丛枝菌根真菌对镉污染土壤中黑麦草幼苗生长的影响

通过不同浓度的镉污染土壤接种丛枝菌根真菌的黑麦草盆栽试验,研究了丛枝菌根真菌对镉污染条件下黑麦草幼苗生长的影响。结果表明:重度镉污染(Cd2+:180 mg/kg)条件下,Glomus mosseae对黑麦草根系的侵染率仍达到30.23%,对黑麦草的生长有较好的促进作用;丛枝菌根在一定程度上缓解了镉污染对黑麦草株高、根长和生物量积累的抑制;镉污染显著降低黑麦草叶片的叶绿素含量,叶绿素a在重度镉污染时下降幅度最大,不接种丛枝菌根真菌的黑麦草较对照下降37.9%,而接种的黑麦草下降26.7%,接种菌根真菌在中重度镉污染条件下显著提高了黑麦草叶片的叶绿素含量;重度镉污染下接种和不接种的黑麦草根系活力都开始显著下降,但接种植株根系活力下降的幅度小于不接种植株。     

葫芦科蔬菜对丛枝菌根真菌依赖性的研究

在盆栽条件下试验研究了5种葫芦科（Cucurbitaceae)蔬菜对2种丛枝菌根(Arbuscular Mycorrhiza,AM)真菌的语性。结果表明，AM真菌Glomus mosseae(G.m)和Gigaspora rosea(Gi,r)均能有效地促进葫芦科蔬菜的生长，显著增加叶面积和植株干物质量，提高叶片的光合速率，降低气孔阻力。供试葫芦科蔬菜对菌根的依赖程度顺序为黄瓜＞西瓜＞苦瓜＞葫芦＞南瓜。5种葫芦科蔬菜对AM的依赖性与AM真菌对根系的浸染率呈正相关关系，符合直线回归方程：y＝117．19＋0．7468x。     

丛枝菌根真菌对玉米生长生态效应的影响

１９９６～１９９８年试验研究了大田不施肥条件下３种泡囊丛枝菌根真菌Ａｒｂｕｓｃｕｌａｒ ｍｙｃｏｒ－ｒｈｉｚａｌ ｆｕｎｇｉ （ＡＭＦ）,即Ｇｌｏｍｕｓ ｍｏｓｓｅａｅ（Ｇ．ｍ）、Ｇｌｏｍｕｓ ｖｅｒｓｉｆｏｍｅ（Ｇ．ｖ）、Ｓｃｌｅｒｏｃｙｓｉｓ ｓｉｎｏｕｓａ（Ｓ．ｓ）对玉米生长的生态效应。结构表明,ＡＭＦ处理的玉米根系活力为对照的２．３２～３．０５倍,玉米Ｎ素吸收比对照增加２４．１４％～５６．     

长期定位施肥对丛枝菌根真菌多样性的影响

Diversity of arbuscular mycorrhizal fungi (AMF) was investigated in a field that had received long-term fixed ferti-lization (LFF) for 26 years.There were a total of 12 treatments in triplicates with different amounts of manure,urea,calcium phosphate,and potassium chloride.Rhizosphere soil samples of maize and wheat grown in the experimental field in Shandong Province,China,were collected in September 2003 and May 2004,respectively.Arbuscular mycorrhizal fungal spores were isolated and identified using morphological characters.Mycorrhizal colonization percentage,spore density (SD),species richness (SR),relative abundance (RA),and Shannon-Weiner index (SWI) were determined.Nineteen recognized species of AMF belonging to 5 genera were identified.Long-term fixed fertilization significantly influenced colonization percentage,SR,SD,and species diversity of AMF.The adaptability of AMF to soil fertility was different among species.Species richness and SD of AMF in maize and wheat rhizosphere soils were the highest in the nonferti-lization treatment (control) and lowest in the high manure + high nitrogen treatment (M₂N₂).The SWI decreased as the fertilization level increased except in the low manure treatment (M₁) on maize.Compared with the other treatments,Treatment M₂N₂ significantly reduced SD of Glomus,and the high manure + low nitrogen treatment (M₂N₁) significantly retarded sporulation of Scutellospora.Manure treatments stimulated sporulation of Glomus mosseae.Spore density of G.mosseae was higher in the high nitrogen + phosphorus + potassium treatment (N₂PK) than in the high nitrogen + phosphorus treatment (N₂P) and the high nitrogen + potassium treatment (N₂K).The SD of S.pellucida was higher in Treatment N₂K than Treatments N₂PK and N₂P.In conclusion,long-term fixed fertilization,especially with high levels of manure and N,decreased SR,SD,and colonization and changed the species composition of AMF.     

丛枝菌根真菌领域专利情报分析

丛枝菌根真菌 (AMF) 与植物共生在提高植物的抗逆性、抗病性和维护植物健康方面发挥着关键作用,其在农业、林业和生态环境等方面的应用受到广泛关注。本研究基于incoPat科技创新情报平台,检索了2019年前国内外丛枝菌根真菌的专利产出,对专利申请数量、主要申请人、技术构成等方面进行了分析,以揭示国内外丛枝菌根真菌领域的研发状况、技术发展趋势和产学研合作情况。近年来,中国丛枝菌根真菌领域专利数量急剧增加,AMF产品化不断加强,AMF应用领域从农业领域向污染修复领域拓展,结合现代生物、信息技术等新兴技术的AMF检测技术和研究方法正在快速发展,新的研发充分考虑了AMF产品化和应用的结合;我国在丛枝菌根真菌领域的专利申请人多隶属高校和科研院所,企业参与度较低。AMF菌种扩繁和污染修复领域的应用已成为焦点,生物和信息新技术成果正引入AMF检测技术的开发;中国在丛枝菌根真菌领域的产学研合作研发亟需加强。     

丛枝菌根提高植物耐盐性的研究进展

近年来,土地盐渍化越来越多的引起人们的关注,已成为最常见的农业问题之一,其对人类造成的危害主要是使农作物减产甚至绝收,并间接造成生态环境恶化。研究表明丛枝菌根真菌(Arbuscular Mycorrhiza Fungi,AMF)在盐胁迫下能与很多种植物共生,能够提高植物的耐盐性,促进植物在盐胁迫中生长。因此,探索AMF缓解盐胁迫对植物的危害是近年来生态学和农业生产中的热点问题。综述了AMF在植物干物质的积累、营养吸收、渗透调节、抗氧化酶系统、叶绿素浓度、水分状况、植物激素信号以及一些耐盐相关基因方面国内外最新的研究成果,并对利用AMF提高植物耐盐性相关研究提出了展望,以期为盐碱地的改良及农业生产提供参考依据。     

蚯蚓与丛枝菌根真菌的相互作用及其对植物的影响

蚯蚓和丛枝菌根(Arbuscular mycorrhiza,AM)真菌都是有益的土壤生物,对提高土壤养分有效性和植物吸收利用营养元素具有重要影响。本文综述了蚯蚓对AM真菌取食、传播和侵染的影响、蚯蚓与AM真菌相互作用的效应和机制方面的最新研究进展,以及AM真菌与蚯蚓互作改善植物营养和生长以及协同修复土壤重金属方面的作用,以期为今后研究发展提供依据。     

柑橘砧木和砧穗组合对丛枝菌根发育的影响

倍体体细胞杂种砧木)对丛枝菌根发育的影响。结果表明,柑橘丛枝菌根侵染幅度为 4.88 % ~ 40.52 %,土壤内孢子密度不等,大致在 347 ~ 750 个孢子/kg(干土)内。田间菌根侵染率和孢子密度在不同土层深度的分布以深度 10 ~20 cm 为最高。遗传关系相近的国庆 1 号/枳和国庆 4 号/枳组合间以及红肉脐橙/罗伯逊脐橙 36 号/枳和纽荷尔脐橙/罗伯逊脐橙 36 号/枳间的丛枝菌根发育没有显著差异,与红肉脐橙和纽荷尔脐橙遗传关系远的脐血橙组合,较红肉脐橙和纽荷尔脐橙组合的孢子密度间有极显著差异。红桔 枳的菌根侵染率和土壤孢子密度均最高,且显著高于其他 4 种砧木。盆栽砧木孢子密度与菌根侵染率呈显著正相关性。10 种试材的根围土壤孢子密度与菌根侵染率间呈极显著正相关性。     

丛枝菌根真菌根内菌丝碱性磷酸酶活性与菌根共生效应的研究

试验研究 3种丛枝菌根真菌根内菌丝碱性磷酸酶活性与菌根共生效应的结果表明 ,3种丛枝菌根真菌对宿主植物的效应不同 ,与接种G .spp处理和未接种对照相比 ,接种G .m和G .i处理显著增加玉米地上部和根系干物质量、P浓度和吸P量 ,但后两者间无显著差异 ;而接种G .spp处理与对照无显著差异。播种后 35d时接种G .m和G .i处理根内菌丝碱性磷酸酶活性显著高于接种G .spp处理 ,而前二者间无显著差异 ,且随生长时间的变化趋势相似 ,35d时酶活性最高 ,35～ 5 0d呈迅速下降趋势 ,至 70d时酶活性仍下降且趋于平缓。G .spp酶活性则一直处于较低水平 ,随生长时间的延长略有起伏。即接种不同丛枝菌根真菌时 ,根内菌丝碱性磷酸酶活性高的菌根真菌对玉米生长促进作用较大 ,可提高玉米P营养状况 ;反之则对玉米生长和P营养状况无明显促进作用 ,且与对照无显著差异。出苗后 35d时根内菌丝碱性磷酸酶活性是预测丛枝菌根真菌对玉米生长效应的有效生理指标之一。     

丛枝菌根真菌对玉米生长生态效应的影响

1996～1998年试验研究了大田不施肥条件下3种泡囊丛枝菌根真菌Arbuscular mycorrhizal fungi (AMF),即 Glomus mosseae(G.m)、Glomus versifome(G.v)、Sclerocystis sinousa(S.s)对玉米生长的生态效应.结果表明,AMF处理的玉米根系活力为对照的2.32～3.05倍,玉米N素吸收比对照增加24.14%～56.65%,玉米P素吸收比对照增加41.14%～78.29%,促进玉米生长发育显著;在灭菌条件下G.m、G.v、S.s处理分别比对照增产17.63%、22.91%和10.80%;而不灭菌条件下3个处理分别比对照增产10.35%、20.56%和4.53%,同时显著提高玉米的水分供应状况.     

烟草丛枝菌根(AM)研究进展

丛枝菌根真菌（Arbuscular mycorrhizas fungi）作为生物调节剂、生物肥料和生物防治剂，在持续农业和自然生态中的作用越来越受到人们的重视。丛枝菌根真菌不仅能增强烟草对矿质元素的吸收、提高烟草抗逆性、增强抗病性、改善烟草根际微环境，而且能提高其产量和改善品质。本文从烟草丛枝菌根真菌资源、丛枝菌根对烟草的主要作用、丛枝菌根对植烟土壤主要作用3个方面简要综述了烟草丛枝菌根的研究进展。     

Phosphorus nutrition alleviates manganese toxicity in Lolium perenne and Trifolium repens

Phosphorus (P) nutrition has been suggested to play a role in the alleviation of manganese (Mn) toxicity in some higher plant species. However, there are few reports on the role of P in regulating Mn accumulation by forage species. We studied the effect of P nutrition on Mn toxicity in Lolium perenne L. and Trifolium repens L. An increase in Mn concentration in root and shoot tissues was associated with an increase in both P supply and P tissue concentrations. Nevertheless, in both forage species, especially white clover, plant‐growth inhibition caused by Mn excess was decreased with increasing P additions. Moreover, the carboxylate exudation that had increased in response to high Mn was gradually reduced by increasing P supply. We suggest that P supply may have a beneficial effect in reducing the severity of Mn toxicity in forage species.     

N release pattern from green manures can be modified through species composition

Abstract

This study examined whether the N release pattern during decomposition of plant materials used as green manures can be modified in the short term through mixing plant materials with different levels of easily degradable compounds. In a lysimeter study, white clover shoots were mixed with perennial ryegrass shoots or chicory roots. Leaching of clover N was decreased more by inclusion of chicory than by ryegrass. However, decreased leaching losses over the non-growing season did not lead to enhanced N uptake by the crop during the following growing season.     

Effects of repeated clover undersowing,green manure ley and weed harrowing on weeds and yields in organic cereals

Abstract

Cover crops can be used to reduce leaching and erosion, introduce variability into crop rotation and fix nitrogen (N) for use by the main crops, less is however known about effects on weeds. The effects on weed seed bank, weed growth and grain yield of 4 years of annual undersown clover and ryegrass alone and in combination, and one of the 4 years with clover or clover + grass as green manure, were studied in oat and spring wheat at two experimental sites in south-eastern Norway. These treatments were compared with no undersown crop (control) and with weed harrowing. In contrast to many results in the literature, the undersown clover in this study did not suppress annual weeds, but fertilized the weeds as well as the cereals. Undersown clover resulted in a statistically significant increase of grain yield at the two sites to 116% and 121% of control. During the 4-year period relative seed bank and density of emerged weed (dominated by Spergula arvensis) increased significantly about 4.5 and 10 times respectively in the undersown clover plots at Apelsvoll. At Kise both ryegrass alone and ryegrass mixed with clover significantly suppressed the weed biomass to 70% and 74% of control respectively. It is concluded that fertilization effects of undersown clover may have dominated and overriden the competitive effects. One whole-season clover green manure did not increase the mean yield, but resulted in a significant drop in seed bank size the following year, because of limited weed establishment in an established ley. Only a slight increase in average weed biomass was observed at one of the two experimental sites. The weed seed bank and the weed biomass were essentially kept at steady state during the experimental period in harrowed plots, but harrowing decreased grain yield significantly at both sites.     

The effect of arbuscular mycorrhiza fungal propagules on the growth of subterranean clover (Trifolium subterraneum L.) under Mn toxicity in ex situ experiments

The role of intact extraradical mycelium (ERM) as the most effective fungal propagule in the formation of the tripartite symbiosis between indigenous arbuscular mycorrhizal fungi (AMF), rhizobia and subterranean clover was investigated under conditions of Mn toxicity. ERM was previously developed in 8 L pots under greenhouse conditions by growing plants, which exhibited various levels of mycotrophicity and were tolerant to the levels of Mn in the soil used in the experiment (Silene gallica L, Lolium rigidum L, Ornithopus compressus L. and Rumex bucephalophorus L). Contrasting conditions of the integrity of the ERM at the planting of subterranean clover were created by soil disturbance (ERM fragmented – soil disturbed; ERM intact – soil undisturbed). Where an intact ERM was present at the time of planting, growth of subterranean clover was 2.5 times greater after 21 days and 3.9 times after 42 days relative to other forms of AMF propagule. This enhanced growth was associated with a reduction in the Mn concentration of roots due to a greater AMF colonization at 21 days after planting. The protection granted by an enhanced AMF root colonization allowed a greater root nodule development, leading to more N acquisition and plant growth. The ERM can be developed in the soil by mycotrophic plants tolerant to the stressing agent and kept intact at the seeding of the crop to be protected by adopting appropriate tillage techniques.     

Shoot‐produced,light‐dependent factors are partially involved in the expression of the arbuscular mycorrhizal (AM) status of AM host and non‐host plants

Arbuscular mycorrhizal (AM) colonization and hyphal attachment to the roots of a host plant, bean, and a non‐host plant, lupin, were compared when grown either with light or in the dark with the AM fungus Glomus mosseae. When grown with light, bean roots were heavily colonized whereas lupin roots showed no signs of colonization, no formation of appressoria and only scarce hyphal attachment to the roots. In contrast to roots of plants grown with light, to living roots of beans and lupins grown in the dark many hyphae were attached and appressoria were formed. The role of shoot produced, light‐dependent factors in the expression of the AM mycotrophic status of AM host and non‐host plants is discussed.<?show $6#>     

Vermiculite in Some Japanese Soils

Since Gruner's pioneer work in 1934¹⁾, vermiculite has been attracting the attention of mineralogists and soil scientists with much interest, probably because of its unique behaviour on cation exchange and of a component common in most soils derived from various parent rocks. A number of papers thereafter dealt with the mineral, revealing its properties, diagenesis, and distribution in soils. However, as information has been accumulated on vermiculite, especially on clay vermiculite, it became evident that the difference between vermiculite and montmorillonite is due simply to the difference in layer charge and that the division is essentially an arbitrary one²⁾. Walker suggested that the Mg plus glycerol test would be the only one which appeared to be universaIlY valid in the identification of vermiculite, and that although the K test was still of value as an aid in the differentiation, it could no longer be reo commended as of universal validity. In recent years, several workers^4-12) indicated that interlayer materials, especially Al-hydroxyls, prevented vermiculite from contracting to 10 Å in the K test and prevented montmorillonite from expanding to 18 Å in the Mg-glycerol test. This suggests that in the light of new evidences the 14 Å mineral hitherto believed as vermiculite, chlorite, or montmorillonite by the classical test should be reexamined after removal of interlayer materials.     

Impact of arbuscular mycorrhizal fungi on the growth and expression of gene encoding stress protein – metallothionein BnMT2 in the non‐host crop Brassica napus L.

Arbuscular mycorrhizal (AM) fungi are an important component of the soil biota in most agroecosystems, and their association can directly or indirectly affect the diversity of soil microorganisms, nutrient cycling, and growth of host plants. Since not all crops are symbiotic, we hypothesized that the presence of AM fungi can: (1) inhibit the growth of non‐host plants by resulting in biotic stress, or (2) promote their growth indirectly by increased nutrient mobilization. These hypotheses were tested in the present study on the non‐mycorrhizal crop canola (Brassica napus L.) in the presence and absence of other autochthonous soil microorganisms. The soil was inoculated with a mixture of AM fungi (Acaulospora longula, Glomus geosporum, G. mosseae, Scutellospora calospora) and as a control, a non‐inoculated soil was used. The impact of inoculation on plant growth (biomass production, nutrient concentrations) and expression of the stress protein metallothionein gene BnMT2 was investigated in the shoots. B. napus L. did not form mycorrhizal associations on its roots, but its growth was promoted after inoculation with AM fungi. In the soil with autochthonic microorganisms, growth inhibition after inoculation was observed compared to the control. The concentrations of N, P, K, and S in the shoot were always significantly increased after inoculation with AM fungi. However, this was partly combined with reduced growth and thereby decreased total uptake of nutrients. Expression of BnMT2 in the leaves was increased after inoculation with AM spores at the soil devoid of indigenous microorganisms, but decreased in their presence. The expression of stress proteins (BnMT2) significantly increased with increasing length and biomass of shoots. In conclusion, the inhibition of the non‐host plant B. napus L. following inoculation with AM fungi was confirmed, however, only in combination with autochthonous microorganisms. Growth promotion of B. napus L. in the presence of AM fungi in the absence of autochthonous soil microorganisms suggest that plant growth depression in the presence of AM fungi was based on interactive effects of AM fungi with the autochthonous microorganisms in the soil rather than on a direct impact of the AM fungi.     

Genetic diversity for root-knot nematode resistance in white clover and related species

A total of 237 Plant Introduction in eleven Trifolium species were evaluated for resistance to Meloidogyne arenaria (Neal) Chitwood race 1, M. hapla Chitwood, M. incognita (Kofoid & White) Chitwood race 3, and M. javanica (Treub) Chitwood. Plants were infected with 1500 nematode eggs collected from 'Rutgers' tomato (Lycoperiscon esculentum Mill.) roots with 0.5% NaOCl. Ratings of galling severity and egg mass production were assigned to each plant 8 wk after inoculation. Host plant reaction was classified as immune, highly resistant, resistant, moderately resistant, intermediate, moderately susceptible, susceptible, and highly susceptible according to the resistance index . More than 95% of 171 white clover accessions were moderately to highly susceptible to all four nematodes species. The best white clover accessions were only moderately resistant to either M. arenaria (PI 291843 and PI 306286) or M. hapla (PI 100250 and PI 204930). Accessions with moderate resistance or resistance to root-knot nematodes were found among relatives of white clover, with T. ambiguum M. Bieb. exhibiting the greatest resistance level. Among the other Trifolium species evaluated, T. carolinianum Michx. PI 516273 was immune or highly resistant to all four nematode species while accessions of T. hirtum All. showed a wide range of reaction to root-knot nematodes. Identified germplasm of white clover relatives with resistance to root knot nematodes should be useful for the selection of parents in white clover breeding programs.