Abstract

Tunisian Flora is well known for its richness and diversity of medicinal plants such as henna plant a flowering plant belongs to the family of Lyteraceae, distributed in dry tropical and subtropical zones including North Africa. This plant pertains to continental oases where water shortage, constitute the essential limiting factor of agricultural production. The present study was carried out to evaluate the impact of water stress on the germination of the henna plant. Seeds were germinated under stress of aqueous Polyethylene Glycol solutions blended to create water potentials of 0, -0.2, -0.4, -0.6, - 0.8 and -1 MPa. Results showed that seeds germinated in PEG solutions exhibited significantly lower cumulative germination rate than control especially when water potential fell below -0.6 MPa. Mean germination time was delayed by increasing PEG concentrations, while germination stress tolerance index was decreased with the increase in PEG concentrations. The highest percentage of GSTI in stressed condition was 84.13% for PEG whereas, the lowest value was 8.37% for PEG.