Allelopathic effect of cogermination of some aromatic plants and weed
seeds
Ravlić Marija1, Baličević Renata1, Pejić Tamara1,2, Pećar Nina1,2
1
Faculty of Agriculture in Osijek, Kralja Petra Svačića 1d, 31000 Osijek, Croatia
(mravlic@pfos.hr)
2
Student, Graduate study
Abstract
Allelopathic effect of cogermination of aromatic plant seeds [basil (Ocimum basilicum),
coriander (Coriandrum sativum), lovage (Levisticum officinale), oregano (Origanum
vulgare)] and weed seeds [hoary cress (Cardaria draba), scentless mayweed
(Tripleurosperum inodorum)] on germination and early growth of weeds was investigated
under laboratory conditions. Basil, coriander and lovage reduced germination of hoary
cress from 13.8 to 27%. On the contrary, all aromatic plants, except lovage, had
stimulatory effect on germination of scentless mayweed. Coriander decreased root length
of hoary cress and scentless mayweed for 17.5 and 16.5%, respectively. Shoot length of
scentless mayweed was increased in cogermination with all aromatic plants. Only lovage
had significant inhibitory effect on fresh weight of hoary cress, while fresh weight of
scentless mayweed was increased by coriander.
Key words: allelopathy, cogermination, aromatic plants, hoary cress, scentless mayweed
Introduction
Although weed control in modern agriculture primarily relies on use of chemical
herbicides, their excessive use causes serious problems as weed resistance (Macías et al.,
2003), environmental pollution and adverse effects on human and animal health. All this
leads to the increasing importance of non-chemical and environmentally friendly
alternatives in weed management, such as allelopathy. Allelopathy is defined as any direct
or indirect harmful or beneficial effect of one plant, fungus or microorganism on the other
ones through production of allelochemicals that escape into the environment (Rice, 1984).
The use of allelopathically active crops against weeds can be utilized in different ways i.e.
surface mulch, incorporation into the soil, crop rotation, cover crops, intercropping,
smothering or water extracts as natural herbicides (Singh et al., 2003, Reigosa et al., 2001).
Aromatic plants have been investigated as potential allelopathic plants. Đikić (2005a)
reported inhibitory effect of caraway, dill, basil and coriander on germination of hoary
cress. Dhima et al. (2009) found that water extracts of aboveground mass of basil,
coriander and oregano reduced germination and growth of barnyardgrass, while in field
experiments reduced plant number of different weed species when incorporated as green
manure.
The aim of the study was to determine allelopathic potential of aromatic plants coriander,
lovage, basil and oregano on weed species hoary cress and scentless mayweed through
cogermination.
Materials and methods
The experiment was conducted in 2013 in the Laboratory of Phytopharmacy and Plant
Systematics at the Faculty of Agriculture in Osijek.
Seeds of aromatic plants including basil (Ocimum basilicum L.), coriander (Coriandrum
sativum L.), lovage (Levisticum officinale Koch) and oregano (Origanum vulgare L.) were
purchased from seed company Sjemenarna Zagreb, d.o.o. Weed seeds of hoary cress
(Cardaria draba (L.) Desv.) and scentless mayweed (Tripleurospermum inodorum (L.)
C.H. Schultz) were collected during 2012 from agricultural fields in Osijek-Baranja
County. All seeds were surface-sterilized for 20 min with 1% NaOCl (4% NaOCl
commercial bleach), then rinsed three times with distilled water (Siddiqui et al., 2009.).
The effect of cogermination of aromatic crops and weed seeds was investigated according
to Đikić (2005a). In each treatment 30 seeds of aromatic crop and 30 seeds of weed species
were placed in Petri dishes (9 cm diameter) on top of filter paper soaked in distilled water.
Control treatments consisted of 30 seeds of a single weed species per dish. Petri dishes
were kept at room temperature (22 °C ± 2) for 9 (hoary cress) and 12 (scentless mayweed)
days. All treatments had four replications and experiment was conducted twice.
Allelopathic effect of aromatic crops was evaluated at the end of experiment through
number, length of root and shoot (cm) and fresh weight (g) of weed seedlings. Germination
percentage was calculated for each replication using the formula: G = (Germinated
seed/Total seed) x 100. Mean germination time (MGT) was calculated according to the
equation of Ellis and Roberts (1981): MGT = ∑ (Dn) / ∑ n, where n is the number of seeds
that emerged on day D, and D is number of days counted from the beginning of
germination. The collected data were analysed statistically with ANOVA and differences
between treatment means were compared using the LSD-test at probability level of 0.05.
Results and discussion
Aromatic plants showed various allelopathic effects on germination of weed species hoary
cress and scentless mayweed (Figure 1). Basil and coriander reduced germination of hoary
cress for 13.8 and 22.3%, while lovage had the highest inhibitory effect and reduced
germination for 27%. On the contrary, germination of scentless mayweed was significantly
stimulated for 11.1, 17.3 and 28.4% with coriander, basil and oregano, respectively. The
results indicate that allelopathic effect depends on both the allelopathic species and the
target species.
Control
Basil
Coriander
Lovage
Oregano
140
a
ab
Germination, % of control
120
a
100
80
a
b
bc
ab
b
b
c
60
40
20
0
C. draba
T. inodorum
a,b,c - means followed by the same letter within weed species are not significantly
different at P<0.05
Figure 1. The effect of cogermination of aromatic plant and weed seeds on germination (%
of control) of weeds
Similarly, Đikić (2005a) found that seed germination of hoary cress was reduced when it
germinated with seeds of coriander and basil, but germination of quackgrass (Agropyron
repens) was stimulated.
Control
Basil
Coriander
Lovage
Oregano
Mean germination time, in days
9
a
8
7
bc
6
b
bc
c
a
b
5
b
bc
c
4
3
2
1
0
C. draba
T. inodorum
a,b,c - means followed by the same letter within weed species are not significantly
different at P<0.05 (
Figure 2. The effect of cogermination of aromatic plant and weed seeds on mean
germination time (in days) of weeds
Mean germination time of hoary cress was only significantly increased in cogermination
with coriander and was 7.72 compared to the control which was 5.32 days (Figure 2). All
aromatic plants increased mean germination time of scentless mayweed which ranged from
4.64 to 5.44 days compared to the 3.63 days in control.
Control
Basil
Coriander
Lovage
Oregano
Root lenght (cm)
3.5
Shoot lenght (cm)
a
3
2.5
2
b
bc
a
bc
c
1.5
a ab
b
1
a
b
b
b
c
b
d
0.5
c
b
a
c
0
C.draba
T. inodorum
C. draba
T. inodorum
a,b,c - means followed by the same letter within weed species are not significantly different at P<0.05
Figure 3. The effect of cogermination of aromatic plant and weed seeds on root and shoot
length (cm) of weed seedlings
None of the aromatic plants significantly reduced root length of hoary cress, except
coriander 17.5% (Figure 3). Root length of scentless mayweed was reduced with coriander
and lovage for 16.5 and 29.3%, respectively. Basil stimulated root length of hoary cress for
42.9%. Lovage reduced shoot growth of hoary cress for 21%, while it greatly stimulated
shoot growth of scentless mayweed for 107.7%. All other aromatic plants stimulated the
shoot growth of both weeds, especially coriander.
Fresh weight of hoary cress seedlings was significantly influenced in cogermination with
lovage and was reduced for 39%, while with basil, coriander and oregano it was only
slightly reduced (Figure 4). Fresh weight of scentless mayweed was stimulated by basil,
coriander and lovage for 11.9, 64 and 22.6%, respectively. Đikić (2005a) also reported
reduction of hoary cress seedling weight with coriander and basil, but to a greater extent,
for 31.3 and 18.3%, respectively.
Fresh weight, % of control
Control
180
160
140
120
100
80
60
40
20
0
Basil
Coriander
Lovage
Oregano
a
a
a
a
a
b
ab
ab
b
b
C. draba
T. inodorum
a,b,c - means followed by the same letter within weed species are not significantly
different at P<0.05
Figure 4. The effect of cogermination of aromatic plant and weed seeds on fresh weight (%
of control) of weed species
Conclusions
The obtained results demonstrated that aromatic plants show allelopathic effect toward
germination, root and shoot length and fresh weight of weeds, both inhibitory and
stimulatory. The allelopathic effect depended on donor and target species. Lovage showed
highest reduction of germination, shoot length and fresh weight of hoary cress, but only
root length of scentless mayweed. Coriander reduced germination and root length of hoary
cress, but showed high stimulatory effect on shoot length of both weed species and fresh
weight of scentless mayweed. Basil reduced germination of hoary cress for 13.8%, but
stimulated its root and shoot length and germination and shoot length of scentless
mayweed. Oregano showed only stimulatory effect on germination of scentless mayweed.
References
- Dhima, K.V., Vasilakoglou, I.B., Gatsis, Th.D., Panou-Pholotheou, E.,
Eleftherohorinos, I.G. (2009): Effects of aromatic plants incorporated as green manure
on weed and maize development. Field Crops Research, 110: 235-241.
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plants and weed seeds. Herbologia, 6(1): 15-24.
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germination of Galinsoga parviflora, Echinochloa crus-galli and Galium molugo.
Herbologia, 6(3): 51-57.
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seeds. Seed Science and Technology, 9: 373-409.
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C., Molinillo, J.M.G. (2003): Allelopathy as new strategy for sustainable ecosystems
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- Siddiqui, S., Bhardwaj, S., Khan, S.S., Meghvanshi, M.K. (2009): Allelopathic Effect of
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Sažetak
Alelopatski utjecaj zajedničkog klijanja sjemena aromatičnog bilja i sjemena korova
U laboratorijskim uvjetima istraživan je alelopatski utjecaj zajedničkog klijanja sjemena
aromatičnog bilja [bosiljak (Ocimum basilicum), korijandar (Coriandrum sativum), ljupčac
(Levisticum officinale), origano (Origanum vulgare) i sjemena korovnih vrsta [strjeličasta
grbica (Cardaria draba) i bezmirisna kamilica (Tripleurosperum inodorum)] na klijavost i
rani porast korova. Bosiljak, korijandar i ljupčac smanjili su klijavost sjemena strjeličaste
grbice od 13,8 do 27%. S druge strane, svo aromatično bilje, osim ljupčaca, imalo je
stimulativni učinak na klijanje sjemena bezmirisne kamilice. Korijandar je smanjio duljinu
korijena strjeličaste grbice za 17.5%, a bezmirisne kamilice za 16.5%. Duljina izdanka
bezmirisne kamilice povećana je pri zajedničkom klijanju sa svim aromatičnim biljem.
Samo je ljupčac imao značajan inhibitorni učinak na svježu masu strjeličaste grbice, dok je
korijandar povećao svježu masu bezmirisne kamilice.
Ključne riječi: alelopatija, zajedničko klijanje, aromatično bilje, strjeličasta grbica,
bezmirisna kamilica