Effects of pre-cooling treatment, osmotic potential and water stress on seedling growth of some population in two savory species (Satureja bachtiarica and S. sahendica) in laboratory and greenhouse conditions

In order to study، the effect of pre-cooling treatment، osmotic potential and water stress on some population of two species of Satureja bachtiarica and Satureja sahendica was studied by a factorial experiment based on completely randomized design with three replications in laboratory and greenhouse conditions during one year in the gene bank of Institute of forests and range lands by the years of 2010-2011. In laboratory، treatment were including: cold and osmotic potential making of polyethylenglycol (PEG) 6000 Da in 5 concentrations (0، -0. 3، -0. 6، -0. 9، -1. 2 Mgapascal) compared with control. In greenhouse، treatment were including: cold and drought stress in five levels of field capacity (100،80،60،40،20) compared with control. Result showed that seed germination and seed emergence were decreased as rate of 33% and 6% in order of laboratory and greenhouse condition with increasing of osmotic potential and water stress while the ratio of root to shoot and ratio of dry weight to fresh weight was increased. In both experimental conditions، the most of the seed characteristics were higher with pre-cooling than other treatments. In response to osmotic potential in germinator، and dry stress in greenhouse، Bijar 2 population from Sahandy savory and piranshar from bachtiary savory showed more tolerant to dry stress due to have more vigor index and ratio of dry weight to fresh weight and they introduced as superior population. Comparing of the population showed that population of the takestan of Sahandy savory had lower tolerance.