African Journal of
Plant Science

  • Abbreviation: Afr. J. Plant Sci.
  • Language: English
  • ISSN: 1996-0824
  • DOI: 10.5897/AJPS
  • Start Year: 2007
  • Published Articles: 798

Full Length Research Paper

Effect of native mycorrhizal fungi inoculants on the growth and phosphorus uptake of tree legumes: Erythryna brucei and Millettia ferruginea

Beyene Dobo
  • Beyene Dobo
  • School of Natural Resources Management and Environmental Sciences, Haramaya University, P. O. Box 138, Dire Dawa, Ethiopia.
  • Google Scholar

  •  Received: 07 November 2016
  •  Accepted: 02 February 2017
  •  Published: 31 October 2018


The inoculation study was conducted in the greenhouse to investigate the effect of phosphorus (P) concentrations on growth and arbuscular mycorrhizal fungi (AMF) colonization of multipurpose tree legumes Erythrina brucei and Millettia ferruginea. Plant growth parameters (shoot length, dry weight) and P uptake increased significantly after inoculations with AM fungi, Rhizophagus clarus, Rhizophagus intraradices and the mixed species. Results on effect of P application on total Mycorrhizal Dependency(MD) of studied tree species showed that maximum MD values were recorded for R. clarus (34.87%) in M. ferruginea and (26.19%) in E. brucei respectively. For the mixed species was recorded, the next highest MD values 26% in M. ferruginea and 16.67% in E. brucei. The least MD values were recorded for treatments with Rh. intraradices in both trees under study. The optimum P concentrations for maximum benefits from the AM symbiosis in aforementioned tree species varied from 0.005 to 0.02 mg g-1 and corresponding peaks of arbuscules, vesicles, percent root colonization, and spore count per 50 cm3 sand were noticed at similar concentrations. Thus, the results showed that the recorded plant growth peaks were due to AM colonization of the tree seedlings. Therefore, inoculating plants with a suitable AM inoculant could result in a benefit comparable to high P input and lead to a significant saving of inorganic P fertilizer.


Key words: Agroforestry, trees, root colonization, spore density.



Erythrina brucei (Schweinf) and Millettia ferruginea (Hochst) Baker from the family Fabacae (Leguminosae) are the most common shade trees in agroforestry systems of Gedeo and Sidama of Southern Ethiopia. In addition to Gedeo and Sidama, E. brucei grows  naturally in open places and along edges of upland forests or woodlands in Wello, Gojjam, Shewa, Bale and Hararge, and Keffa agroforestry systems at altitudes between 1400 and 2600 masl. It flowers from November up to January and at times of fruiting  most  of its leaves shed adding to the organic fertility of the soil.
M. ferruginea is also one of the most valuable multipurpose tree species of Ethiopia (Legesse, 1995; Tadesse et al., 2000). It is used to improve soil physical and chemical properties in agricultural activities, as fodder for ruminants, as a shade tree, building materials, and used as medicine (Legesse, 1995, 2002; Tadesse et al., 2000).
M. ferruginea commonly occurs between 1100–2500 m above sea level and is characterized as a component of upland forest (Thulin, 1989). E. brucei and M. ferruginea (Hochst) Baker (Fassil Assefa, 1993; Fassil Assefa and Kleiner, 1998, 2011; 2002) are good biological nitrogen fixers and can be used as organic sources of nitrogen in agroforestry systems.
These multipurpose shade trees play a vital role in the rural economy of the region. In order to meet the future demand of these shade trees, their growth and productivity has to be hastened from the nursery stage onwards and their requirements for major fertilizers like Phosphorus should be known. Furthermore inappropriate and untimely application of fertilizer in agricultural fields generated several environmental and soil problems (Tilman et al., 2002; Foley et al., 2005).
The perceived need to seek alternatives to current agricultural practices has resulted in an enhanced interest in agroforestry systems (Ingleby et al., 2007), which can conserve resources, improve environmental quality, rehabilitate degraded lands, and provide multiple outputs to meet the daily demands of the rural population (Pande and Tarafdar, 2004; Muleta et al., 2008).
Agroforestry, a land use system/technology in which trees are deliberately planted on the same unit of land with agricultural crops, has been recognized as one of the most promising strategy for rehabilitating degraded areas. Arbuscular mycorrhizal (AM) fungi can rehabilitate degraded lands subjected to agroforestry systems (Mutuo et al., 2005; Cardoso and Kuyper, 2006). The common mycorrhizal network may further enhance the benefits of agroforestry through vertical niche expansion of AMF (Cavagnaro et al., 2005; Theuerl and Buscot, 2010).
The need to increase food, fibre, and fuel wood production to keep pace with the fast-growing population is crucial (Wrage et al., 2010). The low biomass production of agroforestry tree species such as in degraded areas can, therefore, be circumvented by the use of AM fungi (Shukla et al., 2009).
Phosphorus (P) is an essential nutrient for plant growth (Schroeder and Janos, 2005) and it is taken up by plants as phosphate (Landis and Fraser, 2008), which is unevenly distributed and relatively immobile in soils (Baird et al., 2010; Gianinazzi et al., 2010). The key function of AM fungi is the exploration of the soil beyond the range of roots for better plant growth and nutrition (Oehl et al., 2002; van der Heijden et al., 2006; Yadav et al., 2013a) AMF has the potential to make cultivation successful   at    a   lower   soil   P   level   through   more effective exploitation of the P sources (Jakobsen et al., 2005; Ma and Rengel, 2008).
The P level has been shown to significantly influence AM colonization (Covacevich et al., 2007). Addition of P fertilizers above optimum can delay or decrease colonization of roots (de Miranda et al., 1989; Hinsinger, 2001) and reduce chlamydospore production by the fungus (de Miranda and Harris, 1994). Agroforestry is not only concerned with beneficial effect of one component on another, but also involves the manipulations of negative effects to minimize their influence on the productivity of the overall system. At the tree-crop interface of an agroforestry system, trees and crops compete inevitably for light, water, and nutrients and AMF play an important role in P uptake. Therefore, the present study was conducted to identify the effect of AMF inoculation and application of different rates of phosphorus on growth and P uptake of leguminous tree species E. brucei and M. ferruginea that grow in Sidama and Gedeo agroforestry.


In this study, seeds of the selected shade trees in Sidama and Gedeo agroforestry were used. Three native species of AM fungi isolated and purified from the rhizosphere of trees and crops from Sidama agroforestry were used as AM inoculants. Taxonomic identification of spores was checked to be matched with the description provided by the International Culture Collection of Arbuscular Mycorrhizal Fungi (INVAM, 2006). Inoculum used in this study was consisted of soil along with chopped root bits of Sorghum bicolor, spores, and extrametrical mycelia from trap culture pots.
To study the effect of P concentrations on tree growth and P uptake after inoculation with AMF, separate experiments were carried out for the two multipurpose shade trees in the agroforestry. The trials consisted of six P concentrations (0, 0.005, 0.01, 0.02, 0.05, and 0.1 mg/g) and three mycorrhizal treatments (Rhizophagus clarus, Rhizophagus intraradices and mixture of the two) and un-inoculated plants (control). Thus, a total of 24 treatments were carried out per each plant species, and each treatment was replicated three times. Seeds were surface sterilized with Sodium hypochlorite, washed several (five to six) times with sterilized distilled water and germinated on sterilized river sand at 30°C. In this study plastic pots filled with 2 kg sterile sand were used.
At the time of sowing, 50 g of mycorrhizal inocula was applied to the hole where pre-germinated seedlings were individually transplanted. Phosphorus was applied to the pots at 0, 0.005, 0.01, 0.02, 0.05, and 0.1 mg/g as KH2PO4. Plants were grown under greenhouse conditions and watered daily. One seedling was maintained per pot and half-strength Hoagland's solution in deionized water was applied at weekly intervals. The composition of the Hoagland's solution was (0.51 g/L KNO3, 0.246 g/L Ca(NO3)2, 0.245 g/L MgSO4.7H2O, 1.43 g/L H3BO3, 0.91 g/L MnCl2.7H2O, 0.11 g/L ZnSO4.5H2O, 0.04 g/L CuSO4.5H2O, and 0.04 g/L H2MoO4.H2O). To reduce the risks of cross contamination, pots were kept on separate benches, with a space of 40 cm between each treatment.
Seedlings were harvested after three months and analyzed for shoot length and dry weight by standard methods. Phosphorus uptake was recorded using Molybdenum blue method according to Jackson (1973). Mycorrhizal dependency was calculated according to Plenchette et al. (1983): [(M-NM)/M] × 100, where: M is the total dry biomass of  mycorrhizal plant; NM  is  the  total  dry  biomass  of non-mycorrhizal plant.
To study the effect of P application on AM colonization of the two trees, aforesaid treatments (24) were replicated four times and six plants were maintained per replicate/pot. Two plants per pot were harvested after 1, 2, and 3 months of sowing, for observations. Formation of arbuscules and vesicles were monitored and then, was calculated the colonization index and spore count per 50 cm3 sand. Fine roots were cleared with 10% KOH and stained with acid fuchsin (0.01% in lactoglycerol) as reported by Phillips and Hayman (1970) and then was recorded colonization rates of arbuscules and vesicles. Colonization percentage was determined by gridline intersection method of Giovannetti and Mosse (1980). Sporocarp and spores were isolated according to Gerdemann and Nicolson (1963) and counted.
Statistical analysis
All the data on plant growth were subjected to a one-way analysis of variance for testing the effects of AM inoculation and P application, and their interactions. The means were compared and ranked using Duncan’s Multiple range test (P<0.05). The mean of experiments were analyzed statistically using a general linear model for analysis of variance of completely randomized designs. Analysis of variance (ANOVA) and correlation analysis were carried out with the SPSS software package (version 20.0). (SAS, 1982).


Plant growth, shoot dry biomass and P uptake
The results on effect of AM inoculation (Rh. clarus, Rh. intraracices and the mixed species) and P (0, 0.005, 0.01, 0.02, 0.05, and 0.1 mg g-1) application on growth and P uptake by E. brucei and M. ferruginea are presented in Figure 1. Most of the peaks of shoot length, and dry weight, by these trees occurred from 0.005 to 0.02 mg g−1. In un-inoculated plants, such peaks were inclined towards increasing P concentration. For the three AM fungi studied, these peaks indicate that the optimum P concentrations for maximum benefits from the AM symbiosis in plant species lied mostly from 0.005 to 0.02 mg g−1 P concentration. For shoot length the optimum P concentration for most effective AM inoculants, Rh. clarus, Rh. intraradices and the mixed species in E. brucei and M. ferruginea was 0.02 mg P g-1. In both E. brucei and M. ferruginea inoculated with the three AM species, plant height increased with increasing P concentration until P=0.02 mg g-1 and shoot dry weight has increased with increasing P concentration until P=0.01 mg/g. However, the increase both in shoot length and dry weight of both E. brucei and M. ferruginea has decreased with increasing P concentration above p= 0.02 and P=0.01 mg g-1 respectively. Thus, the two tree species inoculated with the three AM species has positively reacted with increasing P concentration and inoculating above-mentioned trees, with a suitable AM inoculant (at lower P concentration) can be effective as high inputs of recommended P fertilizers.
Therefore,  the  optimum  P  concentration  for  the  two selected agroforestry shade trees studied with different AM fungi for maximum be it from the symbiosis was low (0.005–0.02 mg P g−1 substrate). Since different AM fungi can transport different amounts of P to plants, their effects on plant growth can also be different. Despite this fact however, in the current study the two species from Glomeromycota and the mixture of the two has produced similar results in the green house as compared to the un-inoculated which has been given similar P concentration with other treatments. In both trees studied, AM inoculants used; Rh. clarus, Rh. intraradices and the mixed species has significantly increased shoot length, dry weight, and P uptake at P<0.05% level.
Mycorhizal dependency (MD) of seedlings of the trees
Total results on mycorrhizal dependency of E. brucei and M. ferruginea seedlings are presented in Table 1. In both trees, the three AM inoculants: Rh. clarus, Rh. intraradices and the mixed species significantly (p<0.005) increased shoot length and total shoot dry biomass. Maximum MD values were recorded for Rh. clarus (34.87%) in M. ferruginea and (26.19%) in E. brucei respectively. For the mixed species was recorded, the next highest MD values 26% in M. ferruginea and 16.67% in E. brucei. The least MD values were recorded for treatments with Rh. intraradices in both trees under test.
Effect on AMF structural colonization and spore density
Arbuscular mycorrhizal fungi structural colonization (Arbuscules & Vesicles) of the trees after inoculation with Rh. clarus, Rh. intraracices and the mixed species are presented in Table 2. In the current study, formation of arbuscules by Rh. clarus and Rh. intraradices and the mixed species was more favored at lower P concentrations (0.05 to 0.02 mg P g-1 substrate). However, there were also some rates of colonization below and above 0.05 and 0.02 mg g-1 p concentration in all inoculated tree species (Table 2). The result also indicates that arbuscule formation was the earlier during the 1st month of inoculation and that of formation of vesicles was intensive during the 2nd and 3rd months of the inoculation.
Finally, the tree species inoculated with AM fungi showed mycorrhizal colonization that was characterized by the presence of arbuscules and vesicles (Table 2). However, mycorrhizal colonization, arbuscule and vesicle formation decreased significantly with the increase in P concentration. Also similar trend was observed with mycorrhizal spore number (Table 3), and positive correlation was recorded between mycorrhizal spore number and percentage root colonization.
Maximum root colonization and spore count per 50 cm3  sand was observed at P concentrations ranging from 0.005 to 0.02 mg g−1 in tree seedlings infected by AM fungi (Table 3). In this study, results showed that the P optimum for maximum benefit from AM symbiosis for inoculated agroforestry tree seedlings was in between 0.005 and 0.02 mg g-1 and the seedling growth reduced with increasing P concentration.
Therefore, inoculating trees with a suitable AM inoculants could result in a benefit comparable to high P input. However,  extrapolation  of the  results  to  the  real conditions of agroforestry systems should be done with precaution because of differences in the substrate used, that is, sand in the present study. The information on P optimum can form the basis of further pot/field experiments involving integration of chemical fertilizers with AM fungi.


Previous  studies,  in  field   conditions  have  shown  that agricultural management practices, such as tillage, fertilization and cropping systems, have a negative impact on the AMF associated with temperate and tropical agronomic plant species (Cardoso and Kuyper, 2006). Fertilization is an important abiotic factor influencing growth, colonization, sporulation, composition and distribution of AMF (Wang et al., 2009).
Other studies conducted in green house conditions (Habte and Manjunath, 1991) have demonstrated that AM fungi usually have their maximum effect on host plant growth when the level of P in the growth medium is optimum. According to Habte and Manjunath (1991), when the soil solution P concentration is at or near 0.002 mg/l, most plant species will respond dramatically to mycorrhizal colonization.
Results of the current study on agroforestry trees and crops revealed the pick for maximum benefit at 0.02 mg P g-1 growth medium (sand) and that, as P concentration is increased from 0.005 to 0.02 mg/g, the reliance of plants on AM fungi for P uptake increased and diminished progressively as P concentration increased (from 0.05 to 0.1 mg/g) after which only the very highly mycorrhizal-dependent species respond significantly to mycorrhizal colonization.
Our results also confirm previous results (Ravnskov and Jakobsen, 1995). The mechanism underlying the reduction in plant growth just above optimum P probably includes both effects of P on root growth and direct effects on the fungi (Cardoso et al., 2006). Increase in P supply may decrease the availability of organic substrates from roots to fungi. Azcon et al. (2003) reported that low P concentration in lettuce plants allowed the maximum colonization and occurrence of AM fungi. Koide (1991) showed that P levels influenced AM colonization. Addition of P fertilizers above optimum delayed and/or inhibited AM infection (de Miranda et al., 1989; Baon et al., 1992).
Several other authors have reported that mycorrhizal roots are able to absorb several times more phosphate than non-inoculated roots from soils and from solutions (Nielsen, 1983; Fitter, 1988). Increased efficiency of phosphorus uptake by mycorrhizal plants could have led to higher concentrations of P in the plant tissues. The greater phosphate absorption by AMF has been suggested to have arisen due to superior efficiency of uptake from labile forms of soil phosphate, which is not attributable to a capacity to mobilize phosphate sources unavailable to non mycorrhizal roots (Pearson and Gianinaazzi, 1983). Mycorrhizal roots are known to have not only a considerably greater phosphate inflow rates, but also to possess a pathway of phosphate uptake with a much higher affinity for phosphate than non mycorrhizal roots.
In our study, maximum root colonization and spore count per 50 cm3 sand was observed at P concentrations ranging from 0.005 to 0.02 mg g−1 in plants infected by AM fungi and effectiveness decreased with  increasing  P concentration. Our results support reports by Kahiluoto et al. (2000) who observed that with increasing P supply, there was a decrease in the colonization and the effectiveness of mycorrhizal colonization. The results are also in agreement with many reports which suggest that addition of phosphate fertilizers above optimum levels results in a delay in infection and reduced chlamydospore production by AM fungi (Koide, 1991; Thingstrup et al., 1998).
In general, the trees studied are fast growing plants, requires more nutrients during the initial stage of seedling establishment. During this period, the root system is not well developed and the AM fungal symbiosis might play a vital role by supplying the nutrients to the host plant (Muthukumar and Udaiyan, 2006). The results of present study showed that mycorrhizal inoculations increased the plant growth and P uptake in different treatments with a few exceptions. This can be due to increase in the sand volume explored for nutrient and water uptake by the mycorrhizal plants from the medium as compared to non-mycorrhizal plants. Our results support previous studies.
The high rate of P fertilizer application, that is, 0.05 and 0.1 mg g-1 lead to antagonistic inhibition of mycorrhizal colonization whereas in lower dose with application of the vigorous AM fungi Rh. intraradices, was able to increase the root colonization and spore density significantly. However, increased P supply increased some growth parameters connected to plant height, shoot and root dry weight. Thus, soil amendment with AM fungi have the potential to possibly reduce the application of phosphorus fertilizer for crop improvement, growth, yield and nutritional value of the perennial crops and shade trees in Sidama agroforestry.
Our results indicated that inoculating plants with a suitable AM inoculant could result in a benefit comparable to high P input. However, extrapolation of the results to the real conditions of agroforestry systems should be done with precaution because of differences in the substrate used, i.e., sand in the present study. The information on minimum P concentration for better performance of AMF in the agroforestry can form the basis for further pot/field experiments involving integration of chemical fertilizers with AM fungi.


The present study demonstrated that inoculation of multipurpose shade trees with Rh. intraradices, Rh. clarus and mixture inoculums of the two, increased all plant growth parameters, but at the same time decreased percentage of mycorrhizal colonization and spore density as the concentration of P increased. Thus, soil amendments with AM fungi have the potential to possibly reduce the application of phosphorus fertilizer for tree and crop growth and improvement in agroforestry. However, in order  to  come  up  with  more  accurate and reliable information on functional efficiency of the AMF species applied, further pot and field experiment should be carried out.


The author has not declared any conflict of interests.



The author would are grateful to Hawassa College of Teacher Education for financial and logistic supports, Department of Microbial, Cellular and Molecular Biology, Addis Ababa University, Wendo Genet College of Forestry and College of Agriculture, Hawassa University for providing laboratory equipment and chemicals.



Azcon R, Amebrosano E, Charest C (2003). Nutrient acquisition in mycorrhizal lettuce plants under different phosphorus and nitrogen concentration. Plant Science 165:1137-1145.


Baird JM, Walley FL, Shirtliffe SJ (2010). Arbuscular mycorrhizal fungi colonization and phosphorus nutrition in organic field pea and lentil. Mycorrhiza 20:541-549.


Baon JB, Smith SE, Alston AM, Wheeler RD (1992). Phosphorus efficiency of three cereals as related to indigenous mycorrhizal infection. Australian Journal of Agricultural Research 43:479-491.


Cardoso IM, Boddington CL, Janssen BH, Oenema O, Kuyper TW (2006). Differential access to phosphorus pools of an Oxisol by mycorrhizal and non-mycorrhizal maizeCommunications in Soil Science and Plant Analysis 37:1537-1551.


Cardoso IM, Kuyper, TW (2006). Mycorrhizas and tropical soil fertility. Agriculture, Ecosystems & Environment 116:72-84.


Cavagnaro TR, Smith FA, Smith SE, Jakobsen I (2005). Functional diversity in arbuscular mycorrhizas: exploitation of soil patches with different phosphate enrichment differs among fungal species. Plant, Cell & Environment 28:642-650.


Covacevich F, Echeverría HE, Aguirrezabal LAN (2007). Soil available phosphorus status determines indigenous mycorrhizal colonization of field and glasshouse-grown spring wheat from Argentina. Applied Soil Ecology 35:1-9.


de Miranda JCC, Harris PJ (1994). Effects of soil phosphorus on spore germination and hyphal growth of arbuscular mycorrhizal fungi. New Phytologist 128:103-108.


de Miranda JCC, Harris PJ, Wild A (1989). Effects of soil and plant phosphorus concentrations on vesicular-arbuscular mycorrhizae in sorghum plants. New Phytologist 112:405-410.


Fitter AH (1988). Water relations of red clover Trifolium pratence L. as affected by VA mycorrhizal colonization of phosphorus supply before and during drought. Journal of Experimental Botany 39:595-603.


Foley JA, De Fries R, Asner GP, Barford C, Bonan G, Carpenter SR, Chapin FS, Coe MT, Daily GC, Gibbs HK, Helkowski JH, Holloway T, Howard EA, Kucharik CJ, Monfreda C, Patz JA, Prentice IC, Ramankutty N, Snyder PK (2005). Global consequences of land use. Science 309:570-574.


Gerdemann JW, Nicolson TH (1963). Spores of mycorrhizal Endogone species extracted from soil by wet sieving and decanting. Transactions of the British Mycological Society 46:235-244.


Gianinazzi S, Gollotte A, Binet MN, van Tuinen D, Redecker D, Wipf D (2010). Agroecology: the key role of arbuscular mycorrhizas in ecosystem services. Mycorrhiza 20:519-530.


Giovannetti M, Mosse B (1980). An evaluation of techniques for measuring vesicular arbuscular mycorrhizal infection in roots. New Phytologist 84:489-500.


Habte M, Manjunath A (1991). Categories of vesiculararbuscular mycorrhizal dependency of host species. Mycorrhiza 1:3-12.


Hinsinger P (2001). Bioavailability of soil inorganic P in the rhizosphere as affected by root induced chemical changes: a review. Plant Soil 237:173-195.


Ingleby K, Wilson EJ, Munro ERC, Cavers S (2007). Mycorrhizas in agroforestry: spread and sharing of arbuscular mycorrhizal fungi between trees and crops: complementary use of molecular and microscopic approaches. Plant Soil 294:125-136.


INVAM-International Culture Collection of Vesicular Arbuscular Mycorrhizal Fungi (2006). 


Jackson ML (1973). Soil chemical analysis. Prentice Hall of India, New Delhi.


Jakobsen I, Chen BD, Munkvold L, Lundsgaard T, Zhu YG (2005). Contrasting phosphate acquisition of mycorrhizal fungi with that of root hairs using the root hairless barley mutant. Plant, Cell & Environment 28:928-938.


Kahiluoto H, Ketoja E, Vestnerg M (2000). Promotion of utilization of arbuscular mycorrhiza through reduced P fertilization. 1. Bioassays in a growth chamber. Plant Soil 227:191-206.


Koide RT (1991). Nutrient supply, nutrient demand and plant response to mycorrhizal infection. New Phytologist 117:365–386.


Landis FC, Fraser LH (2008). A new model of carbon and phosphorus transfers in arbuscular mycorrhizas. New Phytologist 177:466-479.


Legesse N (1995). Indigenous trees of Ethiopia: Biology, Uses and Propagation techniques. Printed by the SLU Reprocentralen, Umea, Sweden, p. 285.


Legesse N (2002). Review of Research Advances in some African Trees with special reference to Ethiopia. Ethiopian Journal of Biological Sciences 1(1):81-126.


Ma Q, Rengel Z (2008). Phosphorus acquisition and wheat growth are influenced by shoot phosphorus status and soil phosphorus distribution in a split-root system. Journal of Plant Nutrition and Soil Science 171:266-271.


Muleta D, Assefa F, Nemomissa S, Granhall U (2008). Distribution of arbuscular mycorrhizal fungi spores in soils of smallholder agroforestry and monocultural coffee systems in southwestern Ethiopia. Biology and Fertility of Soils 44:653-659.


Muthukumar T, Udaiyan K (2006). Growth of nursery-grown bamboo inoculated with arbuscular mycorrhizal fungi and plant growth promoting rhizobacteria in two tropical soil types with and without fertilizer application. New Forests 31:469-485.


Mutuo PK, Cadisch G, Albrecht A, Palm CA, Verchot L (2005). Potential of agroforestry for carbon sequestration and mitigation of greenhouse gas emissions from soils in the tropics. Nutrient Cycling in Agroecosystems 71:43-54.


Nielsen JD (1983). Influence of vesicular-arbuscular mycorrhiza fungi on growth and uptake of varius nutrients as well as uptake ratio of fertilizer P for lucerne (Medicago sativa). Plant Soil 70:165-172.


Oehl F, Oberson A, Tagmann HU, Besson JM, Dubois D, Mader P, Roth HR, Frossard E (2002). Phosphorus budget and phosphorus availability in soils under organic and conventional farming. Nutrient Cycling in Agroecosystems 62:25-35.


Pande M, Tarafdar JC (2004). Arbuscular mycorrhizal fungal diversity in neem based agroforestry systems in Rajasthan. Applied Soil Ecology 26:233-241.


Pearson VG, Gianinazzi S (1983). The Physiology of vesicular-arbuscular mycorrhizal roots. Plant Soil 71:197-209.


Phillips JM, Hayman DS (1970). Improved procedure for clearing roots and staining parasitic and vesicular arbuscular mycorrhizal fungi for rapid assessment of infection. Transactions of the British Mycological Society 55:158-161.


Plenchette C, Fortin JA, Furlan V (1983). Growth responses of several plant species to mycorrhizae in a soil of moderate P fertility. I. Mycorrhizal dependency under field conditions. Plant Soil 70:199-209.


Ravnskov S, Jakobsen I (1995). Functional compatibility in arbuscular mycorrhizas measured as hyphal P transport to the plant. New Phytologist 129:611-618.


SAS Institute Inc. (1982). SAS User's Guide: Statistics. SAS Institute, Inc., Cary, NC.


Schroeder MS, Janos DP (2005). Plant growth, phosphorus nutrition, and root morphological responses to arbuscular mycorrhizas, phosphorus fertilization and intraspecific density. Mycorrhiza 15:203-216.


Shukla A, Kumar A, Jha A, Chaturvedi OP, Prasad R, Gupta A (2009). Effects of shade on arbuscular mycorrhizal colonization and growth of crops and tree seedlings in Central India. Agroforestry Systems 76:95-109.


Tadesse H, Legesse N, Olsson M (2000). Millettia ferruginea from Southern Ethiopia: Impacts on soil fertility and growth of maize. Agroforestry Systems 48:9-24.


Theuerl S, Buscot F (2010). Laccases: toward disentangling their diversity and functions in relation to soil organic matter cycling. Biology and Fertility of Soils 46:215-226.


Thingstrup I, Rubaek G, Sibbesen E, Jakobsen I (1998). Flax (Linum usitatissimum L.) depends on arbuscular mycorrhizal fungi for growth and P uptake at intermediate but not high soil P levels in the field. Plant Soil 203:37-46.


Tilman D, Cassman KG, Matson PA, Naylor R, Polasky S (2002). Agricultural sustainability and intensive production practices. Nature 418:671-677.


van der Heijden MGA, Streitwolf-Engel R, Riedl R, Siegrist S, Neudecker A, Ineichen K, Boller, T, Wiemken A, Sanders IR (2006). The mycorrhizal contribution to plant productivity, plant nutrition and soil structure in experimental grassland. New Phytologist 172:739-752.


Wang FY, Liu RJ, Lin XG (2009). Arbuscular mycorrhizal status of wild plants in saline-alkaline soils of the yellow river delta. Mycorrhiza 14:133-137.


Wrage N, Lardy LC, Isselstein J (2010). Phosphorus, plant biodiversity and climate change. In. Lichtfouse E (ed) Sustainable agriculture reviews, vol 3, Sociology, organic farming, climate change and soil science. Springer Science Business Media pp. 147-169.


Yadav K, Aggarwal A, Singh N (2013a). Arbuscular mycorrhizal fungi (AMF) induced acclimatization, growth enhancement and colchicine content of micropropagated Gloriosa superba L. plantlets. Industrial Crops and Products 45:88-93.