Fumigation by sulphur dioxide (50 pphm) and ozone (10 pphm) alone and in combination for four hours of seeds of Cyamopsis tetragonoloba var. Pusa Navbahar in the laboratory showed that seed germination was adversely affected and the effect was more due to the combination of the pollutants than the alone as indicated by the redueed % germination, germination index, root length and shoot length, as compared with that of the control.

INTRODUCTION

Plants are rarely exposed to a single phytotoxic air pollutant in field. The atmospheric environment usually contain a mixture of potential phytotoxicants emitted from the number of sources. The effects of mixture of air pollutants on plants are of much more concern and have been described by many workers, Menser and Heggestad1, Tingey et al2.y Agrawal et a/.,3 and Boralkar and Shinde.4 The present work is in the direction of the study of effect of sulphur dioxide and ozone, alone and in combination, on seed germination.

MATERIALS AND METHODS

Extensive experimental trials were earned out on 100 seeds of Cyamopsis tetragonoloba Tnub. var. Pusa Navbahar (vern. Gawar) which were soaked in distilled water for two hours and spread on sterilised filter paper in petri dishes. Seeds were exposed to sulphur dioxide (50 pphm) and ozone (10 pphm) for four hours in a 1 m3 fumigation chamber of dynamic type5'6. Seeds were then left for gemination. The emergence of radical was taken as mark of germination which was noted every 24 hours for five consecutive days and Germination Index values were calculated as described by Carley and Watson7. Root and shoot length of seedlings were measured on the fifth day. Similarly a control was also run simultaneously with the same number of seeds.

RESULTS AND DISCUSSION

The results so obtained from the extensive experimental observations made on 100 seeds of Cyamopsis tetragonoloba var. Pusa Navbahar are submarised in Table 1. The percentage germination was slightly affected due to alone ozone and sulphur dioxide but reduction was 12% due to the mixture of S02 and 03 as compared with that of controls where the seed germination was 100%.

The Germination Index (GI) values also showed similar pattern of the effect The Germination Index values were 1323 and 1159 in the seeds fumigated by O3 and SO2 respectively which were little less than that of the control, but the reduction in GI was quite significant in the seeds fumigated by the mixture of O3 and SO2 which was more than 35% as compared with that of controls.

Both roots and shoots developed less due to the fumigation of pollutant gases, singly and in combination. The reduction in root length was 31 and 34% in the seeds fumigated by O3 and SO2 alone

Table 1 : Effect of a 4-hour SO2 and O3 singly and in combination on seed germination of Cyanopsis tetragonoloba var. Pusa Navbahar.

Treatment	% Germination	Germination Index	Root length (cm)	Shoot lenght (cm)	RL / SL
			Mean of 100 obserations	Mean of 100 obserations
Control	100	1370	3.9	3.8	1.02
O3(10pphm)	99	1323	2.7	3.6	0.75
SO2(50pphm)	95	1159	2.6	3.2	0.81
O3(10pphm)
SO2(50pphm)	88	894	2.2	2.8	0.78

respectively while it was 44% in the seeds fumigated by the mixture of O3 and SO2. Shoot length was also affected more or less in similar pattern like the root length. It was slightly affected due to O3 treatment but sulphur dioxide produced more adverse effect on shoot length which was 3.6 cm and 3.2 cm in the seeds fumigated by O3 and SOa respectively. However, the shoot length was greatly affected due to fumigation by mixture of O3 and SO2 where the reduction in the shoot length was 27%. The root shoot ratio was less in all the three treatments as compared with that of controls. It was 0.75, 0.81 and 0.78 in seeds fumigated by O3 SO2 and mixture of O3 and S02 respectively, while control had 1.01

CONCLUSION

The observations revealed the fact that the seed germination in Cyamopsis tetragonoloba var. Pusa Navbahar was affected due to the fumigation of O3 SO2, however, the effect was more adverse due to mixture of O3 and S02. The adverse effect on root growth was more than the shoot as indicated by the reduced root to shoot ratio which will hamper the establishment of the plant species in the ecosystem and thus reduce the comparability of the speies.

ACKNOWLEDGEMENTS

Authors are thankful to Principal Prof. R.M. Raverkar, and Prof. B.G. Dhavale, for encouragement and University Grants Commission for financial help through the Scheme of Restructed Courses sanctioned to the Science College, Karad.

REFERENCES

• Menser. H. A. and H. E. Heggestad. 1966. Ozone and sulphur dioxide synergism : Injury to tobacco plants. Science, 153:424-425.
• Menser. H. A. and H. E. Heggestad. 1966. Ozone and sulphur dioxide synergism : Injury to tobacco plants. Science, 153:424-425.
• Agrawal, M., P. K. Nandi and D. N. Rao. 1983. Eoophysical responses of Eggplants to ozone, sulphur dioxide and a mixture of these two pollutants. Ind. J. Air Poliut. Coutr., 4(1 & 2): 27-32.
• Boralkar, D. B. and D. B. Shinde. 1983. Effects of sulphur dioxide and ozone, singly and in combination, on germination and chlorophylls of Abelmoschus esculent us var. Pusa Savni J. Environ. Biol., 4 (3):99-102.
• Rao, D.N. and D. Pal. 1975. A plant growth chamber for air studies, Ind J. Environ. Health. 17:105-110.
• Bancrjee, A. K., D. B. Boralkar and S. B. Chaphekar. 1980. A closed chamber for exposing plants to air pollutants, Ind. J. Air Pollut. Contr., 3 (1):23-26.
• Carley, E.H. and R. D. Watson. 1968. Effects of various aqueous plant extracts upon seed germination. Bot. Gaz. 129 (1):57-62.