Conservation of masbedda (Gymnemasylvestre R.Br.) through propagation

Abstract

Several activities could be undertaken aimed at conservation and sustainable use of medicinal plants. Some of them are undertaken directly at locations where plants are naturally occurring. while others are less direct, such as commercial cultivation systems. Cultivation of medicinal plants is particularly important for species, which already have a good market demand. Gymnema sylvestre is one such rare medicinal plant. Therefore, the present study was aimed at developing cost effective and simple propagation techniques for Gymnema sylvestre. Investigations on both sex-ual and vegetative means of propagation of Gymnema have been carried out, at the Faculty of Agriculture, University of Ruhuna, Mapalana, Kamburupitiya from October 2002 to November 2003. Viable, uniform seeds were screened and used for seed propagation studies. The effect of sowing media on germination of Gymnema seeds has been investigated using four kinds of sowing media; sand, coir dust, a mixture of top soil and sand (1:1) and a mixture of sand top soil and coir dust (1: 1:1). Seeds were stored in an open system under room temperature (30°C) and germination percentage was recorded at 15-day intervals. This was to find out the effect of storage period on germination of seeds. Complete Randomized Design was used for the experiments with five replicates, each contained ten seeds. Germination percentage was calculated and the experiments were repeated to confirm the results. For vegetative propagation studies, three separate experiments were carried out using stem cuttings. Double nodal semi-hard wood cuttings were rooted in polybags filled with different rooting media including sand, a mixture of sand and top soil (1: 1), a mixture of sand, top soil and compost (1:1:1) and top soil alone to investigate the effect of media on rooting. Hard wood, semi-hard wood and soft wood cuttings were planted in polybags filled with a mixture of sand, top soil and compost (1:1:1), to determine the effect of maturity of cuttings on rooting. Effect of watering on rooting of cuttings was investigated using semi-hard wood cuttings planted in polybags contained a potting mixture of sand, top soil and compost (l:1: 1) with three watering frequencies. Complete Randomized Design was used for the studies with ten replicates. Number of roots, root length and root biomass accumulation were measured at the end of 6,10 and 14 weeks after planting. Results showed that germination percentage of seeds was significantly (p≤0.05) high (92 %) in coir dust, whereas the lowest germination percentage (28 %) was observed from top soil media. There were no significant (p ≤ 0.05) differences in germination of seeds throughout the first two months of storage under normal condition. Results of the vegetative propagation studies revealed that a mixture of sand, top soil and compost (1:1:1) was the most suitable rooting media for Gymnema cuttings, whereas the semi-hard wood cuttings rooted significantly (p ≤ 0.05) higher than the hard wood and soft wood cuttings. With regard to the watering frequency, cuttings watered once in two days rooted and performed significantly (p≤ 0.05) better than the other treatments. Results can be concluded that Gymnema sylvestre can be propagated by means of both sexual and asexual methods. Semi-hard wood cuttings, which appear to be more amenable to rooting and potting mixture of sand, top soil, and compost watered once in two days, showed the best results, while high germination percentage of seeds could be obtained within first two months of storage.