Abstract:
Clidemia hirta (Katakaluwa) and Chromolaena odorata (Podisinnomaran) were introduced
into Sri Lanka as ornamental plants but now they have become invasive species. The
present study was aimed at finding the influence of C. odorata and C. hirta extract on seed
germination, seedling growth and their potential uses as a liquid fertilizer to enhance the
growth and yield performance of local Radish (Raphanus sativus) cultivar “Beeralu”. In the
laboratory different concentrations (25, 50, 75, 100 g L-1) of aqueous leaf extracts which
was prepared separately by pooled samples of randomly selected plants of C. odorata and
C. hirta were tested for seed germination and seedling growth of Radish using petri dishes
(four replicates for each treatment containing 20 seeds in each petri dish) and seed trays
(eight replicates for each treatment and sand as the growth medium) by adding 10 mL of
the test extract. Distilled water was used as the control. Different concentrations (25, 50,
75, 100 g L-1) of leaf extracts were tested with five replicates for each concentration, for
growth and yield performance of R. sativus seedlings using pots containing 3 kg of solarized
soil mixture in the pot experiment. The pots were treated with 300 mL of the extract every
other day. The pots were arranged according to the randomized block design in an open
environment in the Warakapola area and root and shoot fresh weights, leaf area, girth of
the roots, length of the leaves and roots, number of leaves were recorded 45 days after
seed sowing. Data were analyzed with MINITAB 16 statistical software (ANOVA (p<0.05)
and Tukey’s pair wise comparison tests). The laboratory experiment results showed that
seed germination, root and shoot lengths of Radish were significantly reduced by both leaf
extracts compared to the control. Higher degree of seed germination inhibition and the
shortest mean shoot and root lengths were recorded with increasing concentrations of
extracts and therefore inhibition was dose dependent and it could be due to the presence
of allelochemicals in the leaf extracts. In the field experiment addition of leaf extracts on
germinated seedlings indicated significantly higher mean shoot and root biomasses in the
presence of 75 g L-1 C. odorata and 25 g L-1 C. hirta treatments than their control (One way
ANOVA, p<0.05). Higher concentrations of C. hirta extracts (>50 g L-1) have shown
reduction in the yield performance of R. sativus. In R. sativus higher growth and yield
performance was recorded in C. odorata 75 g L-1 treatment.
Keywords: Allelochemicals, Clidemia hirta, Chromolaena odorata germination and growth
performance, Raphanus sativus
vijinirathnayake88@gmail.
