The shoot tips,cotyledons,hypocotyls and radicles of Zygophyllum xanthoxylon(Bunge) Maxim were cultured in vitro to develop rapid propagation technology.The results showed that the shoot tips are good explants of shoot multiplication and the cotyledons,hypocotyls and radicles are good explants of callus induction;the optimum multiplication medium is MS+6-BA 5.0 mg·L-1+NAA 1.0 mg·L-1;the best medium for rooting is MS+IAA 1.5 mg·L-1;the desirable callus induction medium is MS+6-BA 1.0 mg·L-1 or MS+6-BA 1.0 mg·L-1+NAA 0.5 mg·L-1.Plantlets with well-developed shoots and roots were acclimatized successfully in fluviatile sand and then grew vigorously in soil,mixed with sand(1∶1).

This study describes a reliable protocol for callus induction and rapid mass propagation of the ecologically important plant, Zygophyllum xanthoxylon (Bunge) Maxim. The optimum callus induction medium was Murashige and Skoog (MS) supplemented with 4.4 μM 6-benzylaminopurine (BAP) and 2.7 μM α-naphthalene–acetic acid (NAA), on which the callus induction frequencies from different seedling explants were all 100%. However, seedling-derived callus did not form regenerated shoots. In order to achieve shoot multiplication, shoots were developed from cultured plumules, at an average of 3.1 shoots per explant, and the regenerated shoot tips were further multiplied by subculture. The best shoot multiplication from shoot tips was achieved on MS supplemented with 5.4 μM NAA and 22.2 μM BAP after 40 d of culture. Seventy-three percent of regenerated shoots formed roots when cultured on MS supplemented with 8.6 μM IAA after 4 wk of culture. The plants that acclimatized successfully in sand flourished the following year, with normal morphology and growth characteristics.

Newly research progresses were summarized in effect of ion beams on seed surface,biological effect,growth,development,gravitropism and so on.Furthermore,mutation molecular mechanism of Arabidopsis thaliana was discussed,for example,alteration of DNA bases,DNA damage,chromosomal recombination,characteristics of mutant transmissibility,etc.Meanwhile,the achievements of transferring extraneous gene to Arabidopsis thaliana by ion beams were reviewed in the paper.At last,the future prospective are also discussed here in mutation molecular mechanism and the potential application of biological effect of heavy ion beams.

The study of heavy ion beams as a new irradiation resource on seeds of linseed (Linum usitatissmum L.) was reported. After irradiated by 12C 6+ heavy ions (with irradiation dose: 6×108 cm-2,1.8×109 cm-2 and 3.6×109 cm-2 respectively),the biological characters,agricultural traits,pollens and polymorphic DNA of sample was studied in Linum usitatissmum L.. The results showed that 6×108 cm-2 of 12C 6+ could promote the linseed germination rate,plant height and pollen viability. The 1000-seed weight and the oil content of seed irradiated by 12C6+ heavy ions was increased with augment of irradiation dose respectively. It has been found that 3.6×109 cm-2 is the most effective dose for increment both of seed weight and oil content with 16.5% and 19.9%,respectively. Cytological observation re-veals that the highest dose (3.6×109 cm-2) can also induce alteration of pollen shape of linseed. Furthermore,RAPD(Randomly amplified polymorphic DNAs) analysis shows that 99 DNA fragments are amplificated by 14 primers and the polymorphic ratio is 52.5%.

Dry seeds of Brassica napus were irradiated by 12C6+ ion beams with 30,90,and 180 Gy,and the mutagenic effects of M1 generation were investigated.In comparison to the control group,the irradiated seeds showed positive changes in emerged seedling rate,plant height and blooming rate,with obvious inhibitive effects on pollen vitality,1000-seed weight and seed oil content.The 30 Gy irradiation group outperformed the others in pods per plant and seed yield per plant.By means of RAPD method,the results showed specific bands,such as increasing bands,flawing bands and bands with different fluorescence intensity were observed in 13 primers selected.The variation rates under 30 Gy,90 Gy and 180 Gy 12C6+ irradiation were 22.1%,23.7% and 36.2%,respectively.The research is valuable to the application of 12C6+ heavy ion beam in improving Brassica napus breeding.

Cytological effects and RAPD analysis of root-tip cells of Allium fistulosum L., the dry seeds were irradiated by()~(12)C~(6+) heavy ions,were studied.Micronucleus and chromosomal aberration observed in the root-tip cells showed that obvious "linear rise" trend was in the frequency of micronucleus,multi-micronucleus and total chromosomal aberration.But a "U-formed" trend was observed only in the chromosomal aberration frequency.At the same time,RAPD analysis revealed()~(12)C~(6+) heavy ions exerted great effect on DNA variation of Allium fistulosum L..Flawing bands,increasing bands and the ones with different transport ratios were observed in amplified bands of 28 selected primers.The DNA variation rate for 30,90 and 180Gy treatments was 29.91%,41.05% and 22.14%,respectively.This study also found that high micronucleus frequency and chromosomal variation lead to high lethality,resulting in low DNA variation rate in the survived plants which seeds were irradiated with high doses.

Crops of Brassica napus L., Linum usitatissmum L., Allium fistulosum L. and Lens culinaris Medic. were irradiated by 80 MeV/u 12C6+ ion beams with doses of 30, 90 and 180 Gy. The germination rates and heights of seedlings of M1 and M2 generation of these four plants were studied. The results indicated that germination rates and average heights of the B. napus and L. usitatissmum were improved by appropriate dose treatment, while great suppression was found in the irradiated groups of the A. fistulosum. As far as the L. Culinaris was concerned, little differences was observed on M1 germination rate, but the 90 Gy irradiation was favorable to growth of plant. The treatments with 30, 90 and 180 Gy were inferior to contrast one on M2 germination rate of the four species. Seedlings of M2 generation of the B. napus, L. sitatissmum and L. culinaris under 30 Gy grew better than the other groups, while the best performance of the A. fistulosum was shown by the control group.

用30Gy、90Gy和180Gy 12C6+重离子辐照处理大葱干种子,研究了它对大葱的生物学效应。经过不同剂量12C6+重离子照射过的大葱,幼苗发芽率、株高等表型随着辐照剂量的增大,呈现明显的"抛物线"趋势。适量的12C6+重离子照射（30Gy）能提高大葱发芽率和抗旱、抗倒伏能力,促进生长发育。重离子辐照能有效地诱导大葱根尖细胞微核和染色体畸变形成,180Gy处理的大葱微核率和染色体畸变率最高达到9.09%和10.03%。本实验为大葱的重离子辐照育种打下基础。