1. Rakwal R, Agrawal GK, Kubo A, Yonekura M, et al. Defense/stress responses elicited in rice seedlings exposed to the gaseous air pollutant sulfur dioxide. Environ. Exp. Bot. 2003; 49: 223-235.
2. Irshad AH, Fayaz Ahmad S, Sultan P. Effect of Sulphur dioxide on the biochemical parameters of Spinach (Spinacea oleracia). Trakia J. Sci. 2011; 9(1): 24-27.
3. Smith SJ, Aardenne JV, Klimont Z, Andres RJ, et al. Anthropogenic sulfur dioxide emissions: 1850–2005. Atmos. Chem. Phys. 2011; 11(3): 1101–1116.
4. Hill GR, Thomas MD. Influence of leaf destruction by sulfur dioxide and clipping on yield of alfalfa. Plant physiol. 1933; 8:334-345.
5. Solberg RA, Adams DF. Histological responses of some plant leaves to hydrogen fluoride and sulfur dioxide. Am. J. Bot. 1956; 43(10): 755-760.
6. Pyatt BF. Lichens as indicators of air pollution in a steel producing town in south wales. Environ. Pollut. 1970; 1: 45-55.
7. Sharma GK. Cuticular features as indicators of environmental pollution. Water Air Soil poll. 1977; 8(1): 15-19.
8. Lang C, Popko J, Wirtz M, Hell R. et al. Sulphite oxidase as key enzyme for protecting plants against sulphur dioxide. Plant Cell Environ. 2007; 30(4): 447–455.
9. Sahgl M, Johri BN. The changing face of rhizobial systematics. Curr. Sci. 2003; 84(1): 43-48.
10. Ahemad M, Khan MS. Functional aspects of plant growth promoting rhizobacteria: recent advancements. Insight Microbiology. 2011; 1(3): 39-54.
11. Yang J, Kloepper JW, Ryu CM. Rhizosphere bacteria help plants tolerate abiotic stress. Plant Sci. 2009; 14(1): 1-4.
12. Erdemli S, Colak E, Kendir H. Determination of some plant and agricultural characteristics in Persian clover (Trifolium resupinatum L.). Tarim Bilimleri Dergisi. 2007; 13(3): 240-245.
13.Ates E. Influence of some hard seededness-breaking treatments on germination in Persian clover (Trifolium resupanatum ssp. typicum Fiori Et Paol.) seeds. Rom. Agric. Res. 2011; 28: 229-236.
14. Abbas SM, Kamel EA. Rhizobium as a biological agent for preventing heavy metal stress. Asian J Plant Sci. 2004; 3(4): 416-424.
15. Abbasi MR. Genetic diversity of Persian clover (Trifolium resupinatum) gene pools in National Plant Gene Bank of Iran. Iranian Journal of Rangelands and Forests Plant Breeding and Genetic Research. 2008; 16(1): 37-49.persian
16. Swift M, Bignell D. Standard methods for assessment of soil biodioversity and land use practice. International centre for research in Agroforestry (ICRAF) Southeast Asia 2001. Availible from: URL: http://www.icraf.cgiar.org/sea.
17. Molla AH, Shamsuddin ZH, Halimi MS, Morziah M, et al. Potential for enhancement of root growth and nodulation of soybean co-inoculated with Azospirillum and Bradyrhizobium in laboratory systems. Soil Bio. Biochem. 2001; 33: 457-463.
18. Caetano-Anolles G, Wall LG, De Micheli AT, Macchi EM, et al. Role of motility and chemotaxis in efficiency of nodulation by Rhizobium meliloti. Plant Physiol. 1988; 86: 1228-1235.
19. Sadovinkova YN, Bespalova LA, Antonyuk LP. Wheat gram agglutinin is a grown factor for bactrerium Azospirillum brasilense. Dokl. Biochem. Biophys. 2003; 398:103-105.
20. Bai Y, Zhou X, smith DL. Crop ecology, management and quality: enhanced soybean plant growth resulting from coinoculation of Bacillus strains with Bradyrhizobium japonicum. Crop Sci. 2003; 43: 1774-1781.
21. Wang YX, Oyaizu H. Evaluation of the phytoremediation potential of four plant species for dibenzofu-ran-contaminated soil. J. of Hazard. Mater. 2009; 168: 760-764.
22. Bashan Y, Levanony H, Mitiku G. Changes in proton efflux of intact wheat roots induced by Azospirillum brasilense Cd. Cana. J. Microbiol. 1989; 35: 691-697.
23. Agrawal M, Nandi PK, Rao DN. Effects of sulphur dioxide fumigation on soil system and
growth behaviour of Vicia faba plants. Plant Soil. 1985; 86(1): 69-78.
24. Cocking EC, Davey MR, Kothari SL, Srivastava JS. et al. Altering the specificity control of the interaction between rhizobia and plant. Symbiosis. 1992; 14: 123-130.
25. Noori M. Characterization of the Iranian species of Shophorea and Ammodendron (Leguminosea: Sophorea). Phd thesis, University of London and Royal Botanic Gurden, Kew, UK. 2002.
26. Gostin IN. Air pollution effects on the leaf structure of some Fabaceae species. Not. Bot. Horti. Agrobo. 2009; 37(2): 57-63.
27. Kiernan JA. Histological and histochemical methods: theory and practice. 3th edn. Oxford. UK: Butterworth-Heinemann. 1999.
28. Lillie RD. Histopathologic technic and practical histochemistry.3nd Ed. New York: the Blakiston Company. 1965.
29. Persello-Cartieaux F, Nussaume L, Robaglia C. Tales from the underground: molecular plant-rhizobacteria interactions. Plant Cell Environ. 2003; 26(2): 189-199.
30. Timmusk S. Mechanism of action of the plant growth promoting bacterium Paenibacillus polymyxa. Uppsala, Sweden: Acta Universities Upsaliensis. Comprehensive Summaries of Uppsala Disserations from the Faculty of Science and Technology 908. 2003; 40pp
31. Maekawa-Yoshikawa M, Muller J, Takeda N, Maekawa T, et al. The temperature-sensitive brush mutant of the legume Lotus japonicus reveals a link between root development and nodule infection by rhizobia. Plant Physiol. 2009; 149: 1785–1796.
32. Melotto M, Underwood W, Koczan J, Nomura K, et al. Plant stomata function in innate immunity against bacterial invasion. Cell. 2006; 126(5): 969–980.
33. Romas LJ, Volin RB. Role of stomatal opening and frequency on infection of Lycopersicon spp. by Xanthomonas campestrispv. vesicatoria. Aps. Symp. Ser. 1987; 77(9): 1311-1317.
34. Omosun G, Markson AA, Mbanasor O. Growth and anatomy of Amaranthus Hybridus as affected by diferrent crude oil concentrations. Am.Eurasian J. Scientific Res. 2008; 3 (1): 70-74.
35. Wali B, Iqbal M, Mahmooduzzafar. Anatomical and functional responses of Calendula ofﬁcinalis L. to SO2 stress as observed at different stages of plant development. Flora. 2007; 202: 268–280.
36. Khan I, Ahmad A, Iqbal M. Sulphur in theenvironment. In Tandon P, Khatri S, Abrol Y. P, (eds). Biodiversity and its signiﬁcance. New Delhi: IKBooks; 2006; 90-99.
37. Hijano CF, Dom´inguez MDP, Gim´enez RGS, ´anchez PH, et al. Higher plants as bioIindicators of sulphur dioxide emissions in urban environments. Environ. Monit. Assess. 2005; 111: 75–88.
38. Singh SN, Yunus M, Srivastava K, KulshreshthaK, et al. Response of Calendula officinalis L. to long-term fumigation with SO2. Environ. Pollut. 1985; 39: 17-25.
39. Wali B, Iqbal M, Mahmooduzzafar. Plant growth, stomatal response, pigments and photosynthesis of Althea ofﬁcinalis as affected by SO2 stress. Indian J. Plant Physi. 2004; 9: 224–233.
41. Duldulao MCG, Gomez RA. Effects of vehicular emission on morphological characteristics of young and mature leaves of sunflower (Tithonia diversifolia) and Napier grass (Pennisetum purpureum). BSU grad. School Res. J. 2008; 85: 142-151.
42. Tanvir-Ali S, Mahmooduzzafar, Abdin MZ, Iqbal M. Ontogenetic changes in foliar features and psoralen content of Psoralea corylifolia Linn.exposed to SO2 stress. J. Environ. Biol. 2008; 29(5): 661-668.
43. Krishnayya NSR, Bedi SJ. Effect of sulphur dioxide and ascorbic acid on the plastid ultrastructure of Azadirachta indica leaves. Ann. Bot-London. 1980; 64(3): 311-313.
44. Hui-zhen Q, Zhu-jun W, Jia-xi W, Da-fu Q, et al. The effects of the harmful gases SO2 and HF on plant leaf structure. Acta Bot.Sin. 1980; 22(3): 232-236.