Micropropagation Technique of Paraboea doitungensis for Conservation

Abstract

Paraboea doitungensis, which belongs to family Gesneriaceae, is an endemic speciesfound only in Chiang Rai province of Thailand. It is currently listed as endangered makingthe study on germplasm multiplication by in vitro propagation technique indispensable. Thisresearch was divided into 2 parts : study on seed pod sterilization method and findingappropriate medium for micropropagation. The results showed that appropriate sterilizationmethod was by immersing seed pod in 95% ethanol, followed by burning the outer surface of seed pod and dipping seeds inside pod in 5% hydrogen peroxide (H2O2). This sterilization method could yield the uncontaminated seedlings up to 50%. The microplants from leaf culture were transferred to MS medium supplemented with 0, 0.1, 0.5 and 1.0 mg/L Naphthalene acetic acid (NAA) and Benzyladenine (BA). The results showed that addition of 0.1 mg/L NAA alone could induce the average number of vigorous shoots of 2.48. They were further transfered to MS and MS medium supplemented with 0, 0.1, 0.5 and 1.0 mg/L NAA in order to investigate the root induction. The results demonstrated that ½ MS could induce the number of root and root length superior to MS in every NAA concentration. They also suggested that ½ MS without NAA was the better medium for root induction. It provided the average root number of 7.29 and average root length of 6.62 cm. Further research on acclimatization of the plantlets for successful transplanting and establishment under greenhouse conditions is still needed.