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Objective: Environmental concern is a global issue. As a citizen of India, we must care about the environment where we are living to be aware of the upcoming threats. Hence, this study was aimed to analyse the biochemical changes in plants and their ability to tolerate pollution a common stress factor prevailing in the environment in order to know their tolerance, sensitivity. Methods: Standard methods were adopted for ascorbic acid, pH, chlorophyll, relative water content, air pollution tolerance index analysis. Results: Highest ascorbic acid content (4.65mg/g) was observed in Albizia lebbeck. pH was acidic in Delonix elata. Water content was found to be high for almost all the plants selected and chlorophyll was high with Albizia amara (24.38mg/g) and Caesalpinia pulcherrima (24.19mg/g). The air pollution tolerance index falls in the range of 06.75 -21.80. Conclusion: The changes in air pollution tolerance index are biochemically induced due to the surrounding environmental condition. Thus, it is concluded that Albizia amara was found to be an intermediately tolerant species whereas all the other species were found to be sensitive.
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Research Article
BIOCHEMICAL CHANGES IN PLANTS INDICATING AIR POLLUTION
M. KRISHNAVENI*
Department of Biochemistry, Periyar University, Salem. Email: logasarvesh@gmail.com
Received: 05 Dec 2011, Revised and Accepted: 03 Jan 2013
ABSTRACT
Objective: Environmental concern is a global issue. As a citizen of India, we must care about the environment where we are living to be aware of the
upcoming threats. Hence, this study was aimed to analyse the biochemical changes in plants and their ability to tolerate pollution a common stress
factor prevailing in the environment in order to know their tolerance, sensitivity.
Methods: Standard methods were adopted for ascorbic acid, pH, chlorophyll, relative water content, air pollution tolerance index analysis.
Results: Highest ascorbic acid content (4.65mg/g) was observed in Albizia lebbeck. pH was acidic in Delonix elata. Water content was found to be
high for almost all the plants selected and chlorophyll was high with Albizia amara (24.38mg/g) and Caesalpinia pulcherrima (24.19mg/g). The air
pollution tolerance index falls in the range of 06.75 -21.80.
Conclusion: The changes in air pollution tolerance index are biochemically induced due to the surrounding environmental condition. Thus, it is
concluded that Albizia amara was found to be an intermediately tolerant species whereas all the other species were found to be sensitive.
Keywords: APTI, Plants, Environment, Pigment.
INTRODUCTION
A major environmental concern to most city is air pollution and it
remains a major challenge. According to World Bank experts,
between 1995 through 2010, India has made one of the fastest
progress in the world, in addressing environmental issues and
improving its environmental quality. [1,2] Population density in
2011, was about 368 human beings per square kilometre. Per capita
oxygen requirement for a day is 0.75kg. So, it is a must to keep the
air clean and safe as we live by inhaling air. The air in a forest is
pleasant as trees discharge approximately 12 ton oxygen through
photosynthesis. Therefore, it is our responsibility to know our
environment and the role plants in indicating pollution. Hence,
present study was aimed to evaluate the biochemical changes in
plant leaf that are collected in and around Salem city.
MATERIALS AND METHODS
Preparation of Extract
100mg of fresh leaf samples from the selected twelve tree species
were brought to the laboratory for air pollution tolerance index
(APTI) analysis by estimating the contents of ascorbic acid [3],
chlorophyll [4], relative water content [5,6], pH in leaf [7] using
water extract of the leaf. Readings were taken using UV
Spectrophotometer for the biochemical analysis. The formula
proposed by Singh and Rao 1983 [7] was used for air pollution
tolerance index: APTI = A (TC + P) +R/10. Where, A= ascorbic acid
content in leaf (mg/g), T= total chlorophyll content in leaf (mg/g),
P= leaf extract pH and R= per cent water content of the leaf. The sum
value obtained is divided by 10 to get a value in reduced scale. This
study was carried out during February, March 2013.
RESULTS AND DISCUSSION
Biochemical, APTI analysis
The results of biochemical changes observed and its impact on APTI
is shown in Table.1. Likewise Table.2 depicts grades allotted to APTI.
Ascorbic acid
The ascorbic acid content was high for Albizia lebbeck, Albiziz amara,
moderate amount of ascorbate was observed with Tridax
procumbens, Syzygium cumini, Morinda pubescens, Delonix elata,
Annona squamosa, Strychnos nux-vomica,Alangium salviifolium,
Holarrhena anti dysenterica and very low levels of ascorbate was
observed with Aegle marmelos. Ascorbic acid being a strong
reductant protects chloroplast against sulphur dioxide induced H2O2,
O2ˉ and OH accumulation. Similarly, it protects the enzymes of CO2
fixation cycle and chlorophyll from inactivation. [8] Defence
mechanism in plants cause increased level of ascorbic acid.
pH
The pH was found to be alkaline for Annona squamosa, Tridax
procumbens, Strychnos nux vomica, Alangium salviifolium, Albizia
lebbeck, Morinda pubescens, neutral pH was observed with Syzygium
cumini, Aegle marmelos, whereas Delonix elata, Albizia amara,
Holarrhena antidysenterica, Caesalpinia pulcherrima showed acidic
pH. Chlorophyll aiding in starch synthesis can indicate
environmental pollution likewise pH helps in physiological
responses caused by stress. pH change influence stomatal sensitivity
and leaves with low pH are more susceptible to pollution but those
having neutral pH are more tolerant.
Table 1: Biochemical parameters, APTI of selected plants
Botanical Name
Family
Ascorbic acid mg/g
pH
RWC
%
Chlorophyll
mg/g
APTI
Annona squamosa L.
Annonaceae
1.35
8.0
96.07
00.06
10.71
Tridax procumbens L.
Asteraceae
3.45
8.0
95.32
00.31
12.40
Syzygium cumini (L.) Skeels
Myrtaceae
3.45
7.0
98.60
00.42
12.42
Aegle marmelos (L.) Corr.
Rutaceae
0.45
7.0
99.25
19.55
11.11
Strychnos nux-vomica L.
Loganiaceae
1.95
8.0
99.64
16.99
14.83
Albizia amara (Roxb.) Boivin
Mimosaceae
4.05
5.0
99.67
24.38
21.80
Alangium salvifolium Lam.
Alangiaceae
1.05
8.0
80.34
22.05
11.18
Caesalpinia pulcherrima (L.) Sw.
Caesalpiniaceae
2.85
6.0
64.18
24.19
15.02
Albizia lebbeck (L.) Willd.
Mimosaceae
4.65
8.0
97.50
01.67
14.24
Delonix elata (L.) Gamble
Caesalpiniaceae
1.65
4.0
50.45
06.36
06.75
Holarrhena antidysenterica (Roxb.) Wall.
Apocynaceae
2.55
6.0
81.94
17.29
14.13
Morinda pubescens J.E. Smith
Rubiaceae
2.58
8.0
65.30
12.5
11.81
RWC- Relative water content, APTI - Air pollution tolerance index.
International Journal of Pharmacy and Pharmaceutical Sciences
ISSN- 0975-1491 Vol 5, Suppl 3, 2013
Krishnaveni et al.
Int J Pharm Pharm Sci, Vol 5, Suppl 3, 585-586
586
Relative water content
Relative water content was found to be high for all the selected
plants whereas it was moderate for Delonix elata , Morinda
pubescens. Water is an essential factor for the transportation of food,
minerals. So, Plants with relatively high water content are highly
resistant to pollution [9].
Chlorophyll
Chlorophyll was found to be high for Albizia amara, Delonix elata,
Alangium salvifolium, Holarrhena antidysenterica, Strychnos nux-
vomica, Aegle marmelos, Morinda pubescens, whereas it was very low
for Syzygium cumini, Tridax procumbens, Annona squamosa. Loss in
total chlorophyll content of plant depends on the degree of pollution.
Degradation of photosynthetic pigment indicates air pollution [10].
Air pollution tolerance index
APTI can be used as bioindicators of air quality. The air pollution
tolerance index found to decrease in the following order
Albizia amara < Caesalpinia pulcherrima<Strychnos nux-vomica<
Albizia lebbeck < Holarrhena antidysenterica< Syzygium cumini<
Tridax procumbens< Morinda pubescens< Alangium salvifolium<
Aegle marmelos< Annona squamosa< Delonix elata. Sensitivity of
plants are always related to low APTI value. Their tolerance is
relatively proportional to the levels of pollution which gives
variation from one species to another species and capacity to resist
pollutants in the environment without showing any external damage
or loss. The obtained index were graded [11], values below 10 was
considered negligible.
Table 2: Showing air pollution tolerance index and their grades
Botanical Name
Air pollution
tolerance
index
Grade
allotted
Annona squamosa L.
10.71
+
Tridax procumbens L.
12.40
+
Syzygium cumini (L.) Skeels
12.42
+
Aegle marmelos (L.) Corr.
11.11
+
Strychnos nux-vomica L.
14.83
+ +
Albizia amara (Roxb.) Boivin
21.80
+ + +
Alangium salvifolium Lam.
11.18
+
Caesalpinia pulcherrima (L.) Sw.
15.02
+ +
Albizia lebbeck (L.) Willd.
14.24
+
Delonix elata (L.) Gamble
06.75
Negligible
Holarrhena antidysenterica (Roxb.)
Wall.
14.13
+ +
Morinda pubescens J.E. Smith
11.81
+
CONCLUSION
The importance of plants in tolerating pollution is studied through
APTI analysis as it is economical and does not involve costlier
equipments. Air pollution tolerance index is a synergistic effect of
biochemical indices. All plants studied were found to be sensitive
species to pollution except Albizia amara as it have APTI of 21.8 and
+++.
ACKNOWLEDGEMENT
The author thank Dr. T. Parmelazhagan, Associate Professor,
Department of Botany, Bharathiar University, Coimbatore, for his
help.
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