1.	Title of the thesis	:	A CONTRIBUTION TO THE STUDY OF THE EFFECTS OF INDUSTRIAL AIR POLLUTANTS ON PLANTS.
2.	Subject	:	BOTANY
3.	Degree	:	Ph.D.
4.	Name of the guiding teacher	:	DR. S. B. CHAPHEKAR, ASSOCIATE PROFESSOR OF ECOLOGY, DEPARTMENT OF BOTANY, THE INSTITUTE  OF SCIENCE, BOMBAY- 4OO 032.
5.	Institution where work was done	:	DEPARTMENT OF BOTANY, THE INSTITUTE OF SCIENCE, BOMBAY -  400 032.

With the progress of, industrialization, quantities of industrial effluents being added to the environment are on an increase. The effluents are emitted by industries in air, water and-soil. The airborne effluents may be in gaseous or particulate form and affect life. The effects are physical, physiological and in some cases, genetic.

In a place like Bombay city where a large number of industries are located along with dense human population, it is difficult to segregate different air pollutants from one another. The industries emit sulphur dioxide, ammonia, oxides of nitrogen hydrogen fluoride, para-aceyl nitrate (PAN)., hydrocarbons, oxygenates, carbon monoxide, hydrogen bisulphide, benzopyrenes, etc. depending upon the process involved. Industries in Greater Bombay region throw about 1000 tons of pollutants per day, into the atmosphere. Of these, 38.4 °/o is carbon monoxide, 34.4 %. sulphur dioxide, and the rest is made up of particulates, oxides of nitrogen and others (NEERI Report, 1975).

The general pattern of morphological damage to plants caused by air pollution is, by now well known. Subeuent to the publication of of a review by Thomas (1951), a lot of information has been added to the subject. Intercostal soft patches to leaf senescence caused by ambient sulphur dioxide, have been variously described by different authors (Brandt, et al, 1968, David,1972, Pandey and Rao, 1978, etc.). Reduced rates of germination and adverse effect on roof nodulation in beans, were reported by Bandyopadhyaya (1976), in this laboratory.

For the last few years, industrial development in the countries like India has been going on at a very fast pace. The work presented here is an attempt to learn about the effects of industrial air pollutants on plants, for which the following aspect have been studied.

Relative sensitivity of plant species

A few plant species grown commonly in and around Bombay were studied for their sensitivity to sulphur dioxide Sensitivity was studied at different ages of the following plants.

• Spinacia oleracea L. ( vern. Palak).
• Abelmoschus esculentus Moench. var. Pusa Savni (vern. Bhendi ).
• Amaranthus viridis L. ( vern. Math )
• Phaseolus aureus Roxb. var, Vaishakhee (vern. Mung ).

Plants at the ages of 10, 20 and 30 days were fumigated in laboratory under static conditions, / in a closed perspex chamber at 9 parts per hundred million (pphm) or 257° ug / m3 of sulphur dioxide concentration for four hours. All of them were analysed for their responses on the 40th day from sowing. Growth perfoman as indicated by the shoot length, number of nodes per plant, hi of leaves per plant, length of numbered internode from the-top number of flowers per plant whenever present, oven dry weights above ground phytomass. Chlorophylls and total proteins were also estimated.

It was observed that all the plants were adversely affected, though to a different degree. Spinacia was greatly affected while Phaseolus was least affected, Amaranthus and Abelmoschus showing intermediate levels of damage. Plants fumigated at 10 day-old stage showed more damage compared to those fumigated at higher ages as evidenced by dry matter production and growth performance. The depletion in protein contents of fumigated plants was more compared to that in the unfumigated controls. Chlorophylls on the other hand, were less depleted on fumigation with sulphur dioxide. On the basis of dry matter production the sequence of sensitivity was as follows, at all the tested stages of growth i.e. 10,20 and 30 day-old plants :

Amaranthus > Spinacia > Abelmoschus > Phaseolus

This indicated a possibility that the relative sensitivity of different plant species was the same, irrespective of the age of the plant, (upto the age of 30 days) i.e. while the vegetative growth was vigorous.

Effects of different concentrations of SO3 / in plants

Five plant species were studied for their responses to different concentrations of sulphur dioxide at four stages of growth.
The plant species tested were :

• Sorghum vulgare Pers. var. CSH-1. (vern. Jowar).
• Crotalaria juncea L. (Sunnhemp, vern. Taag).
• Cvamopsis tetragonaloba Taub. var. Pusa Navbahar (vern. Gawar).
• Commelina benghalensis L.
• Trigonella foenum-graecum L. (vern. Methi).

Stages of growth when the plants were fumigated for 3 hours at 4,9,50 and 100 pphm sulphur dioxide concentrations were - soaked- seeds and 15, 30 and 45 day-old plants. Plant response to fumigation was studied 24 hours after fumigation for chlorophyll,protein, sugar contents and leaf area damage whenever present. Commelina was propagated by cuttings and was not tested at soaked seed stage.

The seed germination studies showed marginal decrease percentage germination with the increase of sulphur dioxide concentration. The early growth of seedlings Was also adversely affected with increasing concentration of the pollutant, as indicated by the reduced root and shoot lengths. At all the stages of growth and concentrations of sulphur dioxide tested, chlorophyll, protein and sugar contents showed drop, as observed 24 hours after the fumigation. The reduction was found to be related to the age of the plant sulphur dioxide concentration. A visible damage on leaves was perceptible in Jowar and Methi plants within 24 hours. It was seen that the leaf area, damage increased with an increase in sulphur dioxide concentration. Older leaves were less damaged than the younger ones.

Some of the plants were allowed to grow for 30 days after fumigation. They were harvested and their growth performance as indicated by the dry matter production was studied. Generally plants showed more resistance with increasing age.