Assessment of 1H heavy ion irradiation induced effects in the development of rice (Oryza sativa L.) seedlings

The effects of different fluences (10(7)-10(8) particles per cm(2)) of H-1 heavy ion irradiation on absorption, fluorescence and thermoluminescence (TL) spectra were studied during the development of rice (Oryza sativa L.) seedlings. Considerable inhibition in germination of irradiated rice seeds was observed. Both shoot and root growth was inhibited by the irradiation, though it was more prominent in the root. The absorbance of the chlorophyll (Chl) pigments of the irradiated samples was seen to be reduced on all the days of observation. On irradiation with the highest fluence (10(8) particles per cm(2)), the intensity of Chl and blue-green fluorescence decreased. The fluorescence intensity ratios of red/far-red (F684/F730) and blue/green (F420/F530) of the irradiated samples were seen to be increased. In case of TL glow curves, the splitting of B band into its components B-1 and B-2 or their merging into B band again was observed in the irradiated samples. For highest fluence, the C band was found to be the most prominent band on all the days of observation. On 14th day after germination emergence of a new peak at 18 degreesC in addition to the other TL peaks was observed for the lowest fluence. The above observations indicate that H-1 heavy ion radiation affects root and shoot growth, Chl biosynthesis as well as inhibition at the acceptor side of PS II of photosynthetic apparatus during developmental stages of rice seedlings. (C) 2003 Elsevier Ireland Ltd. All rights reserved.