The gradual and sudden additions of sodium chloride salt and the role of proline in minimizing their effects on two wheat (Triticum aestivum L.) cultivars cultured in vitro

Abstract

Series of experiments were conducted at Plant Tissue Culture Laboratory, Biology Department, College of Education for pure sciences, University of Basrah to estimate the effect of adding sodium chloride salt (NaCl) in gradual and direct manner and the role of adding proline to the nutrient medium on callus induction and somatic embryos germination percentage of two wheat cultivars named Ebaa’99 and Tamuz2. MS medium (Murashige and Skoog, 1962) was used as nutrient medium with the addition of sucrose, sodium hydrogen orthophosphate, myoinositol, adenine sulfate and thiamine acetic acid (Tisserat, 1981).The auxin 2,4-D( 4 mg.l-1) and agar( 5 g.l-1) were also added to the nutrient medium. NaCl was added alone and in mixing with proline (50 mg.l-1) at concentrations of 0, 0.5%, 1% and 1.5% either directly where a weighed amount of callus was cultured suddenly on each of the previous salt concentrations for one month or gradually were the same weighed amount of callus were transferred from the lower to the higher concentration after one month of culturing. Results indicated that NaCl at 1% and 1.5% caused a significant decrease in callus fresh weight while there was a significant increase in the fresh weigh at 0.5% of the salt compared to the control treatment. Proline addition to the nutrient medium caused a significant increase in callus fresh weight when compared with control treatment and proline-free medium. Salt effect and proline role on somatic embryos germination percentage was identical to their effect on callus fresh weight except that there is no significant difference between the cultivars understudy in their germination percentage as average for NaCl concentration with or without proline in each type of additions.