Distribution and bioaccumulation of radiocarbon ( 14 C) into biochemical components of wheat in relation to antioxidant system under saline stress conditions

In the current study two wheat cultivars (Masr1 and Gimmeza9) were cultivated in saline soil (6215 ppm) and irrigated with saline water (4654 ppm). After 30 days from cultivation, plants were sprayed with 14 C labeled glycine (specific activity 0.025 µCi/1ml/plant of 60 ppm glycine); samples were collected after 3, 6, 24, 48 and 96 hours in addition to 7 and 15 days to study the distribution and bioaccumulation of 14 C labeled glycine into different biochemical components and its relation to antioxidant system. Results revealed the presence of 14 C in all plant extracts used in the current study, but the distribution and bioaccumulation were different depending on the type of plant extract and the time of sampling. This proves that glycine had clear role in the biosynthesis of many important biochemical components of the two wheat cultivars under saline conditions. The highest amount of 14 C was found in E3 extract in roots and shoots of two wheat cultivars compared with the other plant extracts. The total recovery percent of 14 C glycine in the two cultivars decreased by time reaching the lowest value at 15 days of the application (27.53% in Masr1 and 20.81% in Gimmeza9); this may be attributed to the loss of 14 C glycine as 14 CO2 through respiration after complete metabolism of the applied glycine. Antioxidant enzymes (superoxide dismutase, catalase and peroxidase) are important enzymes that increase the defense capability of wheat plants, where protect the biomolecules from free radicals damage (detoxification) under glycine treatment conditions. Also, it was noticed the important role of glycine on hydrolyzing enzymes (α and β-Esterase). With respect of free amino acids, data showed that thirty three free amino acids were detected in two wheat cultivars. The most abundant amino acids noticed were serine, asparagine, proline, alanine, cystine, δ-aminobutyric, lysine and arginine. Current research is recommended to activate the use of radioactive carbon 14 C in wheat plants under saline condition, to stand on the effective role of many important biomolecules. The research also confirms the positive role of glycine acid in salt stress tolerance, through its contribution to the biosynthesis of many important biochemical components in plant cell and its association with the activity of antioxidant defense system. (Mohamed H. Hendawey and Hedaya A. Kamel. Distribution and bioaccumulation of radiocarbon ( 14 C) into biochemical components of wheat in relation to antioxidant system under saline stress conditions. J Am Sci 2015; 11(10):8-21). (ISSN: 1545-1003). http://www.jofamericanscience.org. 2