LAUSR

PURPOSE A field experiment was took place to investigate the impact of gamma-rays low dose on growth parameters as well as bioactive compounds of white radish (Raphanus sativus L.). MATERIALS AND METHODS Dry seeds of white radish were irradiated by gamma radiation at dose levels (10, 20, 40 and 80 Gy) beside un-irradiated sample as control. Physiological and biochemical markers were performed to follow the effect of gamma radiation on white radish. RESULTS The results of this study revealed that gamma rays increased growth parameters with increasing gamma irradiation dose to a 40 Gy then the growth was decreased with the dose of 80 Gy. As the results gave the maximum increments 14.64, 48.30 (cm), 20.84 (cm) and 5.51 (cm) for leaves number, leaves length, roots length and roots diameter respectively with dose of 40 Gy. With increasing the irradiation dose to 80 Gy the results showed reduction in all parameters studied i.e 6.84, 34.37 (cm), 11.58 (cm) and 2.78 (cm) for leaves number, leaves length, roots length and root diameters, respectively. The biochemical compounds such as ascorbic acid which gave the maximum increase with the dose 40 Gy (3.7 and 3.0 mg/g FW for leaves as well as roots, respectively). While, phenols, flavonoids, antioxidant activity, peroxidase and polyphenol oxidase showed the highest increase with 80 Gy i.e. 5.5 mg/g FW, 5.4 mg/g FW, 70.5%, 340 unit.min-1 mg-1 proteins and 185 unit. min-1 mg-1 proteins respectively in radish leaves. For radish roots, phenols, flavonoids, antioxidant activity, peroxidase and polyphenol oxidase were 2.0 mg/g FW, 1.8 mg/g FW, 68%, 280 unit. min-1 mg-1 proteins and 170 unit. min-1 mg-1 proteins. Furthermore, the protein and isoenzyme profiles of peroxidase and polyphenol oxidae changed and induced alteration by different irradiation dose levels. CONCLUSION It can be concluded the gamma irradiation was a useful method for increasing the growth and biochemical content of white radish plants.