Soil Mycorrhiza Research Articles

Attempt of Costus arbuscular mycorrhizal inoculants association with leguminous foliage whey on chlorophyll of sunflower (Helianthus annus L.) plants

Reporters founded that mycorrhizal association in plant kingdom improves the plant growth. The present attempt has been on the use of Mycorrhiza for Helianthus growth in stress condition of the adverse red soil of konkan region, India and other climatic factors. Earlier reporters for the purpose to avoid chemical fertilisers, founded that Deproteinised juice (DPJ) or foliage whey induces appropriate plant growth and enhance soil fertility. During present investigation, mycorrhiza from Costus sp application to soil of potted sunflower plants influence was compared with organic DPJ addition obtained from fenugreek foliage during the process of green crop fractionation (GCF) technique. This whey is randomly disposed during this technology of leaf protein preparation, so appropriate use of it is advised. Whether the mycorrhiza and DPJ combination treatment were feasible for seed germination and the seedling growth of the Helianthus plant, it was analysed and compared with control. Studies were experimented on the effect of mycorrhiza treated alone and DPJ treated alone whether improves the plant growth. DPJ if added with mycorrhiza in soil, showed significant rate of germination. In earlier research, it was elucidated that the DPJ contains phytohormones auxins, gibberellins and cytokinins in unknown quantity which boosts the plant growth comparative to mycorrhizal influence. The chlorophyll content of the DPJ treated plants enhanced as compared with control while the content showed no significant difference with mycorrhiza.

Sour Orange (Citrus Aurantium L.) Growth is Strongly Mycorrhizal Dependent in Terms of Phosphorus (P) Nutrition Rather than Zinc (Zn)

ABSTRACTThe partial sterilization of soil eliminates useful microorganisms, resulting in the reduced growth of mycorrhizae-dependent citrus plants, which are often unresponsive to the application of fertilizer. Research was conducted to test the hypothesis that indigenous mycorrhizae (IM) inoculation is as efficient as selected mycorrhizal inoculation under sterile and non-sterile soil conditions. Rhizophagus clarus and indigenous mycorrhiza spores, isolated from citrus orchards, were used as arbuscular mycorrhizae fungi under greenhouse conditions with sterile and non-sterile Çanakçi series (Typic xerofluvent) soils with low phosphorus (P) fertility. Different P (0 and 100 mg kg−1) and zinc (Zn) (0, 5 and 10 mg kg−1) concentrations were used at the start of the experiments. The shoot, root dry weight (RDW), root colonization, and P, Zn, iron (Fe), copper (Cu) and manganese (Mn) concentrations of the shoot were determined; mycorrhizae dependency (MD) was also calculated.The results indicate that R. clarus and indigenous mycorrhiza in sterile and non-sterile soil conditions considerably increased the growth of citrus plants. Owing to existing beneficial indigenous rhizosphere microorganisms, citrus plant growth without inoculation was better in non-sterile soils than in the sterile soils. In non-sterilized soil, the plant growth parameters of R. clarus-inoculated soils were higher than those of indigenous mycorrhiza-inoculated soils. Mycorrhizae infection increased certain citrus plant growth parameters, such as root infection, biomass and nutrient uptake (P, Zn, Fe, Mn and Cu). In sterile soil, the addition of up to 5 mg kg−1 soil Zn and the inoculation of R. clarus significantly increased plant growth; inoculation with indigenous mycorrhiza produced more dry weight upon the addition of up to 100 mg kg−1 phosphorus pentoxide (P2O5). Under sterile soil conditions, without considering fertilizer addition, MD was found to be higher than that of non-sterile soils. In general, the contribution of the indigenous soil spores is significant. However, indigenous soil mycorrhizae may need to be managed for better efficiency in increasing plant growth and nutrient uptake. The major finding was that the inoculation of citrus seedlings with mycorrhiza is necessary under both sterilized and non-sterilized soil conditions.

Fall cover cropping can increase arbuscular mycorrhizae in soils supporting intensive agricultural production

Intensive agricultural practices, such as tillage, monocropping, seasonal fallow periods, and inorganic nutrient application have been shown to reduce arbuscular mycorrrhizal fungi (AMF) populations and thus may reduce benefits frequently provided to crops by AMF, such as nutrient acquisition, disease resistance and drought tolerance. We have evaluated the ability of different cover crops to elevate the native mycorrhizal inoculum potential of soils under soil–climatic conditions typical of the upper Midwest U.S. production agricultural region. We measured the number of soil AMF propagules at three sites in the late fall following cover crops that were seeded into summer-harvested small grains within a no-till rotation. At all three sites, soil AMF propagule numbers were generally low (≤1propaguleg−1). Fall cover crops significantly increased the mycorrhizal inoculum potential of the soils. Forage oats (Avena sativa (L.) Hausskn.), by itself or in mixtures, was most effective at both sites where it was planted. At the third site, a cover crop mixture doubled the inoculum potential of these soils. The effect of cover crop treatments on AMF propagules was corroborated at one site over two seasons by measuring AMF biomass with the neutral lipid fatty acid mycorrhizal biomarker, C16:1cis11. Identification of AMF-promoting cover crops for inclusion in diversified, no till cropping rotations in the upper Midwest U.S. will provide opportunity for reduced inorganic nutrient application with economic and environmental benefit.

Plant‐Mycorrhizal Community Dynamics Associated with a Moisture Gradient within a Rehabilitated Prairie Fen

AbstractWetland ecosystems have ecological significance in areas such as natural waste purification and nutrient cycling. Much has been accomplished in determining the floristic and edaphic characteristics of wetlands, but little is known about key structure‐function relationships such as mycorrhizae. We collected descriptive data on the plant and mycorrhizal fungal community associated with a moisture gradient along a rehabilitated prairie fen to assist in ongoing restoration efforts (Zimmerman Prairie, Greene County, Ohio). Analysis of soil samples from the prairie fen indicated that significant levels of arbuscular mycorrhizal fungal infection occurred within both the prairie and fen plant species (infection level means ranging from 20% to 47%). Mycorrhizal root infection was significantly correlated with all edaphic factors tested—soil moisture, organic matter, potassium, phosphorus, calcium, magnesium and pH—from May to October 1994. The plant‐mycorrhizal data clearly indicate the presence of mycorrhizae in soils that are saturated or even inundated. The functional role of mycorrhizae in wetlands is still unclear, however. For example, is the species interaction we are observing truly mutualistic or of some other form due to environmental conditions? Arbuscular mycorrhizal fungal relationships in all classes of wetland ecosystems need to be studied further if we are to understand their potential role in the ecological restoration of wetland ecosystems.

Growth and extracellular phosphatase activity of arbuscular mycorrhizal hyphae as influenced by soil organic matter

Two experiments were set up to investigate the influence of soil organic matter on growth of arbuscular mycorrhizal (AM) hyphae and concurrent changes in soil inorganic P, organic P and phosphatase activity. A sandy loam soil was kept for 14 months under two regimes (outdoor where surplus precipitation leached through the soil, or indoor at constant moisture) with or without 9% (w/w) chopped wheat straw plus mineral N. Then the soils were partially sterilized and placed in two-compartment pots where mycorrhizal or non-mycorrhizal cucumber plants were grown in one root compartment (RC), and soils differing in organic matter were placed in six parallel hyphal compartments (HC) separated from the RC with a 37 μm mesh. In the first experiment, using Glomus caledonium, hyphal length densities were measured in the HC after 31 days. Added straw increased hyphal length densities by 34 and 62% for soil kept outdoors and indoors, respectively. In the second experiment, using G. invermaium and only soil kept outdoors, three treatments were included: soil with no added straw with or without a new addition of 0.5% (w/w) of ground clover leaves, and soil with 9% straw plus mineral N. After 41 days hyphal length density was twice as high in soil with added straw compared to the two other treatments. Mycorrhizal colonization resulted in lower activity of acid phosphatase in the HC for two out of three treatments. Alkaline phosphatase activity was only decreased by mycorrhiza in soil without organic matter additions. In soil with added clover alkaline phosphatase activity increased due to the presence of mycorrhizal hyphae. We suggest that mycorrhizas may influence the exudation of acid phosphatase by roots. Hyphae of G. invermaium did apparently not excrete extracellular phosphatases, but their presence may have influenced alkaline phosphatase excreted by other microorganisms, probably through competition for nutrients. Phosphatase activity was not correlated with the concentration of labile organic P in soil extracts.

Field bioassessments for selecting test systems to evaluate military training lands in tallgrass prairie. Ecosystem health. V

Ecosystem responses to physical or chemical stress may vary from changes in single organisms to alteration of the structure and function of the ecosystem. These responses to stress cannol be predicted exactly. Ecosystems repeatedly exposed to physical and/or chemical stress can be used to study the separate and combined environmental effects of stress. Such studies also allow the development of procedures to select test systems for the analysis of stress in ecosystems. A preliminary field survey of six military training sites at Fort Riley, Kansas, USA, was conducted to identify and verify ecological test systems for evaluating ecosystem responses to physical and/or chemical stress. Comparisons of these data with data collected concurrently from Konza Prairie Research Natural Area reference sites showed that soil microarthropods, some species of macroarthropods, small mammals, and native earthworm species were negatively affected by stress. In contrast, plant species diversity, plant foliage biomass, soil mycorrhizae, and many soil characteristics were within the boundaries of nominal variations observed on “pristine” Konza Prairie. Introduced European earthworms appeared to be positively affected by training activities. This study provided a test of systematic procedures to support impact analysis, ecological toxicology, and ecosystem risk assessments.