Allelopathic Impact Of Certain Weeds On Oryza Sativa L.

Transcription

1 Research Paper Volume 3 Issue 3 November 2015 International Journal of Informative & Futuristic Research Allelopathic Impact Of Certain Weeds On Paper ID IJIFR/ V3/ E3/ 060 Page No Subject Area Botany Keywords Allelopathy, Weeds,, Cynodon Dactylon, Synedrella Nodiflora 1 st Liza Jacob 2 nd Sruthy S. Dev Assistant Professor Department Of Botany, St. Teresa s College (Autonomous), Ernakulum, Kerala, India M.Sc. Student Applied Mechanics Department, Department Of Botany, St. Teresa s College (Autonomous), Ernakulum, Kerala, India Abstract The present work was undertaken with the objectives to make a comparative study on the impact of different weed plants on the growth and yield of rice () The weeds selected were Synedrella nodiflora and Cynodon dactylon. Plants grown in control showed higher growth rate and productivity than the plants grown in the potting mixture amended with weed residues of Cynodon dactylon and Synedrella nodiflora. The chlorophyll and carotenoid content of leaves was also higher in control condition. The slow growth of paddy in soils containing Cynodon and Synedrella may be due to allelochemicals produced by the weed plants. In the control condition the paddy plants are healthier than the other two. The study revealed that there is a considerable variation in the growth and productivity of plants. Plants that are grown in the control condition showed higher growth and productivity than other plants which are grown in soil containing weed plants. From the result of the present study, it may be concluded that certain allelochemicals present in the weed plants have impaired the growth and the crop production of paddy. 1. Introduction Rice (Oryza sativa L.) is the main food crop in Asia and the staple food of the majority of the population in many regions of the world. The population pressure in rice-consuming countries demands that more attention be directed towards new approaches to sustainable rice production. Available online through - Published Online On: November 30, 2015 Copyright IJIFR

2 Allelopathy refers to the harmful effects of one plant on another plant, both crop and weed species, from the release of biochemicals, known as allelochemicals, from plant parts by leaching, root exudation, volatilization, residue decomposition, and other processes in both natural and agricultural systems. Allelochemicals are a subset of secondary metabolites not required for metabolism (growth and development) of the allelopathic organism. The term allelopathy is from the Greek- allelo and pathy (meaning "mutual harm" or "suffering") and was first used in 1937 by Austrian scientist Hans Molisch in the book Der Einfluss einer Pflanze auf die andere - Allelopathie (The Effect of Plants on Each Other) (Willis 2010). First widely studied in forestry systems, allelopathy can affect many aspects of plant ecology, including occurrence, growth, and plant succession, the structure of plant communities, dominance, diversity, and plant productivity. There are about species of weeds affecting billion worth of crops are lost each year, accounting for 10% of production. Many high yield crops have been bred, but this simultaneously increases the heavy dependence on agrochemicals. Weeds have been a persistent problem for farmers ever since beginning of agriculture because it causes economic losses of farmers by reduction in crop yield, increase costs at crop production and reduced crop quality. Alarmingly greater loss in the yield of rice due to weed infestation has been reported by many investigators from the different parts of the world. Weeds cause the major yield losses in crops and also reduce their quality. Without weed management, rice yield may reduce by 16 to 86% or even 100%.Worldwide more than 1000 weed species have been reported in rice. However 13 species are the most serious weeds species. They are Cynodon dactylon, Cyperus rotundus, Echinochloa crus-gali, Echinochloa colonum, Eleusine indica, Eichhornia crassipes, Protulaca oleracea, Chenopodium album,digitaria arvensi, Sorghum halepense, Imperata cylindrical, Avena fatua and Amaranthus retroflexus. The allelochemicals released from the plants incorporated into paddy soil play a crucial role in inhibiting the paddy growth. Many inhibitors identified from weeds belong to phenolic acids, fatty acids, lactones, and amino acids. As the paddy field always has a high moisture content, weed infestation is a serious problem. Ploughing the field and leaving the weeds in the field itself as a green manure is a very common practice in many rice growing countries. At times these weeds may be possessing allelochemicals which in turn can produce an allelopathic impact negatively affecting the growth of the crop. Keeping this view, the present work was carried out to analyse the allelopathic effect of two common weeds on the growth and development of rice. 2. Materials And Methods 2.1 Weeds Selected for Study i.) Cynodon dactylon, ii.) Synedrella nodiflora The study was conducted in the home garden. Rice seedlings were raised in earthenware pots. The whole plant of C. dactylon was finely chopped and the potting mixture was prepared in the ratio sand: soil: farmyard manure and Cynodon in 1:1:1:2. Likewise S. dactylon was also chopped finely and potting mixture was prepared in the ratio- sand: soil: farmyard manure: Synedrella - 1:1:1:2. The control pot was filled with potting mixture having sand: soil: farmyard manure in 1:1:1 ratio. The paddy grains were sown in these pots and were watered regularly. 1056

3 2.2 Parameters of Study 2.1 The following growth parameters were studied at regular intervals i.) Shoot length Shoot length of each plant was measured at two week interval ii.) Fresh weight Fresh weight was obtained using weighing balance after uprooting the plant on,45 th and 105th day. iii.) Dry weight Dry weight (Oven dried) of the plants was obtained on day after uprooting the plant. iv.) Fresh weight of spikelets Fresh weight of spikelets was obtained on day. v.) Dry weight of spikelets The spikelets were dried in the oven at 70 0 C till constant weight was obtained and were weighed vi.) Chlorophyll and Carotenoid contents The method of Arnon(1947)was employed for the quantitative estimation of chlorophyll and carotenoid contents. 3. Result 3.1 Shoot Length Table 1: Shoot length of the plants in different experimental set up Sl. No. Soil condition Day Shoot length (cm) 1 Cynodon 15 th 45 th 60 th 75 th 90 th 105th Synedrella 3 Control 15 th 45 th 60 th 75 th 90 th 105th 15 th 45 th 60 th 75 th 90 th 105th Oryza Sativa grown in the soil containing Cynodon weed residue. The shoot length observed was 10 cm, 24cm, 31cm,36cm, 41.8cm, 55cm, 60.8 cm on the 15 th day, day, 45 th day, 60 th day, 75 th day, 90 th day and day respectively. 1057

4 Oryza Sativa grown in the soil containing Synedrella The shoot length were was16.98 cm, 26.4 cm, cm, cm, 65 cm, 67.5 cm and 70 cm on the 15 th day, day, 45 th day, 60 th day, 75 th day, 90 th day and day respectively. Oryza Sativa grown in the soil containing manure alone The shoot length of the control plants was cm33.2 cm51.75 cm70.3 cm73.8 cm77.3 cm 80.8 cm on the 15 th day, day, 45 th day, 60 th day, 75 th day, 90 th day and day respectively. Number of spikelts was counted on 105th day The number of spikelts of Oryza sativa grown in the soil containing Cynodon weed residue was counted on 105th day was 7 The number of spikelts of Oryza sativa grown in the soil containing Synedrella weed residue The number of spikelts day was just 1 The number of spikelts of Oryza sativa grown in control was Fresh Weight Table 2: Fresh weight of grown in soils amended with weeds Sl. No. Soil condition Day Fresh weight 1 Cynodon 0.89 gm 1.27gm 2.66gm 2 Synedrella 3 Control 1.10 gm 1.76 gm 4.06 gm 1.40 gm 1.49 gm 4.15 gm Fresh weight was found out after uprooting the plant on 30th, and 105th day. Fresh weight of whole plant in Cynodon weed residue was measured on the 30th day was 0.89g.Fresh weight of whole plant in Cynodon weed residue was measured on the 45th day was 1.27g. Fresh weight of whole plant in Cynodon was measured on the 105th day was 2.66 g. Fresh weight of plant in Synedrella on the 30th day was 1.10g. Fresh weight of plant in Synedrella on the 45th day was 1.76 g. Fresh weight of single plant in Synedrella on the 105th day was 4.06 g. Fresh weight of plant in manure on 30th day was 1.40 g. Fresh weight of plant in manure on 45th day was 1.49g. Fresh weight of the plant in control on 105th day was 4.15 g Fresh weight of spikelets was found out on 105th day Fresh weight of the spikelets produced by Oryza grown in soils with Cynodon residue on 105th day was 3.6g. Fresh weight of the spikelets produced by Oryza grown in soils with Synedrella weed residue on 105th day was 1.0 g. Fresh weight of the spikelets produced by Oryza grown in soils with manure on 10th day was 5.2 g 1058

5 3.3 Dry weight of whole plant Table 3: Dry weight of Oryza sativa L. grown in soils amended with weeds Sl. No. Soil condition Day Dry weight 0.12 gm 1 Cynodon 2 Synedrella 3 Control 0.18 gm 2.9 gm 0.17 gm 0.32 gm 0.9 gm 0.21 gm 0.40 gm 4.1 gm Oryza sativa grown in the soil containing Cynodon weed residue Dry weight of plant grown in Cynodon weed residue on 30th day was 0.12 g Dry weight of plant grown in Cynodon weed residue on 45th day was 0.18 g Dry weight of plant grown in Cynodon weed residue on 105th day was 2.9 g Oryza sativa grown in the soil containing Synedrella weed residue Dry weight of plant grown in Synedrella weed residue on 30th day was 0.17g Dry weight of plant grown in Synedrella weed residue on 45th day was 0.32 g Dry weight of plant grown in Synedrella weed residue on 105th day was 0.9 g Oryza sativa grown in the soil containing manure Dry weight of plant grown in manure on 30th day was 0.21 g Dry weight of plant grown in manure on 45th day was 0.40 g Dry weight of plant grown in manure on 105th day was 4.1 g Dry weight of spikelets The dry weight of spikelets was found out on 105th day after drying in the hot air oven. Oryza sativa grown in the soil containing Cynodon weed residue The dry weight of spikelets on 105th day was 2.5 g Oryza sativa grown in the soil containing Synedrella weed residue The dry weight of spikelets on 105th day was 0.6 g Oryza sativa grown in the soil containing manure The dry weight of spikelets on 105th day was 4.0 g 3.4 Chlorophyll and carotenoid content (mg/g) Oryza sativa grown in the soil containing Cynodon weed residue Chlorophyll a content calculated colorimetrically on 30th day was chlorophyll b content calculated colorimetrically on 30th day was carotenoid content calculated colorimetrically on 30th day was Total chlorophyll content calculated colorimetrically on 30th day was

6 Oryza sativa grown in the soil containing Synedrella weed residue chlorophyll a content calculated colorimetrically on 30th day was chlorophyll b content calculated colorimetrically on 30th day was carotenoid content calculated colorimetrically on 30th day was Total chlorophyll content calculated colorimetrically on 30th day was Oryza sativa grown in the soil containing manure chlorophyll a content calculated calorimetrically on 30th day was chlorophyll b content calculated colorimetrically on 30th day was carotenoid content calculated colorimetrically on 30th day 3 was 0.22 Total chlorophyll content calculated colorimetrically on 30th day was Table 4 : Leaf pigment content of Oryza sativa L. grown in different soil conditions Sl. No. Soil condition Day Chlorophyll a (mg/g) Chlorophyll b (mg/g) Total Chorophyll (mg/g) Carotenoid (mg/g) 1 Cynodon Synedrella Control Discussion The present work was carried out to study the growth response of Oryza sativa Linn. to selected weed residues in the soil. The weeds selected were Synedrella nodiflora and Cynodon dactylon. According to the study on weed management conducted by Swain et al., it was found that Echinochola colona (L.) is a very problematic weed in upland and medium land rice causing significant reduction in yield. The decomposition leachetes of E. colona showed strong toxic effect on root and shoot growth of rice, the highest bring noted which 10% leachetes of 60 days old plant residue. It inhibits the root and shoots growth by 100% and 43.9% respectively as compared to control. The corresponding decomposed leachetes inhibited rice germination by 90%, root & shoot growth by 70% and 25% respectively. Comparable results were obtained in the case of present study too. The plant grown in control showed higher growth rate than the plants grown in the weed residues like Cynodon and Synedrella.The shoot length and the root length of the plant grown in control was more than that of other plants. The growth of the plants grown in weed residue was inhibited by the allelochemicals produced by weeds. Yet another study was made with the same parameters by Rajan Katoch et al,.(2012) on the effect of weed plants like Ageratum conyzoides, Lantana camara and Eupatorium adenophora on the growth of crop plants like Triticum aestivum and maize. These are rapidly spreading weeds species. The shoot weight of wheat seedlings grown in soil amended with E. adenophorum (5g/100g soil) L. camara (5g/100g soil) A. conzoides (10g/100g soil) was significantly lesser as compared to the control. Ambika et. al.,(1993) reported that E. adenophorum contains a large amount of allelochemicals especially in the leaves which inhibit the growth of many plants in nurseries and plantations.similarly allelochemicals from Ageratum conyzoids have been reported to inhibit seed germination and seedling growth of many plants (Batish et al., 2006) In the present study also it was found out that the plants grown in control have higher shoot and root weight than the plants grown in weed residues like Cynodon and Synedrella. Yet another study on weed management was conducted by Semina et al, (2012) and it was found out that the leaf extract of weed the plant Tridax procumbens L. suppresses the germination of leguminous plants. The 1060

7 maximum seed germination percentage was shown in the control where no extract was used. Another study on allelopathy and weed management was conducted by Emman et,. al.(2013) and they revealed that weed plant L. camara is one of the top 10 worst weeds of the world. It suppressed seed germination and seedling growth of the both P. minor & S. bicolor and the suppressive effect increased with increase of extract concentration. The root elongation and shoot development of the recipient species were markedly inhibited. Yet another study on the same topic was conducted by Elavazhagan and Natarajan (2014) on the effect of A. conyzoides and C. viscosa on Sesamum indicum. It was observed that the weeds caused a significant inhibition of germination of seeds over control. The intensity of inhibition varied depending upon the concentration of weed extract. The studies conducted by researchers prove that weed plants are capable of producing growth and yield inhibition of crop plants. In many parts of the world, the weed plant growing in the crop field are uprooted and are left in the field and mixed with soil as source of green manure. Some of these weeds may be possessing allelochemicals which in turn can produce an allelopathic impact negatively affecting the growth of the crop. While amending the soil with weed plants as green manure, the farmers have to be very careful so as to avoid such troublesome weeds. 6. Summary And Conclusion The present work was undertaken with the objectives to make a comparative study on the impact of different weed plants on the growth and yield of paddy (Oryza sativa L.) The weeds selected were Synedrella nodiflora and Cynodon dactylon. Various parameters such as height of the plants, length and number of roots, number of branches and spikelets, biomass of plants and spikelets were observed and compared. The study revealed that there was a considerable variation in the growth and productivity of plants. Plants which grown in control (farmyard manure) showed higher growth and productivity than the plants grown in the potting mixture amended with weed residues of Cynodon dactylon and Synedrella nodiflora. The chlorophyll and carotenoid content of leaves was also higher in control condition. In the control condition the paddy plants grew quickly, but in the case of the plants grown in soil containing Cynodon and Synedrella the growth rate was slower compared to the paddy in the control condition. The slow growth of paddy in soil with Cynodon and Synedrella may be due to allelochemicals produced by the weed plants. In the control condition the paddy plants were healthier than the other two. The study revealed that there is a considerable redusction in the growth performance of the plant grown in soils amended with the weeds. 7. References [1] Abhas,H.K;Tanaka,T.K,.Duke,so,.&Boyette,D.(1995). Susceptibility of various crop and weed species to AAL. Toxin, A Natural Herbicide.Weed Technol.9, [2] Ambika et al:poornima S,. Palani raj R,.Sathi H.C,.Nerval S.S,.(2003). Allelopathic plant [3] Lantana camara L. Allelopathy Journal 12: [4] Arnon,D.I.,(1949).Copper enzyme in isolated chloroplast,polyphenol oxidase in Beta vulgaris.plant Physiol,24,1-15. [5] Bansal, G.L, Allelopathic effects of Lantana camara on rice and associated weeds under the midhill conditions of Himachal Pradesh, India. In M. Olofsdotter (ed.), Proc. Workshop on Allelopathy in Rice, Manila (Philippines): International Rice Research Institute. pp

8 [6] Batish D :,Kohli R.K,.Lavanya K,.Singh H.P,.(2007). Root mediated allelopatic inference of neetle leaf goose food(chenopodium murale L. )on weeds (Triticum aestivum L.),.J Ag. On Crop Sci.,193(1):37-44 [7] Elavazhagan P., Natarajan A,.Prabhakaran. (2014). Allelopathic potential of Billy goat weed and Cleome viscosa L.on germination and growth of Sesamum indicum L. International Jounal of Current Biotechnology Botany wing-dde, Annamalai university,tamil nadu, 32(2) [8] Emman T.E: E.L-Darier.,E L Salamomum,. (2013). Suppression effect Lantana camara L. aquoes extract on germination efficiency of Salaris minor,phalaris minor retz and Sorgum bicolor L. Journal of Taibah university for science vol.no:7, issue-2 pg no:64-71 [9] Semina D.,Lekshmipriya,. Manomani T,. R.,Subha S,. (2012),Allelopathic effect of weed (Tridax procumbance L.)exatract on seed germination and seedling growth of some leguminous plants Department of botany,holly cross college,thiruchirappally, Tamil nadu,3(6) [10] Swain D et al,.(2004) Evaluation of allelopatic effect of Echino chola colona weed on rice Oryza sativa L.)