The response of some medicinal and aromatic plants against drought stress

In this study, the effects of various drought stress on the seeds of Brassica juncea (L.) Czern., Salvia officinalis L., Satureja hortensis L., Tymus vulgaris L., Ocimum minumum L., Mentha piperita L., Hypericum perforatum L. and Prunella vulgaris L. which are potential medicinal and aromatic plant species in terms of cultivation, were examined. For that reason, various drought stress levels (Control, -2, -4, -6, -8 Bar) applied to the seeds with polyethylene glycol (PEG 6000) and the effects of this application on Germination speed (GS) and Germination percentage (GP) were evaluated. Based on variance analysis and Duncan test, difference among the species for drought resistance were determined. Satureja hortensis showed the highest GS (% 33) whereas Salvia officinalis, Tymus vulgaris and Prunella vulgaris showed the lowest (%2) degree of GS. The highest GS for Satureja hortensis observed in control treatment with % 85 and together with increasing drought stress, the GS is decreased. In terms of GP, Satureja hortensis showed the highest figure ( % 45) whereas Salvia officinalis (% 3), Tymus vulgaris (% 8) and Prunella vulgaris (% 6) showed the lowest level. As a general meaning, germination speed and germination percentage decreased together with increasing of drought stress level. No germination was obtained at -8 Bar stress level for the species. To be used of the result of this study will contribute the productivity and irrigation regimes of the cultivation of medicinal and aromatic plants in arid and semi-arid regions.