Induksi mutasi dan seleksi in vitro purwoceng (Pimpinella pruatjan Molk) untuk ketahanan terhadap suhu tinggi

Abstract

Purwoceng (Pimpinella pruatjan Molk., P. alpina KDS.) is one of Indonesian medicinal plants. It is a high altitude endemic species. Planting expansion through the development of low and medium land tolerant variety is needed to optimize the use of purwoceng as a medicinal plant. Those varieties are not available yet. The purpose of this research was to achieve high temperature resistant (insensitive) varians of purwoceng through induction of mutations using ethyl methanesulphonate (EMS) and in vitro selection. Four hundreds and thirty two somatic embryo explants (size 0.5 x 0.5 x 0.5 cm3 ) were treated with aquades (control) and 0, 0.1, 0.3, 0.5 and 0.7% (v/v) EMS solutions for 1 or 2 hours. EMS was dissolved in buffer sodium phosphate pH 7 0.M and DMSO (dimethyl sulfo-oxida) 4% (EMS 0%). Afterwards, those explants were selected at three room temperature levels i.e. 17.3 ± 0.5ºC, 23.3 ± 2.1ºC and 32.8 ± 1.7ºC for 3 months. The temperature of 17.3 ± 0.5ºC was used as control. Variables observed were explant fresh weight increment, percentage of explant forming shoot, number of shoot per explant, percentage of survive explant and phenotipic variations in shoots formed. The result showed that the average of explant fresh weight increment, percentage of explant forming shoot and number of shoot per explant were decreased with increasing of temperature and EMS doses. The growth of purwoceng somatic embryos was inhibited at the temperature of 32.8 ± 1.7ºC and EMS dose 0.7% for 2 hours. The percentage of survive explant was also decreased by the increase of temperature selection. The average of survive explant at the end of selection reached 100 and 75-100% at control temperature and 23.3 ± 2.1ºC respectively, while at 32.8 ± 1.7ºC was only 0 - 25%. The resistant (insensitive) varians at 32.8 ± 1.7ºC were obtained from both EMS treated and untreated explants. The result also showed the increase of phenotipic variation in EMS treated shoots.