Abstract

Hossein Ghasemi* and Ruhollah Fattah Shah

Drought and high salinity are important environmental factors that cause osmotic stress and as a result reduce plant growth and crop productivity. Alfalfa or lucerne (Medicago sativa L.) is a valuable forage crop, which is grown in areas of limited rainfall and high temperatures and where the land is often salt affected. In this paper, we studied the germination responses of two cultivars of M. sativa (Yazdi and Hamedani) to drought stress caused by PEG-6000 at the different potentials: 0.0 (distilled water or control), -0.2, -0.4, -0.6, -0.8, and -1.0 Mega Pascal (MPa) and tolerance to salt (NaCl) in different salinity levels including: distilled water (control), 30, 60, 90, 120, 150, 180, 210, 240, 270, and 300 mmol. The objective of this study is to determine factors responsible for germination and early seedling growth due to drought and salinity and to optimize the best priming treatment for these stress conditions. The results indicated that salinity and drought levels effects were significant (P < 0.05) for seed germination percentage, seed germination velocity, mean time to germination, length of the tigella and radicle, and seed vigor. Seed germination decreased significantly by increasing salinity and drought levels. Totally, the results showed that M. sativa cul. Yazdi is more tolerant than M. sativa cul. Hamedani against drought and salt stresses.