In vitro propagation of Zehneria platysperma (W.J. de Wilde & Duyfjes) H. Schaef. & S.S. Renner (Cucurbitaceae), an endemic plant of Thailand

Abstract

© 2020 International Society for Horticultural Science. All rights reserved. The genus Zehneria belongs to the Cucurbitaceae family and includes plant species that contain glycosides and sphingolipids in roots and leaves. Some species of Zehneria are used in local folk medicine for curing skin diseases. It also shows antimicrobial and antitumour activities. In Thailand, Zehneria platysperma is classified as an endemic plant which is found only in northern and south-western regions. This plant may risk extinction due to the deforestation problem. Therefore, this study established an in vitro propagation protocol for conservation of Z. platysperma. Detached seeds were surface sterilized using sodium hypochlorite and inoculated onto Murashige and Skoog (MS) agar medium for initiating the in vitro culture. Sixteen-week-old seedlings were selected for use as plant materials. The first and second nodes from base of seedling were excised and used as explants. Nodes were cultured on MS agar medium supplemented with different concentrations of N6-benzyladenine (BA; from 0 to 4 mg L-1) before transferring onto BA-free MS agar medium. After 8 weeks, the highest shoot numbers (9.30 shoots explant-1) with an average shoot height at 9.45 cm was obtained from Z. platysperma that had been cultured on MS agar medium supplemented with 1 mg L-1BA. This medium also provided an average root number explant-1at 12.40 with the longest root length (20.67 cm). Increasing of BA concentration in culture medium reduced shoot and root regeneration. Moreover, hyperhydric symptom was found from explants that were cultured on 2 and 4 mg L-1of BA. In addition, flowering and fruiting were found during in vitro condition. Vigorous plantlets with well-developed roots survived in natural condition after acclimatization process. This protocol can be a useful tool for rapid proliferation and conservation of Z. platysperma which could be used for future phytochemical or medical studies.