| In this study, the dried Moso seeds were irradiated by 60Coγray with six kinds of dosages. Moso seeds were studied more in-depth from the cellular level, biochemical and DNA molecular level on their biological effects-induced.So that we can provide technical reference and theoretical basis for radial breeding of Moso. And bamboo's genetic improvement and breeding of superior germplasm is important. The major results were as follows:1. Moso seeds were irradiated by 60Coγray with six kinds of dosages. The effects of chromosomal aberration, nuclear aberration and mitosis of root tip cell in Moso byγray irradiation indicated thatγray irradiation with less than 90 Gy dosages could stimulate and promote mitosis of root tip cell. Andγray irradiation with higher than 90 Gy dosages could inhibit mitosis of root tip cell. Furthermore,γray irradiation could induce many types of chromosomal aberration and nuclear aberration, such as chromosome bridges, chromosome fragment, laggard chromosome (clump), free chromosome (clump), chromosome conglutination, micronucleus, minornucleus, double nucleus, nuclear budding, nuclear bleb, nuclear fragmentation and so on. The relationship between dosages and frequencies of chromosomal aberration and nuclear aberration of root tip cell was fitted in with the model Y = 0.0390X - 0.3756, Y = 0.0530X– 0.0783 respectively. The correlation coefficient was 0.8934 and 0.9982. The relationship between frequency of chromosomal aberration and frequency of micronucleus of root tip cell in Moso was fitted in with the model Y = 0.8836X - 0.4525. The correlation coefficient was 0.8345, F = 25.22>F0.01.2. The cytoskeleton's structure of root tip cell on Moso changed by 60Coγ-ray irradiation,majorly in performance of density and thin difference.When the dose was lower than 60 Gy, the cytoskeleton is only a small density, compared with the controls.This indicated that Moso's cytoskeleton were less affacted by the lower than 60 Gy dosesγ-ray irradiation. When the dose was 90 Gy or greater, as the dose increased, the density of cytoskeleton became smalle, and the thin of cytoskeleton became loose. When the dose was 180 Gy or greater, reticular formation was damaged and cytoskeleton became exiguous. This indicated that as the dose increased,cell was damaged greatly.3. Peroxidase (POD) isoenzyme test results on Moso seeds by 60Coγray irradiation with different dosages showed that: on the whole,peroxidase activity enhanced on Moso seeds byγray irradiation,compared with the controls. But peroxidase activity were different between the different doses of radiation, mainly in enzymes with the width and the painted degree. Peroxidase activity in 30Gy enhanced markedly.This shows the protective effect on Moso seeds by 60Coγ-ray irradiation.When the dose was between 60Gy and 90 Gy, peroxidase activity reduced, compared with 30Gy.But peroxidase activity in 120Gy enhanced markedly again. This shows the damage effect on Moso seeds by 60Coγ-ray irradiation.4. RAPD molecular test results on Moso seeds by 60Coγray irradiation with six kinds of dosages showed that: Four primers could amplificate different bands in selected 80 .And when the dose was higher than 120 Gy, the differnce was obvious.This indicated that DNA molecular were less affacted greatly by the high-doseγ-ray irradiation. At the same time, the different segments were recycled and their sequences were tested. The result is that the size of the new amplificated bands in 60 Gy and 150 Gy were 811 bp.And the two bands had three differences, the 376th,378th and 517th base respectively.The size of control's band was 1137bp. The size of 180Gy band was 1137bp.The difference was 42bp. And the base sequence changed greatly. This indicated that the sequence of DNA bases were changed by 60Coγ-ray irradiation, the two new band in60 Gy and 150 Gy were inputed NCBI databases and were analysed, did not find that the two new bands were homologous with the sequence of genebank. |
