Effect of root exuded allelochemicals of sorghum (Sorghum bicolor) on growth and development of purple nutsedge (Cyperus rotundus L.) and other weeds of pulses
DOI:
https://doi.org/10.59797/jfl.v26i1&2.900Keywords:
Allelochemicals, Anagalis arvensis, Chenopodium album, Cyperus rotundus, Melilotus alba L, Root exudates, Sorghum bicolor, Spergula arvensis, Vicia sativaAbstract
Laboratory experiments were conducted during 2006-09 at IIPR, Kanpur, Uttar Pradesh to find out the effect of allelochemicals released via roots of sorghum as exudates against purple nutsedge (Cyperus rotundus L) and other weeds of winter pulse crops. Emulsifiable concentrate (EC) formulation developed from the isolated exudates, caused severe reduction in vegetative growth, root biomass and tuber regeneration . The formulation (400 µg/g of soil) caused 70-75% reduction in shoot biomass and total biomass of the weed, and 80% reduction in average biomass of roots and their tuber regeneration tendency. The vegetative growth of lambsquarters (Chenopodium album, L.), scarlet pimpernel (Anagalis arvensis, L.), corn flurry (Spergula arvensis, L.), common vetch (Vicia sativa, L.) and white sweet clover (Melilotus alba, L. Medik.) was also reduced. The formulation was more toxic to V. sativa by inhibiting total biomass by 67.26 % followed by C. album (62.59%), M. alba (51.52%), S. arvensis (50.82%) and A. arvensis (26.21%).
References
Journal of Food Legumes 26 (1&2): 48-53, 2013
Effect of root exuded allelochemicals of sorghum (Sorghum bicolor) on growth and development of purple nutsedge (Cyperus rotundus L.) and other weeds of pulses
LALIT KUMAR, G. K. SRIVASTAVA and A. P. KHARE
Indian Institute of Pulses Research, Kanpur-208024, Uttar Pradesh, India; E-mail: [email protected] (Received: November 06, 2012; Accepted: May 29, 2013)
ABSTRACT
Laboratory experiments were conducted during 2006-09 at IIPR, Kanpur, Uttar Pradesh to find out the effect of allelochemicals released via roots of sorghum as exudates against purple nutsedge (Cyperus rotundus L) and other weeds of winter pulse crops. Emulsifiable concentrate (EC) formulation developed from the isolated exudates, caused severe reduction in vegetative growth, root biomass and tuber regeneration . The formulation (400 µg/g of soil) caused 70-75% reduction in shoot biomass and total biomass of the weed, and 80% reduction in average biomass of roots and their tuber regeneration tendency. The vegetative growth of lambsquarters (Chenopodium album, L.), scarlet pimpernel (Anagalis arvensis, L.), corn flurry (Spergula arvensis, L.), common vetch (Vicia sativa, L.) and white sweet clover (Melilotus alba, L. Medik.) was also reduced. The formulation was more toxic to V. sativa by inhibiting total biomass by 67.26 % followed by C. album (62.59%), M. alba (51.52%), S. arvensis (50.82%) and A. arvensis (26.21%).
Keywords: Allelochemicals, Anagalis arvensis, Chenopodium album, Cyperus rotundus, Melilotus alba L, Root exudates, Sorghum bicolor, Spergula arvensis, Vicia sativa.
Plants continuously release variety of chemicals in form of leachates volatiles and root exudates in their immediate environment during their life cycle. These chemicals generally known as allelochemicals may interfere with survival and growth of neighboring or succeeding plants, and may also discourage insects and pathogens attack. Various reports indicated the strong allelopathic effect of extracts or the released compounds of various parts of sorghum against different weeds and other crop plants (Alsaadawi and Dayan 2009) because of its rapid growth and ability to suppress weeds. Species specific allelopathic interferences of sorghum have also been reported (Enhelling and Souza 1992). Though the allelopathic effect of sorghum in field experiments may be due to the release of allelochemicals from different plant parts but practically no effort has been made so far to isolate and assess the allelopathic potential of root exudates particularly released by plants via their roots as exudates which may be more potent inhibitor than the compounds released from other parts of plant. With this in view present study was undertaken to isolate root exudates from intact live plants of sorghum and to assess the effect of isolated compounds against purple nutsedge and other weeds of pulses.
MATERIALS AND METHODS
Root exudates collection and isolation of chemicals: A newly developed exudate trapping system was employed to collect root exudates from the intact live plants of sorghum, pusa chari-1, (Kumar 2004, Kumar and Varshney 2008). Approximately 100 lit of root zone water was collected periodically from 50-60 plants of sorghum grown till maturity (120-150 days) in 20 sets of root exudate trapping system as shown in fig 1. Initially, entire collected root zone water was slowly reduced to 15-20 % of the original volume by pouring it in Petri plates and allowing to evaporate under continuously
Fig 1 Sorghum grown in root exudates trapping system for collection of root exudates.
Kumar et al. : Effect of root exuded allelochemicals of sorghum (Sorghum bicolor) on growth 49
moving fan. The concentrated root zone water obtained so was transferred to a separating funnel and partitioned with equal amount of ethyl acetate. In this process allelocompounds got fractionated into two major groups viz., polar (water layer) and non – polar (ethyl acetate layer). Non-polar layer was evaporated to dryness under vacuum. White crystalline product received was taken for bioassay study.
Bioassay: For bioassay, 10% emulsifiable concentrate (EC) formulation was prepared by emulsifying the appropriate quantity of isolated product in a mixture of tween-80 (10%) and cyclohexanone. Emulsification was obtained by vigorously agitating the mixture at 45 + 20C for an hour. The test solutions of different concentrations were prepared by taking the appropriate amount of the emulsion concentrate formulation and diluting it in a definite volume of water so as to get the desired concentration (150,200, 250, 300, 350 and 400 mg/g) in soil filled in petriplates and pots.
For testing the efficacy of developed formulation on the growth and development of test weeds the experiments were laid out in replicated Petri plates and pots. Effect of formulation on the growth and development of Chenopodium album, Anagalis arvensis, Spergula arvensis, Melilotus alba, Fumaria parviflora and Vicia sativa L. was observed in petriplates, whereas, the replicated pot experiments were conducted for bioassay tests against Cyprus rotundus L. For bioassay, pre sterilized petriplates were filled to the capacity i.e. 150 g of sand moistened with 5.0 ml Hoagland’s nutrient solution and surface sterilized (0.1% mercuric chloride solution) germinated seeds of each test weeds were sown in them. Plates were treated with 15 ml solution of different dilutions viz., 1500, 2000, 2500, 3000, 3500, and 4000 mg/ml which deposited 22.5, 30, 37.5, 45, 52.5 and 60 mg product that respectively, produced concentrations of 150, 200, 250, 300, 350, and 400 mg/ g with the sand filled in petriplates. After treatment the Petri plates were kept into a controlled environmental chamber (25±2 0C, 12 h. light: 12 h. dark). All treatments were replicated thrice under identical conditions. A set of experiment was kept as control treated with formulation auxiliaries. Observations were recorded for, root and shoot length and their biomass after 25 days of the experimentation.
Small pot experiments were conducted to confirm the bioefficacy potentials of isolated compounds against Cyprus rotundus under natural environment. Pots were filled to the capacity (1.25 kg) with the normal soil collected from IIPR Farm (alluvial, pH 7.5, EC 0.3 DS/M, OC 0.3%, N,P,K 250, 15, 120 kg/h). Two uniform size tubers were sown in each pot. Pots were treated twice at an interval of 15 days with the 50 ml solution of different dilutions viz., 3750, 5000, 6250, 7500, 8750, and 10000 ìg/ml prepared by taking appropriate amount of 10% EC formulation to get a concentration of 150, 200, 250, 300, 350 and 400 µg/g with the soil filled in pots. First treatment was made after 7 days or proper germination of tubers. The
second treatment was made exactly after 21 days of sowing. Experiments were maintained in three replications along with an untreated set of control for two and half months at ambient condition. During the period, sufficient moisture in pots was maintained by applying necessary water as and when required. After two months of treatment, plants were taken out from the pots by exposing the pots under running water tap and the observations were taken on root and shoot biomass, total biomass, new tuber development and newly formed tuber biomass etc.
HPLC analysis: Water HPLC system fitted with Rheodine 7161 injector with 20 µl loop, Lichrosphare 100 RP 18 e stainless steel column (5 x 25 cm), and 996 photodiode array detector were used for analysis of crystallized and purified compounds of sorghum root exudates. The operating conditions were: mobile phase, methanol and water (65: 35) at 0.75 ml min flow rate, detector wavelength 217, 239, 286 nm. Quantification was done in the post analysis session at ëmax 217 nm.
RESULTS AND DISCUSSION
Nature of chemicals and their composition: Approximately a total of 20 gram white crystalline product of non-polar nature (ethyl acetate soluble) with an average productivity of 0.3 to 0.4 g/plant was recovered from the entire collected root exudate water (approximately 100 liters) of 50-60 plants of sorghum, grown throughout the season in 20 sets of root exudates trapping system. A typical HPLC chromatogram of the extracted fraction revealed the presence of total three different compounds at distinct Rt’s viz., 2.659, 3.741 and 4.910 . As per area under peak, the crystallized mixture was found to be constituted only by these three compounds in the ratio of 55, 30 and 15%. Therefore, the compound resolved at Rt 2.659 was observed to be the major component of the fraction. Apart from these three, some minute peaks were also observed within the HPLC chromatogram at different Rt’s that may be assumed either by the coloring impurities of the fraction or by the impurities derived from the solvents, used. When these compounds were further fractionated and purified as single pure compounds up to the extent of >95% purity and instrumentally analyzed via 1HNMR, 13CNMR and IR all the three compounds were observed to contain the identical flavanol moiety in their chemical structures however they only differ to each other in respect of functional substituents at flavanol skeleton (Kumar et al., 2010). The study is in good agreement with other findings as very recently dihydroquinone derivative were identified in the oily fraction of hydrophobic droplets, exuded from root hairs of sorghum that is quickly oxidized to an ap-benzoquinone (2-hydroxy-5- methoxy-3-[(8’Z, 11’Z)-8’, 11’, 14’ pentadecatriene]-p benzoquinone) named as sorgoleone (Dayan et al, 2009, Einhellig and Souza 1992, Kagan et al. 2003, Rimando et al. 2003). Apart from sorgoleone, several derivatives of 3- deoxyanthocyanidins viz., apigeninidin, 7-
Journal of Food Legumes 26 (1&2), 2013
compounds released via intact live plant as exudates were
confirmed by us as distinct derivatives of 3-
deoxyanthocyanidins which were found to retained the
identical flavanol skeleton in their chemical structures as
reported by others but seems to be different in complete
chemical structures in respect of their functional substituents
attached at different places of the flavanol skeleton (Kumar et
al, 2010). Therefore, the allelopathic compounds utilized in
present study seems to be a metabolic produce of already
reported phytoalexins i.e. 3-deoxyanthocyanidins.
Activity against Cyprus rotundus: EC formulation developed from the crystallized non-polar fraction of sorghum root
Fig 2 Effect of formulation on vegetative growth and induction of new shoots at higher concentration of formulation.
methoxyapigeninidin, 5,7-dimethoxyapigeninidin, luteolinidin etc. (contained flavanol skeleton in their chemical structures i.e. a heterocyclic aromatic structure) were also reported as defense mechanisms in sorghum plant against pathogen attack (Chun-Hat et al, 2007, Joseph et al, 2004 and Liyi et al. 2009). In the germinated seedlings of sorghum, a high level accumulation of 3-deoxyanthocyanidins derivatives are also known as a defense mechanism against pathogen attack (Hipskind et al. 1990 and Lo et al, 1996). Though all these compounds reported in different part of sorghum but the
exudates showed considerable adverse impact on purple nutsedge in several respects. Developed formulations was not only found effective in reducing the vegetative growth of weed but also observed to be predominately effective in drastically reducing the roots and new tuber development. The effect of formulation on all theses growth parameters of test weed was found concentration dependent i.e. increase in concentration caused more reduction. Results clearly indicated that the developed EC formulation caused considerable adverse impact on the entire development of test weed with different capabilities at doses ranged from 150-400 µg/g of soil (Table 1). As compare to control, approximately 76 and
Table1. Effect of non-polar fraction of sorghum root exudates on vegetative growth, root and tuber development of Cyprus rotundas in pot experiments.
Concentrations Effect on vegetative growth Effect on root and tuber development
μg g-1 of soil Induction of shoots
Average shoot
biomass (g)
Total
biomass (g)
Total no. of tubers
newly
developed
Average tuber
biomass (g)
Average biomass of each tuber (g)
Total biomass of roots including tubers weight (g)
Average
biomass of roots excluding
tubers (g)
control 2 → 20 (0.00) 3.52 (0.00)
2→19 (5.0) 3.10 (11.93)
2→ 19 (5.0) 2.69 (23.58)
2→18 (10.0) 2.32 (34.1)
2→15 (25.0) 1.75 (50.28)
2→14 (30.0) 1.18 (66.47)
2→11 (45.0) 0.99 (71.87)
17
(0.00) 11.24 (7.64) 9.78
(19.64) 8.31
(31.72) 6.85
(43.71) 5.66
(53.49) 2.83
(76.75)
(0.00) 18
(14.28) 18
(14.28) 13
(38.09) 10
(52.38) 8
(61.90) 4
(80.95)
68
(0.00) 3.31
(10.05) 2.72
(26.08) 2.05
(44.29) 1.81
(50.81) 1.11
(69.83) 0.72
(80.43)
177 (0.00)
180 (+ 1.69) 0.153 (13.56)
163 (7.91)
177 (0.00)
141 (20.34)
183 (+ 3.39)
12
(0.00) 7.72
(15.35) 6.28
(31.14) 5.05
(44.63) 4.11
(54.93) 2.55
(72.04) 1.65
(81.90)
44
(0.00) 4.41
(18.93) 3.56
(34.56) 3.00
(44.85) 2.3
(57.72) 1.44
(73.53) 0.93
(82.90)
CV 17.27 15.134 9.726 25.70 22.83 9.91 9.115 7.32 SEM 1.67 0.194 0.456 1.95 0.289 0.0096 0.274 0.1274 CD at 5% 5.081 0.5981 1.405 6.013 0.893 .0295 0.845 0.393 F-Ratio 3.597 0.407 51.740 10.27 14.351 2.715 96.89 158.98 *Figures in parenthesis indicate % reduction
Kumar et al. : Effect of root exuded allelochemicals of sorghum (Sorghum bicolor) on growth 51
Table 2. Effect of non-polar fraction of sorghum root exudates on vegetative growth of important weeds infesting in pulse crops. Treatments (concentrations μg g-1 Growth )
parameters
Weed
species Cont. 150 200 250 300 350 400
CV SEM CD at 5%
F-Ratio
Average shoot length (cm)
Average shoot weight (g)
Average total biomass (g)
C. album 4.69 (0.00)
A. arvensis 4.77 (0.00)
S. arvensis 3.54 (0.00)
V. sativa 6.2 (0.00)
M. alba 3.5 (0.00)
C. album 1.066 (0.00)
A. arvensis 0.876 (0.00)
S. arvensis 0.348 (0.00)
V. sativa 1.707 (0.00)
M. alba 0.132 (0.00)
C. album 1.139 (0.00)
A. arvensis 1.007 (0.00)
S. arvensis 0.364 (0.00)
V. sativa 2.349 (0.00)
M. alba 0.165 (0.00)
51
(3.84) 4.65
(2.51) 3.39
(4.24) 5.86
(5.48) 3.26
(6.85) 0.968 (9.19) 0.862 (1.60) 0.333 (4.31) 1.530
(10.36) 0.115 (12.87) 1.031
(9.48) 0.983 (2.38) 0.354 (2.75) 2.167 (7.75) 0.150 (9.09)
36
(7.04) 4.37
(8.38) 3.25
(8.19) 5.06
(18.38) 3.10
(11.43) 0.848 (20.45) 0.826 (5.71) 0.313 (10.06) 1.242
(27.24) 0.104 (21.21) 0.912 (19.93) 0.950 (5.66) 0.326 (10.44) 1.746
(25.67) 0.130 (21.21)
86
(17.69) 4.08
(14.46) 3.06
(13.56) 4.73
(23.71) 2.83
(19.14) 0.733 (31.24) 0.795 (9.25) 0.296 (14.94) 1.174
(31.22) 0.101 (23.48) 0.773 (32.13) 0.916 (9.04) 0.325 (10.71) 1.305
(44.44) 0.124 (24.85)
95
(15.78) 3.16
(33.75) 2.66
(24.86) 4.33
(30.16) 2.53
(27.71) 0.694 (34.89) 0.734 (16.21) 0.247 (29.02) 1.097
(35.73) 0.092 (30.30) 0.733 (35.64) 0.869 (13.70) 0.252 (30.77) 1.255
(46.57) 0.125 (24.24)
49
(25.59) 2.72
(42.97) 2.29
(35.31) 3.70
(40.32) 2.50
(28.57) 0.545
(48.87) 0.696
(20.54) 0.214
(38.50) 0.950
(44.35) 0.074
(43.94) 0.579
(49.16) 0.822
(18.37) 0.209
(42.58) 1.066
(54.62) 0.098
(40.61)
90
(38.17)
19
(54.08) 1.93
(45.48) 3.36
(45.80) 2.36
(32.57) 0.388 (63.60) 0.595 (32.07) 0.202 (41.95) 0.845 (50.50) 0.061 (53.79) 0.426 (62.59) 0.743 (26.21) 0.179 (50.82) 0.769 (67.26) 0.080 (51.52)
13 0.3237 0.998 3.74 5.61 0.120 0.370 70.94 8.53 .059 0.181 103.65 8.67 .238 0.734 19.52 11.55 0.19 0.590 5.051 13.64 0.059 0.182 15.98 7.950 0.036 0.110 7.089 5.105 .0082 .0253 50.032 10.46 0.074 0.227 17.305 13.408 0.0075 0.023 10.109 14.68 0.068 0.208 13.44 1.979 0.0105 0.0317 83.34 4.019 0.0067 0.0205 121.38 19.071 0.167 0.516 12.115 11.668 0.0083 .0258 11.79
*Figures in parenthesis indicate % reduction
%, respective reduction in total biomass and shoot biomass of test weed was achieved at highest test concentration ie. 400 µg/g of the formulation. Reduction in vegetative shoot biomass of treated plants in the treatments of formulation seems to caused by both i.e. the growth retarding effect of allelochemicals as well as the germination inhibitor action of chemicals as the less numbers of new shoots emerged out in treated pots. Since the experiments were maintained for sufficient longer period (two and half months) hence by the time of observations, apart from the original two shoots burgeon by the tubers originally sown in pots, many more new shoots were emerged out due to the germination of newly developed and timely mature tubers . Therefore, this factor is also considered as an important parameter for assessing the efficacy of developed formulation. Compare to control, nearly
% reduction in such kind of newly induced shoots was observed at highest concentration (400 µg/g) of the formulation which clearly revealed the role of allelochemicals as germination inhibitor. Against C. rotundas, germination inhibitory effect of allelochemicals of sesame was also reported by Kumar and Varshney 2008, Kumar et al. 2011. Certain cyanogenic glycosides and a number of phenolic breakdown products released from the shoots of sorghum were also reported as potent contributors towards their effects on short term plant growth suppression.
Apart from the inhibitory effect on vegetative growth of test weed, significant effect of developed formulation was also observed on suppression of root growth and tuber development.. Results (table 1 and fig 3) indicated that compare to control, approximately 80% reduction in the total biomass
Journal of Food Legumes 26 (1&2), 2013
Fig 3 Effect of formulation on root growth and tuber development at highest concentration (400µg g-1) of formulation.
including the tuber weight was observed at 400 µg/ g concentration of the formulation. Therefore, the bioefficacy data strongly suggest that the isolated allelopathic compounds of sorghum root exudates possess potential herbicidal activity against purple nut sedge in all respects. The extracted allelo molecules not only showed their activity against purple nutsedge as growth retardant but also possess tremendous ability to destroy the weed via degrading their roots and not allowing the survived roots to form many tubers on them. All these together certainly would lead to break down the propagation cycle of this weed which is very much required for its effective management since it’s propagates in field by continuously forming the tubers.
Activity against other winter weeds: The effect of developed formulation on vegetative growth of other weed viz., Chenopodium album, Anagalis arvensis, Spergula arvensis, Vicia sativa and Melilotus alba, crops was also observed in different treatments. Results revealed a significant reduction in shoot length, shoot biomass and total biomass of test weeds (Table 2). The magnitude of reduction was proportional to concentration of the formulation Approximately, over the control, 3-6 %, 2-13% and 2-9%, respective inhibitions in shoot length, shoots biomass and total biomass of test weeds was observed at lowest concentration (150 mg/g),. The maximum inhibitions approximately (50-60%) in all the growth parameters was observed at the highest concentration (400 mg/ g). The magnitude of inhibition as per shoot biomass shoot length at 400 mg/g concentration was in order of A. arvensis (54.08%) V. sativa (45.80%), S. arvensis (45.48%), C. album (38.17%), and M. alba (32.57%) whereas, the order of magnitude of inhibition as per shoot biomass was C. album (63.60%), M. alba (53.79%). V. sativa (50.50%), S. arvensis (41.95%) and A. arvensis (32.07%). Based on total biomass inhibition, the highest concentration (400µg/ g) was more toxic to V. sativa by reducing total biomass by 67.26 % followed by C. album (62.59%), M. alba (51.52%), S. arvensis (50.82%) and A. arvensis (26.21%). Numerous studies have shown that grain
sorghum residues can suppress weeds for at least 8 weeks after cover crop kill and, when turned under, have inhibited weed growth throughout the following season (Einhellig and Rasmusssen 1989). Apart from this sorgoleon secreted by root hairs of sorghum has also been reported to be a potent inhibitor of chlorophyll formation in Lemna minor L. and known to inhibit the growth of some broadleaf and grass weeds (Netzly et al. 1988). Since the allelocompounds utilized in present study was found structurally, very close relative of already reported 3- deoxyanthocyanidins and sorgoleon in respect of their major chemical moieties hence, the broad spectrum activity of these compounds too can be assumed. However, functional substituents attached to the major chemical moiety in isolated compounds have not yet been identified correctly which may have their own role in imparting the toxicity of isolated compounds. Hence the obtained bioefficacy data strongly suggested that isolated allelopathic compounds of sorghum root exudates not only possess potential herbicidal activity against purple nut sedge in all respects but also found quite effective against a variety of weeds.
REFERENCES
Alsaadawi I S, and Dayan F E. 2009. Potentials and prospects of sorghum allelopathy in agroecosystems. Allelopathy Journal 24: 255-270.
Chun-Hat S, Siu-On S, Ricky N G, Elaine W, Lawrence C M C, Ivan K C and Clive Lo. 2007. Quantitative analysis of anticancer 3- deoxyanthocyanidins
in infected sorghum seedlings. Journal of Agricultual and Food Chemistry 55: 254-259.
Dayan F E, Howell J and Weidenhamer J. 2009. Dynamic root exudation of sorgoleone and its in planta mechanism of action. Journal of Experimental Botany 60: 2107-2117.
Enhellig F A and Rasmussen J A. 1989. Prior cropping with grain sorghum inhibits weeds. Journal of Chemical Ecology 15: 951-960.
Einhellig F A and Souza I F. 1992. Phytotoxicity of sorgoleone found in grain sorghum root exudates. Journal of Chemical Ecology 18: 1–11.
Hipskind J D, Hanau R, Leite B and Nicholson R L. 1990. Phytoalexins accumulation in sorghum: identification of an apigeninidin acyl ester. Physiol. Mol. Plant Pathol. 36: 381-396.
Joseph M A, Lloyd W R and Ralph D W. 2004. Properties of 3- deoxyanthocyanidins from sorghum. Journal of Agricultural and Food Chemistry 52: 4388-4394.
Kagan I A, Rimando A M and Dayan F E. 2003. Chromatographic separation and in vitro activity of sorgoleone congeners from the roots of Sorghum bicolor. Journal of Agricultural and Food Chemistry 51:7589–7595.
Kumar L. 2004. IIPR technique for the extraction, separation and purification of allelocompounds from plant species. Full length paper in the proceeding of International workshop on protocols and methodologies in Allelopathy,2-4 April 2004 at CSKHPKV Agriculture University Palampur, India. pp 34-42.
Kumar L, Chaudhary R G, Shukla N and Prajapati R K. 2010. isolation of sorghum allelochemicals and their efficacy against important pathogens of pulse crops. Allelopathy Journal 25 : 369-382.
Kumar L, and Varshney J G. 2008. Efficacy of sesame (Sesamum indicum) root exudates against major weeds of pulse crops. The Indian Journal of Agricultural Sciences 78: 842-847.
Kumar L, Varshney Jay G and Bhattacharya A. 2011. Bioefficacy of formulations of different allelofractions of sesame (Sesamum indicum) against purple nutsedge (Cyprus rotundus). The Indian Journal of Agricultural Sciences 81 : 67-73.
Liyi Y, Jimmy D B and Joseph M A. 2009. Sorghum 3- deoxyanthocyanidins possess strong phase II enzyme inducer activity and cancer cell growth inhibition properties. Journal of Agricultural and Food Chemistry 57: 1797-1804.
Lo S C, Weiergang I, Bonham C, Hipskind J, Wood K and Nicholson R L. 1996. Phytoalexin accumulation in sorghum: identification of methyl ether of luteolinidin. Physiological and Molecular Plant Pathology 49: 21-31.
Netzly D, Riopel J L, Ejeta G and Butler L G. 1988. Germination stimulants of witchweed (Striga asiatica) from hydrophobic root exudates of sorghum (Sorghum bicolor). Weed Science 36: 441- 446.
Rimando A M, Dayan F E and Streibig J C. 2003. PSII inhibitory activity of resorcinolic lipids from Sorghum bicolor. Journal of Natural Products 66: 42–45.
