of temperature and bark injuries on the occurrence of crown rot of peach trees caused by P. cactorum and P. citrophthora were examined in field and laboratory. Lesions developed at 35 °C (the complete range of temperatures tested) but maximum development occurred at 20–25 °C. Greatest growth of these fungi on cornmeal agar (CMA) also occurred between 15 and 30 °C. Both pathogens could infect injured trees up to 20 days after wounding, but could not infect uninjured plants or plants wounded 40 and 30 days before inoculation, respectively. This study showed that temperature is a critical factor for the development of Phytophthora crown rot of peach trees. In addition, crown rot developed from recent wounds inoculated with agar plugs of Phytophthora.     

Nitrogen-enriched ground kenaf (Hibiscus cannabinus L.) stem core as a component of soilless growth media

Summary

Four experiments showed that stem core (xylem of kenaf (Hibiscus cannabinus L.) in combination with sphagnum peat moss and fertilizer nutrients was a satisfactory growth medium for plants of ‘Toy Boy’ tomato (Lycopersicon esculentum Mill.). Greater shoot growth was achieved in media containing 20 to 35% kenaf by volume than 50%, and with fine kenaf (2–4 mm diameter) than coarser grades. In the absence of weekly solution fertilization, N-enrichment of the kenaf was necessary to support greater shoot growth than occurred in commercial growth media. Soaking the kenaf in solutions of increasing nitrogen (N) concentration (0 to 15,000 mg N l^?1) increased shoot growth, but urea ammonium nitrate (UAN, 30N–0P–OK) generally resulted in greater shoot growth than 20N–4.4P–16.6K at the same N concentration. The soaking time for kenaf in UAN was considerably less than in the complete fertilizer to produce similar shoot dry weights. Only a small portion of the kenaf in the growth media required pre-plant N enrichment provided the N concentration of the soak solution was increased in ‘ proportion to the volume reduction. Increasing the N concentration of weekly solution fertilization (20N–4.4P–16.6K) from 0 to 500 mg N l^?1 increased shoot growth irrespective of the N concentration of the kenaf soak solution. In media receiving 0 or 100 mg N l^?1 weekly solution fertilization, shoot growth increased with increasing N concentration of the kenaf soak solution.     

Factors affecting shoot proliferation and root initiation in organ cultures of the apple ‘Northern Spy’

Factors affecting the establishment, proliferation and adventitious root initiation of ‘Northern Spy’ are described. Shoot-tips established best in Linsmaier and Skoog medium with 5 μM BAP and 1 μM IBA supplemented with 1 mM phloroglucinol, but after the fourth sub-culture, proliferation was similar in media without phloroglucinol. Shoot proliferation was influenced by cytokinin type and concentration, light level and ex-plant type. Of the cytokinins tested, BAP was superior to zeatin, kinetin and 2iP. Proliferation was better with 10 μM BAP than with 5 or 1 μM BAP, but at 10 μM shoots were dwarfed. Single nodes and basal mass expiants produced significantly more shoots than did shoot-tips. Shoot proliferation was maximum at photon flux densities of 75 μmolm^?2s^?1. Roots can be readily induced with IBA, but salt concentration and the physical support on which shoot-tips are grown influence both root initiation and growth. Half-strength salts and 1 μM IBA gave best root initiation. With agar, coarse sand, perlite and rotated liquid medium, 90–100% root initiation occurs, but root growth was poor in agar.     

Adventitious shoot formation from sections of sweet potato grown in vitro

Sweet potato (Ipomoea batatas Lam.) root sections were obtained from the cultivars ‘Centennial’, ‘Redmar’ and ‘Jewel’ with a No. 6 cork borer. These sections were cut into 2–3-mm discs and explanted on to modified Murashige and Skoog (MS) medium consisting of MS high mineral salts, myo-inositol (100 mg l^?1), Staba vitamins, 6-benzyl-aminopurine (2.0 mg l^?1), naphthaleneacetic acid (0.1 mg l^?1), sucrose (30 g l^?1) and agar (10 g l^?1). Root discs from internal regions of the tuberous roots gave rise to calli and meristematic bud-like centers (MBLC's). A small percentage of ‘Centennial’ MBLC's burst open to reveal plantlets which grew and rooted well on the medium. Some of the ‘Jewel’ MBLC's contained only roots, while those of ‘Redmar’ did not differentiate. MBLC-formation occurred most often on discs taken from fresh (unstored) roots of ‘Centennial’. Petiole sections taken from in vitro-cultured plants of all 3 cultivars developed plants quite readily on the medium. Shoots of all 3 cultivars grew rapidly, to yield whole rooted plants which could easily be moved to soil and grown in the greenhouse and field.     

天女木兰叶斑病病菌生物学特性研究

以天女木兰叶斑病病菌为试材,研究不同碳、氮源对天女木兰叶斑病病菌生长的影响;试验结果表明：适合菌丝生长碳源是乳糖与葡萄糖;适合菌丝生长的氮源是硝酸铵;最适合孢子萌发的碳源是葡萄糖;适合孢子萌发的氮源是硝酸铵;25益适宜菌丝的生长,适宜孢子萌发的温度是20~25益;全光适宜菌丝的生长和孢子萌发。适合菌丝的生长和孢子萌发PH8与PH7。     

Response of ornamental Eucalyptus from acidic and alkaline habitats to potting medium pH

Seedlings of 35 Eucalyptus species were grown in a peat-based growing medium amended with limestone and dolomite (1:1) to provide an experimental pH range of 5.1–8.9. The species were largely of the multi-stemmed (mallee) growth habit, relatively new to commercial cultivation, and known to occur naturally on alkaline, neutral or acidic soils. Growth was generally greater under acidic (pH 5.1–5.6) than under more alkaline conditions in all species, regardless of natural soil occurrence of the parent trees. Above pH 5.6, species showed a range in the degree of response to pH, from those that were unaffected even at pH 8.9 (e.g. E. erythrocorys and E. extensa), to those for which growth was reduced at pH 6.8. There was generally good correspondence between pH response and the pH of the soil in which parent plants occurred naturally, i.e. accessions from trees growing on alkaline soils tended to exhibit less growth reduction at high pH. Leaf elemental analyses of selected species indicated that tolerance of high pH was associated with an ability to maintain relatively low Ca/Mg and P/Fe concentration ratios (<∼5). Eucalyptus species from alkaline as well as acidic soils can be best grown in the nursery at a pH in the range 5.1–5.6.     

Selection and testing of epiphytic yeasts to control anthacnose in post-harvest of papaya fruit

Anthracnose, caused by Colletotrichum gloeosporioides, is a major post-harvest disease in papaya fruit. The major objectives of the present work were to isolate, select and test the in vitro and in vivo ability of epiphytic microorganisms, isolated from papaya fruit and leaf surfaces, in controlling anthracnose onset after harvest. A total of 75 bacteria, 67 yeasts and 22 mycelial fungi were isolated. Thirty yeast isolates were able to inhibit the mycelial growth of C. gloeosporioide in vitro and seven of those were used in in vivo assays, resulting in the identification of two very effective isolates. Isolate CEN63, identified molecularly as Cryptococcus magnus, was the most effective in controlling the disease and therefore was studied in more detail. The results of the assays with C. magnus provided evidence that when fruit were treated with the antagonists at concentrations of 10⁷ to 10⁸ cells/ml, as early as 24 h, preferentially 48 h, before inoculation with the pathogen, the development of disease was significantly reduced. C. magnus is a potential antagonist for the development of a commercial product. Additional studies on the modes of action of this yeast isolate, as on its ability to interact with fungicides are being conducted to generate solid basis for the development of an environmentally friendly control agent.     

废弃葡萄枝条作香菇培养配料试验

以废弃葡萄冬剪枝条为主料设置不同培养料配方栽培香菇,观察、记录、分析不同培养料对香菇菌丝生长及子实体形态、产量的影响。试验结果表明,用废弃葡萄枝栽培香菇是可行的,其中以配方葡萄枝40%、杂木屑38%、麦麸20%、石膏1%、糖1%为最好,香菇菌丝发菌快,子实体个体大,产量高,生物效率高。