The Sixth National Conference on Science and Technology Sept 25 - 27, 2012 ALLELOPATHIC EFFECT OF AQUEOUS EXTRACT OF MIKENIA MICRANTHA (L.)KUNTH ON SEED GERMINATION, SEEDLINGGROWTH AND BIOCHEMICAL QUALITY OF TRITICUM AESTIVUM LINN.B. Adhikari, P. Dhungel, R. Parajuli, D. P. Gauchan Department of Biotechnology, School of Science, Kathmandu University, Dhulikhel, Kavre P.O. Box 6520, Kathmandu, Nepal
Content:1. Objective2. Introduction3. Methodology4. Result and discussion5. Conclusion6. Acknowledgement7. References
Objective• To analyze the effects of aqueous extract of Mikenia micrantha (L.) kunth on seed germination, root and shoot growth of wheat (Triticum aestivum Linn.)• To Evaluate the impact of aqueous extract of Mikenia micrantha (L.) kunth on the biochemical parameters (protein, carbohydrate, starch and chlorophyll).• To determine some control measures for this weed.• To analyze if this weed also has detrimental effect on other Invasive alien species (IAS) and harmful weeds.
Introduction• Mikenia micrantha is also known as "mile by a minute" because of its fast spreading rate, the weed can smother anything that gets in its way - from grasses to even large trees. It is a.k.a. vegetation imposition.• As the weed can penetrate crowns, smother, choke and pull over plants.• Thus, Mikenia mikrantha (L.) Kunth is stifling the vegetation and threatening wildlife as well.• The weed changes the pattern of growth of affected plants and it has been listed as one of the world’s worst weeds. (Parker, 1972; Holm et al..,1977)• May be due to competition, altered ecosystem process or through other pathway such as allelopathy or phytotoxicity. (Samuel et al., 2005)
Introduction Contd…• Allelopathy is known to include both harmful and beneficial biochemical interaction between all types of plants, including microorganisms (Rice, 1984).• Biochemicals are known as allelochemicals and can have beneficial (positive allelopathy) or detrimental (negative allelopathy) effects on the target organisms.
Introduction Contd…• The effects of mikenia on a crop may extend beyond the normal competition for nutrients , light and soil moisture.• Eg. 1. Watson et al.;(1964) reported lower nitrate- nitrogen levels in soil planted with mikenia. 2. Mikenia extract significantly reduced the dry weight and nitrogen content of tomato seedlings and legume cover crops ( Wory, 1964).
Seed collection Khumaltar, ktm Pre treatment of the wheat seeds, 0.1% HgCl 2 for 4 minutesAqueous extracts (0.5%, 1%, 2%, 3%, 4% and 5% Germination Analysis; petriplate methodv/v) prepared from fresh leaves of M. micrantha Biochemical analysis; spectrophotometer Protein contents: Lowry et al. 1951. Total Soluble Sugar: Dubois et al. 1956. Total Starch: Mc Cready et al. 1950. Total Chlorophyll content: Arnon 1949.
Results and discussion
1. Germination percentage and time of germination 120 Percent germination & time of 100 germination(Hrs.) 80 60 40 % of germination time of germination 20 0 Extract concentration (%)Figure 1: Effect of Mikania. extract on Percent germination and time of germination of Triticum aestivum Linn.
2. Root length and number of roots 14 Number of Roots & Length of the 12 10 root (cm) 8 6 length of the root number of roots 4 2 0 control 0.5 1 2 3 4 5 Extract Concentration (%)Figure 2: Effect of Mikania. extract on Number of roots and length of root of Triticum aestivum Linn.
3. Shoot length 12 10 Length of the shoot 8 control 0.5 6 1 2 4 3 2 4 5 0 2 days 4 days 6 days Number of daysFigure 3: Effect of Mikania. extract on Length of the shoot of Triticum aestivum Linn.
4. Biochemical Analysis a. Chlorophyll content: 0.45Chlorophyll content (mg/g) 0.4 0.35 0.3 0.25 0.2 Ch (a) 0.15 Ch (b) 0.1 Total Ch 0.05 0 Control 0.5 1 2 3 4 5 Extract Concentration (%) Figure 4: Effect of Mikania extract on Chlorophyll content of Triticum aestivum Linn.
b. Protein content: 0.08 0.07Protein content (mg/g) 0.06 0.05 0.04 0.03 Protein 0.02 0.01 0 Control 0.5 1 2 3 4 5 Extract Concentration (%) Figure 5: Effect of Mikania extract on protein content of Triticum aestivum Linn.
c. Carbohydrate content 1 0.9 Carbohydrate Content (mg/g) 0.8 0.7 0.6 0.5 0.4 Starch 0.3 Soluble Starch 0.2 0.1 0 Control 0.5 1 2 3 4 5 Extract Concentration (%)Figure 6: Effect of Mikania extract on Carbohydrate content of Triticum aestivum Linn.
Conclusion• Results showed different concentrations of aqueous leaf extracts caused significant inhibitory effect on germination, root and shoot elongation and biochemical quality of receptor crop.• Inhibitory effect was proportional to the concentrations of the extracts.• The inhibitory effect was much pronounced in seed germination, shoot development and biochemical parameters rather than root development.• For the last two objectives further research is going on!!!
References• Bell D.T. and Koeppe D.E. 1972 Noncompetitive effects of giant foxtail on the growth of corn. Agron. J. 64,321-325.• Bomer H. (1960). Liberation of organic substances from higher plants and their role in the soil sickness problem. Bot. Rev. 26, 393-424.• Colton C.E., Einhellig F.A. (1980). Allelopathic mechanisms of velvetleaf (Abutilon theophrasti Medicus, Malvaceae) on soybean. Amer. J. Bot. 67: 1407–1413.• Ismail B.S., Mah L.S. (1993). Effects of Mikania micrantha H.B.K. on germination and growth of weed species. Plant and Soil 157:107-113• Ismail B. S. and Suat M.L. (1994). Evidence for Allelopathic Activity of Mikania micrantha H.B.K. on Three Weed Species. Pertanika J. Sci. & Technol. 2(1): 73-83.• Li J. and Jin Z. (2010). Potential allelopathic effects of Mikania micrantha on the seed germination and seedling growth of Coix lacryma-jobi. Weed Biology and Management 10, 194–201• Lara-Nunez, A.T. Romero-Romero, J.L. Ventura, V. Blancas, A.L. Anaya, R. Cruz-Ortega (2006). Allelochemical stress causes inhibition of growth and oxidative damage in Lycopersicon esculentum Mill. Plant Cell Environ., 29, 2009-2016.• Muller C .H. (1969). Allelopathy as a factor in ecological process. Vegetatio 18, 348-357.• Pacifce, R.E., K.J.A. Davies, (1990). Protein degradation as an index of oxidative stress. Methods Enzymol., 186, 485- 502.• PARKER, C. (1972). The Mikania problem. Pest Artic. News Summ. 18:312Y315.• Rice E.L. (1979). Allelopathy-an update. Bot. Rev. 45, 17- 109.
References• Rice E.L. (1984). Allelopathy, 2nd Ed., Academic Press, LondonRimando AM, Dayan FE, Czarnota MA, Weston LA, Duke SO, 1998. A new photosystem II electron transfer inhibitor from Sorghum bicolor. J. of Natural Products. 61, 927-930• Saha A.K. (1986). Rice yield improvement on dry abandoned terraces in midhills of Mizoram by green manuring. Indian Journal of Agricultural Science. 56(3): 210-212.• Samuel O.P., Jennifer A.R., Keith C. (2005). Invasive Plant can Inhibit Native Tree Seedling: Testing Potential allelopathic Mechanism. Plant Ecology 18:153-165• Shao H., Peng S.L.,Wei X.Y., Zhang D.Q. and Zhang C. (2005). Potential allelochemicals from an invasive weed Mikania micrantha H.B.K. J. Chem. Ecol. 31, 1657–1668.• Sisodia S., Siddiqui M.B., Singh G.P. (2010). Allelopathic Exploitation of Croton bonplandianum on various growth parameters of Garlic, Research Journal of Agricultural Sciences, 1(3): 215-218.• Stewart, C.R., S.F. Boggess, D. Aspinall, L.G. (1977). Paleg Inhibition of protein oxidation by water stress. Plant Physiol., 59, 930-932.• Suharte M. and Santoso E. (1985). The possibility of using Mikania leaves as green manure. Buletin- Penelitian-Hutan. 467: 1-11• Seth A. (1971). Control of Mikania cordata (Burm.f.) B. L. Robinson in plantation crops using paraquat. Weed Res. 11, 77-83.• Tiwari, S., B. Adhikari, M. Siwakoti and K. Subedi (2005). An inventory and assessment of invasive alien plant species of Nepal. IUCN Nepal, Kathmandu.