AMF Root Colonization Research Articles

Short-term temporal variation in sporulation dynamics of arbuscular mycorrhizal (AM) fungi and physico-chemical edaphic properties of wheat rhizosphere

In this study, we investigated the pattern of short-term temporal variation in the arbuscular mycorrhizal (AM) fungi and physico-chemical edaphic properties of some wheat growing areas of the Bundelkhand region, Central India. Rhizospheric soil samples were collected every month from December 2007 to May 2008 from four wheat growing sites around Jhansi (Bundelkhand region). AM fungal root colonization, sporulation and physico-chemical edaphic properties during this period were determined and compared to evaluate the dynamics of response of wheat towards the AMF along crop maturation. Maximum AMF root colonization recorded was 54.3% indicating that AMF, particularly in low phosphorus (P) soils, can be important even in case of less responsive crop like wheat. In the two out of four sites studied, the AMF spore density increased with the increase in soil temperature. Absence of this type of pattern in remaining two sites indicated that site-specific environmental and agricultural conditions may affect the degree of wheat response to AMF. It also suggested that AMF communities inhabiting agroecosystems may exhibit considerable temporal sporulation patterns. The maximum AMF colonization was observed during February–March 2008, whereas maximum AMF sporulation was noticed during March–April 2008. Statistically significant negative correlation of AMF spore density with pH, organic carbon (OC) and available P was observed in the one of the sites studied. Overall assessment of the data indicated that season and location significantly affected the interaction of AM fungi with winter wheat necessitating the further need to understand the ecology of AMF populations with reference to specific host species under different micro-climatic conditions of Bundelkhand region.

Recommendation of Phosphate and Potassium Fertilizers for Maize at Five Locations in Lampung

Existing of vesicular arbuscular mycorrhizal fungi were investigated in continuously cropped, conventional agro ecosystems which had received annual long-term (4 years) amendments of either manure or inorganic fertilizer. The systems had an identical 4–year crops rotation and differed essentially only in the amount and type of fertilizer supplied. Experiment was setup at Taman Bogo, in the vicinity of Probolinggo, East Lampung. The eight farming systems differed mainly in fertilization application. The organic systems were fertilized exclusively with chicken manure (CK), and green manure Glyricidium sp. (GM) 20 Mg ha -1 . One conventional system was fertilized with the inorganic fertilizers (IF) (urea 300 kg ha -1 , SP 36 200 kg ha -1 , and KCl 100 kg ha -1 ). Four proportion combination fertilized organic and inorganic fertilizers i.e combination of 50% CK + 50% IF, 50% GM + 50% IF, 75% CK + 25% IF, and 75% GM + 25% IF. Application of chicken manure both exclusively or combination with inorganic fertilizer gave the higher AMF spore number and root colonization than others treatment. The dominant species of AMF at all treatment was Glomus constrictum .

Existing of Vesicular Arbuscular Mycorrhizal on The Corn Field Subjected by Long-term Organic and Inorganic Fertilizers

Existing of vesicular arbuscular mycorrhizal fungi were investigated in continuously cropped, conventional agro ecosystems which had received annual long-term (4 years) amendments of either manure or inorganic fertilizer. The systems had an identical 4–year crops rotation and differed essentially only in the amount and type of fertilizer supplied. Experiment was setup at Taman Bogo, in the vicinity of Probolinggo, East Lampung. The eight farming systems differed mainly in fertilization application. The organic systems were fertilized exclusively with chicken manure (CK), and green manure Glyricidium sp. (GM) 20 Mg ha-1. One conventional system was fertilized with the inorganic fertilizers (IF) (urea 300 kg ha-1, SP 36 200 kg ha-1, and KCl 100 kg ha-1). Four proportion combination fertilized organic and inorganic fertilizers i.e combination of 50% CK + 50% IF, 50% GM + 50% IF, 75% CK + 25% IF, and 75% GM + 25% IF. Application of chicken manure both exclusively or combination with inorganic fertilizer gave the higher AMF spore number and root colonization than others treatment. The dominant species of AMF at all treatment was Glomus constrictum.

Topographic position modulates the mycorrhizal response of oak trees to interannual rainfall variability

California coast live oak (Quercus agrifolia) forms tripartite symbiotic associations with arbuscular (AMF) and ectomycorrhizal (EMF) fungi. We selected oak individuals differing in topographic position and depth to groundwater (mesic valley vs. xeric hill sites) to investigate changes of tree mycorrhizal status in response to interannual rainfall variability. EMF root colonization, as well as hyphal abundance and viability in upper rhizosphere soil (0-30 cm), were negatively affected by severe multi-year drought, although not to the same extent in each topographic location. Oak trees growing in hill sites showed EMF colonization levels <1% in upper roots during drought. By contrast, oaks in valley sites maintained much higher EMF colonization (>19%) in upper roots during drought. EMF root colonization increased sharply at both topographic positions during the ensuing wet year (78% in valley, 49% in hill), which indicates that the mycorrhizal status of roots in upper rhizosphere soil is highly responsive to interannual rainfall variability. Across sites and years, percentage EMF colonization and soil hyphal density and viability were strongly positively correlated with soil moisture potential, but percentage AMF root colonization was not. Interestingly, changes in percentage EMF root colonization and density of viable hyphae between a wet and a dry year were proportionally much greater in xeric hill sites than in mesic valley sites. The mycorrhizal status of oak trees was particularly responsive to changes in soil moisture at the hill sites, where roots in upper rhizosphere soil shifted from almost exclusively AMF during severe drought to predominantly EMF during the ensuing wet year. By contrast, the mycorrhizal status of oaks in the valley sites was less strongly coupled to current meteorological conditions, as roots in upper soil layers remained predominantly EMF during both a dry and a wet year. Canopy shading and hydraulic lift by oaks in valley sites likely contributed to maintain the integrity and viability of EMF roots and extraradical hyphae in upper rhizosphere soil during extended drought. Our results suggest that oak woodlands in water-limited ecosystems may become increasingly reliant on the AMF symbiosis under future climate change scenarios for the U.S. southwest and other world regions.

The effects of agricultural practices on arbuscular mycorrhizal fungi

Abstract Arbuscular mycorrhizal fungi (AMF) form symbiotic associations with the majority of land plants, including many important agricultural crops. These fungi facilitate plant nutrient uptake, promote soil aggregation and use a significant portion of reduced carbon from the plants. AMF functional traits differ considerably among and within species, meaning that functional properties of a mycorrhizal community depend on its composition. Here we review studies exploring the effects of agricultural practices such as tillage, crop rotation, fertilization, pesticide application, irrigation and grazing on AMF communities. Although it is difficult to generalize the results of studies performed under different soil and climatic conditions, some universal patterns emerge. For example, soil tillage reduces the abundance of Scutellospora spp.; phosphorus fertilization lowers the extent of AMF root colonization; and diversification of crops results in more diverse AMF communities. We now need to design simple and reliable field tests for quantifying the effects of AMF communities on crop growth, yields and sustainability of the agro-ecosystems.

Responsiveness of certain agronomic weed species to arbuscular mycorrhizal fungi

AbstractArbuscular mycorrhizal fungi (AMF) are plant root symbionts that provide many benefits to crop production and agro-ecosystem function; therefore, management of AMF is increasingly seen as important to ecological farming. Agronomic weeds that form a symbiotic relationship with AMF can increase diversity and abundance of agronomically beneficial AMF taxa. Also, AMF can strongly affect plant community composition, and may thus provide some degree of biological control for weeds. Therefore, relationships between weeds and AMF have a dual significance in ecological farming, but are relatively unexamined. In glasshouse experiments, seedlings of 14 agronomic weed species were grown in the presence or absence of AMF inocula sampled from each of three types of cropping systems: organic, transitional-organic or high-input/conventional. For each weed species, AMF root colonization rates and growth responses to AMF were assessed. On the basis of observed colonization levels, the species were classified as strong hosts (five species), weak hosts (three) and non-host species (six). Among species, biomass responses to AMF were highly variable. Strong hosts showed more positive responses to AMF than weak hosts, although the range of responses was great. Non-hosts did not suffer consistent negative biomass responses to AMF, although strong biomass reductions were noted for certain species–inoculum combinations. Biomass responses to inocula from different cropping systems varied significantly among weed species in one of two experiments. Results suggest that weed–AMF interactions can affect weed community dynamics. We recommend investigation of these interactions in agro-ecosystems that use management methods likely to intensify weed–AMF interactions, such as conservation tillage and cover cropping.