不同丛枝菌根真菌对切花菊生长的影响

在温室盆栽条件下,对切花菊品种‘神马’（Chrysanthemum morifolium ‘Jinba’）接种5种不同的丛枝菌根真菌（arbuscular mycorrhizal fungi,AMF）,分别在苗期和花期,通过测定相关形态及生理指标,研究AMF对切花菊生长的影响。结果表明：与未接种对照相比,5种AMF均能不同程度地侵染切花菊根系,增加植株株高、叶片数、根长和花瓣面积等,促进切花菊生长。接种AMF能够增强切花菊根系活力,提高根系、叶片和花瓣中的可溶性糖含量（Glomus mosseae除外）,从而改善渗透调节。综合分析,最终筛选出G. intraradlces是对切花菊生长促进效果最好的菌种。     

摩西管柄囊霉Funneliformis mosseae对连作大豆苗期根系AM真菌菌群结构的影响

中国北方大豆连作问题日益突出并受到广泛关注,为了将AM真菌应用于连作土壤,缓解大豆连作障碍。本试验采用Nested-PCR-DGGE技术分析接种摩西管柄囊霉(Funneliformis mosseae)对3种连作年限3种品种大豆苗期根系AM真菌菌群结构的影响。结果表明,接种F.mosseae后,同一品种连作两年大豆根系中AM真菌的侵染率最高,同一连作年限KF16根系中AM真菌的侵染率最高;不同连作年限不同品种大豆根系中AM真菌菌群中均含有粘性球囊霉(Glomus viscosum)和未培养的球囊霉属(Uncultured Glomus);种植于连作2年土壤的不同品种大豆根系AM真菌的丰度值和Shannon-Wiener指数均高于连作0年和连作1年的。本研究揭示接种F.mosseae对连作1年、连作2年不同品种大豆苗期根系AM真菌菌群结构影响显著。     

Growth and nutrition of cowpea (Vigna unguiculata) under water deficit as influenced by microbial inoculation via seed coating

Drought can drastically reduce cowpea [Vigna unguiculata (L.) Walp.] biomass and grain yield. The application of plant growth‐promoting rhizobacteria and arbuscular mycorrhizal fungi can confer resistance to plants and reduce the effects of environmental stresses, including drought. Seed coating is a technique which allows the application of minor amounts of microbial inocula. Main effects of the factors inoculation and water regime showed that: severe or moderate water deficit had a general negative impact on cowpea plants; total biomass production, seed weight and seed yield were enhanced in plants inoculated with P. putida; inoculation of R. irregularis significantly increased nitrogen (N) and phosphorus (P) shoot concentrations; and R. irregularis enhanced both chlorophyll b and carotenoids contents, particularly under severe water deficit. Plants inoculated with P. putida + R. irregularis had an increase in shoot P concentration of 85% and 57%, under moderate and severe water deficit, respectively. Singly inoculated P. putida improved potassium shoot concentration by 25% under moderate water deficit. Overall, in terms of agricultural productivity the inoculation of P. putida under water deficit might be promising. Seed coating has the potential to be used as a large‐scale delivery system of beneficial microbial inoculants.     

不同氮磷水平条件下接种AMF对玉米生长的影响

以珍珠岩为培养基质的半液培实验比较研究了不同氮磷水平营养液对接种丛枝菌根真菌玉米的影响。研究表明：菌根真菌侵染率随着外界氮、磷浓度的升高而下降。高浓度或低浓度的外界氮或磷存在时,接种丛枝菌根真菌对植物营养无贡献。在正常的供氮（2mol/L）和供磷（0.1mol/L）条件下,接种处理显著提高了植株生物量、磷含量,但对氮含量影响不大,菌根对玉米磷素营养的改善大于氮素。     

Response of Lettuce and Rhizosphere Biota to Successive Additions of Zinc and Cadmium to a Tropical Entisol

Response of lettuce and rhizosphere biota to successive addition of zinc (Zn) and cadmium (Cd) was assessed in a pot experiment using limed and unlimed tropical Entisol. Cadmium (2.5 mg kg^?1 soil) and Zn (50 mg kg^?1 soil) were spiked to soil 1 month after germination, and successive applications were superimposed as 5 and 10 times the first dose. Plants were analyzed for metal uptake and mycorrhizal colonization 1 week after each metal application. Rhizosphere soils were assessed for extractable Zn and Cd as well as populations of bacteria, fungi, and metal-tolerant fungi. The greatest metal doses resulted in 84–88 mg Zn and 8–10 mg Cd kg^?1 soil and 5–7.5 mg Cd and 70–72 mg Zn kg^?1 dry matter. Metal-tolerant fungi population increased from 9–13% to 26–63%, but mycorrhizal colonization and bacterial population were inhibited by 88% and 96%, respectively. Liming had relieved metal stress on rhizosphere biota but did not affect metal uptake.     

土著AMF与氮形态对辣椒||菜豆间作系统植株氮利用及其影响因素研究

近年来设施辣椒连作障碍日益突出,其中氮肥的大量不合理施用和高残留是限制辣椒高产、优质栽培的主要因素之一。研究土著丛枝菌根真菌(arbuscular mycorrhizal fungi, AMF)与间作体系强化蔬菜对不同形态氮(N)的利用并结合土壤菌丝密度、N形态及酶活性的反馈作用,可为设施土壤N素的高效利用和降低土壤N残留提供依据。本研究采用盆栽试验,设置辣椒||菜豆间作和各自单作种植模式,不同AMF处理[不接种(NM)、接种土著AMF]和不同形态N处理[不施N(N0)、无机氮(碳酸氢铵120mg·kg~(-1),ION)和有机氮(谷氨酰胺120 mg·kg~(-1),ON)],探讨了设施条件下接种土著AMF、施用不同形态N与间作对辣椒、菜豆根围土壤菌根建成、酶活性及N利用的影响。结果表明,与NM相比,接种土著AMF使设施辣椒、菜豆植株生物量及N吸收量显著增加(除菜豆单作-ON处理),显著降低土壤NH_4~+-N、NO_3~--N含量。无论施用何种形态N,均显著增加辣椒、菜豆植株生物量(除菜豆单作-AMF处理)及N吸收量,表现为ONION。与单作-ON-AMF处理相比,间作-ON-AMF处理下的辣椒N吸收量显著增加39.9%、菜豆N吸收量显著增加93.0%。对N利用影响因子的分析结果表明,间作协同接种土著AMF较大程度上增加了土壤有机质含量及蛋白酶、脲酶、硝酸还原酶活性。相关性分析显示,辣椒、菜豆植株N吸收量与AMF侵染率呈极显著正相关关系,而土壤NH_4~+-N和NO_3~--N含量则与AMF侵染率呈现一定的负相关关系。此外,土壤蛋白酶、脲酶和硝酸还原酶活性与辣椒、菜豆植株N吸收量呈正相关关系。可见,所有复合处理中,以间作体系接种土著AMF与施用适量有机氮的组合明显促进了设施辣椒、菜豆生长和N素利用。     

Arbuscular mycorrhizal fungus and rhizobacteria affect the physiology and performance of Sulla coronaria plants subjected to salt stress by mitigation of ionic imbalance

Salt stress has become a major menace to plant growth and productivity. The main goal of this study was to investigate the effect of inoculation with the arbuscular mycorrhizal fungi (AMF; Rhizophagus intraradices) in combination or not with plant growth‐promoting rhizobacteria (PGPR; Pseudomonas sp. (Ps) and Bacillus subtilis) on the establishment and growth of Sulla coronaria plants under saline conditions. Pot experiments were conducted in a greenhouse and S. coronaria seedlings were stressed with NaCl (100 mM) for 4 weeks. Plant biomass, mineral nutrition of shoots and activities of rhizosphere soil enzymes were assessed. Salt stress significantly reduced plant growth while increasing sodium accumulation and electrolyte leakage from leaves. However, inoculation with AMF, whether alone or combined with the PGPR Pseudomonas sp. alleviated the salt‐induced reduction of dry weight. Inoculation with only AMF increased shoot nutrient concentrations resulting in higher K⁺: Na⁺, Ca²⁺: Na⁺, and Ca²⁺: Mg²⁺ ratios compared to the non‐inoculated plants under saline conditions. The co‐inoculation with AMF and Pseudomonas sp. under saline conditions lowered shoot sodium accumulation, electrolyte leakage and malondialdehyde (MDA) levels compared to non‐inoculated plants and plants inoculated only with AMF. The findings strongly suggest that inoculation with AMF alone or co‐inoculation with AMF and Pseudomonas sp. can alleviate salt stress of plants likely through mitigation of NaCl‐induced ionic imbalance, thereby improving the nutrient profile.     

Optimization of a Novel Vegetable Nursery Substrate Using Date Palm Wastes Peat and Indigenous Arbuscular Mycorrhizal Fungi

Quality of vegetable seedlings is affected by nursery management practices, essentially growing media. For sustainable greenhouse horticulture, it is important to characterize biologically based approaches to improve plantlet quality. Here, we investigate the possibility of developing a biotized growth substrate for nursery production using date palm wastes (DPWs) peat as an alternative to commercial sphagnum peat and indigenous arbuscular mycorrhizal fungi (AMF). A greenhouse experiment was established using different rates of DPWs peat to substitute commercial peat in both conventional and organic nursery production systems. Lettuce seedlings were inoculated or not with native AMF isolated from plots with conventional or organic production system (CM and OM respectively). When lettuce plantlets attained commercial size, a microscopic observation revealed that the establishment of mycorrhizal association was successful in all mixtures of growing media. Significant increase in growth parameters (height shoot, number and area of leaves, shoot and root biomass) were observed on plantlets inoculated with indigenous AMF isolated from organic plot compared to those isolated from conventional plot and to control (without AMF). Commercial peat partial substitution with DPWs peat in proportion of 25–50% improves better lettuce performance than complete-peat use. Consequently, these mixtures seem to be an appropriate formulation for sustainable nursery production.     

丛枝菌根真菌群落对白三叶草植株生物量磷吸收和土壤磷酸单酯酶活性的影响

丛枝菌根真菌（AMF）在土壤与植物的磷素循环中发挥着关键的作用。采用盆栽实验研究了丛枝菌根真菌群落对白三叶草植株生物量、磷吸收和土壤磷酸单酯酶活性的影响。结果表明,接种不同AMF群落均能显著地促进白三叶草植株的生长及其对磷素的吸收,提高根际土壤磷酸单酯酶的活性。Mnp处理中,白三叶草生物量最大,白三叶草总生物量、茎叶生物量和根系生物量分别比对照处理（-M）提高64.48%、61.48%和84.91%。不同菌根处理中,Mck处理显著地提高白三叶草磷吸收和土壤磷酸单酯酶活性,白三叶草磷吸收总量和茎叶磷吸收量分别比对照（-M）提高107.18%和91.91%,土壤碱性磷酸单酯酶和酸性磷酸单酯酶活性相对对照（-M）分别提高54.33%和138.43%。碱性磷酸单酯酶活性与AMF群落中的Acaullospora属孢子数呈显著的正相关关系,而酸性磷酸单酯酶活性则主要受Paraglomus属孢子数的影响。说明接种AMF群落可显著地影响土壤的磷酸单酯酶活性,从而影响白三叶草的生长及其对磷素的吸收。     

转Bt基因作物对丛枝菌根真菌的影响研究进展

在过去的十年里，世界范围内转基因作物尤其是抗虫性转Bt基因作物的品种和种植面积迅速增加。同时，转Bt基因作物的环境安全性评价问题成为人们关注和研究的热点。丛枝菌根真菌（AMF）是生态系统中普遍存在的土壤微生物，能与绝大多数植物种类形成共生关系，在农业生态系统中起重要作用。转Bt基因作物环境释放后，其与AMF问的共生关系是否受所转入Bt基因的影响，以及影响机制需要及时研究。为此，综述了转Bt基因作物与AMF共生特征方面的研究进展，并根据Bt毒素发生的空间和时间规律提出了危害机制以及转Bt基因植物的规模化种植将降低农田系统中的AMF的生物多样性的观点。