Specific Variations of Arbuscular Mycorrhizal (AM) Fungi in Potential Timber Yielding Tree Species From the Western Ghat Region of Goa,India

Studies were carried out on the arbuscular mycorrhizal (AM) fungal association in four potential timber yielding tree species from four forest areas of the Western Ghat region of Goa, India. The edaphic factors selected for the study varied within the four study sites. Significant positive and negative correlations were exhibited between spore density and root colonization of AM fungi at two sites, Collem and Dharbandoda. The study recorded the presence of 21 AM fungal species belonging to three genera—viz., Acaulospora, Gigaspora, and Glomus. The present study suggests that there is a site specific variation in root colonization (except at Mollem) and spore density as well as edapho-specific variation in association, composition, and distribution of AM fungi associated with potential timber yielding trees from four forest areas in the Western Ghat region of Goa. Further investigations of AM fungal dynamics if carried out can help elucidate the ecological significance of AM fungal associations in the Western Ghat region of Goa. To add, learning more about the ecology and intricacies of the AM association is crucial for attaining a good understanding of its life cycle and functions in edapho-climatic conditions of the Western Ghat region of Goa to further use it in the management of reforestation practices.     

印度东北部黄兰种植区丛枝菌根真菌的侵染和分布(英文)

调查了印度东北部梅加拉亚邦(Meghalaya)3个黄兰种植区(Umdihar,Umsaw和Mawlein)内丛枝菌根真菌和暗隔真菌的侵染。分离和鉴定了丛枝菌根真菌孢子,根据不同黄兰种植区内菌根菌种分布和丰富度评价了菌根菌多样性和寄主选择性。结果表明,丛枝菌根真菌侵染显著高于暗隔真菌。丛枝菌根真菌和暗隔真菌的侵染分别是50.91%～58.95%和1.84%～4.11%。真菌孢子密度在三个种植区内变化较大(p0.05)。在所鉴定的7个属29个菌种中,球囊霉属菌种的丰富度最高。Sorenson系数在0.35-7.0之间。种植区内菌种丰富度在2.0～2.9之间。总的菌种丰富度与总的相对丰富度显著相关(p=0.001)。真菌分布、相对丰富度和主成分分析结果表明,大果球囊霉(Glomus macrocarpum)、Glomus multicaulic、缩不囊霉(G.constrictum)和无梗囊霉是黄兰最偏好的菌种,可能是由于寄主的营养获得和生长较为适当。图6表5参27。     

Arbuscular mycorrhizal associations in different forest tree species of Hazarikhil forest of Chittagong, Bangladesh

Biodiversity of arbuscular mycorrhizal (AM) colonization and AM fungal spores were studied in the roots and rhizosphere soils of Acacia catechu (L.f). Wild., A. mangium Willd, Anthocephala cadamba Miq., Artocarpus chaplasha Roxb., Chickrassia tabularis A. Juss., Swietenia macrophylla King., Tectona grandis L. from plantations; Albizia procera (Roxb.) Benth., A. falcataria L., Alstonia scholaris (L.) R. Br., Aphanamixis polystachya (Wall.) Parker., Hydnocarpus kurzii (King.) Warb., Heynea trijuga Roxb., Lagerstroemia speciosa (L.) Pers., Messua ferrea Linn., Podocarpus nerifolia Don., Swintonia floribunda Griff., Syzygium fruticosum (Roxb.) DC., S. grandis (Wt.) Wal. from forest and nursery seedlings of A. polystachya, A. chaplasha, Gmelina arborea Roxb. and S. cuminii (L.) Skeels from Hazarikhil forest, Chittagong of Bangladesh. Roots were stained in aniline blue and rhizosphere soils were assessed by wet sieving and decanting methods. The range of AM colonization varied significantly from 10%-73% in the plantations samples. Maximum colonization was observed in A. mangium (73%) and minimum colonization was observed in C. tabularis (10%). Vesicular colonization was recorded 15%-67% in five plantation tree species. The highest was in A. cadamba (67%) and the lowest was in T. grandis; A. chaplasha and C. tabularis showed no vesicular colonization. Arbuscular colonization was recorded 12%-60% in four plantation tree species. The highest was in A. mangium (60%) and the lowest was in A. cadamba. Roots of Artocarpus chaplasha, C. tabularis and T. grandis showed no arbuscular colonization. Among 12 forest tree species, nine tree species showed AM colonization. The highest was in A. falcataria (62%) and the lowest was in S. fruticosum (10%). Significant variation in vesicular colonization was recorded in seven forest tree species. The highest was in H. trijuga (52%) and the lowest was in L. speciosa (18%). Hydnocarpus kurzii, M. ferrea, P. nerifolia S. fruticosum and S. grandis showed no vesicular colonization. Arbuscular colonization was recorded in seven forest tree species. The highest was in A. falcataria (60%) and the lowest was in A. procera (10%). All the nursery seedlings showed AM colonization and the range was 10%-73%. Vesicules were recorded in G. arborea (40%) and S. cumini (40%). Arbuscular colonization was recorded in G. arborea (100%) and S. cumini (100%). Spore population was recorded 77-432/100 g dry soils, 80-276/100 g dry soils, and 75-153/100g dry soils in plantation, forest and nursery, respectively. Glomus and Acaulospora were dominant genera among the six AM fungi recorded. Significantly positive correlation was observed between AM colonization and AM fungal spore population in Hazarikhil plantation tree species, forest tree species and nursery tree seedlings. The present study showed the biodiversity of root colonization and AM fungi are active in nutrient cycling, survivals and seedling establishment of the plants in the Hazarikhil forest, plantation and nursery.     

孟加拉国Madhupur林区内不同森林树种中丛枝菌根多样性的研究

从 Madhupur 林区的不同地点采集了 Acacia auriculi-formis A. Cunn. ex Benth., A. mangium Wild., Artocarpus het-erophyllus Lamk. C., Dalbergia sissoo Roxb. ex A. P. D., Euca-lyptus camaldulensis Dehnn., Hevea brasiliensis (Wild. ex Juss) Muell. Arg., Swietenia macrophylla King. and Tectona grandis L. 8个树种的根和根际土。采用简单常规的根围土壤真菌孢子分离、形态鉴定和树木细根染色、显微镜观察等方法,进行了孟加拉国Madhupur林区内不同森林树种中丛枝菌根多样性的研究。图2表2参46。     

Biodiversity of arbuscular mycorrhizal fungi in different trees of madhupur forest, Bangladesh

Roots and rhizosphere soils of Acacia auriculiformis A. Cunn. ex Benth., A. mangium Wild., Artocarpus heterophyUus Lamk. C., Dalbergia sissoo Roxb. ex A. P. D., Eucalyptus camaldulensis Dehnn., Hevea brasiliensis （Wild. ex Juss） Muell. Arg., Swietenia macrophylla King. and Tectona grandis L. were collected from different locations of Madhupur forest area to study the biodiversity of Arbuscular Mycorrhizal （AM） fungal colonization and spore population. All the plants showed AM colonization. Out of eight selected plants, mycelial colonization was lowest in the roots of A. heterophyllus （22%） and the highest was in the roots of H. brasiliensis （78%）. Mycelial intensity was observed poor （25%-77%） and moderate （23%-57%） in all plants species and abundant （11%-40%） was in most of the plant species. Vesicular colonization was observed in five plant species. The lowest was recorded in E. camaldulensis （4%） and the highest was in H. brasiliensis （21%）. Poor （24%-56%）, moderate （16%-100%） and abundant （11%-40%） type of vesicular intensity were observed. Arbuscular colonization was observed in three plants. The highest was in A. mangium （72%） and the lowest was in S. macrophylla （17%）. Arbuscular intensity was recorded as poor （12%-44%）, moderate （22%-100%） and abundant （4%-47%）. The highest AM fungal spore population was in A. auriculiformis （714） and the lowest was in D. sissoo （102）. Five AM fungal genera were recorded. Glomus was found to be dominant. A few spores remained unidentified. Significant correlation was observed between percent coloniza- tion and spore population. The results of the present study indicate the occurrence of AM fungi and the mycotrophism of the plants of Madhupur forest area and the applicability of AM technology in the forest management of Madhupur forest.     

气候变暖对寒地果树的影响

为更好地指导寒地地区果树生产,并为科学引种提供理论依据,对气候变暖对河北省张北地区果树生长发育的影响进行了调查研究.结果表明,20世纪80年代前后,气候变暖对该地区苹果的生长发育影响显著.     

果树胚败育研究概述

胚败育是限制果树杂交育种工作的一个关键问题。本文从细胞学、矿质营养元素和激素角度对胚败育机理的研究进行了综述,并进一步阐述了胚培养、生长调节剂、矿质营养元素和授粉、受精条件在克服胚败育中的作用。     

Arbuscular mycorrhizas and performance of Polylepis australis trees in relation to livestock density

Polylepis australis trees endemic to Argentina dominate the canopy of subtropical high altitude forests. Here, livestock rearing is the main economic activity and is suspect of the low performance of P. australis trees through direct and indirect effects which could include the reduction in arbuscular mycorrhizal fungi (AMF) and their benefit to trees. To elucidate the role of AMF, we compare plant performance indicators, arbuscular mycorrhizal (AM) colonization and AMF communities in 20 trees distributed in two areas of central Argentina which differed in livestock grazing intensity. The area with high livestock density presented more soil degradation and trees with a lower overall plant performance than the area with reduced livestock density. The AM colonization values of P. australis were considerably higher than reported for other tree species and the area with high livestock density had a lower proportion of arbuscules and higher proportion of hyphae, while vesicles and AM colonization – all structure considered together – did not differ between areas. Overall AMF spore number and of most species when considered separately was significantly higher in the area with high livestock density, suggesting a high tolerance and adaptation of AMF to livestock. We conclude that a reduction in livestock improves the performance of P. australis, that this improvement could be mediated by an increase in the proportion of arbuscules, but there does not appear to be any limitation in AM colonization or AMF spore number which could otherwise be limiting forest restoration.     

呼伦贝尔退化草场土壤AM真菌多样性及与土壤因子的相关性分析

指出了草原是我国面积最大的陆地生态系统,约占陆地总面积的20%,在国家生态安全中有着重要的作用。但是由于近年来过量的放牧和毁草开荒等人为因素,使草原生态环境受到严重破坏,这严重影响了我国的社会经济发展。以内蒙古呼伦贝尔退化草原为研究对象,调查研究了不同退化程度草场的牧草根段AM真菌侵染率及多样性的变化,根据土壤因子分析引起这种变化的原因。研究结果显示:土壤含水量、土壤团聚体结构数量、总碳含量、土壤脲酶活性随草地退化程度的加深而显著下降,土壤pH值和EC值随草地退化程度的增加而显著升高,而土壤有效磷含量、土壤蔗糖酶活性和碱性磷酸酶活性则呈现出轻度退化>未退化>中度退化>重度退化的趋势。牧草根段AM真菌侵染率随退化程度加深而显著下降,并与土壤含水量、脲酶活性呈显著正相关,与土壤pH值、EC值呈显著负相关。从土壤样品DNA中扩增AM真菌特异性片段并采用DGGE技术对AM真菌多样性进行分析,发现AM真菌多样性指数、丰富度、均匀度变化均呈现轻度退化>未退化>中度退化>重度退化的趋势,且都与土壤有效磷、碱性磷酸酶活性呈显著正相关,与蔗糖酶活性呈极显著正相关。研究表明:人为干扰对草原土壤根际AM真菌群落有不同程度的影响,且于土壤因子之间存在一定的相关性。这些研究可为更好地理解草原退化原因及更有效地进行草原植被开发和修复提供可靠地理论依据。     

氮和生物炭添加对毛竹林AMF侵染率和孢子密度的影响

目的 探讨氮沉降和生物炭添加对毛竹林丛枝菌根真菌特征的影响,为全球变化背景下毛竹林的可持续经营提供科学参考。 方法 以毛竹林为研究对象,探讨了不同梯度的氮沉降（0、30、60和90 kg·hm−2·yr−1）和生物炭添加（0、20和40 t ·hm−2）及其复合作用对毛竹林AMF侵染率和孢子密度以及土壤理化性质的影响。 结果 与对照（0 kg·hm−2·yr−1 N + 0 t·hm−2 BC）相比,氮添加显著降低了AMF侵染率（16.1%～51.7%）。高生物炭添加（40 t·hm−2）显著降低了AMF侵染率（46.0%）,但提高了孢子密度（162.5%）。在氮添加处理下,生物炭添加提高了AMF侵染率,对孢子密度无显著影响。AMF侵染率与土壤pH呈显著正相关关系,与有效氮和有效磷呈显著负相关关系。AMF孢子密度与有效磷呈显著正相关关系。 结论 在氮添加处理下,生物炭添加提高了AMF侵染率,增强了毛竹与AMF的共生关系,表明在氮沉降背景下生物炭添加是实现毛竹林可持续经营的有效措施之一。     

苹果苦痘病与果实品质及矿质元素含量的相关性分析

为了探明苹果果实品质及果实中主要矿质元素含量与苦痘病发生的关系,从而为其生产施肥提供参考依据,测定了'长富2'苹果苦痘病不同发病等级果实的外观与内在品质指标及果实中主要矿质元素N、P、K、Ca的含量与比值,分析了其与苦痘病发生的相关性。测定结果表明:果实硬度、糖酸比、果形指数与苦痘病病级均呈显著负相关,其相关系数分别为-0.91、-0.93、-0.89;可溶性固形物、可滴定酸的含量与苦痘病病级均呈极显著正相关,其相关系数分别为0.96、0.97;单果质量、横径、总糖与苦痘病病级均呈显著正相关,其相关系数分别为0.92、0.92、0.90。果实中的Ca含量,苦痘病病果低于正常果;而果实中N、P、K的含量,苦痘病病果却高于正常果。苦痘病病级与果实中N、P的含量均呈显著正相关,而与Ca含量呈极显著负相关,与N/Ca、K/Ca、P/Ca之值均呈极显著正相关,而与K/P、N/P之值均呈显著负相关。分析结果表明:苦痘病的发生会影响苹果的单果质量、硬度、可溶性固形物、总糖、可滴定酸含量等果实品质指标;而且果实中较低的Ca含量和较高的N、P、K含量及较高的N/Ca、K/Ca、P/Ca之值、较低的K/P、N/P之值,都是导致或者加重苦痘病发生的主要因素。     

Effect of the arbuscular mycorrhizae <Emphasis Type="Italic">Glomus fasciculatum</Emphasis> and <Emphasis Type="Italic">G. macrocarpum</Emphasis> on the growth and nutrient content of <Emphasis Type="Italic">Cassia siamea</Emphasis> in a semi-arid Indian wasteland soil

The effect of two arbuscular mycorrhizal (AM) fungi, Glomus fasciculatum and G. macrocarpum on shoot and root dry weights and nutrient content of Cassia siamea in a semi-arid wasteland soil was evaluated. Under nursery conditions, mycorrhizal inoculation improved growth of seedlings. Root and shoot dry weights were higher in mycorrhizal than non-mycorrhizal plants. The concentration of P, K, Cu, Zn and Na was significantly higher in AM inoculated seedlings than in non-inoculated seedlings. Mycorrhization led to decrease in alkalinity of the rhizosphere soil from pH 8.5 to 7.4. Under nursery conditions, the degree of mycorrhizal dependency increased with age of C. siamea seedling. On transplantation to the field, the survival rate of mycorrhizal seedlings (75%–90%) was higher than that of non-mycorrhizal seedlings (40%). Besides better survival rate, AM inoculation improved the growth performance of seedlings in terms of height and stem diameter. Among the two AM fungi used, the efficiency of Glomus macrocarpum was higher than that of G. fasciculatum under both nursery and field conditions.This revised version was published online in May 2005 with corrected page numbers.     

Fine-root dynamics of coffee in association with two shade trees in Costa Rica

Fine-root dynamics (diameter < 2.0 mm) were studied on-farm in associations of Coffea arabica with Eucalyptus deglupta or Terminalia ivorensis and in a pseudo-chronosequence of C. arabica-E. deglupta associations (two, three, four and five years old). Coffee plants were submitted to two fertilisation types. Cores were taken in the 0–40 cm soil profile two years after out-planting and subsequently in the following year in depth layers 0–10 and 10–20 cm, during and at the end of the rainy season, and during the dry season. Fine root density of coffee and timber shade trees was greater in the coffee fertilisation strip as compared to unfertilised areas close to the plants or in the inter-rows. Coffee fine roots were more evenly distributed in the topsoil (0–20 cm) whereas tree fine roots were mostly found in the first 10 cm. Although the two tree species had approximately the same fine root length density, lower coffee / tree fine root length density ratios in T. ivorensis suggest that this shade tree is potentially a stronger competitor with coffee than E. deglupta. Coffee and tree fine root length density for 0–10 cm measured during the rainy season increased progressively from two to five-year-aged associations and coffee fine root length density increased relatively more than E. deglupta fine root length density in the four and five-year-aged plantations suggesting that contrary to expectations, coffee fine roots were displacing tree fine roots.     

Dual inoculation of a woody legume (Centrolobium tomentosum) with rhizobia and mycorrhizal fungi in south-eastern Brazil

The integration of N₂ fixing trees into stable agroforestry systems in the tropics is being tested due to their ability to produce high biomass N and P yields, when symbiotically associated with rhizobia and mycorrhizal fungi. The growth of Centrolobium tomentosum Guill. ex Benth, a native leguminous tree from the Brazilian Atlantic Forest, was assessed with dual inoculation of Rhizobium spp and mycorrhizal fungi under field conditions. Complete fertilization was compared to treatments of inoculation with selected rhizobia strains BHICB-Ab1 or BHICB-Ab3, associated or not to arbuscular mycorrhizal (AM) fungi. The dual inoculation increased the height and growth in relation to the plants treated with rhizobia alone. Plants inoculated with strain BHICB-Ab1 and arbuscular mycorrhizal fungi (AMF) exhibited an increase of 56% dry matter over uninoculated control and nitrogen accumulation was greater than with BHICB-Ab3 inoculated plants. Strain BHICB-Ab1 presented a synergetic relationship with mycorrhizal fungi since the combined inoculation with BHICB-Ab1 enhanced plant height and dry weight more than single inoculation while the growth of BHICB-Ab3 plants was not modified by AMF inoculation. Arbuscular mycorrhizal fungi enhanced plants survival and seemed to favour the nodule occupation by rhizobia strains as compared to the non-mycorrhizal plants. Inoculation with selected rhizobia and AMF improved the growth of C. tomentosum under field conditions. This revised version was published online in June 2006 with corrections to the Cover Date.     

Growth of Nursery-grown Bamboo Inoculated with Arbuscular Mycorrhizal Fungi and Plant Growth Promoting Rhizobacteria in two Tropical Soil Typeswith and without Fertilizer Application

A nursery experiment was conducted to assess the effect of bioinoculants (Glomus aggregatum, Bacillus polymixa, Azospirillum brasilense) on seedling growth promotion of bamboo (Dendrocalamus strictus (Roxb.) Nees.) in two soil types (alfisol, vertisol) with or without fertilizer application. Bamboo seedlings were grown in the presence or absence of bioinoculants either individually or in all combinations for 180 days in field soil under tropical nursery conditions. Shoot, rhizome and root length, dry masses, nutrient concentrations and arbuscular mycorrhizal (AM) colonized root lengths were determined at harvest. Under the experimental condition tested combined inoculation of AM fungi, PSB and A. brasilense resulted in maximum growth response both under fertilized and unfertilized conditions in both soil types. Fertilizer application enhanced the efficiencies of N, P and K uptake, whereas reduced their usage efficiencies. Though soil type did not affect microbial inoculation response, fertilizer application significantly affected plant response to microbial inoculation.