Effects of salinity on some morphological and physiological parameters in four canola (Brassica napus L.) cultivars

A laboratory experiment was carried out to investigate the effect of salinity on some morphological and phys-iological parameters in four Canola (Brassica napus L.) cultivars (Talaye, Sarigol, Zarfam and Opera) under salinity stress. Plants were grown in hydroponic solution (Hoagland 1/4 strength) under greenhouse conditions and on five-leaf stage, treated with different concentrations of NaCl: 0 (control), 50, 75 and 100 mM. After 14 days of treatment, plants were harvested and the length of shoots and roots, photosynthesis, chlorophylls and carotenoids contents of leaves were measured on four studied cultivars. In general the results showed that increasing salinity reduced leaf relative water co-ntent, shoot and root lengths and leaf area. Photosynthetic rate was declined in Talaye and Sarigol, but it was elevated in Opera and Zarfam. It should be noted that the changes induced by salinity on photosynthetic pigments was not regu-lar. The results of this study showed that among the investigated cultivars, in vegetative phase, Opera and Zarfam had higher capacity and function to salt stress tolerate than other cultivars. It also seems that Sarigol may be more vuln-erable than other cultivars under salinity stress.