Micropropagation studies of Thatch Saw-sedge (Gahnia radula, Cyperaceae)

Abstract

Thatch saw‐sedge (Gahnia radula (R.Br.) Benth.) is a ‘rare’ understorey plant in South Australia, valued for its economic and conservation benefits. Effective methods to propagate this plant are required to facilitate conservation of local populations and to enable restoration of bushland and other habitats which have been affected by urban development and mining. However, to date, most attempts at propagation using conventional techniques have failed. Therefore, this research was conducted to evaluate the possibility of using micropropagation (plant tissue culture) techniques on G. radula. Half strength Murashige and Skoog (MS) media supplemented with different level of 6‐benzyladenine (BA) and α‐naphthaleneacetic acid (NAA) were able to trigger some growth responses from meristematic explants of this plant. However, excised tissues of G. radula tended to produce brown phenolic exudates in culture that appeared harmful for the tissues. Standard treatments designed to reduce or overcome phenolic browning issues in tissue culture (e.g. adding activated charcoal and antioxidants to media, or pre‐soaking tissues in antioxidant solutions) failed to prevent premature death of explants. The liquid media treatment was the only treatment tested that showed some capacity to delay the browning process. Nevertheless, the early growth response of G. radula in culture suggests that there is a possibility that G. radula can be successfully propagated using plant tissue culture techniques. However, further studies are required to understand and control the browning issues associated with G. radula. It may also be worth examining explants from other parts of the G. radula plant for suitability as micropropagules.