Weeds are considered unwanted plants that cause damage to our crops. They compete with
crops, harbour diseases and insects and act as alternate host when present in fields and
on bunds. Parthenium hysterophorus L., locally known as "Gajar ghas", is
one of the problematic weed of Chhattisgarh (Madhya Pradesh) region (Oudhia and Dixit,
1994). Its harmful effects on several crops have been reported (Narwal, 1994). Molisch
(1937) coined the term allelopathy which refers to all biochemical interactions
(stimulatory or inhibitory) among plants including micro-organisms. The allelopathic
effects of Parthenium hysterophorus L. on linseed have not been reported. In order
to explore the allelopathic potential (stimulatory or inhibitory) of Parthenium
hysterophorus L. on linseed, an experiment was carried out under laboratory condition.
Root, stem, leaf and stem+leaf of Parthenium hysterophorus. L.
were allowed to decay for the period of five, seven, nine and eleven days corresponding to
120, 168, 216 and 264 hours as per treatment in water in the ratio of 1:10 w/v of plant
material and water, respectively. The experiment was laid out in complete randomized
design with control in linseed cv. Kiran. The treatment, were replicated thrice. The
experiment was repeated twice. The experiment was carried out in petridishes in sterile
sand.In each petridish 50 representative seeds were placed in sand and 15 ml. of extract
was applied. Extracts were applied only at the time of sowing . In case of control, only
water was used. The petridishes were kept at 21±2oin a germinator. Germination of seeds was recorded at 3,5,7,9, and
11 days after sowing (DAS).
The aqueous extraets of different parts and their decaying periods
produced significant effect on germination. At 5 and 7 DAS, root stem, leaf and stem+ leaf
extract of 120 and 264h extraction produced significantly higher germination as compared
to rest of the treatment combinations including control. Maximum germination at 5 DAS was
noted under stem+leaf extract of 264h, whereas, at 7 DAS, stem extract of 120h resulted in
maximum germination. At 3,5,7,9 and 11 DAS, root, stem, leaf and stem+leaf extract of 120h
and root, stem and stem+leaf extract of 264h resulted in comparable germination with
control ( Table I) . Allelopathic effect of Parthenium hysterophorus L. has been
reported on many field crops. Narwal (1994) reported that Parthenium root, stem,
leaf and inflorescence extracts reduced the seed germination and seedling growth in
various crops.
Table I. Allelopathic effect of Parthenium huysterophorus
L. on germination ( %) of linseed.
| Days after sowing |
|
| Treatments |
5 |
7 |
9 |
11 |
| (Extraction time) |
|
|
|
|
| Root extract |
|
|
|
|
| 120 hours |
81.00(64.17) |
84.50(66.82) |
84.50(66.82) |
85.10(67.30) |
| 168 hours |
65.60(54.12) |
66.80(54.86) |
68.10(55.65) |
68.10(55.65) |
| 216 hours |
66.90(54.92) |
74.90(59.93) |
77.00(61.35) |
77.00(61.35) |
| 264 hours |
79.80( 63.34) |
80.30(63.70) |
86.10(68.13) |
86.10(68.13) |
|
|
|
|
|
| Stem extract |
|
|
|
|
| 120 hours |
85.70(67.81) |
88.20(69.91) |
89.40(71.01) |
89.40(71.01) |
| 168 hours |
11.70(20.95) |
52.60(46.53) |
63.30(52.74) |
65.30(53.94) |
| 216 hours |
60.90(51.29) |
63.10(52.82) |
65.40(53.98) |
65.40(66.96) |
| 264 hours |
82.60(65.41) |
84.60(66.96) |
84.60(66.95) |
84.60(66.96) |
|
|
|
|
|
| Leaf extract |
|
|
|
|
| 120 hours |
82.00(64.94) |
84.70(67.01) |
85.50(67.64) |
85.50(67.64) |
| 168 hours |
4.90(12.90) |
26.50(30.99) |
47.30(43.46) |
53.50(47.05) |
| 216 hours |
66.70(54.78) |
72.00(58.06) |
72.00 (58.06) |
72.00(58.06) |
| 264 hours |
80.00(63.46) |
82.00(64.92) |
82.00(64.92) |
82.00(64.92) |
|
|
|
|
|
| Stem + Leaf
extract |
|
|
|
| 120 hours |
80.10(63.51) |
82.20(65.10) |
82.20(65.10) |
82.20(65.10) |
| 168 hours |
2.20(8.57) |
15.40(23.16) |
33.80(35.66) |
41.90(40.39) |
| 216 hours |
73.00(58.69) |
78.80(61.21) |
77.80(61.21) |
76.80(61.21) |
| 264 hours |
86.00(68.06) |
86.00(68.06) |
86.00(68.06 |
86.00(68.06) |
| Control (Water) |
52.30(46.35) |
77.00(61.35) |
88.30(70.05) |
89.30(70.90) |
| CD at 5% |
(10.14) |
(8.17) |
(6.44) |
(5.98) |
Figures in parentheses indicate angular value.
In the present study, stimulatory effect on 5th and 7th
day was noted when different parts were decayed for specific period. It is possible that
at these decaying period the interaction between micro-organisms and plant material might
have produced some. allelochemicals which have stimulatory effect on germination. In
present study, inhibitory effect on germination might be due to some inhibitors like
p-coumaric aacid, parthenin, coronpilin, caffeic acid, alkaloids and sesquiterpene
lactones indentified in Parthenium extract ( Narwal, 1994). The differential
response of the extract of Parthenium hysterophorus ( L.) on linseed in present
investigation as against of other crops is in line with the hypothersis advanced by Ashraf
and Sen (1978) who propounded that plants interact differently in response to the
allelochemicals. This study also showed that different parts of weed have potential to
alter the allelopathic effects.
REFERENCES
Ashraf, N., and Sen, D. N. ( 1978). Allelopathic potential of ztlyxs argentea
in arid land crop fields. Oecologica Plantarum, 13: 331-338.
Molisch, H., ( 1937). Allelopathy, A methodological approach into root exudations, MS
thesis, Cornell Univ. Ithaca. pp. 68
Narwal, S. S. (1994) Allelopathy in crop production. Scientific Publishers, Jodhpur pp.
145.
Oudhia, P. and Dixit, A. (1994). Weeds in Ambikapur ( Madhya Pradesh) region and their
traditional use. Weed New, 1: 19-21. |