Abstract:
Medicinal plants enriched with many types of chemicals secondary metabolites
which also act as allelochamicals. An experiment was conducted to evaluate the
effect of allelochamicals of five medicinal plant species i.e. Asparagus
(Asparagus racemosus wild.), Lebbeck (Albizia lebbeck), Devil's cotton
(Abroma augusta), Scarlet gourd (Coccinea cordifolia), Spreading hogweed
(Boerhavia diffuse linn.) on phytotoxicity regarding root and shoot growth of
two test species (okra and barnyard grass). Five concentrations of each medicinal
plant extract viz. T
0
(control; no extract), T
1
v
(0.01 mg dry wt. eq. extract/mL), T
2
(0.03 mg dry wt. eq. extract/mL), T
3
(0.1 mg dry wt. eq. extract/mL) and T
4
(0.3
mg dry wt. eq. extract/mL) were used for allelopathic test. The experiment was
laid out in Completely Randomized Design (CRD) with three replications.
Results showed that all the test species were found sensitive under extracts of all
five medicinal plants. Results indicated that all concentrations of plant extract
showed allelopathic effect on okra and barnyard grass. Among all concentration
of plant extract, T
4
(0.3 mg dry wt. eq. extract/mL) showed highest allelopathic
effect on both okra and barnyard grass seeds. In terms of root length of okra
seeds, Spreading hogweed and Scarlet gourd extract at T
4
(0.3 mg dry wt. eq.
extract/mL) showed highest allelopathic effect and gave lowest root length
(0.533 mm). The Spreading hogweed (Boerhavia diffuse linn.) extract at T
4
(0.3
mg dry wt. eq. extract/mL) concentration on barnyard grass seeds showed
highest phytotoxic effect for shoot and root length (1.9 mm and 0.93 mm,
respectively). The above results suggested that those Scarlet gourd and
Spreading hogweed may have allelochemicals and could be used as bioherbicide
for successful crop production.
Description:
A Thesis
Submitted to the Department of Agricultural Chemistry
Sher-e-Bangla Agricultural University, Dhaka-1207
in partial fulfillment of the requirements
for the degree of
MASTER OF SCIENCE
IN
AGRICULTURAL CHEMISTRY
