Charge Can Be Ion The Biological Effects Of Physical Mechanism

In recent years, heavy ion biotechnology has attracted considerable attention because of its practical applications in many fields such as botanic mutation breeding and cancer therapy. With the development of new experimental techniques, the studies on bioeffect induced by heavy ions are going deep into molecular level, especially on DNA irradiation damage as it is assumed to be the most critical initial damage responsible for subsequent biological effects. Nucleotide is basic component unit of DNA and plays a crucial functional role in genetic activities of organism. Clarrifying the damage effects of ion irradiation on nucleotide should be important to reveal the physical mechanism and subsequent biological effect. Our research program is aimed at understanding the effects of heavy ions at molecular level and the mechanism of this effects.For this purpose, DNA and its bases were irradiated with N, Ar, He, C, F, Si ions with the energy range from KeV to MeV in the solid state. and their products were analyzed using with Agarose Gel Electrophoresis, High Performance Liquid Chromatograph(HPLC), Liquid Chromatograph-Mass Spectrometer(LC-MS).The results show that both the dose effect of the KeV ion and that of MeV ion was fit exponential decay. Ion electronic stopping power(Se) have significantly influence on the residual rate, especially when Se is lower, When Se increases further, the changes becomes slowly. MeV ions have much higher damage effect compared to KeV ions, the molecular number damaged by one 3 MeV C ion with 1eV energy is seven orders higher than that by one 30 KeV Ar ion with 1eV energy.Besides, dry seeds of Arabidopsis thaliana were irradiated with 30keV N ions with different influence. The inhibition of germination and survival was investigated to study the dose effect of incident ion. After irradiation, a decease-increase-decease type of germination rate and survival rate fluence-response curve was found. The survival rate is much lower than the germination rate at high fluence. The possible mechanism of above experimental results is discussed in this paper.