Seed priming with extracts of two seaweeds alleviates the physiological and molecular impacts of salinity stress on radish (Raphanus sativus)

Abstract

Seeds of radish were primed with the extract of either Codium taylorii or Pterocladia capillacea for 2 h, then sown in clay-sandy soil and left to grow under the effect of either 150 or 200 mM NaCl, however the control treatment was irrigated only with tap water, for 35 days. The results indicated that salinity decreased water content, shoot length, photosynthetic pigments and total lipids, while it increased total soluble proteins, proline, phenolic compounds and alkaloid contents. Priming with C. taylorii or P. capillacea alleviated the adverse effects of salinity on radish seedlings. Under 150 and 200 mM NaCl treatments, 5 bands with molecular weights 40, 70, 80, 100 and 171 kDa were newly synthesized as stress proteins, while that of the salt stressed seedlings primed with seaweed extracts showed appearance of four new bands with molecular weights 4, 15, 21 and 44 kDa with C. taylorii and 5, 6, 23 and 149 kDa with P. capillacea. The data of the ISSR analysis produced by five different primers reflected the appearance of seven new bands with the treatment 150 and 200 mM NaCl, and there was a disappearance of eight other bands. Priming of radish seeds with seaweed extract and treated with 150 and 200 mM NaCl resulted in the disappearance of five other bands. It might be concluded that the priming in seaweed extracts could represent a useful and powerful tool in alleviating salinity stress.