Standardisation of propagation through cuttings in Gymnema sylvestre R. Br.

Abstract

Investigations were carried out at the Department of Plantation Crops and Spices, College of Horticulture, Vellanikkara to standardise the propagation through cuttings in Gymnema sylvestre R.Br., a much sought rare medicinal plant most valued for its hypoglycaemic property. Being a difficult-to-root species through cuttings, the study included vegetative propagation measures with treatment combinations involving two different environments, four different growth regulator treatments and three different types of vines. The investigation conclusively proved that softwood cutting comprising of terminal ends and young lateral shoots is the ideal propagule in Gymnema. Intermittent mist was found to significantly increase the rooting efficiency. Treatment with growth regulators in general gave higher rooting success and among the growth regulators IAA was found to be superior than NAA and IBA. Significant interaction effect was noticed among different treatments. The softwood cuttings treated with IAA 500 mg l-1 and kept in mist showed maximum synergetic effect with regard to rooting success and other qualitative root characters. It was followed by softwood cuttings treated with NAA 500 mg l-1 and kept in mist. The study also showed that presence of leaves was essential for enhancing rooting efficiency in Gymnema cuttings. The rooted cuttings did not ., significantly differ in their field establishment rate irrespective of the type of cuttings or the environment provided for rooting.

The root initials were found to be originating from secondary phloem cells. There was hardly any anatomical difference among the different type of cuttings. No anatomical barriers for rooting could be located. Biochemical analysis revealed that the carbohydrates, nitrogen, protein content and CIN ratio increased during root initiation and primordia formation but decreased during emergence of roots.