investigation of qualitative and quantitative effects of drought and salinity stress on the pennyroyal plant

the effects of drought and salinity stress on the growth and chemical compositions pennyroyal(mentha pulegium l.) plant were investigated. this experiment was carried out in a factorial-randomized design with four replications in controlled conditions and plantlets were subject to four soil moisture regimes (40, 60, 80 and 100 of field capacity (fc)) and five salt treatments with 0, 25, 50, 75 and 100 mm nacl. characteristics were included stem length, root length, shoot fresh weight, root fresh weight, shoot dry weight, root dry weight, internodes length, stolon length, percent of survival, number of total branches, number of total leaf, length of total branches, biomass and essential oil yields. the results showed that total characteristics were reduced in stress condition. under stress, reduced growth was observed in all treatments, although differences in sensitivity to the stress among treatments were noted. stress effects were more pronounced in shoots (leaves and stems) than in roots. essential oil yields per plant under stress were reduced in all treatments, as compared with untreated controls. in pennyroyal, the oil concentration in the plant tissue under stress increased as compared with untreated controls.