Scientia Agriculturae www.pscipub.com/sa E-ISSN: 31-953X / P-ISSN: 311- DOI: 1.1519/PSCP.SA.15.1.3.1515 Sci. Agri. 1 (3), 15: 15-15 PSCI Publications Comparative Influence of Water Soluble Phenolics of Warm Climate Aquatic Weeds on Weeds Species Composition and Rice-Wheat Cropping System. Tasawer Abbas, Muhammad Ather Nadeem, Asif Tanveer, Ali Zohaib Department of Agronomy, University of agriculture, Faisalabad, 3 (Pakistan). Corresponding authors email: tagondaluaf@gmail.com Paper Information Received: 1 March, 15 Accepted: 19 Apriol, 15 Published: June, 15 Citation Tasawer A, Nadeem MA, Tanveer A, Zohaib A. 15. Comparative Influence of Water Soluble Phenolics of Warm Climate Aquatic Weeds on Weeds Species Composition and Rice-Wheat Cropping System. Scientia Agriculturae, 1 (3), 15-15. Retrieved from www.pscipub.com (DOI: 1.1519/PSCP.SA.15.1.3.1515) A B S T R A C T Impacts of water soluble phenolics are very imperative in establishing species composition in agro-ecosystem. Effects of aqueous extracts and residues of Alternanthera philoxeroides, A. sessilis, Conyza stricta, Polygonum barbatumand and Echinochloa crus-galli at different concentration were assessed on germination and growth attributes of rice (Oryza sativa L.) and wheat (Triticum aestivum L.) under controlled conditions, during 1. Results revealed that water soluble phenolics released from these weeds produce strong inhibitory effects on germination and growth of both rice and wheat, however inhibition was dose dependent at higher doses more inhibition was occurred. Allelopthic effects of A. philoxeroides and A. sessilis were stronger as compared to other weeds, which may a reason for invasion of Alternanthera spp. in rice ecosystem. HPLC analysis confirmed that the main phenolic are -Hydroxy-3- Methoxybenzoic acid, m-coumaric acid, p-coumaric acid, Chlorogenic acid, Ferulic acid, Gallic acid Vanilic acid, Caffeic acid and Chlorogenic acid in tested weeds. It may conclude that rice weeds have water soluble phenolics in their tissues which influence the weeds species composition in rice ecosystem and rice-wheat cropping system sustainability. 15 PSCI Publisher All rights reserved. Key words: Allelopathy, Alternanthera philoxeroides, A. sessilis, Conyza stricta, Echinochloa crus-galli, germination, Polygonum barbatum, weed invasion. Introduction To sustain agriculture production control of weeds is a major challenge for growers and scientists, weeds are causing more than 3% loses in crop production worldwide (Oerke ). Weeds influence crop production in different ways including weed crop completion and allelopathy (Sajjad et al., 7; Iqbal et al., 1). To sustain in the ecosystem weeds are adapting herbicide resistance, seed dormancy, short growth periods and inhibiting the growth of associated crop plants and crop which is following in the cropping system by releasing water soluble phenolics. Different weeds have proven their strong inhibitions on crop germination and growth by releasing water soluble phenolics (Herro and Callaway, 3). Residues of allelopathic weeds buried in soil inhibit the emergence and seedling growth of subsequent crop (Khaliq et al, 11). Even under field conditions allelochemicels have shown their potential to adversely affect the crop stand establishment (Inderjit and Duke, 3). The harmful effects of decaying weeds residues depend upon the release of secondary metabolites into the soil. These chemicals may wash out directly from the residues, or may result of microbial activity during decomposition of residues (Kumar et al. ) and affect the germinations and seedling growth of succeeding crop by releasing phenolics in the soil (Batish et al., 5). Alligator weed (Alternanthera philoxeroides (Mart) Griseb), Sessile joyweed (Aternanthera sessilis L.), Erect horseweed (Conyza stricta L.), Joint weed (Polygonumbarbatum L.) and Barnyard grass (Echinochloa crus-galli L.) are common weeds of rice ecosystem in Pakistan and having strong allelopathic potential (Abbas et al., 1). A. pheloxroides and A. sessiles are invase weeds and caused upto 5% yield reduction in rice (Zhang et al., ). These weeds are spreading very quickly all over the country and dominating the other weeds of rice ecosystem. The possible reason for their quick spread may be there strong allelopathic potential which suppress and inhibit the germination and growth of other associated weeds.
Sci. Agri. 1 (3), 15: 15-15 Therefore, this study was conducted to identify the reason of quick spread of alternatheria species in rice ecosystem, to determine the type and quantity of water soluble phenolic, to evaluate the comperative allelopathic potential of these weeds and to check the possible effects of water soluble phenolics on rice and wheat crop. Materials And Methods Collection of Weeds Whole mature plants of selected weeds viz. Alternanthera philoxeroides, A. sessilis, Conyza stricta, Polygonum barbatumand and Echinochloa crus-galli were uprooted randomly from Agronomic research area, University of Agriculture, Faisalabad, Pakistan, during 1. These weeds were washed in distilled water for removing dust and soil particles (these may influence the chemical composition of leachate) for minimum period (to avoid leaching losses of water soluble allelochemicals) and then were dried in shade for a week at 5 o C. After drying, whole plants of each species were chopped into small pieces. Preparation of aqueous extracts and residues of weeds. The dried pieces of the weeds plants were weighed and put in distilled water separately in the ratio of 1: (w/v) at room temperature for hours. The extract of whole plant was obtained by filtering it through whatman No.1. The leachates were collected in separate bottles and tagged. The extract obtained after filtering was used for study. Dried whole plants pieces of A. philoxeroides, A. sessilis, C. stricta, P. barbatum and E. crus-galli were ground into small pieces (to make decomposition and mixing of plant residues easy in the soil) with the help of grinder. Wheat crop was used to test the effect of tested weeds aqueous extract and residues at different concentration on the germination and early seedling growth. A completely randomized design (CRD) with factorial arrangement with replications was used to conduct experiments. Experiment 1: Effects of water soluble phenloics of whole plant aqueous extract of warm climate aquatic weeds on germination and seedling growth of wheat and rice. In first experiment, seeds of rice and wheat sown in petri dishes were treated with weed aqueous extract and distilled water used as a control. Ten seeds of each crop were placed in one petridish separately lined with doubled layered filter paper. At start of experiment 7 ml of each extract at.5% and 5% concentration was applied in every petri dish, separately. Petri dishes were placed in a laboratory at 19- C for 15 days. The petri dishes were observed daily and extracts/distilled water were added when needed. After 15 days, the seedlings were uprooted and washed with water. The length of roots and shoots was measured. Roots and shoots were oven dried at 7 C until a constant weight was obtained. Experiment : Effects of water soluble phenloics in residues of warm climate aquatic weeds on germination and seedling growth of wheat and rice. In pot experiment ten seeds of rice and wheat were buried in each pot. Residues of weeds were mixed in soil at the rate of % and % before sowing for each species separately. Weeds residues free soil having.3 % organic matter and ph.3 was used. Then distilled water was applied to avoid the drying out of seedlings throughout the growth period. Pots were placed in control condition 19- C for 15 days. After 15 days, the seedlings were washed with water and length of roots and shoots was measured. Roots and shoots were oven dried at 7 C until a constant weight was obtained. Germination/ emergence Time to 5% Germination/ emergence [Days] Time to 5% germination (T 5 ) was calculated according to the following formula of Coolbear et al. (19) modified by Farooq et al. (5): N T 5 = t i + [ n i ] (t n j n j t i ) i Where N is the number of germinated seeds, and n i andn j are the cumulative number of seeds germinated by adjacent counts at times t i and t j, respectively, when n i < N/ >n j.. Seedling Growth All the seedlings from each replication were taken and the length of each root and shoot was measured in cm from the point where root and shoot joins together to the end of root and to the top of shoot. Then average root length and shoot length was worked out then root to shoot ratio was calculated. Roots and shoots of the all seedlings were separated, oven dried at 7 o C till constant weight. The average root and shoot dry weight per plant in mg was calculated. 1
Sci. Agri. 1 (3), 15: 15-15 Types of phenolics and determination of total phenolic content For identification of suspected phytotoxins of A. philoxeroides, A. sessilis, C. stricta, P. barbatum and E. crus-galli, their aqueous extracts were chemically analyzed on Shimadzu HPLC system (Model SCL-1A, Tokyo, Japan). The peaks were detected by UV detector. Standards of suspected phytotoxins (Aldrich, St Louis, USA) were run similarly for their identification and quantification. The identified phenolics are listed Table 1. Total water-soluble phenolics in the weeds were estimated as per the method of Swain and Hillis (1959) using Folinciocalteu reagent. Their amounts were determined spectrophotometrically at 7 nm against the standard of ferulic acid in table 1. Statistical Analysis Date was transformed before statistical analysis using square root transformation to make the date normal. Fisher s analysis of variance techniques was carried out to analyze the transformed data and comparison of treatments means was done using least significant difference test at 5% probability level (Steel et al., 1997). Results Effects of aqueous extract of warm climate aquatic weeds on germination consequences and seedling growth of rice and wheat Results showed that aqueous extract of all tested weeds inhibit the germination of rice and wheat that caused increase in time to 5% germination (T 5%). All weeds were different in their allelopathic potential A. philoxeroides and A. sessilis caused more inhibition than C. stricta, P. barbatum and E. crus-galli. Inhibitory effects were also concentration dependent at 5% more inhibition was occurred as compared to.5% aqueous extract. Both rice and wheat showed almost same trend in cause of T 5% against aqueous extract of different weeds and their different concentrations (Fig. 1-). Results about Root to shoot ratio showed that all weeds caused reduction in root to shoot ratio at both concentrations, except C. stricta which produce no effect on rice root to shoot ratio. Alternanthera philoxeroides and A. sessilis caused more inhibition as compared to C. stricta, P. barbatum and E. crus-galli both against rice and wheat (fig 3-). Data about shoot dry weight revealed that all tested weeds significantly reduced shoot dry weight. Inhibition was more at higher concentration (5 % aqueous extract). A. philoxeroides and A. sessilis caused more inhibition than C. stricta, P. barbatum and E. crus-galli. Effects of all weeds were significant irrespective to type of crop plants (fig 5-). Root dry weight was also significantly reduced in rice and wheat seedlings which were treated with different concentrations of five different weeds. Inhibitory effects were more dependent on the types of weeds as compared to their concentrations. Inhibition due to different weeds was different, A. philoxeroides and A. sessilis caused higher dry weight reduction than other tested weeds. 5% aqueous extract caused more reduction as compared to.5 % concentration (fig 7-). Effects of residues of warm climate aquatic weeds on germination consequences and seedling growth of rice and wheat The results revealed that residues of all tested weed types and their concentrations inhibit the time to 5% emergence (E 5%) of rice and wheat differently. Alternanthera philoxeroides and A. sessilis caused more inhibition both in rice and wheat than C. stricta, P. barbatum and E. crus-galli. E 5% trend was almost similar in both crops rice and wheat. But in case of wheat inhibitory effect was comparatively more than rice (fig 9-1). Results about root to shoot length ratio revealed that inhibition was not due to trade of mechanism between root and shoot. Shoot and root length both were reduced due to allelopathic effects of tested weeds. Inhibitory effect was dependent on types of weed and their concentration but rice and wheat crops under study showed same type of responses (fig 11-1). Shoot dry weight of both rice and wheat was significantly reduced due to residual effects of allelopathic weeds at all residual concentrations. Inhibitory effect on shoot dry weight was more sever at higher dose (% residues). Like other traits shoot dry weight was also less in pots which were treated by A. philoxeroides and A. sessilis residues (fig 13-1). Root dry weight of both rice and wheat was also reduced by weeds residues at all concentrations. More inhibitory effect was produced in pots where A. philoxeroides and A. sessilis residues were incorporated. Wheat crops showed more sensitivity in case of reduction in root dry weight (fig 15-1). Discussion All weeds under study showed that they have allelopathic impact by releasing water soluble phenolics in rice ecosystem. Difference in allelopathic activities was due to specie specific nature of allelopathic potential of different weed species. It may be due to difference in concentration of phenloics and types of phenloics present in that weed. Literature revealed that allelopthic effects are species and concentration dependent (Abbas et al., 1). Strong allelopathic potential of Alternanthera philoxeroide and A, sessilis are supported by the finfinds of Zuo et al. (1) who reported that alternanthera species grown under aquatic condition produce more allelopthic chemicals. Findings are also supported by literature which revealed that A. philoxeroides, A. sessilis and E. crus-galli inhibit the growth of agronomic crop due to weed crop competition and release of water soluble phenolics in ecosystem (Zhang et al. 9; Dhole et al. 11). 17
Sci. Agri. 1 (3), 15: 15-15 Allelopathic effects of weeds in agro-ecosystem are very important to determine the densities of different plant species in that ecosystem. Weeds with more allelopathic potential suppress the germination and growth of other weeds and crop plants (Benyas et al., 1). In this way these allelopathic plant win competitive advantages over other plant having low allopathic potential. This competitive advantage increases the spread and dominance of these plants in agro ecosystem. This ecological phenomena help in invasion of new weed species (Rejmánek ). As results of present research revealed that alternanthera species having more allelopathic potential than other weeds of rice ecosystem which were under study, it may be a possible cause of quick spread of these weed species in rice ecosystem. Inhibition of germination and growth attributes of rice and wheat crop was due to release of water soluble phenolics from these weeds. As HPLC analysis revealed that -Hydroxy-3- Methoxybenzoic acid, m-coumaric acid, p-coumaric acid, Chlorogenic acid, Ferulic acid, Gallic acid Vanilic acid, Caffeic acid and Chlorogenic acid are water soluble phenolics identified in these weeds. Concentration and types of phenloics were different depending upon the type of weed. Literature showed that these phenloics have strong inhibitory effects on the germination and seedling establishment of different crops and weeds plants (Dhole et al. 11). Inhibition of rice and wheat due to presence of water soluble phenloics is also reported in the literature (Liu et al. 7; Zhang et al. 9, Abbas et al., 1). Conclusion Results revealed that rice aquatic weeds including A. philoxeroides, A. sessilis, C. stricta, P. barbatum and E. crusgalli proved their inhibitory potential against wheat and rice by release of water soluble phenloics. Of the species considered, A. philoxeroides and A. sessilis showed more inhibition as compared to C. stricta, P. barbatum and E. crus-galli. Stronge allelopathic potential is possible cause of invasion of Alternanthera species. Therefore these weeds should be controlled at early stages to reduce their possible allopathic effects on rice and wheat to sustain rice-wheat cropping system. Table 1. Types and total phenolics contents quantified in warm climate aquatic weeds of rice ecosystem Aquatic weeds Types of phenolic identified Total phenolic ( µl ml -1 ) Alternanthera philoxeroides -Hydroxy-3- Methoxybenzoic acid, m-coumaric acid and p- Coumaric acid. 111 Alternanthera sessilis Chlorogenic acid, Ferulic acid, Gallic acid and Vanilic acid. 11 Conyza stricta Chlorogenic acid, Ferulic acid and m-coumaric acid. 11 Echinochloa crus-galli m-coumaric acid, p-coumaric acid and Vanilic acid. 31 Polygonum barbatum Caffeic acid, Chlorogenic acid, m-coumaric acid and p-coumaric acid. 1 %.5 % 5 %.5 % 5 Figure 1-. Time taken for 5% germination (Days) 1/ 1 / / / / 1/5 1 /5 Figure 3-. Root length to shoot length ratio 1
Sci. Agri. 1 (3), 15: 15-15 35 3 5 15 1 5 35 3 5 15 1 5 1 Figure 5-. Dry weight of shoot (mg) 5 3 1 Figgure 7-. Dry weight of root (mg) 1 % % % % Figure 9-1.Time taken for 5% germination (Days) /5 / /3 / /1 /5 / /3 / /1 Figutr 11-1. Root length to shoot length ratio 19
Sci. Agri. 1 (3), 15: 15-15 3 1 3 1 Figure 13-1. Dry weight of shoot (mg) 1-1 1 Figure 15-1. Dry weight of root (mg) Effects of residues of warm climate aquatic weeds on germination consequences and seedling growth of rice Effects of residues of warm climate aquatic weeds on germination consequences and seedling growth of wheat References Abbas T, Tanveer A, Khaliq A, Safdar ME, Nadeem MA. 1. Allelopathic effects of aquatic weeds on germination and seedling growth of wheat. Herb 1: -3. Batish DR, Singh HP, Pandher JK, Kohli RK. 5. Allelopathic interference of Parthenium hysterophorus residues in soil. Allelopathy J 15: 7-7 Benyas E, Hassanpouraghdam MB, Salmasi SZ, Oskooei OSK. 1. Allelopathic effects of Xanthium strumarium L. shoot aqueous extract on germination, seedling growth and chlorophyll content of lentil (Lens culinaris Medic.). Rom Biotech Lett 15: 53-5. Coolbear P, Francis A, Grierson D. 19. The effect of low temperature per sowing treatment under the germination performance and membrane integrity of artificially aged tomato seeds. J Exp Bot 35: 19-117. Dhole JA, Bodke S, Dhole N. 11. Allelopathic effect of aqueous extract of five selected weed species on seed mycoflora, seed germination and seedling growth of Sorghum vulgare Pers. (Jawar). RJPBCS : 1-1. Farooq M, Basra SMA, Hafeez K, Ahmad N. 5. Thermal hardening: a new seed vigor enhancing tool in rice. J Integr Plant Biol 7: 17-193. Herro JL, Callaway RM. 3. Allelopathy and exotic plant invasion. Plant and Soil 5: 9-39. Inderjit SD. 3. Ecophysiological aspects of allelopathy. Planta 17: 59 539. Iqbal J, Karim F, Hussain S. 1. Response of the wheat crop (Triticum aestivuml.) and its weeds to allelopathic crop water extracts in combination with reduced herbicides rates. Pak J Agri Sci 7: 39-31. Khaliq A, Matloob A, Cheema ZA, Farooq M. 11. Allelopathic activity of crop residue incorporation alone or mixed against rice and its associated grass weed jungle rice (Echinochloa colona [L.] Link). Chil j Agric Res 71: 1-3. Kumar M, Lakiang JJ, Gopichand B.. Phytotoxic effects of agroforestry tree crops on germination and radicle growth of some food crops of Mizoram. Lyonia 11: 3-9. Liu AR, Zhang YB, Zhang XM, He XL, Wu Q. 7. Effects of aqueous extract from alligator weed on seed germination and seedling development of Loliumperenneand Festucaarundinacea. ActaPratacult Sin 1: 9 11. Oerke EC.. Crop losses to pests. J Agric Sci 1: 31 3. Rejmánek M.. Invasive plants: approaches and predictions. Austral ecology 5: 97-5. Sajjad H, Sadar S, Khalid S, Jamal A, Qayyum A, Ahmad Z. 7. Allelopathic potential of Senna (CassiaangustifoliaVahl.) on germination and seedling characters of some major cereal crops and their associated grassy weeds. Pak J Bot 39: 115-1153. Steel RGD, Torrie JH, Dickey D. 1997. Principles and Procedures of Statistics: A Biometrical Approach. 3 rd Ed. pp: 17-177 McGraw Hill Book Co. Inc. New York, USA. Swain T, Hillis WE. 1959. The phenolic constituents of PrunusdomesticaI. The quantitative analysis of constituents. J Sci Food Agric 1: 3. Zhang Z, Xu L, Ma YT, Li J. 9. Allelopathic effects of tissue extract from alligator weed on seed and seedling of ryegrass. ActaBot. Boreali-Occidentalia Sin 9: 1 153. Zhang JX, Li CH, Lou YL, Deng YY, Qiu CY.. Studies on the transplanting rice yield loss caused by weed Alternanthera philoxeroides and its economic threshold. Acta Agric. Shanghai : 95-9. Zuo S, Ma Y, Shinobu I. 1. Differences in ecological and allelopathic traitsamong Alternantheraphiloxeroidespopulations. Weed Biol Manag 1: 13 13. 15