The results showed that the seed treatment with
C. sappan and
C. magna extracts was not significant (p<0.05) to promoted the seed germination of rice at 7 DAS and 14 DAS when compared with the control. The average germination percentages of rice seeds at 7 DAS and 14 DAS were 97.9% (Table 1) and 96.0% (Table 2), respectively. The overall effect of the two plant extracts at 7 DAS was significant increased the rice seedling especially to shoot dry weight at each concentration when compared to the water treatment. Furthermore, the
C. magna crude extract (1,000 ppm) was effective in increasing fresh weight of root (Table 1).
The results at 14 DAS showed that the effect of
C. sappan and
C. magna extracts was significant (all p<0.05) increased root length, fresh weight of root and shoot and shoot and root dry weight of rice seedlings over control. Root fresh weight and root length were affected by both plant extracts at each concentration but only
C. magna at a concentration of 1,000 ppm did not significantly increase the root fresh weight of rice seedlings. Specifically,
C. magna extract at a concentration of 100 ppm resulted in the highest shoot fresh and dry weight of all rice seedlings, which were 4.453 g and 0.488 g, respectively (Table 2). Accordingly,
C. magna extract at a concentration of 10 ppm was effective in increasing the root dry weight to 0.118 g. The overall effect of
C. sappan extract at each concentration was significant and led to an increase in almost all growth indicators of rice seedlings when compared to the control. Treatment with
C. sappan and
C. magna extracts led to significantly greater vigor of the KDML105 rice seedling cultivar. The seedling vigor index was significantly higher when it had been treated with the
C. magna extract at a 100 ppm concentration, compared to the control. However, the positive effect of both
C. sappan and
C. magna extracts in enhancing seedling vigor was significantly demonstrated. Interestingly, the seed treatment with
C. magna extract at a 100 ppm concentration was found to have resulted in the highest enhancement in overall rice seedling growth, including the vigor index of seedlings (Fig 1).
Hence the study indicated that rice seeds treated with different concentrations of
C. sappan and
C. magna extracts at 14 DAS had been improved with regard to the overall seedling growth of the rice. In the rice seeds treated with different concentrations of
C. sappan and
C. magna extracts at 7 DAS and 14 DAS, the results of the seed germination rate were not significantly different from the water control. Seed germination is the most important stage for critical stage under conditions of stress and crop yields. Plant leaf and fruit extracts were more composed of allelochemicals than root, stem and seed extracts. However, allelochemicals can reduce seed respiration substrates and metabolic energy, with a decrease in plant seed germination and seedling growth
(Yarnia et al., 2009; Verma et al., 2012).
The results revealed that
C. sappan and
C. magna extracts of different concentrations had an effect on the growth of rice cultivar KDML105 seedlings. Most of the initial growth parameters improved by stimulating the application of plant extract under
in vitro conditions. Rice seedlings treated with
C. sappan and
C. magna extracts at each concentration improved all growth parameters, including seedling vigor index at 14 DAS.
C. magna extract at a 100 ppm concentration resulted in significantly higher growth parameter results than the control. After treatment with
C. magna extract at 100 ppm concentration, the seedling growth parameters, including root length, root fresh and dry weight, shoot fresh and dry weight and seedling vigor index, were 10.23 cm, 1.008 g, 0.110 g, 4.453 g, 0.488 g and 2245, respectively, at 14 DAS. However, the two plant extracts at each concentration improved the overall growth parameters of rice seedlings. A low concentration of
C. sappan (10 ppm) applied to rice seeds resulted in a shoot fresh and dry weight and root fresh and dry weight which were significantly different when compared to the seeds treated with high concentration.
Yang et al., (2002) also reported that seedlings treated with allelopathic phenolics had improved seedling growth of rice and some allelochemical substances from plant extracts had caused a reduction in root growth
(El-khatib et al., 2004). The results demonstrated that
C. sappan and
C. magna extracts could potentially have an effect on rice as indicated by its effect on plant growth parameters,
i.e., root length, root fresh and dry weight, shoot fresh and dry weight and the seed vigor index of seedlings. Improvement in the efficacies of plant extracts regarding the growth parameters of crop plants has been reported by various researchers; these crops include indigenous rice and rice
(Kulkarni et al., 2006; Lu et al., 2017); soybean and haricot bean (
Netsere and Mendesil, 2011); wheat
(Akram et al., 2017); and papaya
(Chumpookam et al., 2012). However, the efficacies of these two plant extracts in inhibiting the growth of plant pathogenic fungi have been reported
(Jantasorn et al., 2016). It has been reported that the extract from
C. sappan was more efficient in inhibiting the growth of
P. palmivora and
S. rolfsii but the application of
C. sappan and
C. magna extracts in improving the seedling growth of cereal crop plants has not been reported. The results of the experiment showed the potential of seed treatment with
C. sappan and
C. magna extracts at 14 DAS to promote improvement in the seedling growth of rice across the overall growth parameters.