study was carried out on Neem (Azadirachta indica) and Sheesham
(Dalbergia sissoo) trees grown abundantly around the Badarpur Thermal
Power Plant where atmosphere is polluted due to coal-smoke pollutants
emitted from the stacks of the power plant. The observations were
carried out for three consecutive years. Plant materials (mature
leaves) collected from five selected sites, located at different
distances from the pollution source, were studied and analyzed so
as to assess the impact of environmental degradation on anatomical,
physiological, biochemical, pharmacognostical and phytochemical
traits of the test plants.
SO2, NO2 and SPM (Suspended Particulates matter) concentrations
were maximum at site III, whereas site V had the minimum stress
(comparable with the non-polluted atmosphere) and was, therefore,
considered as the reference site.
soil was slightly alkaline sandy loam at all the sites. Nitrogen
content of the soil was minimum at the highly polluted site (site
III), and maximum at site V. Soil sulphur was low at sites I and
IV. Potassium in soil was lowest at the most polluted site.
length and width of phloem fibres, seive tube elements, relative
proportion of seive tubes and fibres, amount of conducting phloem
and the vascular tissues in the petiole of leaf of both species
decreased at all sites in all seasons. However, proportion of axial
parenchyma and ray parenchyma of conducting phloem in the stem increased.
net photosynthetic rate and stomatal conductance of leaves declined
at the polluted sites but the intercellular CO2 concentration increased.
nitrate, sugar and sulphur contents of leaf and secondary phloem
enhanced at almost all sites, with the maximum enhancement at site
III. However, the reduced nitrogen, reducing sugar and sulphate
contents in both leaves and bark decreased at all sites.
pharmacognostic parameters varied with respect to pollution. Loss
on drying, per cent ash value content, water-soluble ash, sulphated
ash and acid insoluble ash contents were enhanced with respect to
pollution load. The various extractive values increased at various
distances from the pollution source. The maximum increase was recorded
at 8 km from the pollution source. However, the petroleum ether
extractive decreased with respect to site V.
content decreased proportional to the pollution load in case of
in the crude fibre was also observed. The protein content (crude
protein) declined under pollution stress in both A. indica and D.
compounds, mostly flavonoids, terpenoids and fatty acids, were isolated
from the barks of A. indica and D. sissoo. Their amounts declined
under pollution stress.
content in the leaves of both the trees also reported decreased.
new compounds were isolated through column chromatography in order
to mark them as reference or marker compounds for quantitative estimations.
Compounds isolated from the bark of A. indica are;
- RN-I 5-methyl-n-triacotane.
- RN-2 n-heptacosan-8-ol
- RN-3 n-hexacosanoic acid
- RN-4 2,6,10,14-tetramethyl-pentadeca-8-en-2, 7-diol
- RN-5 2,6,10-trimethyl-14-cyclopentanyl-n-tetradecan-6a-ol
- RN-6 5,7-dien,3b-ol-b-D-glucopyranoside
- RN-7 9,9-dimethyl-decan 7-en-2-ol-11,12-dioic acid
- Compounds isolated from the bark of D. sissoo are;
- RD-I n-hexacosa-5-ol -yl propionate
- RD-2 n-tetracosa-5-ol -yl propionate
- RD-3 6-hydroxy-7-methoxy-4-(2-hydroxybenzyl)-benzopyron
- RD-4 9,11,12-trihydroxy-10-methoxyanthracare-14,17-[2H]-pyran
have a greater capacity to accommodate very wide fluctuations in
their environment but the buffering capacity they endow finally
fails, resulting in chronic sub-optimal growth. The recorded accumulative
toxic effects of pollution in the morphological, physiological,
biochemical and phytochemical characteristic are suitable indicators
for biological monitoring. The pollution load alter, not only the
quantity but also the quality of active compounds of the trees,
thereby decreasing the therapeutic value of a compound or a combination
of compounds. The maximum effect was observed during winter, confirming
that the test species were more sensitive to pollution during winter.