1
The Alleviative effects of isolated bacteria on growth of coriander under lead stress
Hamideh Fatemia,*, Behrooz Esmaielpour,b Ali-Ashraf Soltanic, Ali Nematollahzadeh d;
a: PhD student of oleiculture, Horticulture Department, Mohaghegh Ardabili University of
b Associate Professor of olericulture, Horticulture Department, Mohaghegh Ardabili University of mohaghegh ardabili c Associate Professor,, Soil science Department, Mohaghegh Ardabili University
d Associate Professor, Department of Chemical Engineering , Mohaghegh Ardabili University
*Corresponding author: [email protected]
ABSTRACT
To study the effect of biofertilizers on the growth and physiology of coriander (Coriandrum sativum) under lead stress conditions to a factorial experiment based on completely randomized design was conducted in four replications in research greenhouse of Mohaghegh Ardabili University at 2015-2016. Experimental factors included soil contamination by lead (0, 500, 1000, 1500 mg/kg soil) and inoculation with isolated bacteria (AHG1, AHG2 & AHG3). During this experiment traits such as plant height, plant dry and fresh weight, leaf number, diameter stem, and root dry weight were measured. Results showed that the interaction between stress and the use of lead and bacteria has been significant traits.
The highest Pb treatment (1500 ppm) had decreased 57, 50, 20, 41, 15, 42, 25 % shoot weight, stem diameter, root diameter, root length, Plant height, leaf area and root dry weight and control was highest in all factors compare other treatments. The Pb concentration had not effect on root weight and stem dry weight. In this study strain AHG3 is better than other strain in morphological characteristic under lead stress.
Keywords: Bacteria, Coriander, Morphology
INTRODUCTION
Anthropogenic activities and developing industrialization release toxic wastes into the soil, water and air. This toxic waste is categorized as pollution. These pollutants include heavy metals, which have a density greater than 5 g cm 3, but this definition varies (Abdelatey et al., 2011). The main sources of heavy metals are mining, smelting, fertilizers, pesticides, coal combustion, medical waste, combustion of leaded petrol, and batteries (Rodrigues et al., 2012).
Lead (Pb) is one of the ubiquitously distributed most abundant toxic elements in the soil. The toxic level of Pb in soil results from disposal of municipal sewage sludge, mining and smelting activities, Pb containing paints, paper and pulp, gasoline and explosives. It exerts adverse effect on morphology, growth and photosynthetic processes of plants. High level of Pb also causes inhibition of enzyme activities, water imbalance, alterations in membrane permeability and disturbs mineral nutrition (Sharma and Dubey, 2005). Pb inhibits the activity of enzymes at cellular level by reacting with their sulfhydryl groups. High Pb concentration also induces oxidative stress by increasing the production of ROS in plants (Reddy et al., 2005).
Heavy metal contamination of soils has received considerable attention in the contemporary science.
Application of biological processes for decontaminating the contaminated/polluted sites is a challenging task because heavy metals cannot be degraded and hence persist in the soil.
Several techniques have been used for the removal and/or recovery of heavy metals from polluted environments. Some established conventional procedures for heavy metal removal and/or recovery from solution, include adsorption processes, chemical oxidation or reduction reactions, chemical precipitation, electrochemical techniques, evaporative recovery, ion exchange, reverse osmosis, sludge filtration and biological processes (Ma et al., 2011). However, these techniques are expensive, sometimes impracticable, and are not specific for metal-binding properties. Furthermore, the
2
generation of toxic waste, the high reagent requirement, and the unpredictable nature of metal ion removal, highlights some of the disadvantages of these methods. The majority of these methods are ineffective when metal concentrations in solution are less than 100 mg/L. Separation by physical and chemical techniques is also challenging due to the high solubility of most heavy metal salts in solution. Thus, there is a need to evaluate alternative techniques for a given procedure and such an approach should be suitable, appropriate, and applicable to the local conditions, and must be able to meet the established permissible limits.
Plants and microorganisms are used to remove toxic contaminants from the environment; this is known as biological remediation (Singh et al., 2009). Biological remediation is considered as the most effective method of toxic metal removal because it is a natural process, environmentally friendly, has a low cost, and high public acceptance (Doble and Kumar, 2005). Biological remediation techniques include bioremediation, phytoremediation, bioventing, bioleaching, land forming, bioreactors, composting, bioaugmentation and biostimulation. Among these approaches, bioremediation and phytoremediation are the most useful techniques. These methods have advantages over physicochemical methods because they preserve natural soil properties and depend on solar energy (Beskoski et al., 2011).
MATERIALS & METHODS
Coriander plants (Coriander sativum) were cultivated in pots filled with soil contaminated with heavy metals. Experimental factors included soil contamination by lead (0, 500, 1000, 1500 mg/kg soil) and inoculation with isolated bacteria (AHG1, AHG2 & AHG3). The soil was amended with heavy metals 6 month before cultivation and allowed to equilibrate. Each pot contained 10 kg of separately prepared soil. The bacteria isolated from contamination soil added to seed before planting.
This procedure was repeated several times. After completion of the treatment (6 months), the plants were removed from polythene bags and their parts (root, shoot and leaf) separated. Characteristic was measured: shoot weight, root weight, stem diameter, leaf number, root diameter, root length, plant height, leaf area, dry stem weight, dry root weight.
All values reported in this study are mean of at least three replicates. A two- way analysis of variance (ANOVA) was performed by using a statistical package, SAS version9.4. LSD test was done to determine the significant difference between treatments.
RESULTS AND DISCUSSION
During this experiment traits such as plant height, plant dry and fresh weight, leaf number, diameter stem, and root dry weight were measured. Results showed that the interaction between stress and the use of lead and mycorrhiza has been significant traits. The highest Pb treatment (1500 ppm) had decreased 57, 50, 20, 41, 15, 42, 25 % shoot weight, stem diameter, root diameter, root length, Plant height, leaf area and root dry weight and control was highest in all factors compare other treatments. The Pb concentration had not effect on root weight and stem dry weight.
The bacteria inoculation effect all characteristic in coriander plant. The strain AHG3 was significant effect in characteristic. The morphological effect was higher in this strain compare than other strain.
3
Exposure to high concentrations of heavy metals may produce toxic effects on the growth and development of medicinal plants (Rai and Mehrotra 2008). The plant growth changes recorded from exposure to heavy metals include alterations in seed germination potential and curtailment in root and shoot length, biomass production, and leaf area (Street et al. 2007).
Lead toxicity is primarily inhibiting root growth and reduce the development of root system and shoot growth is limited. Reduced root and shoot growth lead stress because of the high concentration of lead in root, lignin wall is influenced by heavy metal and seedling growth reported in three species tested (Almeida et al., 2007).The soil near plant roots (rhizosphere) important habitat for the activity of microorganisms, including bacteria and plant growth promoters that these microorganisms naturally associated in different ways with plants (Hao et al., 2012). In addition, the biosynthesis of plant growth promoting bacteria, sugars, enzymes and organic acids, which play a positive role in the solubility of heavy metals in plants leads, are responsible for (Ullah et al., 2015). Bacterias, by consolidation, evaporation and separation of heavy metals from the soil and through the increased production of detoxification enzymes in plant cells prevents damage to plants are metals (Pavel et al., 2013). The antioxidant enzyme system is one of the protective mechanisms, which can be found in plants and plants from damage by oxygen free radicals produced by heavy metals protect among these enzymes, catalase and peroxidase (Gara et al., 2003). Reported that maize plants inoculated with Pseudomonas activity of antioxidant enzymes such as catalase and peroxidase when exposed to increased water stress (Sandhya et al., 2010). And also inoculated (Lactuca sativa L.) with Pseudomonas production of catalase to reduce oxidative damage in plants (Kamel et al., 2008).
Heavy metals have a devastating impact on microbial activity and soil fertility and plant growth (Lenart et al., 2013). In fact, in high concentrations of lead, may be seen drastic changes in the genetic and physiological soil microbial community (Aliasgharzad et al., 2011). So that sensitive species that may have any beneficial soil are gone and there is a heavy metal tolerant species and resulting in reduced functional diversity and species diversity (Almas et al., 2004).
Application of PGPR increased germination, seedling vigor, root length, surface and root density was in (Oryza) (Baset Mia et al., 2012). The use of bio-fertilizers, plant height increased compared to control (Makizadeh et al., 2012). In vegetables, such as potato (Singh et al., 2013), Eggplant (Seymen et al., 2013), Cucumber (Gul et al., 2013), Lettuce (Chamangasht et al., 2012). It is reported, IAA produced by bacteria in the roots of plants, cause water absorption and more nutrients from the soil by plants, and by transferring them to different parts of plants results in increased biomass growth and high crop production. Rhizosphere interactions between plants and microorganisms useful can biomass production and increase plant tolerance to heavy metals Promotion of mutual relations among the plants and rhizosphere microorganisms beneficial that may increase the production of biomass and the tolerance of plants to heavy metals (Glick, 2003).
REFERENCES CITED
Aliasgharzad, N., Molaei, A. and Oustan, S, (2011). Pollution induced community tolerance (PICT) of microorganisms in soil incubated with different levels of lead. WASET 60: 1469-1473.
Almas, AR., Bakken, LR. and Mulder, J. (2004). Changes in tolerance of soil microbial communities in Zn and Cd contaminated soils. Soil Biol Biochem 36: 805-813.
Almeida, A.F., Valle, A.A., Mielke, M.S., Gomes, F.P., and Braz, J. 2007. Tolerance and prospection of phytoremediator woody species of Cd, Pb, Cu and Cr. Plant Physiol. 19:83-98.
Baset Mia, M.A., Shamsuddin, Z.H., and Mahmood, M. 2012. Effects of rhizobia and plant growth promoting bacteria inoculation on germination and seedling vigor of lowland rice. Afr. J.
Biotech. 11: 16. 3758-3765.
4
bdelatey, L.M., W.K.B. Khalil, T.H. Ali and K.F. Mahrous. 2011. Heavy metal resistance and gene expression analysis of metal resistance genes in Gram-positive and Gram-negative bacteria present in Egyptian soils. Journal of Applied Sciences in Environmental Sanitation 6:201-211.
Beskoski VP, Gojgic-Cvijovic G, Milic J, Ilic M, Miletic S, Solevic T, Vrvic MM (2011) Ex situ bioremediation of a soil contaminated by mazut (heavy residual fuel oil)—a field experiment.
Chemosphere 83:34–40Demir, 2004).
Chamangasht, S., Ardakani, M.R., Khavazi, K., Abbaszadeh, B., Mafakheri, S., 2012. Improving lettuce (Lsactuca sativa L.) growth and yield by the application of biofertilizers. Ann. Biol.
Res. 3, 1876–1879.
Gara LD, Pinto MC, Tommasi F (2003) The antioxidant systems and reactive oxygen species during plant-pathogen interaction. Plant Physiology and Biochemistry 41: 863-870.
Glick B.R. (2003). Phytoremediation: synergistic use of plants and bacteria to clean up the environment.Biotechnology Advances, 21: 383–393.
Gul, A., Ozaktan, H., Kıdo˘glu, F., Tuzel, Y., 2013. Rhizobacteria promoted yield of cucumber plants grown in perlite under Fusarium wilt stress. Sci. Hortic. 153,22–25.
Hao, X., Xie, P., Johnstone, L., Miller, S.J., Rensing, C., Wei, G., (2012). Genome sequence and mutational analysis of plant-growth-promoting bacterium Agrobacterium tumefaciens CCNWGS0286 isolated from a zinc-lead mine tailing. Appl. Environ. Microbiol. 78, 5384–
5394.
Kamel, H.A. (2008). Lead Accumulation and its Effect on Photosynthesis and Free Amino Acids in Vicia faba Grown Hydroponically. Australian Journal of Basic and Applied Sciences 2(3):
438-446.
Lenart, K. Wolny-Koadka, Bull. Environ. Contam. Toxicol.90 (2013) 85–90.
Makizadeh Tafti, M., Nasrilahzadeh, S., Zehtab Salmasi, S., Chaechi, M. and Khavazi, K. 2012.
Effect of bio-fertilizers, and organic chemical on quantitative characterization of basil (Ocimum bsilicum L.). Journal of Sustainable Agriculture and Production, 22(1): 1-12.
Pavel V.L., Diaconu M., Bulg ariu D., Statescu F., Gavrilescu G., (2012), Evaluation of heavy metal toxicity on two microbial strains isolated from soil: Azotobacter sp . and Pichia sp., Environmental Engineering and Management Journal, 11, 165-168.
Rai V, Mehrotra S (2008) Chromium-induced changes in ultramorphology and secondary metabolites of Phyllanthus amarus Schum & Thonn. – an hepatoprotective plant. Environ Monit Assess 147: 307–
315.
Reddy, A. R., K. V. Chaitanya and M. Vivekanandan. 2004. Drought-induced responses of photosynthesis and antioxidant metabolism in higher plants. Journal of Plant Physiology. 161:
1189-1202.inoculation. Microbiology Research 156: 145-149. Rodrigues et al., 2012).
Sandhya V, Ali SKZ, Grover M, Reddy G, Venkatswarlu B (2010) Effect of plant growth promoting Pseudomonas spp. on compatible solutes, antioxidant status and plant growth of maize under drought stress. Plant Growth
Seymen, M., Turkmen, O., Dursun, A., Paksoy, M., Donmez, M.F., 2013. Effects of bacteria inoculation on yield, yield components and mineral composition in eggplant (Solanum melongena L.) ICOEST’-CAPPADOCIA.
Sharma P. and R.S. Dubey. 2005. Lead toxicity in plants. Plant physiol., 17, 35-52.
Singh, R., Tripathi, R. D., Dwivedi, S., Kumar, A., Trivedi, P.K. & Chakrabarty, D. (2010). Lead bioaccumulation potential of an aquatic macrophyteNajas indicaare related to antioxidant system. Bio Resource Technology, 101, 3025–3032.
Street RA, Kulkarni MG, Stirk WA, Southway C, Van Staden J (2007) Toxicity of metal elements on germination and seedling growth of widely used medicinal plants belonging to hyacinthaceae. Bull Environ Contam Toxicol 79: 371–376.
5
Tangahu, B.V., Sheikh Abdullah, S.R., Basri, H., Idris, M., Anuar, N., Mukhlisin, M., 2011. A review on heavy metals (As, Pb, and Hg) uptake by plants through phytoremediation. Int. J.
Chem. Eng. 2011, 1–32.
Ullah, A., Mushtaq, H., Ali, H., Munis, M.F.H., Javed, M.T., Chaudhary, H.J., 2015. Diazotrophs- assisted phytoremediation of heavy metals: a novel approach. Environ. Sci. Pollut. Res. 22, 2505–2514.
