不同丛枝菌根真菌对番茄生长及相关生理因素的影响

对番茄中杂9号接种6种不同的丛枝菌根真菌(Glomus versiforme,Glomus mossea-2,Glomus intraradices,Glomus diuphauam,Glomus mossea,Glomus etuni-catum1),通过测定不同菌种对番茄的生长效应及叶片生理变化,表明不同丛枝菌根真菌对番茄有不同程度的生长促进作用,处理番茄的叶片可溶性糖、可溶性蛋白、硝酸还原酶(NR)活性均比对照有所增加,其中对叶片可溶性糖的影响最为显著,它与番茄根系的菌根侵染率呈极显著正相关,还与植株总干重显著正相关,菌根侵染率亦与植株干重显著正相关。故此提出叶片可溶性糖含量可作为丛枝菌根影响番茄生长的生理鉴定指标,依此指标筛选出Glomus versiforme,Glomusmossea-2是对番茄生长促进效果最好的菌种。     

接种丛枝菌根真菌对玉米小斑病发生的影响

采用磷高效（181）和磷低效（197）两个玉米基因型研究了接种丛枝菌根（AM）真菌对玉米小斑病发生的影响。结果表明:玉米苗期的发病等级与地上部磷浓度呈极显著负相关,说明磷营养的改善是降低小斑病发病率的原因之一。在供磷不足（施磷量为20和50 mg/kg）时,两个玉米基因型小斑病发病率均最高,此时接种AM真菌显著提高了磷低效基因型197的地上部磷浓度、降低了其小斑病发病指数;而对磷高效基因型181接种AM真菌未显著提高地上部磷浓度,因而接种AM真菌对其小斑病的抗性影响不显著。以上结果表明接种AM真菌能够提高玉米对小斑病的抗性,其机理与改善磷营养状况有关。     

Effect of arbuscular mycorrhizal fungi on growth,mineral nutrition,antioxidant enzymes activity and fruit yield of tomato grown under salinity stress

The purpose of this study was to investigate the mechanisms underlying alleviation of salt stress by arbuscular mycorrhizal fungi Glomus mosseae. Tomato (Lycopersicon esculentum L. cv. Zhongzha105) plants were cultivated in soil with 0, 50 and 100 mM NaCl. Mycorrhization alleviated salt induced reduction of root colonization, growth, leaf area, chlorophyll content, fruit fresh weight and fruit yield. The concentrations of P and K were higher in AM compared with nonAM plants grown under nonsaline and saline conditions. Na concentration was lower in AM than nonAM plants grown under nonsaline and saline conditions. AMF colonization was accompanied by an enhancement of activity of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX) in leaves of both salt-affected and control plants. In addition, inoculation with AMF caused reduction in MDA content in comparison to salinized plants, indicating lower oxidative damage in the colonized plants.     

Iron‐reducing bacteria can enhance the activation and turnover of the Fe(III)‐fixed phosphorus for mycorrhizal plants

In a greenhouse experiment, Medicago sativa was grown in iron‐rich soil colonized with iron‐reducing bacteria (IRB) and/or Glomus mosseae (GM) under different inorganic phosphorus levels, which was to understand the effects of IRB and GM on the activation and turnover of the Fe(III)‐fixed phosphorus. The results showed that at the both P rates, dual‐inoculation treatment stimulated the hyphal growth and increased the shoot P content. IRB could accelerate mycorrhizal colonization, and showed a positive effect on plant biomass and P uptake at both P levels. Compared to sole‐IRB or GM treatment, the dual inoculation treatment increased the soil available P content at both P rates (p < 0.05), which was in the following order: the dual IRB+GM > the sole IRB > the sole GM > control for soil SMP content at low P rate, whilst the dual IRB+GM > the sole IRB ≈ the sole GM > control treatment at high P rate. Compared with the IRB treatment, the GM treatment significantly decreased the soil available P content and the MBP content at low P rate, but made no difference at high P rates. The soil MBC in dual‐inoculation treatment was greatest under the high P level, while the highest soil MBC was the sole‐GM treatment under the low P level. The sole GM treatment showed significantly (p < 0.05) higher soil MBC than that of sole IRB at low P rate (p < 0.05), while there was no significant differences between sole IRB and sole GM at high P rate. Our results suggested that the interaction between GM and IRB had synergetic effect on the mobilization of Fe(III)‐fixed P and their relationship could be regulated by the turnover of MBP. The fact that plants acquired more P via mycorrhizal pathway in the GM‐IRB system suggested that the three symbiont of plant‐GM‐IRB had great ecological and functional significance for P activity in tropical and subtropical soil.     

菌根真菌和根瘤菌接种对紫花苜蓿和无芒雀麦混播牧草生物量的影响

丛枝菌根真菌（Arbuscular mycorrhizal fungi,AMF）和根瘤菌是自然界存在的两类重要的共生微生物,分别能与宿主植物形成丛枝菌根和根瘤的共生体系,对宿主植物的生长具有重要影响。本研究通过建立丛枝菌根真菌-禾本科牧草和丛枝菌根真菌-豆科牧草-根瘤菌的共生体,研究AMF和根瘤菌接种对混播中紫花苜蓿（Medicago sativa）和无芒雀麦（Bromus inermis Leyss）生长的影响。结果表明：与CK相比,单独接种根瘤菌处理下单播和混播的紫花苜蓿地上单株生物量分别提高了65.42%和53.41%,地下单株生物量提高了96.66%和114.42%。单独接种AMF处理下单播和混播的紫花苜蓿地上单株生物量分别提高了35.33%和23.20%,地下单株生物量提高了40.00%和46.45%。而AMF和根瘤菌双接种处理下单播和混播的紫花苜蓿地上单株生物量分别提高了105.66%和185.64%,地下单株生物量分别提高了167%和121%。综上所述,AMF和根瘤菌双接种对紫花苜蓿生物量的促进作用具有协同效应。     

Evaluation of arbuscular mycorrhiza with symbiotic and nonsymbiotic pea isolines at three sites in the Alentejo,Portugal

Providing an appropriate negative control for the experimental factor arbuscular mycorrhiza (AM) is a fundamental methodological problem. Therefore, the nonmycorrhizal (myc ^–) and nonnodulating (nod ^–) pea (Pisum sativum L.) mutant P2 was studied together with the parental symbiotic isogenetic variety Frisson in three experiments: (1) growth response to water supply in a climate chamber under nonsymbiotic growth conditions, (2) field evaluation at three sites in the Alentejo, South Portugal, and (3) growth response to P supply in a soil low in available P in a greenhouse‐chamber experiment. In the climate chamber at high NPK levels, mutant P2 achieved the same biomass as Frisson at 80% and 40% water‐holding capacity, respectively. For the field evaluation, three sites were chosen with normal arable use (Évora), extensive use as Montado (Portel), and intensive horticultural use (Mitra). The colonization of pea roots with AM fungi ranged from 4% (Mitra) to more than 90% (Portel), probably caused by differences in P availability. The plant density of mutant P2 was generally 25% lower than that of Frisson . Yield indices were all lowest at Portel, despite the same NPK fertilization. Grain and shoot yield of mutant P2 did not reach the level of Frisson at any site. Differences in N and P concentrations between the two isolines were insignificant in most cases. Differences in the amount of shoot P per plant consistently mirrored the mycorrhizal status of the three sites. Roughly 50% of the yield depression per m² could be attributed to the lower plant density of mutant P2, the remaining 50% must be caused by AM‐fungal colonization or other factors. In the final pot experiment using the soil with low P availability from Portel, the main benefit of AM for peas was enhanced P uptake. Central questions could not be answered using a nonmycorrhizal control. However, mutants remain one interesting tool, best be used in combination with other approaches to estimate the effects of mycorrhization.     

Polysaccharides and monosaccharides in the hyphosphere of the arbuscular mycorrhizal fungi Glomus E3 and Glomus tenue

 Plants colonised with the arbuscular mycorrhizal fungi (AMF) Glomus E3 and Glomus tenue were grown in microcosms that permitted separation into root:hyphae and hyphae compartments. Hydrolysed polysaccharides from the hyphae and water-soluble sugars released into the hyphosphere were assayed using chromatography. Total sugars and most monosaccharides were elevated in the hyphosphere of Glomus E3 but not in the hyphosphere of G. tenue. Differences in the levels of sugars did not depend on hyphal surface area. It is suggested the diversity in sugars produced in the hyphosphere of AMF may drive some of the spatial and temporal variation in microbial diversity and function in soils.     

Mycorrhizal influence on storage metabolites and mineral nutrition in seed propagated potato (Solanum tuberosum L.) plant

Abstract

Potato (Solanum tuberosum) showed a well-established mutualistic association with arbuscular mycorrhizal fungi. In the present study, earthen pots containing autoclaved soil were taken in which surface sterilized potato seeds were sown. The seed sowed earthen pots were inoculated by sterilized spores of arbuscular mycorrhizal fungi along with sterilized inoculated maize-root fragments, while the rest half of the seed filled pots, without any inoculation depicting control but were provided with non-inoculated maize root fragments. The inoculation was performed twice; first inoculation was done 3 days prior to sowing of potato seeds and second at the time of seedling emergence. Sampling of the inoculated as well as of control plants was performed at 20-day intervals till 80?days after tuber initiation. An increment in the level of metabolites as well as mineral nutrient was found in mycorrhizal inoculated potato tubers in contrast to non-inoculated. Our work demonstrates that inoculation has a great potential in enriching storage metabolites and nutrients in potato plant in low yielding soils.     

广东清远石灰岩3个植物群落菌根及土壤AMF孢子多样性

以广东省清远市清新县石灰岩山区风水林、次生草坡和旱作耕地的退化植被群落为主要研究对象,比较研究了3个植物群落常见植物的菌根感染率和根际土丛枝型菌根真菌(AMF)孢子的密度和丰富度。结果如下:在所检测的29种常见植物中,除凹头苋(Amaranthus blitum)外,其余植物均具有典型的丛枝型菌根结构;次生草坡植物的菌根感染强度和频度均较高,风水林次之,旱作耕地杂草的菌根感染强度和频度相对较低;在3个植物群落土样中共分离出70种AMF孢子,以球囊霉属(Glomus)最为丰富,无梗囊霉属(Acaulospora)次之;林相保护较完整、植物较丰富的风水林拥有最丰富的AMF孢子类型和最高的密度,而结构退化、物种贫乏的次生草坡和旱作耕地中的AMF孢子类型少,密度也明显降低。研究表明植物群落的物种多样性与其根际土AMF孢子丰富度和多样性具有密切的联系。