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EFFECT OF AZOTOBACTER ON SEED GERMINATION OF ONION

Devendra Kumar Kurrey and Richa Sharma

ABSTRACT Azotobacter species are nitrogen fixation bacteria dwelling in soil and affect positively on growth and yield. But it is not much exploredas seed priming agent and very less literature is available.Thus present study was carried out to evaluate the response of bio-fertilizer(Azotobacter) on germination and seedling growth in case on onion. Doses (T0: water, T1:0.33ppm, T2:0.66ppm, T3:0.99ppm, T4:132ppm, T5:166ppm ppm) were decided on the basis of nitrogen requirement by the germinating seedling and used for investigation. Germination wasconducted on 'between paper method' and observation for parameters viz; germination percent, shoot length, root length, seedling vigourindices were recorded on 6th and12th day Germination% was observed higher in T5 (85%) in comparison to other treatments. The shootlength (13cm), root length (1.43%), with increase vagour index was significantly higher in T5 treatment followed by T4 in comparison toall other treatments. The conclusion of the present study is that Azotobacter may play effective role as a priming agent in improving seedgermination and seedling growth of onion seeds.

Keywords: Azotobacter, growth, germination, onion, seed

Student, Assistant ProfessorDepartment of Biological Sciences, Sam Higginbottom University of Agriculture, Technology And Sciences

Allahabad – 211007 (U.P.)

INTRODUCTIONGermination is the growth of a plant contained within a seed;

it results in the formation of reactivation of metabolic machineryof the seed resulting in emergence of radical and plumule. (Peteret al., 2005). The seed begins to germinate and the embryonictissues resume growth developing towards a seedling. Seedgermination depends on both internal and external conditions.The most important external factors include temperature, water,oxygen, and sometimes light and darkness. Some seeds aredormant and need more time to be subjected to specificenvironmental conditions before they will germinate. Dormancybreaking often involves changes in membranes. Initiated bydormancy breaking signals. This generally occurs only withinhydrated seed. Factors affecting seed dormancy include thepresence of certain plant hormones, notably abscisic acid, whichinhibits germination, and gibberellin, which ends seed dormancy(Bewley et al., 2006). And other used for breaking seeddormancy softening seed coat and seed coverings: in betterabsorption of water and gases which ultimately leads to bettergermination of the seed. Acid scarification, hot water scarification,warm moist scarification, and stratification under pre chilling, predrying, seed priming under (a) in osmo conditioning (PEG), (b) ininfusion, the hormones, fungicides insecticides, fertilizers andantidotes are infused in to dormant seed through organicsolutions. (Dr. Spuh et al., 2012). Azotobacter is a soil inhabitingnitrogen-fixing bacteria, which is also know to secrete growthpromoting factors as well as antifungal antibiotics. By virtue ofthese attributes pre treatment of seed with a suspension ofAzotobacter has generally shown improvement in seedgermination ant plant stand. Azotobacter inoculation is effectivein onion, wheat, rice, vegetables, cotton, grapes, cereals, etc asthey provide additional nitrogen requirements. Azotobacter alsoincreases germination of seeds by 20-30%.The effect ofAzotobacter on the seed germination, seeding growth and bulbyield of onion was examined. There significant increase in seed

germination and seeding weight due to seed bacterization withAzotobacter. The bulb yield of onion was also enhanced due toAzotobacter inoculation of roots of seeding at the time oftransplanting (Paul et al. , 2002). Seed Inoculated withAzotobacter helps in uptake of N, P along with micronutrientslike Fe and Zn, in wheat, these strains can potentially be used toimprove onion nutrition. Seed inoculations of Azotobacterprofoundly contribute to increase yield by supplying nitrogento the crops. Inoculation of seeds with Azotobacter increased inseed germination and seedling development. Increased rootlength and shoot length in onion crop. In nitrogen-deficient sand,seed inoculation increased plant length, dry weight, and nitrogencontent in addition to a significant increase in soil nitrogen(Jnawali et al., 2015).

Azotobacter being natural agent may be among onion. one ofthe priming agents to improve the seed germination inenvironmental sound way. Present study was conducted toevaluate as a may help break to the dormancy in seed germination.

MATERIAL AND METHODSExperiment was conducted to study the effect of different

concentration of Azotobacter as priming agent for onion seedgermination. Doses were decided on the basis of nitrogenrequirement by the seedlings. Seed were first sterilized by HgCl2

and washed properly. Then seeds were inoculated withAzotobacter in liquid medium for 6 hrs. than rinse with distil water.Germination experiment was conducted through 'between papermethod' and observation for parameters viz; germination percent,shoot length, root length, seedling vigour indices were recordedon 6th and12th day. Treatment details are given in Table 1.

RESULT AND DISCUSSIONAzotobacter in among one of the well- established PGPR for

crop growth and development. Being an natural agent it releasesgroup of organic compound which may also act as a priming

The Allahabad Farmer, Vol. LXXIV, No. 3, July - September, 2018

Received 03-02-2017Accepted 06-03-2018

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agent. Nitrogen being one of the important compounds toinfluence the vegetative growth of plant is being place as one ofthe essentials in organic fertilizer provided externally. But the roleof nitrogenous compound on seed germination is not beingstudied much so far. However some work is done on seedgermination of some plant species (Perez Fernandez et al., 2005)which show nitrogenous compounds increased percentgermination level and rate in three of the species under study.

cm) while minimum was in T1 (6.6 cm and 0.93 cm) (figure 2 and3). Seedling vigour indices on seedling for vigour index- lengthwas best at T5 (1226.55) followed by T4 (934). And seedling vigourindex- mass best performed at T5 treatment 2.235 then followedby T4 treatment 1.245. And was least for T1 (0.816) in comparisonto control (table 3). Azotobacter is basically used to fix nitrogenin soil that helps in plant vegetative growth. There are evidenceslike highest ARA activity was observed in case of A.chroococcum strain M-4. Both IAA production and N2 fixationunder free-living conditions are plant growth promoting activitiesof Azotobacter sp. (Anjum et al., 2007). Our experiments suggestits possible role in seed germination of onion. Basically it takes amonth to raise the nursery for onion but lab experiment suggestpossible increase in rate of germination along with better rootlength and shoot length on 6th day for T5. Work conducted onwheat, maize and onion seed inoculated with A. chroococcumstrains M 4 and OA 4 inoculation significantly enhanced seedgermination as well as seedling development and on radicalgrowth (Paul et al., 2002). There are experiment suggesting that

Table 1: Treatment details of Azotobacter dosesTreatment Concentration of Azotobacter N2%

T0 Normal water 00T1 0.33ppm 0.2%T2 0.66ppm 0.4%T3 0.99ppm 0.6%T4 132ppm 0.8%T5 166ppm 1%

Fig. No. 3: Effect of Azotobacter on onion seedling rootlength (cm)

Fig No. 1: Effect of Azotobacter on the germination of onionseed

Table 2: Effect of Azotobacter on the onion seed germinationand seedling

Treatment Concentration Germination Shoot Root% length length

(c.m) (c.m)T 0 Normal water 70.0% (c) 5.0 cm (c) 0.53cm (c)T 1 0.33ppm 71.0% (c) 6.66 cm (c) 0.93 cm (b)T 2 0.66ppm 79.66% (b) 7.33 cm (c) 1.00cm (b)T 3 0.99ppm 80.33% (b) 10.00cm (b) 0.96cm (b)T 4 132ppm 83.0% (ab) 10.66cm (ab) 1.10cm (ab)T 5 166ppm 85.0% (a) 13.00cm (a) 1.43cm (a)

Table 3: Effect of Azotobacter on Seedling vigour indices foronion

Treatment seedling vigour seedling vigourindex- length index- mass

T0 787.1 0.805T1 538.89 0.816T2 663.56 0.995T3 880.41 1.044T4 934 1.245T5 1226.55 2.235

Fig No. 2: Effect of Azotobacter on onion seedling shootslength (cm)

Our study on seed germination on onion under priming ofAzotobacter inoculate provide better result than control. Thegermination percentage was significantly influenced by differenttreatments and shows positive influence on observed parameterwith increase in dose. Observation recorded at 6th day showsmaximum germination % (80%) for T2 and T5 followed by 75% forT3 and T4. While minimum germination was occurred in To andT2. Finally on 12th day also following the same trait for germination% with maximum to T5 (85%) followed by T4 (83%) and least forT1 (71%) (Figure1). Shoot length at 6th day was maximum (5cm)in T5 followed by T4 (3.5 cm) and minimum shoot developmentwas in T1 2.2cm (Figure 2). Root length was also maximum (1.2cm) for T5 (figure 3). Finally on 12th day T5 Shoot length androot length (13 cm and 1.43 cm) followed by T4 (10.7 cm and 1.1

Devendra Kumar Kurrey and Richa Sharma

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bacteria derived IAA may have stimulatory effect on seedgermination, plant growth and development (Egamberdieva,2009). Azotobacter is known to improve growth of plant throughproduction of IAA and biologically fixed nitrogen (Hafeez et al.,2004). The influence of Azotobacter on germination of rice andcotton seeds by synthesizing the growth promoters andantifungal antibiotics ensure seed safety during germination.These twine attributes of Azotobacter have beneficial effect onthe germination of seeds (Shende et al., 1977). In case of onionmaximum germination percentage was 85 % in comparison tocontrol 70%. However, studies on effect of Azotobacterinoculation on seed germination of onion states that combinedinoculation with A. chroococcum and Azospirillum brasilenseincreased germination (96.5%) over uninoculated control (85.5%)(Musmade and Konde, 1987). Further on okra seed germinationwas increased by 70% over control (Vashist et al., 1979) andsoil inoculation with Azotobacter increased tomato seedgermination by 33% - 46%, shorten the period between sowingand transplanting by 5-7 days and increased the yield by 38-60%(Martinez et al., 1993). Different dose of Azotobacter effectpositively on root Length (0.93 cm - 1.43 cm) and shoot length(6.7 cm - 13.0 cm) in comparison to control. However lower doseswere not showing significant differences with control buttreatment T4 and T5 were proven very effective for healthy growth.Maize and sorghum (Desale, 1980) also shown increase in rootlength and shoot length due to Azotobacter inoculation. The pre-soaking of seed could improve in germination and seedlingestablishment (Ahmad et al., 1998). It has been long proven thatbio-agent may be more beneficial in comparison to syntheticchemicals and can be used as effective priming agent. They couldincrease seed germination and other physiological activity byaccrue tolerance to the other toxic agents (Haroun et al., 1991).

Very less work has been conducted on seed germination ofonion through priming effect of natural agents. Our study statesthe positive effect on seed germination, root and shoot lengthwith increase vigor index. It may also shorten the germinationperiod as onion seed takes more than 30 days to establish nurseryfrom seed germination.

ACKNOWLEDGMENTSI would like to thanks the Department of Biological sciences

Sam Higginbottom University of Agriculture, Technology &Sciences, Allahabad-211007 for providing facilities

REFERENCESAnjum, M. A., Sajjad, M.R., Akhtar, N., Qureshi, M. A., Iqbal, A.,Jami, A. R. and Mahmud-ul-Hasan. (2007). Response of

cotton to plant growth promoting rhizobacteria (PGPR)inoculation under different levels of nitrogen. Journalof Agricultural Research 45: 135-43.

Baral, B. R. and Adhikari, P. (2013). Effect of Azotobacteron Growth and Yield of Maize Nepal AgriculturalResearch Council, National Maize Research Program,Rampur, Chitwan, Nepal SAARC J. Agri., 11(2): 141-147

Bewley, D.J., Michaal, b. and Peter, H. (2006). The encyclopediaof seeds science, technology and uses cabi series. CABI.p. 203. ISBN 0-85199-723-6

Chauhan, J.S., Tomar, Y.K. Singh,N.I., Ali, S. and Debarati.(2009). Effect of Growth Hormones on Seed Germination and

Seedling Growth of Black Gram and Horse Gram Journalof American Science 2009; 5(5):79-84 jaisinghchauahn@gmail.com, jai002004@yahoo.com

Jnawali1, A.D., Ojha, R.B. and Marahatta, S. (2015). Role ofAzotobacter in Soil Fertility and Sustainability A Review.Adv Plants Agric Res. 2(6): 00069. DOI: 10.15406/apar.2015. 02.00069

Hafeez, F.Y., Safdar, M.E., Chaudhry, A. U. and Malik, K. A.(2004). Rhizobial inoculation improves seedling emergence,

nutrient uptake and growth of cotton. AustralianJournal of Experimental Agriculture 44 : 617-22.

Kochehbagh, S.B., Mirshekari, B. and Bagheri, D. (2011).Effect of Inoculation With Bio Fertilizers on Germinationand Early Growth Nitrogen Medicinal Plant Dill(Anethum graveolens) Research Journal of Fisheriesand Hydrobiology, 6(4): 537-540, ISSN 1816-9112

Mahato, P., Badoni, A. and Chauhan, J.S. (2009). Effect ofAzotobacter and Nitrogen on Seed Germination andEarly Seedling Growth in Tomato Researcher, 1(4); 62-66 http://www.sciencepub.net, sciencepub@gmail.com

Martinez, R., Debut, B. and Gonzalez, R. (1993). Stimulationof tomato development and yield by inoculation of redferrallitic with Azotobacter chroococcum. Mem

Milosevicl, N., Tintor1, B., Protic, R. Cvijanovic, G. andDimitrijevic, T. (2012). Effect of inoculation with Azotobacter

chroococcum on Wheat Yield and Seed Quality,Romanian Biotechnological Letters, 17(3):7352-7357

Paul, S., Verma, O. P., Rathi, M. S. and Tyagi, S. P. (2002).Effect of Azotobacter inoculation on seed germinationand yield of onion (Allium Cepa). Annals ofAgricultural Research 23 : 297-9.

Paul, S., Rathi, M.S. and Tyagi, S.P. (2011). Interactive Effectwith Am Fungi and Azotobacter Inoculated Seed onGermination, Plant Growth and Yield in Cotton(Gossypium Hirsutum) Indian Agricultural ResearchInstitute, Pusa, New Delhi 110 012, Indian Journal ofAgricultural Sciences 81 (11): 1041-(5);63-67

Peter, H., Ray, F., Susan, E. and Eichhorn, E. (2005). Biologyof plants,7th edition. New York; W.h. freeman andcompany publishers. pp. 504-508, ISBN 0-7167-1007-2.

Pérez-Fernández, M.A., Magro, C.E., Fernández, M.J. and Oyola-Velasco, A.J. (2006). Seed germination in response to chemicals:

Effect of nitrogen and pH in the media Journal ofEnvironmental Biology January 2006, 27(1) 13-20

Selvarani, K. and Umarani, R. (2011). Evaluation of seedpriming methods to improve seed vigour of onion(Allium Cepa cv. aggregatum) and carrot (Daucuscarota) Journal of Agricultural Technology 2011 Vol.7(3): 857-867 Available online http://www.ijat-aatsea.comISSN 1686-9141

Sengupta, C., Bhosale, A. and Malusare, S. (2015). Effect ofplant growth promoting rhizobacteria on seedgermination and seedling development of Zea maysInternational Journal of Research in AdventTechnology (E-ISSN: 2321-9637)

The Allahabad Farmer, Vol. LXXIV, No. 3, July - September, 2018