Short Communication DEVELOPMENT OF SUITABLE PROPAGATION SYSTEMS FOR Tephrosia spp. IN SRI LANKA

Genus Tephrosia (Fabaceae) commonly known as ‘Pila’ in Sri Lanka. Some Tephrosia spp. are used in many traditional therapeutic preparations in Sri Lanka and also in other countries. Increased use of Tephrosia in traditional therapeutic systems has developed a great demand for these species. Thus production of planting materials for commercial cultivation has become a timely requirement. Therefore, this research was conducted to determine suitable propagation systems for four selected Tephrosia spp.; T. purpurea, T. villosa, T. noctiflora and T. pumila. Even though seeds of Tephrosia spp. showed high viability, lower germination percentage was observed on wet filter paper as well as in six different potting media [M0 (Coir: dust: Sand; 1:1:1), M1 (Coir dust: Sand: Top soil; 1:1:1), M2 (Coir dust: Sand: Top soil: Compost; 1:1:1:1), M3 (Coir dust: Sand: Top soil: Compost: Cow dung; 1:1:1:1:1), M4 (Coir dust: Sand: Compost; 1:1:1), M5 (Coir dust: Sand: Top soil: Cow dung; 1:1:1:1)] during a period of one week. Water impermeability of seed coats was identified as the main reason for the seed dormancy in Tephrosia spp. and soaking seeds in Con. H2SO4: H2O; 3:1 for 25 minutes and rubbing seeds on sandpaper for 2 minutes were determined as suitable dormancy breaking methods.  Corresponding author Email: priyangi@kln.ac.lk A. I. S. Priyadarshan et al. 40 Variation was observed in the growth performance of Tephrosia spp. in six different potting media. Growth performances of seedlings of Tephrosia spp. in hydroponic solution and soil medium were observed and soil medium was selected as the most suitable medium for the growth of Tephrosia species based on their growth performances.


INTRODUCTION
The genus Tephrosia (Vern: Pila) belongs to family Fabaceae and is distributed in warm temperate and tropical areas throughout the world and 10 species are found in Sri Lanka. Tephrosia species are perennial shrubs or herbs with high seed production (Dasanayake et al., 1991). Several species of Tephrosia are commonly used as ingredients in traditional therapeutic preparations and well known for their anticancer properties and healing ability of wounds. Jayaweera (1981) has recorded that the whole plant of T. purpurea and T. villosa are commonly used in disorders in liver, spleen and kidney and also as an anthelmintic in children in Sri Lanka, India, Vietnam, Nigeria and West Africa.
Seeds of many species of the family Fabaceae exhibit dormancy which is primarily due to water impermeability of the seed coat (Baskin and Baskin, 2014). Seed pre-treatments can be used to improve seed germination. Acid scarification is one of the best treatments for seeds with hard, impermeable seed coats (Baskin and Baskin, 2014). The concentrated sulphuric acid treatment has been widely used to improve seed germination of several hard seed coat species (Dole and Wilkins, 1999;Hassen et al., 2005). Scarification of seeds with sulphuric acid (64% v/v) for 30 to 60 mins has been shown as useful to improve seedling emergence (Ali et al., 2011). According to Hassen et al., (2005), scarification by sandpaper appears to be the best method for maximising germination with small amount of seeds whereas immersing the seeds in concentrated sulphuric acid for 20 minutes followed by soaking in water for 24 h is better for large amount of seeds.
Due to the increasing popularity of Tephrosia spp. as ingredients in many traditional therapeutic systems, establishment of propagation systems for commercial cultivation is required to ensure the continuous supply of authenticated material to meet the demand. Therefore, the objective of this research was to establish suitable propagation systems for selected Tephrosia spp.

Establishment of suitable propagation systems for T. purpurea, T. villosa, T. noctiflora and T. pumila
Seeds of T. purpurea, T. villosa, T. noctiflora and T. pumila were collected from different localities in Sri Lanka. Tetrazolium test was carried out to determine the seed viability of each seed lot of the species. Germination of seeds on wet filter paper as well as in different potting media: M0-Coir: dust: Sand; 1:1:1, M1-Coir dust: Sand: Top soil; One-way analysis of variance (ANOVA; α = 0·05) was performed to compare the effectiveness of the treatments. Tukey's mean comparison test was performed to determine the significant differences among treatments. Data were arcsine transformed prior to the analysis (Sahu, 2013).
One batch of two month old seedlings (6 replicates) was grown in the most suitable potting media, selected based on the growth performance, for each Tephrosia spp. and another batch was grown in a hydroponic solution (Albert solution). Growth performance of seedlings was observed by measuring the shoot height and leaf production after period of one month as growth parameters.
One-way analysis of variance (ANOVA; α = 0·05) was used to compare the treatments and Tukey's mean comparison test was performed to determine the differences among treatments.

RESULTS AND DISCUSSION
Even though seeds of T. noctiflora, T. purpurea, T. villosa and T. pumila have shown high viability in the wet filter paper during a period of one week, all the species have very low performance in the germination. It clearly indicates the presence of seed dormancy which prevents the germination of seeds and the necessity of developing effective propagation system. Seeds of Tephrosia spp. soaked in Con. H2SO4: H2O; 3:1 for 25 minutes or rubbed on sandpaper for 2 minutes have exhibited a significantly higher seed germination percentages after a week in different potting media compared to the control.
Further, seeds of Tephrosia spp. soaked in Con. H2SO4: H2O; 3:1 for 25 minutes or rubbed on sandpaper for 2 minutes have exhibited higher seedlings survival, shoot height and leaf production in different potting media after two months compared to the control.
Based on the evaluation of the seed germination rate and the growth performance of the seedlings after undergoing the treatments for seed dormancy breaking and potting media were selected as depicted in table 2 for each Tephrosia spp.
It was evident in the present findings that the seedlings grown in the potting media; M3 for T. purpurea, M4 for T. noctiflora, M2 for T .villosa and T. pumila have shown the highest shoot height, leaf production and shoot to root ratio compared to hydroponic solution. Based on the evaluation of the seed germination rate and the growth performance of the seedlings after undergoing the treatments for seed dormancy breaking and potting media were selected as depicted in table 2 for each Tephrosia spp.
It was evident in the present findings that the seedlings grown in the potting media; M3 for T. purpurea, M4 for T. noctiflora, M2 for T .villosa and T. pumila have shown the highest shoot height, leaf production and shoot to root ratio compared to hydroponic solution.
According to the findings of the present study, mechanical (rubbing on sandpaper) scarification and application of sulphuric acid were found to be the effective in inducing the seed germination of Tephrosia spp. Aliero (2004) has reported that, seed dormancy is usually associated with the factors of the protective coverings of the seed coat or the enclosed embryo. Mechanical or chemical scarification alleviates the coat imposed dormancy, physical dormancy, caused by water impermeable seed coats or physiological dormancy, caused by high mechanical resistance of the coats of seeds as these treatments can disrupt the seed coat and allow the seeds to imbibe or reduce the resistance of the coats to protrude radicle (Baskin and Baskin, 2014 and in terms of their adaptability for these environments.

CONCLUSIONS
Seeds soaked in Con. H2SO4: H2O; 3:1 solution for 25 min. and rubbed on sandpaper for 2 min. were determined as the suitable seed dormancy breaking treatments for T. purpurea, T. villosa, T. noctiflora and T. pumila, based on the germination rate.
Evaluation of the growth performance of Tephrosia spp. has shown that soil medium is more effective compared to the hydroponic system for the growth of Tephrosia spp. These findings provide necessary information in recommending suitable propagation systems for Tephrosia spp. to ensure continuous supply of authenticated raw material for commercial production in herbal industry.

ACKNOWLEDGMENT
Authors wish to acknowledge the financial assistance given by the National Science Foundation, Sri Lanka (Research grant: NSF RG/2011/NRB/06).