Micropropagation of Helianthemum lippii L. var Sessiliforuim (Cistaceae) an important pastoral plant of North African arid areas

Abstract

Helianthemum lippii L. is a perennial, little brush distributed in sandy regions of southern Tunisia as well as of Mediterranean basin. It presents an important ecological, economical and pastoral interest. All these characteristics encourage us to try the in vitro propagation because it is a feasible alternative for the rapid multiplication and the preservation of plants. A very high frequency of sprouting and shoot differentiation were observed in the primary cultures of nodal explants of H. lippii on MS medium, without growth regulators or with a lower concentration of 6-benzylaminopurine (BAP, 0.5 mg L^-1 or 1.0 mg L^-1 BAP). In vitro proliferated shoots were multiplied rapidly by culture of shoot tips on MS medium free or with BAP (0.5 to 2.0 mg L^-1) which produced the greatest multiple shoot formation. BAP had a positive effect on multiplication and on growth, but a concentration that exceeds 2.0 mg L^-1 decreased the growth. A high frequency of rooting (71%) with development of healthy roots was observed with shoots cultured on MS/8 medium hormone-free. After in vitro rooting, and transfer to soil, a number of plantlets suitable for reintroduction in nature were produced.

Key words: Helianthemum lippii, axillary buds, micropropagation, plant conservation.