Evaluation of the two rootstocks (so4 and freedom) for the salt stress in vitro conditions

Abiotic stresses are the major limiting factors in plant productivity. Salinity is considered as significant ecological regarding the productivity of different crops in different arid and semiarid areas all over the world, it’s also the major cause of the reduction in grapevine crop yields worldwide. In the present investigation, two grapevine rootstocks (Freedom & SO4) were evaluated to the effect of different concentrations of salinity under in vitro conditions. Murashige and Skoog (MS) culture medium was used at strength of 3⁄4 in plant tissue culture technique supplemented with 2 mg/L BAP with different concentrations of NaCl (0.0, 2000, 2500 and 3000 ppm) for in vitro culture conditions. The results showed that the survival percentage, vegetative growth (formed shoots, shoot length, shoot number and leave numbers root growth (root number & length) and photosynthetic pigments content (chlorophyll A & B and carotenoids) significantly decreased linearly with increasing the salinity levels. Contrary, the total phenols and free proline contents increased as a result of increasing salinity. Furthermore, increased salinity levels led to high total polyphenyl oxidase expression in Freedom rootstock compared to SO4 rootstock. In conclusion, both rootstocks (SO4 and Freedom) showed great tolerance to high levels of salinity. Although Freedom was more tolerant to salt stress than SO4, both of them can be used widely as salinity tolerant rootstocks in newly reclaimed soils.