Organogenesis dan konservasi in vitro pamelo (Citrus maxima (Burm.) Merr.).

Abstract

Indonesia has high diversity of pummelo (Citrus maxima (Burm.) Merr.) which economically potential. The pummelo diversity must be conserved to overcome its extinction due to biotic and abiotic stresses. In vitro conservation using slow growth technique can be considered as an alternative of ex-situ conservation. The objective of this research was to study pummelo organogenesis and to find out an effective medium to conserve pummelo using slow growth technique. Three experiments were conducted in this research to conserve pummelo. Organogenesis was induced on pummelo leaf, root and epicotyl to find out the best explant and medium to produce pummelo shoot effectively. Two conservation experiments using slow growth were conducted to find out the best medium to conserve pummelo. The first conservation experiment was done using reduction of MS medium and sucrose concentration, while the second conservation method was done using osmotic regulator and retardant. The results showed effective direct organogenesis of pummelo could be induced by culturing epicotyl explant vertically in MS medium without plant growth regulator under 24 hour light. In the first conservation experiment, the best medium to conserve pummelo using reduction of MS medium and sucrose concentration was MS medium without sucrose that inhibited leaf formation 37%, shoot elongation 75%, root elongation 49,4%, and the estimation to conserve pummelo was 30,7 months. While in the second conservation experiment, the best medium to conserve pummelo using osmoticum and retardant is MS + sorbitol 2% + paclobutrazol 7,5 ppm, that inhibited shoot length 65,1%, leaf formation 84,6%, root number 20%, root length 81%, and the estimation to conserve pummelo was 22,2 months. However, based on percentage of growth inhibition to the planlet and the appearance of the conserved planlet, the more suitable medium to conserve pummelo was MS + sorbitol 2% + paclobutrazol 7,5 ppm. After conservation periode, pummelo could grow normally in recovery medium (MS0) and aclimatization medium (soil : husk : compos = 2 : 1 :1).