Irradiations with fast neutrons induce salinity tolerance in potato,Solanum tuberosum L., callus
2011
Hashem, E.A.
Sterilized leaf explants were excised from 30-days old potato plants and cut into discs (1 cm. each). The discs grown under tissue culture techniques using MS-medium (Murashige and Skoog, 1962), supplemented with 0.3 mg.L. 1 2,4-0 and 3.0 mg.L. 1 kinetin. Cultures were incubated at 22:±:2 .ºC in a complete darkness for callus induction. Three weeks later, calli were removed and exposed to different doses of fast neutrons (10. , 10. , 10. , 10. and 10. n/cm. . The control (discs not treated with fast neutrons) and fast neutrons irradiated calli were subcultured on MS media for 5 weeks and left to grow at 22 .ºC under low light intensity (1500 Lux, daily fluorescent tubes). Callus irradiated with 10. n/cm. fast neutrons produced the highest yield on salt free medium as compared with the control sample. Calli treated with fast neutrons as well as the control were subcultured on MS media containing various concentrations (0.0, 50,100, 150 and 200 mM) of NaCI. The potato calli exposed to 10. or 10. n/cm. fast neutrons exhibited more salinity tolerance, and were able to continue their growth even under the higher level of salinity (200 mM) NaCI throughout 6 weeks of growth. However, calli exposed to lower doses 10. and 10. n/cm2 or higer dose 10. n/cm failed to continue their growth under the higher level of salinity (200 mM) NaCI. The data also revealed that salinity tolerance was positively associated with high accumulation of osmoprotectants i.e., sucrose and proline. The results also showed that, increasing the salinity level, induced accumulation of Na+ content while, in contrast k and Ca ++ content decreased. The findings of the present work seem to indicate that fast neutrons could be successfully applied to improve salinity tolerance of potato calli.
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