两种灌木根结线虫病在广西发生的调查

首次报道红背桂Euphorbia cochinchensis Lour和黄栀子Gardenia iasminoides Ellis根结线虫病在广西发生与危害.经鉴定,病原为南方根结线虫 Meloidogyne incognita,2种病害的平均发病株率分别为72.2%和62.2%,平均病情指数为41.3和33.1,在受害区发病普遍且严重,造成了重大经济损失.苗木带病是发病的主要原因.     

铁皮石斛优良共生菌的抗旱机理

为阐明细胞膜保护酶在菌根提高铁皮石斛抗旱能力过程中的作用,采用模拟自然干旱胁迫的方法,对胁迫过程中菌根化铁皮石斛细胞膜保护酶的活性变化进行研究。结果表明:铁皮石斛菌根真菌(JSAFC003、JSAFC004)能够在一定程度上提高植株的抗旱能力,SOD、POD活性与植株抗旱能力呈正相关,MDA含量与植株抗旱能力呈负相关,表明细胞膜保护酶的调节作用在菌根提高铁皮石斛抗旱能力过程中发挥了一定作用。     

Response of Acacia senegal (L.) Willd. to inoculation with arbuscular mycorrhizal fungi isolates in sterilized and unsterilized soils in Senegal

The benefits of inoculation with six arbuscular mycorrhizal fungi (AMF) isolates (Glomus aggregatum, G. fasciculatum, G. intraradices, G. manihotis, G. mosseae, and G. verriculosum) were investigated on seedlings of Acacia senegal (L.) Willd., a multipurpose tree legume highly valued for arabic gum production. Mycorrhizal root colonization, plant growth and relative mycorrhizal dependency (RMD) were measured in A. senegal seedlings growing in soils from three geographical sites in Senegal (Dahra, Bambey and Goudiry) and two soil conditions (sterilized vs unsterilized) in the glasshouse. The impact of inoculation on mycorrhizal root colonization and plant growth depended on AMF isolates, soil origins and soil conditions. Mycorrhizal root colonization and plant growth were increased in sterilized soils regardless of soil origin and AMF isolates. The degree of RMD of A. senegal seedlings varied with soil origin, soil condition and AMF isolates. A. senegal showed the highest RMD values, reaching a maximum of 45 %, when inoculated with G. manihotis. However, in unsterilized soils, no significant effect of AMF inoculation on plant growth was observed despite significant root colonization with certain AMF isolates in Dahra and Goudiry soils. This indicates that the most infective AMF isolates were not the most effective and unsterilized soils may contain effective mycorrhizal propagules. In conclusion, it is important to consider the native mycorrhizal component of the soils before harnessing mycorrhizal inoculation programs for sustainable agroforestry systems.     

The root-knot nematode problem in sesbania fallows and scope for managing it in western Kenya

Sesbania (Sesbania sesban), which is promoted as a short-duration-fallow species in eastern and southern Africa, is an alternative host to root-knot nematode (Meloidogyne spp.). Therefore, it is important to know the extent of sesbania infection by the nematode on farms and its effects to crops grown in rotation with sesbania. A survey of 14 farms in western Kenya indicated that sesbania was infected by root-knot nematode in all the farms. The potential to build up the nematode population was much greater on farms where maize (Zea mays) was previously intercropped with a susceptible bean (Phaseolus vulgaris). Screening of 30 single plant accessions of four sesbania provenances (Kakamega, Siaya, Kisumu, and Kisii) from western Kenya in pots indicated limited scope for selecting material resistant to the nematode. All four provenances were infested by the nematode, and they increased its population in soil and root. A rangewide collection of sesbania germplasm needs to be screened to determine the scope of finding nematode-resistant material. Transplanted seedlings produced in heat-sterilized, nematode-free soil showed less nematode infection than direct-seeded plants. However, both direct seeding and transplanting seemed to increase nematode population similarly. A number of Crotalaria spp. that were found resistant to nematodes can be considered as alternatives to sesbania-planted fallows, but further field-scale testing is necessary to select appropriate species based on biomass production. Among other species suitable for short-duration fallows, only pigeonpea (Cajanus cajan) and senna (Senna siamea) showed promise. Species such as neem (Azadirachta indica), casuarina (Casuarina junghuhniana), and grevillea (Grevillea robusta) that are suitable for boundary plantings were free from the root-knot nematode.This revised version was published online in November 2005 with corrections to the Cover Date.     

土著菌根真菌对西南桦无性系幼苗光合生理的影响

西南桦是一个典型的菌根营养型树种。揭示土著菌根真菌侵染对其幼苗光合作用的影响,旨在为菌根化幼苗的培育提供科学依据。以西南桦4个无性系组培苗为材料,应用12个西南桦人工林样地内表土(编号为S1、S2、S3,…,S12)作为接种剂和育苗基质开展盆栽试验,分析各土接种处理及无性系之间幼苗叶绿素含量、光合参数以及叶绿素荧光参数的差异。结果表明:1)12个土接种处理间幼苗叶绿素含量、光合参数以及叶绿素荧光参数差异显著,其中S12处理的叶绿素含量、净光合速率、气孔导度、蒸腾速率和水分利用效率以及Fv、Fv/Fm、ΦPSⅡ和ETR均显著高于其它处理,而叶绿素a与b含量的比值以及胞间CO2浓度显著低于其它处理;2)FB4、BY1、FB4+等3个无性系之间绝大部分光合生理指标差异不显著,而显著高于无性系A5,仅气孔导度和Fv/Fm在4个无性系之间差异不显著;3)相关分析亦显示,各土接种处理的西南桦幼苗总叶绿素含量、净光合速率、水分利用效率、PSⅡ最大光化学效率和实际光化学效率与其土著菌根侵染率均呈正相关,且绝大多数相关性达到显著或极显著水平。     

绿化树种接种VA菌根真菌的生长效应研究

试验结果表明,VA菌根真菌对10个参试的绿化树种均有不同程度的增效。对苗高和基径均有增效的占参试树种的80%,其中对苗高有增效的占80%,对基径有增效的占100%。但接种效应差异性程度各有不同,处理与对照苗高、基径生长均达到极显著差异的树种有黑金刚、花金刚、巴西榕,差异显著的有竹节树,其余树种接种后虽有增效作用,但没有达到显著水平。综合来看,VA菌根真菌对黑金刚、花金刚、红关公、巴西榕和竹节树的增效效应最为明显,对扭纹铁、红桂木的增效效应较好,而对石楠、红楣和伞花木则稍差。     

灰背杜鹃菌根真菌的分离与鉴定及DGGE的应用

应用传统的培养方法分离菌根真菌,应用ITS rDNA分子生物学手段,进行了菌株的分类鉴定,并结合DGGE(变性梯度凝胶电泳)技术对菌根真菌进行检测。传统培养得到了2种与杜鹃花菌根真菌亲缘关系十分密切的真菌,分别为Phialocephala fortinii和Epacris pulchella root associated fungus。DGGE(变性梯度凝胶电泳)技术检测到1种菌根真菌为Rhizoscyphus ericae。     

Arbuscular mycorrhizal fungi in the rhizosphere of Macaranga denticulata Muell. Arg., and their effect on the host plant

A fallow enriching tree, Macaranga denticulata Muell. Arg., has been shown to increase rice yield in a rotational shifting cultivation system in northern Thailand through increased accumulation of mineral nutrients. As arbuscular mycorrhizal (AM) fungi may play an important role in nutrient accumulation, AM fungi in the rhizosphere of M. denticulata and the effects of the indigenous soil inoculum on the host plant were investigated. The diversity and abundance of AM fungi were documented for the rhizosphere of M. denticulata in the field for two years. Based on morphology, 29 species of AM fungi were found in the rhizosphere of M. denticulata growing in farmers’ fields. Root colonization ranged from 63.5 to 81.5% in the first year and 68.7 to 79.9% in the second year of study. The highest spore density was observed at the end of the wet season. The effects of indigenous soil inoculum, and N and P fertilizers on the host plant were investigated in pots for four months. Inoculation with soil-containing AM fungi strongly increased plant growth and nutrient contents when P was limiting but N was applied. Application of N and P together strongly depressed root colonization and spore density of AM fungi, whereas applying them separately had much less effect. AM fungi may play an important role in nutrient accumulation in M. denticulata-rich fallow and thus in nutrient cycling that is beneficial to the maintenance of upland rice yield and sustainability of the rotational shifting cultivation system. This revised version was published online in June 2006 with corrections to the Cover Date.     

赤松幼苗接种菌根真菌生长效应的初步研究

以赤松幼苗接种松茸菌进行盆栽和圃地栽培试验,研究菌根菌感染数量和菌根菌对苗木生长效应的影响。结果表明:在盆栽条件下,三种处理根系菌根真菌的感染指数分别为80、50、3,截根接种和不截根接种分别为对照的26.7倍和16.7倍,且截根处理是不截根的1.6倍;幼苗苗高、地径生长量显著提高,干重比对照分别增加33.3%和18.5%。在圃地条件下,截根接种与不截根接种的幼苗苗高、地径生长量比对照分别提高5.4%、4.2%和14.9%、6.9%。     

Tree species as hosts for arbuscular mycorrhizal and dark septate endophyte fungi

A survey of 35 tree species(belonging to 28 genera in 19 families) in Aliyar,South India was carried out to ascertain their arbuscular mycorrhizal(AM) and dark septate endophyte(DSE) fungal status.All the tree species examined had AM association.AM and DSE colonization is reported for the first time in 20 and 14 species respectively.Cooccurrence of AM and DSE was observed in 14(40%) tree species.The extent of DSE colonization was inversely related to the extent of AM fungal colonization.Six tree species had Arum-type,18 had intermediatetype and 11 had typical Paris-type AM morphology.AM fungal spore morphotypes belonging to 11 species in two genera were isolated from the rhizosphere soil.AM fungal spore numbers were not related to the extent of AM colonization and Glomus dominated spore diversity.AM association individually and along with DSE were found respectively in the 63% and 44% of the economically important tree species.The occurrence of AM and DSE fungal association in economically important indigenous tree species indicates the possibility of exploiting this association in future conservation programmes of these species.     

Biosolids,mycorrhizal fungi and eucalypts for phytostabilization of arsenical sulphidic mine tailings

The effect of the addition of biosolids combined with a native arbuscular mycorrhizal inoculum on growth of a eucalypt (Eucalyptus cladocalyx), and on trace element stabilization of arsenical sulphidic gold mine tailings was tested. A glasshouse trial was established using four substrates: tailings (T); tailings with a layer of topsoil (TS); tailings amended with 100 t ha⁻¹ biosolids (LB), and tailings amended with 500 t ha⁻¹ biosolids (HB). Half of the pots were inoculated with a mixture of Glomus sp. (WUM51–9227), Scutelospora aurigloba (WUM51–53) and Acaulospora laevis (WUM46) culture mix, and others were uninoculated controls. Two seeds per pot were sown. Leaf and stem weights, leaf area and plant height were measured for each plant. Nutrients and trace element concentrations in leaves and stems were determined. Addition of biosolids significantly increased mycorrhizal colonization (both ectomycorrhizal and arbuscular mycorrhizal) in roots. Biosolids clearly increased the very early establishment and growth of the eucalypts. In general, mycorrhizal inoculum increased plant biomass production and nutrient uptake. Trace element concentrations in trees of the biosolid-amended pots were in general high, however, mycorrhizal inoculation could reduce the uptake of toxic elements by plants.     

野生花卉铃兰、耧斗菜的栽培管理及在园林中的应用

野生花卉是具有抗性强、观赏价值高、地方特色明显、管理粗放等优点,但引种、育种及开发应用还远远不够。仅对铃兰、耧斗菜这两种花卉的生物特性、栽培管理以及在园林中的应用进行探讨。     

Diversity of mycorrhizal fungi and soil indicative species in coastal plantations of northeast Brazil

The aim of this work was to evaluate arbuscular mycorrhizal(AM) fungi as soil indicators and the mycorrhization of native and exotic tree species planted in the Acaraú basin, a transition area from the coast to the Brazilian semiarid region. Plots with 6-year-old trees of four native and three non-native species as well as one non-forested area were evaluated in terms of the diversity of AM fungi in the mycorrhizosphere and the root colonization by AM and ectomycorrhizal(EcM) fungi. Twenty-four AM fungi were identified; Claroideoglomus etunicatum, Glomus sinuosum, Paraglomus albidum, Acaulospora laevis, and Acaulospora brasiliensis were abundant in the forest soil. Diversity, dominance, evenness and richness indices of AM fungi were higher in plots with native trees. All root samples were colonized by AM fungi and only A nadenanthera colubrina,Acacia mangium, Casuarina equisetifolia and Eucalyptus urophylla formed associations with EcM fungi. Acaulospora morphotypes served as soil indicators for coverings with the native species Astronium fraxinifolium and Colubrina glandulosa. Exotic species may favor the proliferation of rarer AM fungi. These fungi–plant relationships may be important in the management of forest systems, and the evidence with mycorrhizal associations allows the inclusion of Brazilian species in tropical reforestation.     

Studies on hypersaline-tolerant white-rot fungi L: screening of lignin-degrading fungi in hypersaline conditions

To search for marine fungi that have significant lignin-degrading ability in a hypersaline environment, eight strains of marine fungi were selected from 28 strains isolated from mushrooms and driftwood sampled from mangrove stands in Okinawa, Japan. We evaluated the decolorization ability, delignification ability, and biobleaching properties of the strains; then strain MG-60 was screened as a hypersaline-tolerant lignin-degrading fungus. We have summarized its growth, decolorization ability, and biobleaching properties at various sea salt concentrations. The strain has been estimated to belong to thePhlebia family.Part of this paper was presented at the 44th Lignin Symposium. Gifu, Japan, October 1999     

Selection of efficient VA mycorrhizal fungi for Casuarina equisetifolia—second screening

An investigation was carried out to screen and select efficient vesicular arbuscular mycorrhizal (VAM) fungi for inoculating the forest tree species, Casuarina equisetifolia. The seedlings were inoculated with 10 different VAM fungi, obtained from various sources. Inoculated seedlings generally had greater plant height, stem girth, biomass and P content than uninoculated plants. They also had more mycorrhizal root colonization and spore numbers in root zone soil. C. equisetifolia seedlings responded best (in biomass) to inoculation with Glomus mosseae (Nicolson and Gerdemann) Gerdemann and Trappe, closely followed by Acaulospora laevis Gerdemann and Trappe and G. fasciculatum (Thaxter Sensu Gerdemann) Gerdemann and Trappe; all the three being statistically on par with each other.     

Distribution,colonization and diversity of arbuscular mycorrhizal fungi associated with central Himalayan rhododendrons

The objective of the present study was to investigate arbuscular mycorrhizal status of five species of rhododendrons distributed in Kumaun region of the Indian Central Himalaya. Root and rhizosphere soil samples of all the five species of rhododendrons, namely, Rhododendron anthopogon, R. arboreum, R. campanulatum, R. barbatum and R. lepidotum were collected from temperate, sub-alpine to alpine location in altitudinal range from 1500 to 4500 m amsl. The arbuscular mycorrhizal colonization in root samples ranged from 28 to 42%; and maximum and minimum colonization was observed in R. arboreum and R. lepidotum, respectively. The highest number of intraradical vesicles (12.5 ± 2.8 cm⁻¹ root segment) was recorded in R. arboreum and the lowest (7.0 ± 1.7 cm⁻¹ root segment) in R. barbatum; vesicles were not observed in R. lepidotum. Spores were extracted from the rhizosphere soil by wet sieving to perform microscopic identification of the species. The maximum and minimum populations of spores were detected in the rhizosphere soil samples of R. anthopogon (52.0 ± 1.5 spores 25 g⁻¹ soil) and R. lepidotum (32.0 ± 2.5 spore 25 g⁻¹ soil), respectively. Spore populations were found to belong to five genera—Acaulospora, Glomus, Gigaspora, Sclerocystis and Scutellispora; genus Glomus was found to be dominant in the rhizosphere soil samples of all the rhododendron species. The most frequent and abundant species was G. fasciculatum, however, this species was not isolated from the rhizosphere soil of R. barbatum. Finger millet (Eleucine coracana) was used to cultivate the trap culture of arbuscular mycorrhizal fungi to confirm the species identity. Spores of Glomus pustulatum, not detected in the rhizosphere soil, were recovered from the trap culture. Contrary to this, genus Gigaspora, which was present in the rhizosphere soil, did not sporulate in the trap culture. Shannon and Wiener index of diversity and Simpson's index of dominance indicated that the species richness, dominance and diversity of arbuscular mycorrhizal fungi decrease with increasing altitude. In two species of rhododendrons, namely R. campanulatum and R. anthopogon, dark septate mycelium was also observed.     

Biodiversity of arbuscular mycorrhizal fungi in Amygdalus scoparia Spach plantations and a natural stand

The biodiversity of arbuscular mycorrhizal fungi(AMF) was surveyed in the Kolm region of Iran in three adjacent sites, a natural stand, a 10-year-old and a 15-yearold plantation of Amygdalus scoparia. To date, there have been few studies of AMF biodiversity in Iran, especially in the western forests of the country. For this study, soil and root samples were taken from A. scoparia rhizosphere soil in spring and autumn. Almost half of the root length was colonized by AMF. We identified 13 AMF species belonging to Glomeraceae, Claroideoglomeraceae or Diversisporaceae. The three plantations differed in terms of soil electrical conductivity, organic C and P. Spore density was significant correlated with P concentration. Root length colonization was correlated only with soil Ca.Species diversity and richness were significantly correlated with soil N, P, organic C and spore density. AMF diversity in 15-year-old plantations was more similar to that in the natural stand than in the 10-year-old plantation. We confirmed that a 15-year-old plantation is not similar in terms of AMF colonization to natural stands. We conclude that more than 15 years are required for AMF colonization of plantations to resemble that of natural stands.     

菌根菌肥料对滨柃抗海雾能力的影响分析

以采用不同处理浓度菌根菌肥料培育下的滨柃2年生幼苗为试材,研究了在模拟海雾环境下,植物叶片外观变化、叶片脯氨酸、叶绿素、相对电导率10-30d的变化情况。结果表明,随着胁迫时间的持续,滨柃叶片植物叶片外观、脯氨酸、叶绿素、相对电导率发生了一定变化,证明菌根菌肥料提高了滨柃的抗海雾能力,200mg.L-1浓度效果最佳。