Allelopathic Effects of Wheat Seed Extracts on Seed and Seedling Growth of Eight Selected Weed Species

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1 International Journal of Agriculture and Crop Sciences. Available online at IJACS/2012/4-19/ ISSN X 2012 IJACS Journal Allelopathic Effects of Wheat Seed Extracts on Seed and Seedling Growth of Eight Selected Weed Species Soheila Porheidar Ghafarbi 1, Sirous Hassannejad 2*, Ramin Lotfi 3 1. MS of weed science 2. Assistant professor of weed science, Department of Plant Eco-physiology, University of Tabriz 3. PhD student of crop physiology, Department of Plant Eco-physiology, University of Tabriz Corresponding author sirous_hasannejad@yahoo.com ABSTRACT: Allelochemicals have the potential to create friendly-eco products for weed management. A factorial experiment (using RCBD design) with 3 replication was conducted in 2011, to evaluation seed germination and seedling growth of some weed soaked in distilled water (control) and aqueous extract of wheat (Triticum aestivum L.) seeds. The first factor included different wheat extract concentrations (0, 2.5, 5, 10 and 20 percent) and the second factor was the eight weed species (Rumex crispus L., Datura stramonium L., Sisiymbrium irio L., Daucus Carota L., Peganum harmala L., Cardaria Draba L., Hordeum spontaneum and Avena ludoviciana).whereas wheat extract concentration increased, the inhibitory effect of allelopathic material on seeds germination and seedling growth indices also increased. As seed germination and seedling growth factors of R. crispus, P. harmala and D. carota were reduced by increasing wheat extract concentration, while seed germination of D. stramonium, C. draba, and S. riro in 5%, 5%, and 2.5% of wheat extract concentrations was increased. The results showed that S. riro was most sensitive to aqueous extract of wheat seeds and R. crispus was most resistant. Wheat seeds extract concentration of 20% has inhibitory effect on all seeds and seedling indices. As a result the allelopathic properties of wheat seeds extract can inhibitory effects on weed species. Key words: Allelopathy, Seedling Growth, Seed Germination, Wheat Seeds Extract, Weeds Species. INTRODUCTION Seeds of some crops possess allelopathic potential or weed-suppressing activity, including wheat (Wu et al., 1999). Aqueous extracts of wheat seed were allelopathic to the germination and growth of a number of weed species (Liebl and Worsham, 1983). Allelopathy has been defined as the inhibitory or stimulatory effects of a plant or microorganism on other plants through the release of chemical compounds into the environment. Most allelochemicals are classified as secondary metabolites of the plant (Kruse et al., 2000). However, these stimulatory and inhibitory effects depend on the concentration of the compounds (Bhowmik and Inderjiit, 2003). When susceptible plants are exposed to allelochemicals, germination, growth and development may be affected (Xuan et al., 2004). The most frequent reported gross morphological effects on plants are inhibited or retarded seed germination and effects on coleoptile elongation and shoot and root development (Kruse et al., 2000). Haig (2008) classified allelochemicals into several categories, such as glucosinolates, phenolic compounds, terpenoids, alkaloids, hydroxamic acids, and other compounds (flavonoids, quinones, polyacetylenes). Allelopathy in cereals (cultivated and wild plants of the Poaceae family) was attributed mostly to hydroxamic acids (Sanchez-Moreiras et al., 2004). Many of such natural compounds have been shown to be promising prospects for natural pesticides development (Dayan et al., 2009; Ma et al., 2011). Bio-herbicides represent solution to heavy use of synthetic herbicides which it causes serious threats to the environment, consumers and increases costs of crop production (Asghari and Tewari, 2007). Allelochemicals may be used to develop new tools to combat the evolution of herbicide resistance in weeds (Anjum and Bajwa, 2005). An equally promising way to use allelopathy in weed control is using extracts of allelopathic plants as herbicides (Dayan, 2002; Singh et al., 2005). Because biosynthesized herbicides are easily biodegradable, they are believed to be much safer than synthesized herbicides (Duke et al., 2000). Many authors reported employ plants extracts for controlling weeds with variable success (Hussain et al., 2007; Iqbal et al., 2009; Naseem et al., 2009).

2 Understanding the response of weed to allelopathic plants potential for weed control is very important. Therefore, the objective of this study was to determine the effects of wheat extract on seed germination and seedling growth of some its main weeds under lab conditions. MATERIAL AND METHODS In order to determine the effects of wheat seeds extract on seed and seedling growth of its main weeds [Rumex crispus L. (curlydock), Datura stramonium L. (datura), Sisiymbrium irio L. (London rocket), Daucus Carota L. (Carrot), Peganum harmala L. (harmel), Cardaria Draba (L.) Desv. (horay cress), Hordeum spontaneum C. Koch. (Wild barley), and Avena ludoviciana Durieu (oat)], a Factorial experiment (using RCBD design) with three replications was carried out in agronomy laboratory of University of Tabriz. The first factor included different concentrations of the wheat seeds extract (0, 2.5, 5, 10 and 20 percent). The second factor was the eight weed species. Two hundred grams of wheat seeds powder were separately suspended in 1000 ml distilled water and shaken for 24 hours by a horizontal rotary shaker in room temperature to obtain 20 percent concentration of aqueous extract. The solution was diluted appropriately with distilled water to give the other extract concentrations of 2.5, 5 and 10 percent. In this experiment, 16 seeds of each weed species were placed on Whatman filter paper in 9 cm petri dishes. Four ml of distilled water and final wheat seed aqueous extract concentrations were added to each petri dish. Their solutions were applied where required during the course of experiment. Then, their petri dishes were incubated at 20±ºC and germinated seeds (protrusion of radicle by 2 mm) were counted every day up to 7 days. Germination rate (GR) and mean germination time (MGT) were calculated according to Ellis and Roberts (1980): GR= MGT= Where n is the number of seeds germinated on day D, D is the number of days from the beginning of the test and GR is the mean germination rate. Then percentage of germination was also determined. At the end of test, number of root, length and fresh weight of root and shoot were measured. Root and shoot of each sample were then dried in an oven at 80 ºC for 24 hours (Perry 1977) and mean dry weight of root and shoot for each treatment at each replicate was determined. All the data were analyzed on the basis of experimental design, using MSTATC and SPSS-16 software. The means of each trait were compared according to Duncan multiple range test at P0.05 and standard error values. Excel software was used to draw figures. RESULTS Germination percentage of H. spontaneum, A. ludoviciana, R. crispus, P. harmala and D. carota seeds in control (wheat seeds extract concentration of 0%) were significantly higher than that of wheat seeds extract treatments. While, seed germination of D. stramonium, C. draba, and S. riro were stimulated in 5%, 5%, and 2.5% of wheat seeds extract concentrations. However, highest concentration of this extract (20%) has inhibitory effect on seed germination of all weed species (Tab. 1). Difference of mean germination time at H. spontaneum, A. ludoviciana, P. harmala, and C. draba among control and wheat seeds extract treatments were not significant. However, with increasing these extract concentrations, mean germination time at D. stramonium, R. crispus, and D. carota was significantly increased (Tab. 1). Wheat extract treatments were significantly reduced germination rate of H. spontaneum, A. ludoviciana and C. draba seeds, compared with control. In contrast, difference in germination rate of S. riro, D. stramonium, R. cricpus, P. harmala, and D. carota in control and wheat extract treatments was not statistically significant (Tab. 1). Table 1. Effects of wheat seeds extract concentrations on weed species seed germination Treatment Hordeum Sisiymbrium Avena Datura Rumex Peganum Cardaria Daucus

3 spontaneum riro ludoviciana stramonium crispus harmala draba carota G% a mno a no fghi cde abc a a 31.2 jklm a lmno ghij def abcd efgh ab o ab klmn hijk efg ab ghij def 0.00 o bcde 8.33 o 8.33 o efg ijkl no o 0.00 o 0.00 o o 6.25 o no 0.00 o 2.08 o MGT g 1.777efg g 4.833cde g g g g g g g fg fg g g g g cd g defg fg g g g g g g bc ab g fg cdef g g g cd a fg g defg GR b fg b fg efg defg cdef defg a efg bcd fg fg defg defg efg bcde fg bc fg fg defg defg efg defg g 2.58 cdef fg fg defg fg fg fg g g fg fg fg g g G%: germination percentage, MGT: germination mean time and GR: germination rate. Different letter in each column indicate significant difference at p0.05 Mean length of root and shoot at H. spontaneum, S. riro, A. ludoviciana, R. crispus, P. harmala, C. draba, and D. carota seedling by increasing of wheat extract concentrations were significantly decreased. However, in seedling of D. stramonium, highest root and shoot length were obtained from wheat extract concentrations of 2.5% (Tab. 2). Treatment Table 2. Effect of wheat seeds extract concentrations on MLR and MLS in seedling weeds Hordeum Sisiymbrium Avena Datura Rumex Peganum Cardaria spontaneum riro ludoviciana stramonium crispus harmala draba Daucus carota MLR a defg 10.50a g b 1.160def defg bc bc g cde fg g g defg defg bcd g efg g g g g g defg g fg g g g g g g g g g g g g g MLS a fg 7.740b g de 1.567efg d de a fg c fg 1.700efg fg fg fg bc g efg g 1.033fg g fg g def g fg g g g g g g g g g g g g g MLR: means length of root and MLS: means length of shoot. Different letter in each column indicate significant difference at p0.05 Means numbers of root was stimulated with increasing of wheat seeds extract concentrations at H.spontaneum up to 5% and at A. ludoviciana and P. harmala up to 2.5%. In seedling of S. riro, D. stramonium, R. crispus, C. draba, and D. carota, number of root in control were significantly higher than that of wheat extracts treatments. This indicated that H.spontaneum, A. ludoviciana, P. harmala were most resistant species than that of S. riro, D. stramonium, R. crispus, C. draba, and D. carota (Fig. 1).

4 Means number of root Wheat seeds extract concentrations H. spontaneum S. riro A. ludoviciana D. stramonium R. crispus P. harmala C. draba D. carota Figure 1. Effect of wheat seeds extracts concentration on means number of root on seedling of weed species; Bar=±SE, P<0.05. Fresh weight of root and shoot at H. spontaneum and A. ludoviciana seedling were reduced by increasing of wheat extract concentrations. Fresh weight of root at D. stramonium, R. crispus, P. harmala, and D. carota seedling was also reduced in this condition. While, difference of fresh weight of shoot in seedling of S. riro, D. stramonium, R. crispus, P. harmala, C. draba and D. carota between control and wheat extracts treatments was not significant (Tab. 3). Table 3. Effect of wheat seeds extract concentrations on FWR and FWS in seedling weed species Treatment Hordeum spontaneum Sisiymbrium riro Avena ludoviciana Datura stramonium Rumex crispus Peganum harmala Cardaria draba Daucus carota FWR a d b cd cd cd d cd c d cd cd d cd d d cd d cd d d d d d cd d d d d d d d d d d d d d d d FWS a e cd e e e e e b e d e e e e e c e e e e e e e cd e e e e e e e e e e e e e e e WFR: fresh weight of root and FWS: fresh weight of shoot. Different letter in each column indicate significant difference at p0.05. Dry weight of root and shoot in seedling of H. spontaneum, A. ludoviciana and D. stramonium were significantly affected by aqueous extracts from seeds of wheat and their trait were reduced with increasing extract concentrations (Tab. 4). Treatment Table 4. Effect of wheat seeds extracts concentrations on DWR and DWS in seedling weeds Hordeum Sisiymbrium Avena Datura Rumex Peganum Cardaria spontaneum riro ludoviciana stramonium crispus harmala draba Daucus carota DWR a 0.00 f b f 0.00 f 0.00 f 0.00 f 0.00 f c 0.00 f d e 0.00 f 0.00 f 0.00 f 0.00 f c 0.00 f f f 0.00 f 0.00 f 0.00 f 0.00 f d 0.00 f f f 0.00 f 0.00 f 0.00 f 0.00 f f 0.00 f f f 0.00 f 0.00 f 0.00 f 0.00 f DWS a 0.00 h e g 0.00 h 0.00 h 0.00 h 0.00 h b 0.00 h f h 0.00 h 0.00 h 0.00 h 0.00 h c 0.00 h h g 0.00 h 0.00 h 0.00 h 0.00 h d 0.00 h h h 0.00 h 0.00 h 0.00 h 0.00 h h 0.00 h h h 0.00 h 0.00 h 0.00 h 0.00 h DWR: dry weight of root and DWS: dry weight of shoot.different letter in each column indicate significant difference at p0.05.

5 DISCUSSION As the wheat seeds extract concentrations increased, the germination and seedling indices of the target weed species significantly decreased and reached the lowest percentage compared with the control. This is in agreeing with the findings of other researchers (Chaves et al. 2001, An et al. 2001, Wu et al. 2001, Asghari and Tewari 2007). Ahn and Chung (2000) have found an inverse relationship between rice hull water extract concentration and target weed seed germination. This finding also agrees with the work of Chaves et al. (2001) who have found that by increasing the concentration of Cistus ladanfer aqueous extracts, the percentage of seed germination, and root and cotyledon length of Rumex crispus were decreased. Mlakar et al. (2012) showed that extract of weeds have stronger inhibitory effect on the germination process and root elongation. Also, similarly result reported by Lai et al. (2012) on tobacco seeds. In some case, extract of wheat seeds have positive effect on germination and seedling indices. This finding is in agreement with that of Swaminathan et al. (1989) who reported a positive effect of seed extracts on radical growth. Nikneshan et al. (2011) reported that with increasing extract concentration from 25 to 100% the inhibitory effect on germination indices increased, while in 25% extract concentration it have incitement effects on seed germination. Boz (2003) also found that allelopathic materials in wheat has no effect on other plants, but may inhibited on some of their most important annual weeds. Results of this experiment showed the effects of wheat seeds extract on germination process are lower than seedling growth indices. Similarly Smith (1991), Smith and Martin (1994) and Ben-Hammouda et al. (1995) found aqueous extracts of several species have suppressed seedling growth in target plants more than seed germination. Indeed, the radicle growth was more sensitive to allelochemicals than the coleoptile growth. This is in agreement with Ahn and Chung (2000) who found that the length and dry weight of roots of Echinochloa crus-galli were more affected by hull extract than the shoots. CONCLUSION Present results showed that seed extracts of wheat significantly influence seed germination and seedling growth of its main weed species. Degree of this effect responds considerably to extract concentrations. Hence, we can conclude that exist of inhibitory substances in aqueous extract seeds of wheat would be the responsible for the observed effects. REFERENCE Ahn JK, Chung IM Allelopathic Potential of Rice Hulls on Germination and Seedlings Growth of Barnyardgrass. Agron. J., 92: An M, Pratley JE, Haig T Phytotoxicity of Vulpia Residues: III. Biological Activity of Identified Allelochemicals from Vulpia myuros. J. Chem. Ecol. 27: Anjum T, Bajwa R A bioactive annuionone from sunflower leaves. Phytochemistry 66: Asghari J, Tewari JP Allelopathic potentials of eight barley cultivars on Brassica jucea (L) Czern. and Setaria viridis (L) p. Beauv. J. Agric. Sci. Technol. 9: Ben-Hammounda M, Kremer RJ, Minor HC, Sarwar M A Chemical Basis for Differential Allelopathic Potential of Sorghum Hybrids on Wheat. J. Chem. Ecol. 21: Bhowmik PC, Inderjit H Challenges and opportunities in implementing allelopathy. Crop prot. 22: Boz O Allelopathic effects of wheat and rye straw on some weeds and crops. Asian J Plant Sci. 2: Chaves N, Sosa T, Alias JC, Escudero JC Identification and Effects of Interaction Phytotoxic Compounds from Exudates of Cistus ladanfer Leaves. J. Chem. Ecol. 27: Dayan FE, Cantrell CL, Duke SO Natural products in crop protection. Bioorg. Med. Chem. 17: Dayan FE Natural pesticides. p In D. Pimentel (ed.) Encylopedia of pest management. Marcel Dekker, Inc., New York. Duke SO, Dayan FE, Romagni JG, Rimando AM Biosynthesized products as sources of herbicides: Current status and future trends. Weed Res. 40: Ellis RH, Roberts EH The quantification of ageing and survival in orthodoxes seeds. Seed Sci. and Technol. 9: Haig T Allelochemicals in plants. In: Zeng RS, Mallik AU, Luo SM (eds) Allelopathy in sustainable agriculture and forestry, Springer, New York, pp Hussain S, Siddiqui S, Khalid S, Jamal A, Qayyum A, Ahmad Z Allelopathic potential of Senna (Cassia angustifoliavahl.) on germination and seedling characters of some major cereal crops and their associated grassy weeds. Pak. J. Bot. 39: Iqbal J, Cheema ZA, Mushtaq MN Allelopathic crop water extracts reduce the herbicide dose for weed control in cotton (Gossypium hirsutum). Int. J. Agric. Biol. 11: Kruse M, Strandberg M, Strandberg B Ecological Effects of Allelopathic Plants A Review. National Environmental Research Institute - NERI Technical Report No Silkeborg, Denmark. Lai R, You M, Chen Sh, Gu G, Wang G, Lai Ch Allelopathic influence of leek (Allium porrum) seeds on germination and radical growth of flue-cured tobacco of different cultivars. Afr. J. Agric. Res. 7:

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