Effect of VA Mycorrhizal Inoculation on Growth of Asparagus Seedlings

Experiments on asparagus (Asparagus of)icinalis L.) inoculated with VA mycorrhizal fungi were conducted under two fluvo-aquatic phosphorus deficient soils. This study was to examine the growth response of VA mycorrhizae and fertilizer effects on the growth of mycorrhizal and non-mycorrhizal asparagus seedlings in pots and under field conditions. Inoculation with VA mycorrhizal fungi significantly increased mycorrhizal infection and enhanced seedling growth. In treatments of fertilization by different batches of NPK or by different amount of application it was shown that phosphorus was most favourable to VAM activity. Both the prevalance of mycorrhizal infection and the dry weight of seedlings in treatment with NPK in 1:0:1 was similar to that in 1:1:1 and 1:2:1 after inoculation. Further more the prevalance of infection, plant growth and P content in the treatment of 1/2 an amount of NPK in 1:1:1 were even higer than those in full amount of NPK and in non-fertilization. It is indicated that phosphorus uptake and plant growth benefit greatly by mycorrhizal inoculation. Mycorrhizal plant requires only about half as much phosphorus to achieve maximum growth as the uninoculated plants.     

Induction of fungal disease resistance in Vicia faba by dual inoculation with Rhizobium leguminosarum and vesicular-arbuscular mycorrhizal fungi

Infection of Vicia faba with Bothytis fabae causes significant decreases in growth vigour, total nitrogen content, number of nodules and nutrient accumulation. Na-uptake and phenolics concentration increased compared to that of noninfected plants. In contrast, dual inoculation of Rhizobium and VA mycorrhizae increased all above parameters suggesting a distinct improvement of the plants. The results also revealed that an inverse correlation may exist between phenolic, calcium, magnesium and zinc concentrations in mycorrhizal plant tissues grown in presence of rhizobial bacteria and the disease severity. From these findings we conclude a possible role of both VA mycorrhizal fungi and rhizobial bacteria in the decrease of susceptibility of plants. This revised version was published online in June 2006 with corrections to the Cover Date.     

Effects of introduced and indigenous VA mycorrhizal fungi on nodulation,growth and nutrition ofMedicago sativa in phosphate-fixing soils as affected by P fertilizers

Summary The legumeMedicago sativa was grown in two phosphate-fixing soils which received soluble or rock phosphate. The effects of the inoculation withGlomus mosseae on plant nutrition and nodulation were studied. The introduced VA fungi became successfully established and improved the degree of infection over level achieved by native endophytes. In all experimental conditions tested, plant dry weight, the total uptake of N and P and nodulation byRhizobium meliloti were increased by mycorrhizal inoculation. The size of the increase was inversely correlated with soluble P content in the soil. Mycorrhization, enhanced by introduction of suitable VA fungi, had similar effects to that of the dose of soluble phosphate tested. Indigenous and native endophytes cooperated in these effects. Results are discussed in terms of reducing the input of soluble P fertilizer to phosphate-fixing soils and the possibility of restoring the phosphate stock using a more rational supply of soluble P, that allows cooperation with VA fungi, or by the use of less soluble and expensive forms of P fertilizers.     

Acacias respond to additions of phosphorus and to inoculation with VA mycorrhizal fungi in soils stockpiled during mineral sand mining

Three pot experiments were conducted to test the hypothesis that the growth ofAcacia spp. in stockpiled soil from two mineral sand mines, could be increased by the addition of phosphorus (P) or inoculation with VA mycorrhizal fungi. In soils from North Stradbroke Island, the dry weight of shoots ofAcacia concurrens was increased by P and by VA mycorrhizal fungi in tailings sand, while in less adsorptive topsoil dry weight was only increased at low levels of applied P. WhenA. concurrens was grown in a layer of topsoil placed over tailings sand, shoot dry weight increased, in response to inoculation with VA mycorrhizal fungi banded between the soil layers.In topsoil from Eneabba, the dry weight of shoots at low rates of applied P was increased by up to 4 times by inoculation with VA mycorrhizal fungi. The response to inoculation in both experiments was due to increases in the uptake of P by the plants.Species of VA mycorrhizal fungi differed in their ability to increase plant growth. However, in soils from both sites, the same fungal species were effective.     

Response of cowpea (Vigna unguiculata) to inoculation with VA-mycorrhizal fungi and to rock phosphate fertilization in some unsterilized Nigerian soils

Summary The effects on cowpea of inoculation with vesicular-arbuscular (VA) mycorrhizal fungi and rock phosphate (RP) fertilization were studied in pots using Alagba and Araromi series soils and in the field on Alagba, Apomu and Egbeda series soils. Inoculation of the plants with VA-mycorrhizal fungi caused very rapid infection of the roots. A higher per cent mycorrhizal infection was maintained during subsequent plant growth in the field. RP application reduced the degree of infection without affecting plant growth in the field and in pot experiments. Nodulation, nitrogen fixation and utilization of RP were increased by inoculation with mycorrhizal fungi in the pot experiments but not in the field experiments. In the pot experiments, inoculated plants supplied with RP flowered earlier, and took up more phosphorus than either inoculated plants without RP or uninoculated plants. The largest response to inoculation in terms of shoot dry matter, nodule yield and nitrogen content of shoots was obtained in Alagba soil under both pot and field conditions.IITA Journal Series Paper No. 136.     

Dual inoculation with VA mycorrhiza and Rhizobium is beneficial to Leucaena

Summary Response ofLeucanea leucocephala to inoculation withGlomus fasciculatum and/or Rhizobium was studied in a phosphorus deficient unsterile soil.G. fasciculatum only inoculation improved nodulation by native rhizobia and Rhizobium only treatment improved colonization of roots by native mycorrhizal fungi. Dual inoculation with both the organisms improved nodulation, mycorrhizal colonization, dry weight, nitrogen and phosphorus content of the plants compared to single inoculation with either organism. Contribution of U.A.S. Research Project DR/AMB-1.     

Practical aspects of mycorrhizal technology in some tropical crops and pastures

Summary Greenhouse and field experiments were conducted on the effect of VA mycorrhiza (VAM) on the growth of cassava, various tropical grass and legume species, as well as beans, coffee and tea. A large number of VAM fungal species were evaluated for effectivity in increasing cassava growth and P uptake in acid low-P soils. The effectivity of VAM species and isolates was highly variable and dependent on soil pH and fertilizer applications, as well as on soil temperature and humidity. Two species,Glomus manihotis andEntrophospora colombiana were found to be most effective for a range of crops and pastures, at low pH and at a wide range of N, P, and K levels. At very low P levels nearly all crops and pasture species were highly mycorrhizal dependent, but at higher soil P levels cassava and several pasture legumes were more dependent than grass species. Mycorrhizal inoculation significantly increased cassava and bean yields in those soils with low or ineffective indigenous mycorrhizal populations. In these soils cassava root yields increased on the average 20–25% by VAM inoculation, both at the experiment station and in farmers’ fields. VAM inoculation of various pasture legumes and grasses, in combination with rock phosphate applications, increased their early growth and establishment. Agronomic practices such as fertilization, crop rotations, intercropping and pesticide applications were found to affect both the total VAM population as well as its species composition. While there is no doubt about the importance of VA mycorrhiza in enhancing P uptake and growth of many tropical crops and pastures grown on low-P soils, much more research is required to elucidate the complicated soil-plant-VAM interactions and to increase yields through improved mycorrhizal efficiency.     

Effects of mycorrhizae and chitin-hydrolysing microbes on Vicia faba

The effect of Streptomyces albovinaceus (S-22) and Bacillus sp. (B1) on the growth response, nodulation, nutrition and nitrogenase activities of faba bean (Vicia faba) varieties infected with Glomus mosseae under pot conditions in sterile soil amended with chitin was studied. The growth, nodulation, nutrients content and nitrogenase activity of mycorrhiza-treated plants of Giza-667 were significantly increased compared to untreated ones. Such increases were related to the increase in mycorrhizal root infection. Amendment of soil with chitin alone reduced the growth, nodulation, total nitrogen contents and nitrogenase activities of mycorrhiza-treated faba bean plants (Giza-667) compared to untreated plants. Inoculation of plants with S. albovinaceus or Bacillus sp. significantly increased the level of mycorrhizal roots infection, but addition of chitin to the soil in combination with Bacillus sp. reduced the mycorrhizal infection of faba bean roots. Highest phosphorus contents of faba bean Giza-667 were recorded after G. mosseae inoculation in the presence of all treatments. Similar results were observed for the other varieties. The microbial populations were significantly increased in rhizospheres amended with chitin. Such increases were not in response to the mycorrhizal inoculation. Generally, the microflora of faba bean rhizospheres was increased after treatment with G. mosseae in the absence of chitin amendment alone compared with non-mycorrhizal rhizospheres.     

Increase in the Formation and Nitrogen Fixation of Soybean Nodules by Vesicular-Arbuscular Mycorrhiza

Symbiotic interactions of the tripartite association of soybeanplant, vesiculararbuscular (VA) mycorrhizal fungus and Rhizobiumjaponicum were shown. Mycorrhizal plants absorbed more P, Ca and Mg and had higherP, Ca and Mg contents in their stems or leaves than non-mycorrhizalplants. Phosphorus concentration was also higher in the nodulesof mycorrhizal plants. VA mycorrhizae increased nodule number, nodule weight and acetylenereduction activity of nodules. Concomitantly seed productionand N content of leaves were enhanced. Both nodulating (A62-1) and non-nodulating (A62-2) cultivarsof soybean plants [Glycine max (L.) Merr.] were colonized byVA mycorrhizal fungi, identified as belonging to the genus Glomus. (Received August 12, 1985; Accepted January 14, 1986)     

Combined inoculation with Glomus intraradices and Rhizobium tropici CIAT899 increases phosphorus use efficiency for symbiotic nitrogen fixation in common bean (Phaseolus vulgaris L.)

This study compared the response of common bean (Phaseolus vulgaris L.) to arbuscular mycorrhizal fungi (AMF) and rhizobia strain inoculation. Two common bean genotypes i.e. CocoT and Flamingo varying in their effectiveness for nitrogen fixation were inoculated with Glomus intraradices and Rhizobium tropici CIAT899, and grown for 50 days in soil–sand substrate in glasshouse conditions. Inoculation of common bean plants with the AM fungi resulted in a significant increase in nodulation compared to plants without inoculation. The combined inoculation of AM fungi and rhizobia significantly increased various plant growth parameters compared to simple inoculated plants. In addition, the combined inoculation of AM fungi and rhizobia resulted in significantly higher nitrogen and phosphorus accumulation in the shoots of common bean plants and improved phosphorus use efficiency compared with their controls, which were not dually inoculated. It is concluded that inoculation with rhizobia and arbuscular mycorrhizal fungi could improve the efficiency in phosphorus use for symbiotic nitrogen fixation especially under phosphorus deficiency.     

Functional activity of VA-mycorrhiza (Glomus mosseae) in the growth and productivity of soybean plants grown in sterilized soil

A greenhouse experiment was conducted to study the response of soybean (Glycine max) to inoculation with the vesicular-arbuscular mycorrhizal fungusGlomus mosseae at flowering and maturity stages of plant growth. Fungal succinate dehydrogenase and alkaline phosphatase activities as enzyme markers were also studied to detect the physiological activity of the VA-mycorrhiza. At the two stages of soybean plant growth, fresh and dry biomass, P and N contents and number of nodules were significantly higher in mycorrhizal plants than that of uninoculated control. However, at the flowering stage, the response of soybean to mycorrhizal infection was higher than that of the maturity stage. VA-mycorrhiza inoculation significantly increased the number and dry matter yield of pods compared to non-mycorrhizal plants. The level of total mycorrhizal infection was not generally related to plant growth and phosphorus content. Fungal alkaline phosphatase staining and, to a lesser extent, succinate dehydrogenase activity showed a relationship between the activity of these enzyme and mycorrhizal growth responses.     

Nitrogen fixation in several grain legume species with contrasting sensitivities to copper nutrition

The nitrogen fixation response to copper nutrition in faba bean, yellow lupin and soybean was studied. Copper nutrition significantly increased the pod yields of all tested grain legumes but faba bean gave the greatest Cu-use efficiency for pod and grain production. The accumulation of dry matter in vegetative parts, nodules, N and leghemoglobin concentration in nodules and nitrogen accumulation in the whole plants were increased by copper supply in faba bean and yellow lupin in contrast with soybean. Cu nutrition significantly increased the Cu concentrations in nodules of all cultivated plants. The differential sensitivity of N₂ fixation in tested grain legume species to copper nutrition could be connected with the level of phenols in nodules and depended on both the host plants and strains of rhizobia, which differ in their ability to produce catechol-like siderophores. Copper requirements by symbiotic N₂ fixation could also depend on the nature of phenols in nodules (presence of o-dihydroxyphenols or number of hydroxyls in molecule).     

Effect of vesicular-arbuscular mycorrhizae on the growth and yield of rice-stubble cultured soybeans

Summary Inoculation with vesicular-arbuscular (VA) mycorrhizal fungiGlomus fasciculatus, G. mosseae, G. etunicatus orAcaulospora scrobiculatus, increased plant dry weight and seed yields of pot-grown soybean plants in sterilized soil. Inoculation with a mixture ofG. fasciculatus, G. mosseae andG. etunicatus, orG. fasciculatus alone, increased seed yields and other agronomic traits of soybean plants grown in a no-tillage, rice-stubble field.     

The Development of Desiccation-tolerance and Maximum Seed Quality During Seed Maturation in Six Grain Legumes

‘Physiological maturity’, i.e. the time when seedsreach their maximum dry weight during development, occurredwhen maturation drying on the parent plant in the field hadreduced seed moisture content to approximately 60 per cent infaba bean (Vicia faba L.), lentil (Lens culinaris Medic.), chickpea(Cicer arietinum L.), white lupin (Lupinus albus L.), soya bean(Glycine max [L.] Merr.) and pea (Pisum sativum L.) The onsetof desiccation-tolerance, i.e. the ability of seeds to germinatefollowing harvest and rapid artificial drying, coincided withphysiological maturity, except in pea where it occurred a littleearlier at about 70 per cent moisture content. Maximum seedquality as determined by maximum viability, minimum seedlingabnormalities and maximum seedling size occurred in pea, chickpeaand lupin when seeds were harvested for rapid drying at physiologicalmaturity; but for maximum seed quality in the other speciesmaturation drying had to proceed further - to about 45 per centmoisture content in soya bean and to about 30 per cent moisturecontent in lentil and faba bean seed crops. Much of this variationamongst the six species, however, was due to differences inthe variation in maturity within each seed crop. Results forindividual pods showed that peak maturity, i.e. maximum seedquality following harvest and rapid artificial drying, was achievedin all six species once maturation drying had reduced the moisturecontent of the seeds to 45–50 per cent. In pea, faba beanand soya bean there was a substantial decline in viability andan increase in seedling abnormalities when harvest was delayedbeyond the optimal moisture content for harvest.     

The role of rock-phosphate-solubilizing fungi and vesicular–arbusular-mycorrhiza (VAM) in growth of wheat plants fertilized with rock phosphate

A total of 36 fungal species isolated from soil were tested for their ability to solubilize rock phosphate (RP) in agar plates. Most of these fungi were non-rock phosphate solubilizers, but two isolates, Aspergillus niger and Penicillium citrinum, had high activity. Liquid culture experiments revealed that both fungi caused a remarkable drop in pH of culture media and solubilized considerable amounts of phosphate. The effects on wheat of inoculation with vesicular–arbuscular mycorrhizal fungi and rock-phosphate-solubilizing fungi and fertilization with rock phosphate were studied in sterilized pot soils, nonsterilized pot trials and in field plot soils. Rock phosphate fertilization and inoculation with Glomus constrictum and rock-phosphate-solubilizing fungi (A. niger and P. citrinum) significantly increased dry matter yield of wheat plants under all experimental conditions. However, the effect was more evident in non- sterilized pot soils and in the field than in sterilized pots. Rock phosphate had no significant effect on the total phosphorus content of plants grown under pot conditions but it was significantly increased in field plots; the effect of inoculation with fungi (G. constrictum, A. niger and P. citrinum) on plant phosphorus was closely related to this in dry matter production. The greatest positive effect on growth and phosphorus contents of wheat plants was recorded in the treatments that received rock phosphate and were inoculated with a mixed inoculum of the three microorganisms used, followed by dual inoculation treatments of G. constrictum plus either A. niger or P. citrinum.     

Recent changes to the classification of symbiotic,nitrogen-fixing,legume-associating bacteria: a review

The Rhizobia are collectively comprised of gram negative soil bacteria that have the ability to form symbiotic nitrogen-fixing root and/or stem nodules in association with leguminous plants. The taxonomy of these bacteria is continually in a state of flux, in large part due to rapid development of refined molecular biology techniques. The isolation and characterization of new, and often different, legumes-nodulating bacteria on a variety of plant hosts has resulted in the naming of many new rhizobial species. Here we update the taxonomy of the legume-nodulating bacteria and describe newly identified rhizobia capable of nodulating edible legumes and legume trees. In 1990, there was only one bacterial species that was known to nodulate common bean worldwide (Rhizobium leguminosarum sv. phaseoli), one species that nodulated faba bean (Rhizobium leguminosarum sv. viciae), and two species that nodulated soybean (Bradyrhizobium japonicum and Rhizobium fredii). Today, nearly 14, 11, 6, 5, 5, 4, 3 and 2 species have been defined that are capable of nodulating common bean, soybean, cowpea, chickpea, peanut, lentils, faba bean and pea, respectively. The recent use of whole genome based taxonomy (genomotaxonomy) will surely change how we define this important group of bacteria. The identification of several rhizobial species that are able to nodulate and fix nitrogen with edible legumes may enhance the production of these crops and can compensate for worldwide deficiencies in human nutritional needs in the future.     

The role of rock-phosphate-solubilizing fungi and vesicular–arbusular-mycorrhiza (VAM) in growth of wheat plants fertilized with rock phosphate

A total of 36 fungal species isolated from soil were tested for their ability to solubilize rock phosphate (RP) in agar plates. Most of these fungi were non-rock phosphate solubilizers, but two isolates, Aspergillus niger and Penicillium citrinum, had high activity. Liquid culture experiments revealed that both fungi caused a remarkable drop in pH of culture media and solubilized considerable amounts of phosphate. The effects on wheat of inoculation with vesicular–arbuscular mycorrhizal fungi and rock-phosphate-solubilizing fungi and fertilization with rock phosphate were studied in sterilized pot soils, nonsterilized pot trials and in field plot soils. Rock phosphate fertilization and inoculation with Glomus constrictum and rock-phosphate-solubilizing fungi (A. niger and P. citrinum) significantly increased dry matter yield of wheat plants under all experimental conditions. However, the effect was more evident in non- sterilized pot soils and in the field than in sterilized pots. Rock phosphate had no significant effect on the total phosphorus content of plants grown under pot conditions but it was significantly increased in field plots; the effect of inoculation with fungi (G. constrictum, A. niger and P. citrinum) on plant phosphorus was closely related to this in dry matter production. The greatest positive effect on growth and phosphorus contents of wheat plants was recorded in the treatments that received rock phosphate and were inoculated with a mixed inoculum of the three microorganisms used, followed by dual inoculation treatments of G. constrictum plus either A. niger or P. citrinum.     

Growth and nutrition of mycorrhizal guayule plants*

Synthesis of mycorrhiza in guayule plants was achieved by inoculation of 8-day-old seedlings with hyphae and chlamydospores of an undescribed Glomus species. There was a five-fold increase in total dry weight of 30-day-old mycorrhizal- compared to nonmycorrhizal-guayule grown in sterile loamy-sand without additional fertiliser. Thirty-day-old, inoculated- and uninoculated-seedlings were transplanted to sterile or unsterile soil and grown an additional 60 days. The greatest total dry weight of guayule was attained by inoculated transplants grown in sterile soil. Inoculated transplants increased two- to three-fold in total dry weight compared to uninoculated transplants, both grown in unsterile soil. After 90 days, uninoculated plants grown in unsterile soil had formed mycorrhizae with resident vesicular-arbuscular mycorrhizal fungi to the same extent as inoculated-plants grown in unsterile soil. Total mineral uptake increased in inoculated guayule, irrespective of soil treatment or the presence of resident VA mycorrhizal fungi.     

Impact of phosphate-solubilizing fungi on the yield and phosphorus-uptake by wheat and faba bean plants

Three fungal isolates (phosphate-dissolvers), Aspergillus niger, A. fumigatus and Penicillium pinophilum were isolated from the rhizosphere of different plants grown in Ismailia and South Sinai Governorates. They effectively solubilized rock phosphate or tricalcium phosphate in Pikovskaya's liquid medium. In pot and column experiments, they significantly reduced pH and increased available phosphorus in the soil treated with either rock phosphate or superphosphate. The yield components of wheat and faba bean plants increased as a result of soil inoculation with the isolated fungi. Penicillium pinophilum was the most efficient isolate. It increased the yield of wheat grains by 28.9 and 32.8% in the soil treated with rock phosphate and superphosphate, respectively. Similarly, it increased the production of faba bean seeds by 14.7 and 29.4% with the same treatments. The uptake of phosphorus by both crops significantly increased due to inoculation of the soil with the tested fungi.     

Integrated use of plant residues,phosphorus and beneficial microbes improve hybrid maize productivity in semiarid climates

Phosphorus unavailability and lack of organic matter in calcareous soils under semiarid climates are the major reasons for low crop productivity. A field experiment was conducted at The Agronomy Research Farm of The University of Agriculture Peshawar (semiarid climate), during summer 2015. The objective of the research was to investigate the effect of plant residues, organic and inorganic phosphorus management on improving yield and yield components of hybrid maize (CS-200) with (+) and without (?) phosphate solubilizing bacteria. The experiment was laid out in randomized complete block design with split plot arrangement, using three replications. A combination of plant residues and phosphorus sources were used as mainplot factor, and phosphate solubilizing bacteria were used as a subplot factor. The results revealed that plant residues, phosphorus sources and phosphate solubilizing bacteria significantly affected all parameters under study except number of plants at harvest. Application of legume residues (Faba bean) increased ear length (22.9 cm), grains row^?1 (46) and ear^?1 (419), 1000 grains weight (365 g), grain yield (6175 kg ha^?1) and shelling percentage (83) as compared to paper mulberry and garlic residues. Phosphorus application at the higher rate of 120 kg ha^?1 from inorganic source (single super phosphate) was superior in terms of higher ear length (24.4 cm), number of grains row^?1 (48) and ear^?1 (455), 1000 grains weight (380 g), grain yield (6558 kg ha^?1), harvest index (42.7%) and shelling percentage (83%) than the lower rate of phosphorus (60 kg P ha^?1). Inoculation of maize seeds with beneficial microbes (phosphate solubilizing bacteria) significantly increased ear length (22.9 cm), number of grains row^?1 (45) and ear^?1 (413), 1000 grains weight (364 g), grain yield (6237 kg ha^?1), harvest index (41.8%) and shelling percentage (82) than without seed inoculation. On the basis of our results from this study, we concluded that application of faba bean residues, 120 kg P ha^?1 as single super phosphate along with seed inoculation with phosphate solubilizing bacteria could improve yield and yield components of hybrid maize under semiarid climates.