Impacts of osmopriming on mitigation of the negative effects of salinity and water stress in seed germination of the aromatic plant Lavandula stoechas L.

Abstract

Butterfly lavander (Lavandula stoechas L.) seed germination is sensitive to salinity and water stress. Seed priming effectively mitigates the adverse effects of salt and water stresses on seed emergence. Although its extensive uses as an ornamental plant, no studies have assessed the effects of seed priming on Butterfly lavander germination under salinity and moisture stress. Here, we investigate whether KCl-osmopriming could improve germination fitness of L. stoechas under salt and watre stresses. Seeds of this species were osmoprimed with different levels of KCl (1 %, 2 %, and 4 %) and germinated in different concentrations of NaCl (0, 50, 100, 150 mM) and water deficit (0, −0.25, −0.5, −0.75, and −1.0 MPa PEG). Non-treated seeds (control) had little dormancy; around 90 % of the seeds were germinated. The germination was significantly decreased with the increase in salinity and water deficit stress. However, seed osmopriming markedly increased the germination percentage and rate in higher salinity and lower water potential levels.The impact of osmopriming was more obvious under the high-stress condition (i.e., higher salinity and lower water potential) than at the less-stress conditions. In addition, hydrotime model analysis indicated that seeds primed with 4 % KCl showed increasing germination rate (decreased θH) and uniformity (decreased σψb) under water deficiency. These results indicate that the application of KCl-osmopriming could alleviate the harmful effects of soil salinity and water stress on seed germination, suggesting that these treatments would enhance L. stoechas establishment in arid and semi-arid bioclimates.