Improved zinc tolerance in Eucalyptus globulus inoculated with Glomus deserticola and Trametes versicolor or Coriolopsis rigida

The potential of interactions between saprophytic and arbuscular mycorrhizal (AM) fungi to improve Eucalyptus globulus grown in soil contaminated with Zn were investigated. The presence of 100 mg kg ⁻¹ Zn decreased the shoot and root dry weight of E. globulus colonized with Glomus deserticola less than in plants not colonized with AM. Zn also decreased the extent of root length colonization by AM and the AM fungus metabolic activity, measured as succinate dehydrogenase (SDH) activity of the fungal mycelium inside the E. globulus root. The saprophytic fungi Trametes versicolor and Coriolopsis rigida increased the shoot dry weight and the tolerance of E. globulus to Zn when these plants were AM-colonized. Both saprophytic fungi increased the percentage of AM root length colonization and elevated G. deserticola SDH activity in the presence of all Zn concentrations applied to the soil. In the presence of 500 and 1000 mg kg⁻¹ Zn, there were higher metal concentrations in roots and shoots of AM than in non-AM plants; furthermore, both saprophytic fungi increased Zn uptake by E. globulus colonized by G. deserticola. The higher root to shoot metal ratio observed in mycorrhizal E. globulus plants indicates that G. deserticola enhanced Zn uptake and accumulation in the root system, playing a filtering/sequestering role in the presence of Zn. However, saprophytic fungi did not increase the root to shoot Zn ratio in mycorrhizal E. globulus plants. The effect of the saprophytic fungi on the tolerance and the accumulation of Zn in E. globulus was mediated by its effect on the colonization and metabolic activity of the AM fungi.     

An AM fungus and a PGPR intensify the adverse effects of salinity on the stability of rhizosphere soil aggregates of Lactuca sativa

A mesocosm experiment was conducted to examine the effect of an arbuscular mycorrhizal (AM) fungus (Glomus mosseae (Nicol & Gerd.) Gerd. & Trappe) and a plant growth-promoting rhizobacterium (PGPR) (Pseudomonas mendocina Palleroni), alone or in combination, on the structural stability of the rhizosphere soil of Lactuca sativa L. grown under two levels of salinity. The plants inoculated with P. mendocina had significantly greater shoot biomass than the control plants at both salinity levels, whereas the mycorrhizal inoculation was only effective in increasing shoot biomass at the moderate salinity level. The aggregate stability of soils inoculated with the PGPR and/or G. mosseae significantly decreased with increasing saline stress (about 29% lower than those of soils under non-saline conditions). Only the inoculated soils showed higher concentrations of sodium (Na) under severe saline stress. The severe salinity stress decreased the glomalin-related soil protein (GRSP) concentration, but the highest values of GRSP were recorded in the inoculated soils. Our findings suggest that the use of AM fungi and/or a PGPR for alleviating salinity stress in lettuce plants could be limited by their detrimental effect on soil structural stability.     

Mycelium of arbuscular mycorrhizal fungi increases soil water repellency and is sufficient to maintain water-stable soil aggregates

Using an in vitro bioreactor system in which the arbuscular mycorrhizal (AM) fungus Glomus intraradices was grown in a soil devoid of detectable living microbes, we could show that the mycelium of this fungus contributed to the maintenance of water-stable soil aggregates and increased soil water repellency, as measured by water drop penetration time. This is to our knowledge the first demonstration of a causal link between AM fungal growth and water repellency of soil aggregates. Our results also place AM fungal contributions to soil aggregation on a firm mechanistic footing by showing that hyphae are sufficient to produce effects, in the absence of other soil biota, which have always been included in previous studies.     

食用菌抗重金属机制研究综述

综述了汞、铅、砷、镉、铜等重金属在食用菌栽培中的富集情况,以及对食用菌生长、抗氧化系统影响的研究现状。食用菌对汞、铅、硒等重金属都表现出了不同程度的富集现象,但是随着重金属浓度增大,对食用菌生长抑制作用增大,从而降低了食用菌对重金属的富集能力。食用菌的抗氧化系统是抵抗重金属胁迫的重要机制,但目前关于这方面的研究较少。     

一种野生食用菌的分子及形态学鉴定

该文对采自福建农林大学金山校区竹林内的一株野生大型食用菌的菌丝、子实体等进行形态学鉴定,并结合现代分子生物学方法对其ITS序列进行测定,通过在基因组数据库中进行比对确定其亲缘关系,属于无隔担子菌亚纲(Homobasidiomycetidae)伞菌目(Agaricales)口蘑科(Tricholomataceae)口蘑属(Tricholoma),暂命名为金山巨菇(Tricholoma sp.)。     

降解玉米秸秆纤维素真菌的筛选及产油特性的研究

通过玉米秸秆纤维素培养基,筛选获得一株高效水解秸秆纤维素的真菌,用形态学方法初步鉴定为峡串孢霉(Paepalopsis Kühn)属,进一步测定其CMC酶活和滤纸酶活,培养6d后分别为45.32U和35.31U。在产油发酵培养基,产油率达菌体干重的14.24%。此试验为纤维素降解利用和微生物油脂的开发利用奠定了一定的理论和研究基础。     

内生真菌AL12对茅苍术代谢产物器官分配的影响(英文)

[目的]研究内生真菌孔球孢霉AL12号菌株对茅苍术组培苗生长及其代谢产物器官分配的影响。[方法]将内生真菌AL12与茅苍术组培苗进行共培养,比较感染前后茅苍术叶、根重量差异,检测接种AL12的组培苗中纤维素、半纤维素、木质素以及可溶性糖在叶片和根中的分布,并利用气相色谱分析挥发油组分。[结果]茅苍术与AL12共生后,与对照组相比,其组培苗叶片和根的鲜重和干重均有明显增加,且叶片木质素和可溶性糖含量增加,根部纤维素、半纤维素、木质素、可溶性糖及挥发油含量均有提高。[结论]该研究结果表明与AL12共生有利于茅苍术根部发育且能促使药用成分向根中转移、积累。     

白藜芦醇及其衍生物对植物病原真菌的抑菌活性

为了明确植物源活性成分芪类化合物在农业病害防治中的前景,在离体条件下分别测定了白藜芦醇(Ⅰ)及其衍生物(Ⅱ~Ⅴ)对植物病原真菌菌丝生长的抑制作用以及对菌丝形态和孢子萌发的影响,采用叶片法和温室盆栽法研究了白藜芦醇的防病作用原理。结果表明:5个供试化合物对6种供试病原菌的菌丝生长均有不同程度的抑制作用,但均对番茄早疫病菌 Alternaria solani 的抑制活性最高,其中又以3,5-二羟基-4'-甲氧基二苯乙烯(Ⅲ)的抑制活性最高;白藜芦醇可造成番茄早疫病菌菌丝体畸形,并可抑制该病菌孢子的萌发,但未引起孢子形态改变。叶片法和温室盆栽法试验的结论一致,即白藜芦醇能够抑制病原菌的侵染,对植株起到一定的保护作用。