بررسي اثرات شوري و دما بر مولفه هاي جوانه زني ارقام مختلف كلزا

The study of temperature and salinity effects on germination components of canola cultivars

In order to study the effects of different NaCI concentrations on germination components of 12 canola cultivars in three constant temperatures (15, 20 and 25°C) two experiment sets were used with CRB design in three replications. The first one was done at 20°C with 5 osmotic potentials (including 0, -0.5, -1, -1.5 and -2 Mpa) to evaluate response range of cultivars to salinity. The second one, was designed with two constant temperatures (15 and 2YC) and six osmotic potentials (0, -0.5, -0.75, -I, -1.25 and -1.5 Mpa equal to zero, 8.57, 12.56, 17.14,21.43 and 25.72ds/m) to evaluate the effects of salinity and temperature levels on germination components, Results indicated that all studied components including germination percentage, germination rate, radicle and shoot length and radicle and shoot growth rate were affected significantly in all cultivars by salinity, but mean values for studied cultivars were not significant. This revealed that tolerance to salinity in all studied varieties is almost same, Also, results confirmed that 8.57 ds/m (-0.5 Mpa) can be considered as salinity tolerance threshold for most of studied components such as germination rate, shoot length, shoot growth rate and radicle growth rate, Also results showed that salinity tolerance threshold can vary from 8.57 to 17.14 ds/m (-0.5 to -1 Mpa), depend upon exposed temperatures. Also, increasing of temperature over than optimum temperature can result in synergistic effects with salinity levels to increase detrimental effects of salinity. Our results showed that optimum temperature for canola germination can be in a range of 15 to 20"C and distancing form optimum temperature can be a cause of different responses in respect to germination components in canola.