In Vitro Selection Of Salt-Tolerant And Mannitol-Toerant Variants Of Wheat And Their Physiol-Biochemical Characterization

Segments of immature inflorescences and immature embryos of the salt-tolerant wheat (850512r) were used as explants for secondary selection of a new salt-tolerant cell line and selection of mannitol-tolerant cell line. A salt-tolerant variant cell line and two mannitol-tolerant cell lines were obtained from the embryogenic calli using positive selection method. Plantlets were regenerated from those tolerant cell lines and grew well on the soil.After being cultured on NaCl-free medium for 2 months, the secondary selected salt-tolerant cell line showed higher relative growth rate on the medium containing 2.0% Sodium Chloride (NaCl) , 20% polyethyleneghycol (PEG-6000) or 50mmol/L hydroxyproline(Hyp) and higher accumulation of free proline than the control. After being cultured on Mannitol-free medium for 2 months, the mannitol-tolerant variant cell lines also showed stronger resistant to 20% mannitol,2.0% NaCl,20% PEG-6000 or 50mmol/L Hyp than the control cell line. The accumulation of free proline in the mannitol-tolerant cell line was lower than that in the control cell line, when both the variant cell line and the control cell line were cultured on the medium added with 20% mannitol. On the contrary, the accumulation of soluble carbohydrate and soluble protein in the mannitol-tolerant cell line was higher than that in the control under the stresses of 20% mannitol. The Sodium dodecyl sulfate (SDS) electrophoresis pattern of soluble proteins of three tolerant variant cell lines showed that some specific proteins were synthesized. Some new bands also appeared in the isoenzyme electrophoresis.The physiol-biochemical characterization of salt-tolerant wheat BAOFENG 7228r and 850512r was studied, after the two variants of wheat were planted on salty soil for 2 generations. The results showed that the salt-tolerant wheat's frequency of burgeoning was higher than that of control , and their growth was better than the control under 1.0% NaCl stress .Not only the accumulation of free-proline but also that of soluble carbohydrate in salt-tolerant wheat was higher than that of control under 0,0.2%,0.4%,0.6%,0.8%or1.0%NaCl stress. The Sodium dodecyl sulfate (SDS) electrophoresis pattern of soluble proteins of the two salt-tolerant genotypes showed that some specific proteins were synthesized. Some new bands also appeared in the isoenzyme electrophoresis.