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Ethnobotanical Leaflets 14: 518-28.
2010. Effects
of Petroleum Products on the Chlorophyll Accumulation in Barbula lambarenensis P.O. Fatoba,
K. S. Olorunmaiye and R. M. Ogunlade Department of Plant Biology, Issued April 1, 2010 Abstract The effects of
petroleum products: Petroleum Motor Spirit (petrol, PMS), Automobile Gas Oil
(diesel. AGO), Dual Purpose Kero (kerosene, DPK), were investigated on the
chlorophyll accumulation in Barbula
lambarenensis. This plant with its substrates were collected from its
natural populations, taken to the screen house and divided into ten regimes
widely separated. Each of these regimes was irrigated with borehole water for
two weeks, thrice a week to bring about hydration. The three petroleum
products were separately diluted with borehole water in 1:1 ratio to give 50%
concentrations. Moreover, 100% of these products were also used .The 50%
concentrations were separately used to irrigate the first three regimes, A, B
and C for 20 weeks .The D, E and F regimes were irrigated with 100% kerosene,
petrol and diesel respectively for the 2 weeks and later with borehole water
for twenty weeks while the G regime was irrigated with borehole
water (Control). Irrigations were done thrice a week. Samples of B. lambarenensis were collected
fortnightly for chlorophyll extraction and the chlorophyll a, b and total
chlorophyll content determined with the aid of spectrophotometer .It was
observed that the 50% treated moss
plants had greater chlorophyll a, b and total chlorophyll than the control
but their concentrations were statistically the same. The 100% treatment gave
greater chlorophyll a content than the control, PMS treatment had greater
chlorophyll b than the control but the reverse were for DPK and AGO treated
moss plant. However, all these values were the same statistically. The same
results were found for the total chlorophyll except that the DPK, AGO and
Control treatments had the same value statistically while DPK, Control and
PMS treatments were the same statistically. The 50% treatments had worse
effects than the 100% followed by borehole water treatments. Furthermore, the
two concentrations had the same effects on the chlorophyll contents but DPK
and AGO had significantly greater chlorophyll b concentrations in 50% treated
regimes than 100% treatments at 5% level of significance. Petroleum products
damaged the chlorophyll apparatus of the plant making the treated to produce
greater chlorophyll contents than the Control. Key
words: Petroleum Products, Chlorophyll Accumulation, Barbula
lambarenensis Introduction Oil industries play a major role in
the economies of oil producing countries such that petroleum products have
constituted the major source of fuel for driving engines and automobiles as
well as for domestic needs. Oil industries have also facilitated the
development of infrastructures such as road, telecommunication, industries
and other facilities that have brought about better standard of living. Apart
from these benefits, this sector has also affected the environment negatively
such that lives and valuable properties have been destroyed. The effects are
worsened by oil spillage into water bodies and land resulting to the death of
man, animals and plants and the pollution of the environment. Their uses have
increased the incidence of oil spillage in the process of transportation as
well as their discharge in depots and petroleum stations or areas where
needed. Petroleum products have been reported
to have adverse effects on plants irrespective of their habits or habitats.
Such effects are manifested in reduced and retarded growth, vestigial plant
parts, morphological defects, and irregular physiological processes such as
chlorosis and in extreme cases, death. Mckendrick (2002) reported that
wilting, defoliation and loss of productive cycle as immediate impacts on
the vegetation. Furthermore,
destruction of normal plant water relation which indirectly affects plant
metabolism with respect to nutrient availability or directly toxic to plant
(McCown et al., 1972). The most urgent problem of man is
environmental pollution as clean air is no more a normal feature of the
environment. The environment is now loaded with pollutants from agricultural
chemicals, radioactive materials, sewage and chemicals in water and solid
wastes on land (Little and Martin,1974). Natural and agricultural sources,
energy production and recycling operation, urban and industrial complexes and
cars are sources of atmospheric pollution (Seaward and Richardson,1990,
Wegner et al.,1990).The presence of
heavy metals such as lead and cadmium in the petroleum products have been
indicted in the blockage of conducting vessels of plants thereby interfering
in the physiological and biochemical processes necessary for plant
development (Jastrow and Koeppe 1980). Petroleum, when subjected to
fractional distillation and refined gives the Dual Purpose Kero (kerosene),
Automobile Gas Oil (diesel) and Premium Motor Spirit (petrol). Each of these
products has important usage in the environment. Kerosene is widely used in
aviation industry as fuel for jet engines as well as in the homes for cooking
in stoves and lightening in lanterns. Diesel is used for power generating
plants and by heavy trucks and also as illuminant. In the same vein, petrol
is used to move automobiles and for light generation by generators. The exploration, transportation and
utilization of these petroleum products pose serious danger to the lives of
the flora and fauna in the environment. There is the need therefore to
ascertain or monitor the pending risk or potential damage level of these
pollutants from time to time. A good bio-indicator is therefore required.
Renzaglia and Vaugh (2000) identified bryophytes as the primary receptors of
atmospheric deposition. To this effect, Barbula
lambarenensis, a common moss has this potential and can be used to
monitor the effects of petroleum products. This
research was designed to investigate the effects of petroleum products on the
chlorophyll accumulation in B.lambarenensis
by simulating oil spillage. Materials
and Methods Barbula
lambarenensis with its sandcrete blocks (substrates) were
collected from their natural habitats and brought to the Screen House in the Three petroleum products: Dual Purpose
Kero (DPK) or simply kerosene, Premium Motor Spirit (PMS) known as petrol and
Automobile Gas Oil (AGO) or simply diesel was used as irrigants of these
different regimes. Two sets of
irrigants were prepared thus: the three products mixed separately with
borehole water in 1:1 ratio (50%) and the second set were 100% DPK, 100% PMS
and 100% AGO. The first set of
irrigants were used to irrigate regimes A B and C at other days for 20 weeks
while the second set were used for 2 weeks at other days followed by borehole
water irrigation for 18 weeks for regimes D, E and F while regime G was
irrigated with borehole water (Control). From each of the regimes, moss samples
were collected fortnightly and chlorophyll extraction carried out with 80%
acetone and the chlorophyll contents determined with the use of
Spectrophotometer model Camspec 105.
The formulae of Strain and Svec (1966) were used to calculate the
chlorophyll a, b and total chlorophyll contents of each sample. Data generated from these analyses
were subjected to Analysis of Variance to show the differences in the effects
of these petroleum products on chlorophyll contents of B. lambarenensis. The
mean values were further separated with the use of Duncan Multiple Range Test
and Students t- test was used to compare the effects of the two
concentrations of petroleum products on
the chlorophyll contents of this plant. Results
and Discussion The effects of the three petroleum
products: DPK, PMS and AGO on the chlorophyll accumulation in Barbula lambarenensis are shown in Figures 1, 2 and 3 for 50% concentration
and Figures 4, 5 and 6 for 100% concentration. Figure 1 shows the effects of
these irrigants on chlorophyll a content of B. lambarenensis. A
close observation of these values for 20 weeks showed no distinct pattern but
fluctuation, when the effects of these irrigants on chlorophyll a were
statistically tested. It was found
that all had similar effect (F=0.593) though there were numerical
differences. The mean values of chlorophyll a for Control was the least
(0.4968mg/g), followed by the DPK (0.5898mg/g), then PMS (0.6134mg/g) and
finally AGO (0.6173mg/g) in an increasing order. Figure 2 shows the effects of 50% of the 3
irrigants in chlorophyll b contents of B.
lambarenensis. The mean values of chlorophylls b contents
are as follow: Control (1.0464mg/g), PMS (1.2555mg/g), AGO (1.3345mg/g) and
DPK (1.3691mg/g). These values were
found to be statistically the same at 5% level of probability (F=1.768). The effects of 50% petroleum products
on total chlorophyll of the plant are shown in Figure 3. The least content was found in the Control
(1.3677mg/g), followed by AGO (1.6016mg/g), DPK (1.6523mg/g) and finally AGO
(1.6953mg/g). These values were found
to be statistically the same (F=1.556). A general observation of these
results showed different effects on the different chlorophyll contents but
the Control had the least showing that these irritants had effects though not
significant on the chlorophyll contents of this plant. Generally, chlorophyll a is usually greater
than chlorophyll b but the reverse was found in this study. Figure 4 shows the effect of 100% of
petroleum products on chlorophyll a content of B. lambarenensis. The
effects were found to be statistically the same (F=1.694) but different
numerically. Chlorophyll a content found in this study were 0.4964mg/g,
0.5285mg/g,0.6630gmg/g and 0.6869mglg for Control, AGO, PMS and DPK
respectively. The effects of these irrigants on chlorophyll b are shown in
Figure 5. All the effects are the same
statistically (F=1.803) and the mean values are 0.7914mg/g,
0.8153mg/g,1.0459mg/g and 1.1096mg/g for AGO, DPK, Control and PMS
respectively. Figure 6 shows the effects of petroleum
products on total chlorophyll contents of B.
lambarenensis. The mean total
chlorophyll contents followed same trend like chlorophyll b. when these
values were tested statistically, they were found to be the same
statistically (F=2.302) at 5% level of significance. A separation of the means:
1.1309mg/g (AGO), 1.2783mg/g (DPK), 1.3685mg/g (control) and 1.5163mg/g
(PMS), with Duncan Multiple Range Test (DMRT) showed that the effects of AGO,
DPK and Control are statistically the same while DPK, Control and PMS are
statistically the same but AGO and PMS different statistically. 100% petroleum products followed by
water had more severe effects on the chlorophyll contents of the plant than
the 50% as all the three products
reduced the chlorophyll contents except chlorophyll a where 100% PMS
increased the content. The effects of
the two concentrations when compared showed that both treatments had the same
values statistically for chlorophyll a and total chlorophyll. However, the
concentrations of chlorophyll b treated with DPK and AGO differed
significantly with the 50% treated moss having more than the 100% treated at
5% level of significance. Photosynthesis is the major
determinant of growth and productivity. The basic raw materials for
photosynthetic process are the chlorophylls a and b which absorb the solar
energy which is later converted to chemical energy contained there in the
synthesized organic food substances.
Chlorophyll a is primarily associated with the light reaction and the
acceptor of the absorbed light energy by chlorophyll b which is used to drive
the photochemical events of photosynthesis (Prezein and Nelson, 1997). The amount of chlorophyll in any plant is
positively correlated to the primary productivity of the plants. Raeymakers and Longwith (1987)
reported that the determination of chlorophyll contents in plant is a useful
estimation of the primary productivity and has been used as bioassays of
environmental stresses in eco-physiological researchers. Any factor that
destroys or brings about chlorosis in plant affects the physiology,
photosynthesis, growth, productivity and respiration of the plants. The treatment of this plant with petroleum
products affected or damaged their photosynthetic apparatus Warner and
Caldwell (1980) reported that plants exposed to strong or high light
intensity can have their photosynthetic apparatus damaged. Heavy metals such as Pb
Ni, Hg, Zn and other pollutants such as SO2 are responsible
for the disappearance and the changes in the flora around the urban and
industrial area (Richardson,1981). The metallic components or additives in
these petroleum products are likely to be associated with the damage of the
chlorophylls. Generally, chlorophyll a
is more than chlorophyll b in mosses (Ogunbiyi, 2003) and same is true of
higher plants. The higher
concentrations of chlorophylls a, b and total chlorophyll observed in the
treated than the Control suggest that the chloroplast could have been damaged
or affected thus liberating these pigments.
Summarily, the pigments could have been damaged by the petroleum
products used. Fergusson et al (1978) attributed the absence of bryophytes in cities and
industrialized areas to pollugenic agents. The hazardous effects of these
petroleum products on the chlorophyll contents may be hinged on the presence
of Pb in these products, which is a borderline metal (Nieboer and Richardson,
1981) and the most toxic in this class (Richardson,1981). References Fergusson,
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