Effect of pretreatment, temperature, gibberellin (GA3), salt and water stress on germination of Lavandula mairei Humbert

Abstract Lavandula mairei Humbert is an endemic species of Morocco, it is considered as rare and threatened species. It grows spontaneously in arid and semi-arid bioclimates, and found its uses in traditional medicine for the treatment of various diseases such as gastrointestinal diseases, microbial infection, cough and asthma. With the optic of conservation, this study aims to evaluate the combined effect of temperature and pretreatment on L. mairei seeds germination. On the other hand, this study looks to assess the effect of different concentrations of gibberellin (GA3), polyethylene glycol (PEG 6000) and sodium chloride (NaCl) on seeds germination. The results revealed, an optimal germination temperature of 25 °C, and over 90 % of seeds are able to germinate without using any pretreatment. Nevertheless, pretreatment of the seeds with sulfuric acid and hydrogen peroxide increased the germination rate to over 96 %. It has also been demonstrated that treatment with gibberellin improves the germination rate of L. mairei seeds. In addition, the water deficit caused a drop in the germination rate (of about 11 %) starting from - 0.53 MPa. Thus, the salt stress estimated by the application of different concentrations of sodium chloride (NaCl) has shown that the germination percentage of L. mairei seeds decreased considerably when the concentration exceeds 150 mM. This study could be a basic guide for the possible cultivation and conservation programs of L. mairei Humbert, Moroccan endemic and threatened plant.