Environmental Engineering Reference
In-Depth Information
4 Discussion
Our results showed that crude oil either in low (1 %) or high (5 %) concentration
could reduce the number of germination, the length of leaves and the plant dry
biomass in both roots and shoots. Increasing the crude oil concentration increased
the changes in the plant. Maximum effect of crude oil on the plant was observed at
5 % concentration. The poor distribution of roots in 5 % contaminated soil proposed
that the pollution could affect the root growth which was in direct contact with toxic
compound of oil. The presence of crude oil in the soil delayed the germination and
caused chlorosis in plants (Gong et al.
2001
; Adam and Duncan
2002
; Ogboghodo
et al.
2004
). The germination was observed in all the oil-contaminated soils sug-
gesting that the plant could tolerate 5 % contamination in the soil. Tolerance is de-
fined here as the ability of the plant to grow in oil-contaminated soil. This does not
necessarily means that the plant is healthy. Some reports showed that diesel fuel
could highly decrease
Poa trivialis
germination in the 5 % concentration (Adam and
Duncan
1999
,
2002
). The other report indicated that
Poa trivialis
can tolerate up to
15 % crude oil in the soil (Minai-Tehrani
2008
).
In this study, peroxidase enzyme was chosen for studying the effect of oil-
contaminated soil on enzyme activity in plant. Determination of peroxidase activ-
ity may be a good index of study of environmental stresses on plants (Fan and
Krishnamurthy
1995
; Riser-Roberts
2010
). The activity of this enzyme changes in
the oxidative stress conditions (Heinonsalo et al.
2000
; Bučková et al.
2010
; Kathi
and Khan
2011
). Our results showed that the kinetics parameters (K
m
and V
max
) of
enzyme in roots of treated samples were different from control sample. This pro-
pose that in the root grown in contaminated soil, the plant uses peroxidase isoform
in comparison with control roots, while in the shoots the same peroxidase was used
in the plant in both contaminated and control. Previous reports also showed that
crude oil can affect peroxidase activity in some plants such as lentil (Naemi et al.
2011
; Masakorala et al.
2013
).
5 Conclusion
In conclusion, crude oil-contaminated soil could delay germination, early chlorosis
and reduce the length of roots and shoots of
Festuca arundinacea
. Crude oil can
induce not only macroscopic changes but also biochemical changes in the root and
shoots of plant. The activity of peroxidase in both roots and shoots of treated sample
was changed. The enzyme activity change was more significant in the root than the
shoots.
