IMPROVEMENT OF MUNG BEAN GROWTH AND PRODUCTIVITY BY PHOSPHATE-

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1 Legume Res., 34 (3) : , 2011 AGRICULTURAL RESEARCH COMMUNICATION CENTRE ccjournals.com / indianjournals.com nals.com IMPROVEMENT OF MUNG BEAN GROWTH AND PRODUCTIVITY BY PHOSPHATE- TE-DISSOL DISSOLVING FUNGI ASPERGILLUS NIGER SEED INOCULATION B.K. Yadav Department of Agricultural Chemistry & Soil Science, Rajasthan College of Agriculture, Maharana Pratap University of Agriculture &Technology, Udaipur , India. Received : Accepted : ABSTRACT Efficiency of Aspergillus niger was studied in a pot experiment to evaluate improvement of mung bean [ [Vigna radiata (L.) Wilczek] growth and productivity.. A significant (p=0.05) increase in plant growth and yield parameters (plant height, number of nodules, number of branches, number of pods, seed yield and test weight) were noticed as compared to uninoculated treatments. In general there e was a significant improvement in uptake of N, P,, K, Fe e and Zn as compared ed to absolute control. It was found that inoculation by A. niger increased uptake of nitrogen by 7%, phosphorus and zinc by 9%, potassium by 8% and iron by 17% as compared to uninoculated treatments. The experiment confirmed that A. niger had a significant effect on growth and nutrient uptake in the mung bean and indicated that this fungi play an important role in growth and nutrition of mung bean in sub-humid region. Key words : Mung bean, Aspergillus niger, Plant growth, Nutrient uptake. INTRODUCTION Phosphorus solubilizing microorganisms (bacteria and fungi) convert unavailable P to available by solubilization. Several soil bacteria, particularly those belonging to the genera Pseudomonas and Bacillus and fungi belonging to the genera Penicillium and Aspergillus possess ability to bring insoluble soil phosphates into soluble form by secreting organic acids such as formic, acetic, propionic, lactic, glucolic, fumaric and succinic. These acids lower the ph and bring the dissolution of bound forms of phosphate (Venkateswarlu et al., 1984). The use of plant growth promoting rhizobacteria (PGPR) including phosphate and potassium solubilizing bacteria/ fungi as a biofertilizers may be used to improve plant nutrition and productivity. Many bkyadav74@yahoo.co.in investigators reported that phosphate dissolving bacteria enhance crop growth, improve seed and straw yields and increase nutrient uptake. Tarafadar et al., (1988) reported that Aspergilli have highest phosphatase activity among the tested fungi in arid soils. Their positive effect on mung bean (Tarafdar et al., 1992), clusterbean. (Tarafdar et al., 1995), wheat and chickpea (Tarafdar and Rao, 1996) had already been assessed in arid soils of western Rajasthan. However, no information was reported on the usefulness of A. niger under sub humid region of southern Rajasthan. Hence, an attempt was made to examine the effect of A. niger on the improvement of mung bean plant growth and productivity.

2 218 LEGUME RESEARCH MATERIALS AND METHODS A pot experiment was conducted in Kharif 2010 at Department of Agricultural Chemistry and Soil Science, Rajasthan College of Agriculture, Maharana Pratap University of Agriculture and Technology, Udaipur. The mean maximum and minimum temperature were 35.5 and 17.4 o C. The mean annual rainfall of the region varied from 650 to 750 mm. The experimental soil (Table 1) was sandy loam in texture, non-saline, slightly alkaline in reaction. The availability of N, K, Cu, Zn and Mn were high, while the availability of P and Fe were reported low in the soil. Aspergillus niger was isolated from arid soils, using a dilution plate technique on Martin s Rose Bengal agar containing streptomycin sulphate (Allen, 1959) and maintained on potato dextrose agar slants. The A. niger was grown for 21 days at 30 C in 250 ml Erlenmeyer flask containing 150 ml Czapek-Dox broth after inoculation with 8 mm disc of 4-day-old agar culture. After 21 days, the inoculum was prepared by blending the culture broth in a homogenizer, diluted with sterilized distilled water and mixed it with sterilized charcoal so that the final inoculum contained 10 5 CFU gm -1. The surface sterilized (0.05% HgCl 2 ) mung bean seed was inoculated with A. niger carrier-based culture in sterilized (20%) jaggery (gur) solution, and seeds were treated with A. niger inoculum (100g kg -1 seed). The seeds were dried under shade to avoid direct sun rays and sown in pots. The experiment was laid out in a CRD with five replications. The treatments consisted of (i) T 1 - Absolute control (ii)t 2 - seed inoculated with A. niger (iii)t 3-10 kg P 2 ha -1 (iv) 10 kg P 2 ha -1 + T 2 (v) 20 kg P 2 ha -1 (vi) 20 kg P 2 ha T 2 (vii) 40 kg P 2 ha -1 and (viii) 40 kg P 2 ha -1 + T 2. The phosphorus was applied through diammonium phosphate. Eight mung bean [Vigna radiata (L.) Wilczek] seeds were sown in pots and four plants were maintained after germination. One pot from each treatment was harvested after one month to count the nodules and remaining four pots were harvested at crop maturity. Plants from each pot were harvested and observation such as plant height, number of nodules, number of branches, number of pods, seed yield and test weight were recorded separately. Soil ph and EC were determined using 1:2.5, soil: water suspension whereas, organic carbon, nitrogen, phosphorus and potassium were determined following the standard methods as described by (Gupta, 2000). The plant samples were dried at 60 C to a constant weight, ground to a fine powder and nutrients were analyzed by standard methods (Gupta, 2000).The soil was extracted with M DTPA for available micronutrients (Lindsay and Norvell, 1978). For micronutrient analysis plant samples were digested in HNO 3 :HClO 4 (4:1) diacid mixture and micronutrient (Fe, Cu, Zn and Mn) in the extract (both plant and soil) were determined by atomic absorption spectrometer (GBC- Avanta Ver- 1.33). Data on all observations were subjected to analysis of variance (ANOVA) as per the procedure outlined by Panse and Sukhatme (2000). RESULTS AND DISCUSSION Results presented in Table 2 showed the effect of phosphorus levels and A. niger inoculation on mung bean growth. Plant height significantly increased with all level of P as compared to absolute control. The increase in plant height (5-6%) was reported when the seed was inoculated with A. niger. With increase in P levels, number of nodules (21-44%) and dry weight of nodules (2-7%) increased, while increase in number of nodules (37-72%) and dry weight of nodules (3-8%) was observed when the seed was inoculated with A. niger. Application of P significantly increased the number of branches (15-39%) and dry matter yield (30-44%). Increase in the no. of branches and dry matter yield was from 23 to 46% and from 33 to 49% when the seed was inoculated with A. niger. On an average, 39% to 46% increase in number of pods, 52% to 61% increase in grain yield was reported with application of P and A. niger inoculation, respectively. The test

3 weight significantly increased with application of P, however, it was non-significant when A. niger was used as bio-inoculant. Increase in mung bean growth parameters (plant height, number of nodules, dry weight of nodules, number of branches, dry matter yield, number of pods, grain yield and test weight) might be due to the higher phosphatases activity in the rhizosphere. Production of organic acids by A. niger solubilized the insoluble phosphate and brought insoluble phosphate in soil into soluble form. This resulted in increased P uptake by the crop. Apart from increased enzyme activities, the beneficial effects of A. niger on plant growth might also include the production of plant growth promoter. Greater phosphatases activity has been directly implicated in the acquisition of more P by plants (Tarafdar and Rao, 1996; Yadav and Tarafdar, 2010). Asea et al., (1988) reported the production of organic acids such as lactic, glycollic and succinic acids in the medium of A. niger which can solubilize unavailable inorganic phosphates. Strzelczyk et al., (1989) reported that plant growth regulators such as ethylene, auxin, gibberellin and cytokinin were produced by non-mycorrhizal fungi associated with the roots of forest trees. Significant increase in macronutrient (N, P and K) and micronutrient (Fe, Zn) uptake was observed with application of P alone and inoculation with A. niger. However, non-significant result was observed in case of Cu and Mn. In general P application increased N (47%), P (90%), K (55%), Fe (75%) and Zn (48%). However, when the seed was inoculated with A. niger the uptake increased by 57% (N), 107% (P), 67% (K), 103% Fe and 61% Zn as compared to absolute control. It was also found that inoculation of A. niger increased the uptake of nutrients by 7% (N), 9% (P, Zn) 8% (K) and 17% (Fe). Application of bio-phosphatic fertilizer led to increment in count of effective microorganisms ie., Azotobacter spp, Azospirillum spp, Rhizobium spp and total viable bacteria. The total uptake of N increased due to the improvement in symbiotic N 2 Vol. 34, No. 3, fixation. Azcon-Aguilar and Barea (1978) attributed higher N concentrations and contents in lucerne plants to increased N2 fixation by plants inoculated with phosphate-solubilizing bacteria. Further, it is well established that if P nutrition of plants is improved, either through fertilization or biological means, symbiotic N 2 fixation, the plant N content got improved. Greater phosphatases activity had directly implicated in the acquisition of P by plants (Dodd et al., 1987; Tarafdar et al., 1992; Yadav and Tarafdar, 2011). A significant improvement in the K uptake upon inoculation might be explained by the activity of Aspergilli in synthesizing organic acids, which could react with K containing minerals. It was also known (Harley, 1969) that one of the most important properties of fungi is the ability to translocate plant nutrients especially N, P and K. These results agreed with findings of Tarafdar et al., (1992). Significant improvement on the uptake of Fe and Zn and non-significant uptake of Cu and Zn in the mung bean upon inoculation with A. niger were noticed. In general, improvements in the plant uptake of various elements, including P, upon inoculation with Vesicular-arbuscular mycorrhizal Table1 : Characteristics of the experimental soil. Soil properties Quantity Sand (%) Silt (%) 7.68 Clay (%) Texture Sandy loam ph 8.2 EC (dsm -1 ) 0.48 Organic matter (g/kg) 11.8 Available N (mg/kg) AvailableP 2 (mg/kg) 8.4 Available K 2 O (mg/kg) Iron ( DTPA extractable, mg/kg) 3.49 Copper ( DTPA extractable, mg/kg) 2.62 Zinc ( DTPA extractable, mg/kg) 4.25 Manganese ( DTPA extractable, mg/kg) 5.86

4 220 LEGUME RESEARCH Table 2 : Growth parameters of mung bean plant due to different level of phosphorus and seed inoculation with A. niger. Treatment Plant Number of Dry weight Number of Dry matter Number of Grain Test height nodules* of nodules* branches yield pods yield weight (cm) (plant -1 ) (mg plant -1 ) (plant -1 ) (g plant -1 ) (plant -1 ) (g plant -1 ) (g) T T T T T T T T LSD (p=0.05) * Number of nodules and dry weight of nodules were estimated after 30 days of sowing. Table 3 : Nutrient uptake by mung bean due to different level of phosphorus and seed inoculation with A. niger. Treatment Macronutrient uptake (mg plant -1 ) Micronutrient uptake ( mg plant -1 ) N P K Fe* Cu Zn Mn T T T T T T T T LSD (p=0.05) NS 0.12 NS *(µg plant -1 ). (VAM) fungi had been observed. Reid et al., (1985) reported that microbial siderophores were important in plant Fe nutrition. These findings was in accordance with those obtained by Tarafdar et al., (1992) and Tarafdar et al., (1995) who found a significant improvement in uptake of N, P, K, Ca, Mg Fe and Zn with the inoculation of different phosphatase producing fungi in mung bean and cluster bean. From these findings it is clear that inoulation of the mung bean with A. niger increased dry matter, grain yields and the uptake of various nutrients. The nutrients were most likely absorbed by the A. niger and translocated by the mycelium to the soil near the root zone. The present experimental result demonstrated the potential of A. niger in increasing the growth and productivity of mung bean under sub-humid region. ACKNOWLEDGEMENT Author is thankful to Department of Science and Technology, New Delhi for financial assistance under SERC Fast Track Scheme (SR/ FT/LS-060/2007) and Head, Department of Agricultural Chemistry & Soil Science, RCA, MPUAT Udaipur for providing the facilities for the investigation.

5 Vol. 34, No. 3, REFERENCES Allen, O.N. (1959). Experiments in Soil Bacteriology. 3 rd Edition. Burgess Publishing Co., p 117. Asea, P.E.A., Kucey, R.M.N. and Stewart, J.W.B. (1988). Inorganic phosphate solubilization by two Penicillium species in solution culture and soil. Soil Bio. Biochem. 20 : Azcon-Aguilar, C. and Barea, J.M. (1978). Effects of interactions between different culture fractions of Phosphobacteria and Rhizobium on mycorrhizal infection, growth and nodulation of Medicago sativa. Can. J. Microbiol. 24: Dodd, J. C., Burton, C.C., Burns, R.G. and Jeffries, P. (1987).Phosphatase activity associated with the roots and the rhizosphere of plants infected with vesicular-arbuscular mucorrhizal fungi. New Phytology 107: Gupta, P.K. (2000). Soil, Plant, Water and Fertilizer Analysis, Agrobios (India), Jodhpur, 438p. Harley, J.L. (1969). The Biology of Mycorrhiza, 2 nd edn. Leonard Hill, London, 334p. Lindsay, W.L. and Norvell, W. A. (1978). Development of a DTPA soil test for zinc, iron, manganese and copper.soil Sci. Soc. Amer. J. 42: Panse, V.G. and Sukhatme, P.V. (2000). Statistical Methods for Agricultural Workers. ICAR, New Delhi, 359p. Reid, R.K., Reid, C.P.P. and Szaniszol, P.J. (1985).Effects of synthetic and micobially produced chelatyes on the diffusion of boron and phosphorus to a stimulated root in soil. Bio. Fert. Soils 1: Strzelczyk, E., Pokojska, A., Kampert, M., Michalski, L. and Kowalski, S. (1989). Production of plant growth regulators by non-mycorrhizal fungi associated with the roots of forest trees. In: Interrelationship Between Microorganisms and Plants in soil (Ed. Vancura, V. and Kunc F.) Elservier, Amsterdam, p Tarafdar, J.C., Rao, A.V. and Bala, K. (1988). Production of phosphatases by fungi isolated from desert soils. Folia Microbiology 33: Tarafdar. J.C. and Rao, A.V. (1996). Contribution of Aspergillus strains in acquisition of phosphorous to wheat (Triticum aestivum L.) and chick pea (Cicer arietinum L.) grown in a loamy sand soil. Applied Soil Ecology 3: Tarafdar, J.C., Rao, A.V. and Kumar, P. (1992). Effect of different phosphatase producing fungi on growth and nutrition of mung beans [Vigna radiata (L.) Wilczek ] in an arid soil. Biol. Fert. Soils 13 : Tarafdar, J.C., Rao, A.V. and Kumar, P. (1995). Role of phosphate producing fungi on the growth and nutrition of clusterbean [Cyamopsis tetragonoloba (L.) Taub.]. J. Arid Environ. 29: Venkateswarlu, B., Rao, A.V. and Raina, P. (1984). Evaluation of phosphorous solubilization by microorganisms isolated from arid soils. J. Indian Soc. Soil Sci. 32: Yadav, B.K and Tarafdar, J. C. (2010). Studies on phosphastase activity and clusterbean production as influenced by the P mobilizing organism Emericella rugulosa. Legume Res. 33: Yadav, B.K and Tarafdar, J.C. (2011). Penicillium purpurogenum, unique P mobilizers in arid agro-ecosystems. Arid Land Res. Manag. 25 :