Mikenia final

The Sixth National Conferenceon Science and Technology

Sept 25 - 27, 2012

ALLELOPATHIC EFFECT OF AQUEOUS EXTRACT OF MIKENIA MICRANTHA (L.)

KUNTH ON SEED GERMINATION, SEEDLING GROWTH 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

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).

Methodology

Pre treatment of the wheat seeds, 0.1% HgCl 2 for 4 minutes

Germination Analysis; petriplate method

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.

Seed collection Khumaltar, ktm

Aqueous extracts (0.5%, 1%, 2%, 3%, 4% and 5% v/v) prepared from fresh leaves of M. micrantha

Results and discussion

1. Germination percentage and time of germination

control

0.5 1 2 3 4 50

20

40

60

80

100

120

% of germinationtime of germination

Extract concentration (%)

Perc

ent g

erm

inati

on &

tim

e of

ger

-m

inati

on(H

rs.)

Figure 1: Effect of Mikania. extract on Percent germination and time of germination of Triticum aestivum Linn.

2. Root length and number of roots

control

0.5 1 2 3 4 50

2

4

6

8

10

12

14

length of the rootnumber of roots

Extract Concentration (%)

Num

ber o

f Roo

ts &

Len

gth

of th

e ro

ot (c

m)

Figure 2: Effect of Mikania. extract on Number of roots and length of root of Triticum aestivum Linn.

3. Shoot length

2 days 4 days 6 days0

2

4

6

8

10

12

control0.512345

Number of days

Leng

th o

f the

sho

ot

Figure 3: Effect of Mikania. extract on Length of the shoot of Triticum aestivum Linn.

4. Biochemical Analysis

a. Chlorophyll content:

Control 0.5 1 2 3 4 50

0.050.1

0.150.2

0.250.3

0.350.4

0.45

Ch (a)Ch (b)Total Ch

Extract Concentration (%)

Chlo

roph

yll c

onte

nt (m

g/g)

Figure 4: Effect of Mikania extract on Chlorophyll content of Triticum aestivum Linn.

b. Protein content:

Control 0.5 1 2 3 4 50

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

Protein

Extract Concentration (%)

Prot

ein

cont

ent (

mg/

g)

Figure 5: Effect of Mikania extract on protein content of Triticum aestivum Linn.

c. Carbohydrate content

Control

0.5 1 2 3 4 50

0.10.20.30.40.50.60.70.80.9

1

StarchSoluble Starch

Extract Concentration (%)

Carb

ohyd

rate

Con

tent

(mg/

g)

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!!!

Acknowledgement

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.

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