effect of seed priming treatments on germination traits of two mustard cultivars (brassica compestris var. parkland and goldrash)

introduction: b. campestris is an old plant that commonly grows in arid and semi-arid areas. it has mucilage in the epidermal cells of canola seeds, a considerable variation in growth form and characteristics across the many cultivars. these species have in general, a flat root without an elongated crown, with stems that typically grow 30 to 120 cm tall. the leaves are large, soft, smooth or soft-hairy. the yellow flowers are small, usually less than 2 cm long (24). seed priming is a procedure in which seed is soaked and then dried back to its original water content. hydropriming uses only water in the process of controlled imbibitions, but osmopriming simply means soaking seeds in an osmotic solution. seed priming is a technique of controlled hydration and drying that results in more rapid germination when the seed is reimbibed. priming can be a valuable process for improving germination and uniformity of heterogeneously matured seed lots. seed priming has been successfully demonstrated to improve germination and emergence in seeds of many crops, particularly vegetables and small seeded grasses. seed priming is a presowing strategy for influencing seedling development by modulating pregermination metabolic activity prior to emergence of the radicle and generally enhances germination rate and plant performance. fast germination and uniform emergence assist the farmer to “catch up” on the time lost to drought (17, 18). this research aimed to study the effect of the best treatments of osmopriming and hydropriming on varieties of mustard seed germination traits was conducted. materials and methods: the present research was conducted under laboratory conditions of the ferdowsi university of mashhad, iran, during 2012 to determine the seed priming effects on germination traits of two cultivars of mustard. the experiment was in completely randomized design with six treatments. seeds of two mustard cultivars including goldrash and parkland (brassica compestris var.) were subjected to hydro priming and osmotic priming (-4 and -16 urea and zinc sulfate solution with osmotic potential mpa) in laboratory conditions. then germination performance was studied. to calculate the germination percentageand rate, mean germination time (mgt) and seed vigor, were used according to equation1, 2, 3and4(11). 1: germination percentage= (n / n) × 100 2: 3: mgt= σ(ni × ti)σn whereni is the number of newly germinated seeds at time of tiafter imbibing, and n = total number of emerged seeds. 4: seed vigor= germination percentage * dry weight the soft ware macro, and charting in excel software were used to analyze the data and lsd test at the 5% level was used for means comparison. results and discussion: priming treatments impressed radica and plumul length, germination percentage and rate, mean germination time and seed vigor at the 5% level (table 3). as maximum germination percentage and rate at the control and hydropriming treatments and at least 16 mpa at osmopriming zinc were (respectively 6/14 and 92/0% for parkland and 6/82, and 15% for goldrash)(tables 1, 2). given that most of micronutrients such as zinc, copper, cobalt thatare also classified as heavy metals when their concentrations in soil and plant tissues above the plant are sufficient to cause poisoning, affect yield and plant growth (19). it seems, the goldrash compared to parkland with imbibitions less metabolic activity has shown better and more tolerance to stresses caused by the toxicity of zinc.hydropriming partially hydrated seeds and cellular turgescenceoccurs. in this experiment when compared to osmopriming, hydration process was accelerated in hydropriming treatment and germination indices were better. benntt and waters (3) reported no germination at osmopriming treatment for largeseed crops (such as corn and soybeans). this method can possibly include other osmotic elements uptake by seeds and create toxicity and reduced oxygen uptake at low osmotic potential was noted. conclusion: in this experiment, the priming process could increase seed vigor and seedling growth of cultivars. it seems that the use of zinc as a heavy metal toxicity in plant tissues and plant growth is reduced. the damage was more severe with increasing concentrations of heavy elements. but the goldrash compared to parkland has shown more tolerance and goldrashhas shown better results in hydroponic conditions.