effects of different drought and salinity stress levels on some morphological characteristics and proline content of annual burr medics (m. polymorpha l.)

breeding medics species to drought and salinity tolerant  can play an important role in herb production and pasture rehabilitation. with the aim of study of the performance of annual burr medics under drought and salinity stresses, a pot study was conducted with factorial arrangement of treatments in a randomized complete block design in shiraz university. sown seeds were two types (threshed and unthreshed), salinity stress had four levels (0, 4, 8, and 12 dsm-1) and drought stress had three levels (irrigated up to 100, 75 and 50% of field capacity). all stress treatments altered morphological traits and proline content. increasing drought and salinity severity significantly declined germination percentage, plant height, vegetative vigour, leaf number and tiller number, although, proline content was enhanced. the plants grown from threshed seeds were affected more than unthreshed one. overall, the applied stresses decreased germination and growth; but increased proline content of medics. results indicated that sowing of threshed seed could improve germination and growth, especially under drought and salinity conditions.