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Journal of Plant Diseases and Protection
Zeitschrift für Pflanzenkrankheiten und Pflanzenschutz
Sonderheft XX, 471-478 (2006), ISSN 1861-4051
© Eugen Ulmer KG, Stuttgart
The allelopathic potential of common dandelion
(Taraxacum officinale WEB.)
V. GYENES1*, I. BÉRES
Institute for Plant Protection, Department of Herbology and Pesticide Chemistry, University of
Veszprém, Georgikon Faculty of Agriculture, H-8361 Keszthely, P.O.Box 71. Hungary,
e-mail: [email protected]
* Corresponding author
Summary
The common dandelion (Taraxacum officinale WEB.) is one of the most troublesome weeds in meadows,
pastures, grasses, turf grasses, orchards and vineyards.
The aim of this study was to establish the allelopathic effect of the perennial dicotyledonous weed and
to ascertain to what degree is it able to influence the germination of grass species widespread in turfs. Seed
of selected Gramineae and Fabaceae species (Lolium perenne L., Arrhenatherum elatior L., Festuca
rubra L., Dactylis glomerata L., Poa pratensis L., Lotus corniculatus L., Trifolium repens L., Trifolium
fragiferum L., Bromus inermis L., Bromus erectus L.), which are regarded as important components of
turfs, were treated with acetonic, ethanolic and aqueous extracts of T. officinale roots and leaves. The
effect of treatments was evaluated by determining seed germination of the test species.
The acetone and ethanol extracts of dandelion roots generally inhibited seed germination the most.
Aqueous, acetone and ethanol extracts of leaves were generally less inhibitive. Germination of test
species’ seed decreased as extract concentrations increased.
Keywords: Allelopathy, Taraxacum officinale, Gramineae species, Fabaceae species, germination
Zusammenfassung
Die allelopatische Wirkung von Taraxacum officinale WEB.
Mit diesen Versuchen würde überprüft, ob die aus gemahlenen Teilen der Blätter und Wurzeln
hergestellten Extrakte die Keimung von Samen hemmen. Die Keimung der Diasporen von 10 Kulturpflanzen wurde durch den Saft von T. officinale in artspecifischer Weise beeinflußt. Die Extrakte aus
Pflanzenteilen hatten eine unterschiedliche Wirkung auf die Keimrate von Kulturpflanzensamen. Die
Extrakte aus Blättern und Wurzeln von Taraxacum officinale zeigten signifikante Hemmwirkungen auf
Blätter (4,87-90,09 %) und auf Wurzeln (0,99-96,56 %). Bei diesem Unkraut wurden in Laborversuchen
phytotoxische Wirkungen auf Testpflanzen festgestellt.
Stichwörter: Allelopathie, Taraxacum officinale, Grasarten, Kleearten, Keimung
Introduction
The term ”allelopathy” was first used by MOLISH (1973), and since then it has become generally accepted
in the botany and herbology sciences. The word “allelopathy” has Greek origins and stems from the
words: ”mutual” and ”influence”. It serves to denote chemical interaction between plants, and therefore,
allelopathy means that the donor plant has an inhibitory or stimulatory effect on the acceptor plant.
Allelopathy differs from other negative plant interactions, such as competition, because in the former case
472
GYENES, BÉRES
the donor plant has a harmful influence on other plants by emission of allelochemical compounds. These
compounds are secondary metabolites that often are involved with different protective mechanisms.
In Hungary, T. officinale is a widespread weed that is most troublesome in the rainy western part of the
country (KARAMÁN 2000). Its importance is demonstrated by data of the Hungarian Weed Survey for
vineyards (MIHÁLY 2005). In Sághegy the weed was ranked in 3rd place due to its 5.04 % average cover
In Somló it was also ranked in 3rd place based on 2.40 % cover, but in Badacsony it was ranked 5th as a
result of 1.41 % cover. The importance of the weed was similar in orchards DANCZA et al. (2005). This is
demonstrated by the latest data from the Hungarian Weed Survey for orchards (cherry and apple
plantations). Based on average cover % the weed is ranked in 5th place in apple plantations, and in 9th
place in apple plantations.
The beautiful yellow, shining inflorescences of T. officinale are recognized from a distance in those
areas where chemical weed control was not effective. Such localities include orchards, roadsides, gardens,
ditches, etc. The weed could become a dominant weed in planted grasses and fodder crops. It is often not
found in cereals and row crops under normal crop production conditions (KARAMÁN 2000).
Dandelion is a perennial weed with leaves arranged in rosette pattern, and its thick taproot extends
vertically to deep soil layers (UJVÁROSI 1973). Its rootstock is reddish-brown and leaf scars of the
previous year are visible on it. The rootstock of stronger and older plants is polyandrous. After the death
of the principal bud the new shoots develop from lateral buds. In the vegetative stage the different
aboveground parts are well developed in a rosette pattern and with a short stem. In the reproductive phase
a new scape is raised from the short stem. The capitulum occurs on the end of the scapes (CZIMBERMAGYAR 2005). The capitulum is 2.5-7.5 mm in diameter, and often convex. Inflorescences are 12-25 x
15-25 mm; outer bracts up to 17 mm, linear-lanceolate, usually rather dark, more or less glaucous green,
paler on inner surface, pale margin often present but never conspicuous, erect to deflexed, ecorniculate or
slightly callosed. Ligules are long, narrow, medium yellow, usually with a brownish stripe (TUTIN et al.
1990). Principal flowering time is middle of April, beginning of May (KARAMÁN 2000). Achenes are
brownish, 2.5-3.5 mm, tuberculate or spinulose. The cone is 0.2-0.7 mm long, conical; beak is 7-15 mm,
slender (TUTIN et al.1990).
The root contains economically-important secondary metabolites, such as: taraxacin, taraxerin,
taraxerol, taraxasterol, rubber, sugar, wax, fats, mucilage, choline, and saponin acids (SIMON 1984).
Common dandelion is a serious weed because it is able to spread with seed and also vegetatively with
its well-developed taproot and leaves arranged in rosette pattern, it can be very harmful in turfgrasses. It
is a serious weed in turfgrasses because its optimal germination time in early spring coincides with that of
grass seeds. Due to its rapid development it is particularly suppressive towards weakly developed and
poorly growing grasses (KARAMÁN 2000).
The weed does not tolerate frequent cultivation. Weed numbers can be reduced significantly with welldesigned tillage and stubble-stripping operations. Mechanical control needs to be done continuously in
order to reduce plant numbers as well as seed numbers in the seed bank. In small gardens, the size of turfs
(lawns) allows for individual dandelion plants weed to be removed by hand. The advantages of this weed
control method are that important components of turfs will be not damaged, and weed control will be
realized without any herbicides. Disadvantage is that it requires a lot of human energy (KARAMÁN 2000).
Where the weed occurs in crops or on roadsides glyphosate or gluphosinate-ammonium herbicides can
be used. Gluphosinate-ammonium has a scorching effect therefore it is more effective on weed seedlings.
Weed control in turfs is mainly done with auxintype herbicides (KARAMÁN 2000).
Materials and methods
The test (acceptor) species were: Lolium perenne L., Arrhenatherum elatior L., Festuca rubra L., Dactylis
glomerata L., Poa pratensis L., Lotus corniculatus L., Trifolium repens L., Trifolium fragiferum L.,
Bromus inermis L., and Bromus erectus L.
Fresh rootstock and shoots of T. officinale were collected at the flowering stage in Keszthely, from
ruderals in June, 2005. Bioassay experiments were set up in Petri-dishes in June, 2005. Fresh roots and
leaves of the weed were cleaned with water and cut into small (1-1.5 cm) pieces, which were homo-
Allelopathy of Taraxacum officinale
473
genized in a grinder. Based on the technique of Béres (1992), the following treatments were prepared:
50 g fresh leaf/200 ml acetone, 50 g fresh leaf/200 ml ethanol, 50 g fresh root/200 ml water, 50 g fresh
root/200 ml acetone, 100 g fresh root/200 ml acetone, 50 g fresh root/200 m ethanol. Soaking of the
material in the various solvents lasted 24 hours, and then the mixtures were filtered through filter paper.
Not all of the afore-mentioned treatments were tested on every test species. Supernatant volume was
placed on filter paper discs in Petri-dishes of 10 cm diameter, and their lids were removed to allow the
solvents to evaporate. Thereafter water volume was added to the dry filter paper in the dishes, and 100
seeds were placed on the filter paper in each Petri-dish. Treatments were replicated four times.
Allelopathic effect was assessed based on the germination rate of seeds of the various test species.
Germination percentage was recorded on 12th, 14th, 21st and 28th day by MSZ 6354/3. The Microsoft
Excel statistic programme was used for analyzing the data.
Results
Certain aqueous, acetone or ethanol extracts of roots or leaves of common dandelion significantly
decreased the germination percentage for several Gramineae and Fabaceae species (Tab. 1-10).
Tab. 1: The allelopathic effect of Taraxacum officinale on the germination of Lolium perenne’s seeds.
Tab. 1: Wirkungen der Extrakte aus Taraxacum officinale auf die Keimung von Lolium perenne Samen.
Species
Treatments
N1
X2
Decrease in
germination %
7.82
10.16
2.87
3.65
28.91
30.99
SD3
CV%4
Lolium perenne
(perennial
ryegrass)
Control
4
96
2.828
2.945
50 g fresh leaf/200 ml acetone
4
88.25
5.446
6.153
50 g fresh leaf/200 ml ethanol
4
86.25
4.924
5.708
50 g fresh root/200 ml acetone
4
93.25
2.061
2.210
50 g fresh root/200 ml water
4
92.5
2.516
2.720
4
68.25
3.403
4.986
100 g fresh root/200 ml ethanol
4
66.25
5.619
8.481
P < 0.01; LSD5% = 5.97
1
N = number of replicates, 2X = mean germination %, 3SD = standard deviation, 4CV% = variation coefficient
Tab. 2: The allelopathic effect of Taraxacum officinale on the germination of Arrhenatherum elatius’s
seeds.
Tab. 2: Wirkungen der Extrakte aus Taraxacum officinale auf die Keimung von Arrhenatherum elatius
Samen.
Species
Treatments
N1
X2
Decrease of
germination %
48.23
51.78
47.52
80.86
92.91
SD3
CV%4
Arrhenatheru
m elatius
(tall oatgrass)
Control
4
70.5
1.290
1.829
4
36.5
2.362
6.471
50 g fresh leaf/200 ml ethanole
4
34
4.966
1.460
4
37
3.109
8.402
4
13.5
1.500
11.111
4
5
2.081
41.62
P < 0.01; LSD5% = 4.206
1
474
GYENES, BÉRES
Tab. 3: The allelopathic effect of Taraxacum officinale on the germination of Festuca rubra’s seeds.
Tab. 3: Wirkungen der Extrakte aus Taraxacum officinale auf die Keimung von Festuca rubra-Samen.
Species
Treatments
N1
X2
Decrease of
germination
%
76.29
64.75
78.85
74.36
76.93
SD3
CV%4
Festuca rubra
(red fescue)
Control
4
39
2.160
5.538
4
9.25
3.201
3.460
4
13.75
2.217
16.123
4
8.25
1.707
20.690
4
10
2.106
21.600
4
9
4.546
50.511
P < 0.01; LSD5% = 4.203
1
Tab. 4: The allelopathic effect of Taraxacum officinale on the germination of Dactylis glomerata’s seeds.
Tab. 4: Wirkungen der Extrakte aus Taraxacum officinale auf die Keimung von Dactylis glomerataSamen.
Species
Treatments
N1
X2
Decrease of
germination
%
24.30
25.36
27.47
79.23
9.51
80.29
SD3
CV%4
Dactylis
glomerata
(orchardgrass)
Control
4
71
3.162
4.453
4
53.75
7.932
14.757
4
53
2.449
4.620
4
51.5
8.736
16.963
4
14.75
4.031
27.328
4
64.25
5.057
7.870
4
14
4.242
30.300
P < 0.01; LSD5% = 8.153
1
Tab. 5: The allelopathic effect of Taraxacum officinale on the germination of Poa pratensis’s seeds.
Tab. 5: Wirkungen der Extrakte aus Taraxacum officinale auf die Keimung von Poa pratensis Samen.
Species
Treatments
N1
X2
Decrease of
germination
%
90.09
82.33
93.54
96.56
1.73
95.69
SD3
CV%4
Poa pratensis
(Kentucky
bluegrass)
Control
4
58
2.943
5.074
4
5.75
7.135
124.086
4
10.25
5.315
51.853
4
3.75
0.957
25.52
4
2
2.160
108
4
57
3.651
6.405
4
2.5
2.081
83.24
P < 0.01; LSD5% = 5.85
1
475
Tab. 6: The allelopathic effect of Taraxacum officinale on the germination of Lotus corniculatus’s seeds.
Tab. 6: Wirkungen der Extrakte aus Taraxacum officinale auf die Keimung von Lotus corniculatus Samen.
Lotus
corniculatus
(birdfoot
deervetch)
Species
SD3
CV%4
74
70.5
Decrease of
germination
%
4.87
3.651
2.082
4.933
2.953
57.5
22.3
3.109
5.406
N1
X2
Control
4
4
4
Treatments
P < 0.01; LSD5% = 4.82
1
Tab. 7: The allelopathic effect of Taraxacum officinale on the germination of Trifolium repens’s seeds.
Tab. 7: Wirkungen der Extrakte aus Taraxacum officinale auf die Keimung von Trifolium repens Samen.
Trifolium
repens
(white clover)
Species
SD3
CV%4
57.5
52.5
Decrease of
germination
%
8.69
2.646
2.646
4.601
6.318
41.5
28.83
3.317
6.375
N1
X2
Control
4
4
4
Treatments
P < 0.01; LSD5% = 4.82
1
Tab. 8: The allelopathic effect of Taraxacum officinale on the germination of Trifolium fragiferum’s
seeds.
Tab. 8: Wirkungen der Extrakte aus Taraxacum officinale auf die Keimung von Trifolium fragiferum
Samen.
Trifolium
fragiferum
(strawberry
clover)
Species
SD3
CV%4
24.3
23
Decrease of
germination
%
5.35
1.633
1.258
5.176
7.1
23
5.35
5.477
23.813
N1
X2
Control
4
4
4
Treatments
P > 0.05; LSD5% = N = number of replicates, 2X = mean germination %, 3SD = standard deviation, 4CV% = variation coefficient
1
476
GYENES, BÉRES
Tab. 9: The allelopathic effect of Taraxacum officinale on the germination of Bromus inermis’s seeds.
Tab. 9: Wirkungen der Extrakte aus Taraxacum officinale auf die Keimung von Bromus inermis Samen.
Bromus
inermis
(smooth
brome)
SD3
CV%4
81.3
Decrease of
germination
%
-
3.403
4.185
80.5
0.99
3.109
3.862
N1
X2
Control
4
4
Species
Treatments
P > 0.05; LSD5% = N = number of replicates, 2X = mean germination %, 3SD = standard deviation, 4CV% = variation coefficient
1
Tab. 10: The allelopathic effect of Taraxacum officinale on the germination of Bromus erectus’s seeds.
Tab. 10: Wirkungen der Extrakte aus Taraxacum officinale auf die Keimung von Bromus erectus Samen.
N
X
Control
4
86.3
Decrease of
germination
%
-
4
71
17.73
Bromus
erectus
(erect
brome)
Species
Treatments
1
2
SD3
CV%4
2.754
3.191
2.582
3.636
P > 0.01; LSD5% = 4.62
1
From the data in Table 1 it appears that the germination of perennial ryegrass was significantly reduced
by both the acetone and ethanol extracts of 100 g root material, by 30.99 and 28.91 %, respectively.
Germination of tall oatgrass was influenced similarly as ryegrass (Tab. 2). The germination percentage of
this species was 13.5 % in the acetone extract of 100 g root material, and 5 % in the ethanol extract of 100
g root material. Germination of red fescue (Tab. 3.) was significantly reduced by all treatments. The
acetone extract of 50 g root material and the ethanol extract of 100 g of the same material had the most
pronounced inhibitory effect on the germination of red fescue, with reductions in germination percentage
of 78.85 and 76.93 %, respectively.
Results for the remaining grass species appear in Tables 4, 5, 9 and 10. From data in Table 4 it appears
that the aqueous extract of 50 g root material affected germination of orchard grass the least (64.25 %
germination). The aqueous extract was not significantly different from the control treatment, but a
significant and similar difference was found between both the acetone and ethanol extracts of 100 g root
material and the control treatments (79.23 and 80.29 % germination decrease, respectively). Results for
Kentucky bluegrass (Tab. 5.) indicate that germination was significantly (p < 0.01) reduced by all treatments except the aqueous one.
Birdfoot deervetch, white clover and strawberry clover are representatives of the Fabaceae family.
Results for these species are given in Tables 6, 7 and 8, respectively. For these species only two
treatments were applied: 50 g leaf and 100 g root/200 ml acetone. The germination of birdfoot deervetch
(Tab. 6) and white clover (Tab. 7) was significantly inhibited by the root treatment. No significant
inhibitory effects were observed in the case of strawberry clover (Tab. 8).
Discussion
Results indicate allelopathic effects for particular acetone, ethanol and aqueous extracts of common
dandelion’s leaves or roots on the germination of certain species from the Gramineae and Fabaceae
477
families. The acetone and ethanol extracts of roots generally had greater inhibitory effects on seed
germination than the aqueous extracts.
BENDALL (1975) and BÉRES (1992) reported similar results. They pointed out that Cirsium arvense had
a significant allelopathic effect, and that root extracts inhibited the germination of crop seeds as well as
the development of seedlings.
Several articles on allelopathy by Hungarian authors report allelopathic effects. KAZINCZI (2004)
examined the allelopathic effect of Cirsium arvense and Asclepias syriaca under bioassay conditions.
KAZINCZI (2004) evaluated the allelopathic effect of Ambrosia artemisiifolia, Abutilon theophrasti,
Datura stramonium, Cirsium arvense and Asclepas syriaca under laboratory conditions, with sunflower
(Helianthus annuus L.) as test plant. She examined the allelopathic effect of extracts of fresh root and leaf
material, and the base of evaluation was germination rate. Root extracts had the greatest inhibitory effect
on the germination of sunflower.
SOLYMOSI (2004) examined the allelopathic effect of root extract of Sorghum bicolor. He pointed out
that an aqueous extract of S. bicolor was less inhibitory than an ethanol extract.
Own findings suggest that common dandelion is an allelopathic weed shows, theeby emphasizing its
importance and significance. With its strong basal development and rosette leaf pattern, it could be very
harmful in grasses. It is a serious interferer with planted grasses because in early spring it germinates
together with grass seeds. Dandelion’s rapid rate of development gives it a distinct advantage over grasses
that do not develop as quickly, or which are weak due to stress conditions. The compounds taraxacin,
taraxerin, taraxerol, taraxsterol, which have been found to leach from its roots (SIMON 1984), inhibit the
germination and growth of grasses.
Acknowledgement
The authors whish to thank the Hungarian Scientific Research Found (OTKA) for its financial support
(T 037931).
References
BENDALL, G.M.: The allelopathic activity of Californian thistle (Cirsium arvense (L.) Scop.) in Tasmania.
Weed Research. 15, 77-81, 1975.
BÉRES, I.: Adatok a Cirsium arvense (L.) Scop. biológiájához. Növényvédelem, XXVII. Évfolyam, 7-8.
szám. 322-327, 1992.
CZIMBER, GY., L. MAGYAR: Pongyola pitypang vagy gyermekláncfű (Taraxacum officinale WEB.) In:
Benécsné Bárdi G. et al. (szerk) Veszélyes 48, veszélyes, nehezen irtható gyomnövények és az ellenük
való védekezés. Mezőföldi Agrofórum Kft, Szekszárd, 188-14, 2005.
DANCZA, I. Á. TÓTH, L. SZENTEY, G. BENÉCSNÉ BÁRDI, CS. DOMA, L. HÓDI, A. HORNYÁK, CS.
KŐRÖSMEZEI, J. MADARÁSZ, F. MOLNÁR, -R. NOVÁK, R. SZABÓ, P. UGHY, L. VARGA: A szőlő- és
gyümölcsültetvények első országos gyomfelvételezésének előzetes eredményei. 51.-ik Növényvédelmi
Tudományos Napok, Budapest, 2005.
KARAMÁN, J.: Szántóföldeink gyomnövényei – Pongyola pitypang (Taraxacum officinale Web.).
Agronapló, IV évfolyam, 12, 2000.
KAZINCZI, G., I. BÉRES, J. HORVÁTH, A.P. TAKÁCS: Sunflower (Helianthus annuus) as recipient species
in allelopathic research. Herbologia, Vol. 5. No. 2, 2004.
KAZINCZI, G., I. BÉRES, J. MIKULÁS, E. NÁDASY: Allelopathic effect of Cirsium arvense and Asclepias
syriaca. Zeitschrift für Pflanzenkrankheiten und Pflanzenschutz. Sonderheft XIX, 301-308, 2004.
MIHÁLY, B.: Szőlők gyomnövényei három vulkáni tanúhegyen. Doktori (Ph.D.) értekezés. Gödöllő, 2005.
MOLISH, H.: Der Einfluss einer Pflanze auf die andere. Allelopathie. Fischer, Jena, 1937.
RICE, E.L.: Allelopathy. Academic Press, Inc. New York, 353, 1974.
SIMON, J.E., A.F. CHADWICK, and L.E. CRAKER,: Herbs: An indexed bibliography. 1971-1980. The
Scientific Literature on Selected Herns, and Aromatic and Medicinal Plants of the Temperate Zone.
Archon Books, Hamden, CT, 770, 1984.
478
GYENES, BÉRES
SOLYMOSI, P.: A tarka cirok [Sorghum bicolor (L.) Moench]. Növényvédelem, 40, 237-243, 2004.
SZABÓ, L.GY.: Fitokémiai analógiák ökológiai vonatkozásai. Gyógyszerészet 38, 567-571, 1994.
TUTIN, T.G., V.H. HEYWOOD, N.A. BURGES, D.M. MOORE, D.H. VALENTIN, S.M. WALTERS, D.A.
WEBB: Flora Europea. Reprinted edition. Cambridge University Press, Cambridge, 332-343, 1990.
UJVÁROSI M.: Gyomnövények. Mezőgazdasági Kiadó, Budapest, 1973.

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