Effect of salt stress on germination and seedling of Vicia faba L. [Effet du stress salin sur la germination et le développement des plantules de Vicia faba L.]

In arid and semi-arid areas,salinity is one of the main factors responsible for the degradation and reduced productivity of agricultural lands. by their excessive salt concentration,the saline soils constitute an unfavorable environment for the growth of several legume plants. this work aims to compare the germinative behaviour of six varieties of faba bean (vicia faba l.) in salt stress conditions. seed germination and seedling growth are critical steps of the plant development. six varieties of faba bean cultivated and marketed in morocco were tested. the obtained results showed that salinity has a negative impact on the germination and early seedling growth of v. faba. the high levels of salinity increase latency time and reduced the germination behaviour,especially at the concentrations of 150 mm and 200 mm. the final germination rate at 200 mm is 7.5 %,15 %,17.5 % and 20 % respectively for vita,luz de otno,reina mora and defes,whereas the germination rate is higher for aguadulce and alfia 5 (42.5 % and 67.5 % respectively). salinity can affect germination by two different effects: the first is reversible osmotic effect and the second is irreversible toxic effect. during our study,we show that the faba bean varieties are affected by osmotic and toxic effects except aguadulce and alfia 5 which appear to be affected only by osmotic effect. the growth of faba bean seedlings,cultivated in vitro during 10 days,is also reduced under salinity exposure. the size and the density of the root hairs are also affected. moreover,we note a change of anatomical structure of roots,resulting in a decrease in beam xylem cells and a decrease in the number of the cortical parenchyma cells.