[en] Since the mid of 1980's, ion beam had been widely used in mutagenic breeding of various crops. Ion beam biotechnology had provided a new way for improving corn variety and creating new germplasm resources, and had promoted the development of maize breeding. The ion beam characteristics, the mutagenic mechanism and its application in maize breeding were described. (authors)

[en] Young shoots of Dahlia pinnata Cav cultivar were irradiated by 80 MeV/u ¹²C⁶⁺ ions. The differences at DNA level between dwarf mutant and wild type were detected by using RAPD (Random amplified polymorphic DNA) method. The results showed that there were different polymorphic bands induced by 18 primers among the tested 25 primers, and the ratio of polymorphic bands and total bands accounted for 19.57% after 1.80 x 10⁸C⁶⁺/cm² irradiation. Meanwhile, after 1.08 x l0⁸ C⁶⁺/cm² irradiation the polymorphic bands were induced by only 6 primers and the ratio accounted for 5.76%. Using the Jaccard formula, statistic analysis of amplified bands were obtained and it showed that after 1.80 x 10⁸ C⁶⁺/cm² and 1.08 x 10⁸ C⁶⁺/cm² irradiation the similarity index were 0.65 and 0.92 respectively. The results suggested that DNA should prone to mutant at high doses, and high dose irradiation might be more effective in corn improving and mutagenic breeding. (authors)

[en] Heavy ion biotechnology has received much attention since the mid-1980s, when the first mutagenic effect of heavy ion beams was found in rice. Since then, plant breeding is one of the focuses in heavy ion biotechnology. In this paper we outlined the recent developments in plant breeding by heavy ion beams. We introduced briefly the essential characteristics and superiority of heavy ion beams applied in plant breeding, and reviewed further the mutagenic research in three levels (e.g., molecular, cell and individual) of plants. At last, we summarized artificial mutants obtained in plants irradiated by heavy ion beams. (authors)

[en] To explore the effects of different linear energy transfer(LET)of 12C6+ ion beam irradiation to BJ1, survivals and biocontrol effects were cultured and treated with LET=40 keV/ m and LET=60 keV/ m and irradiated to 50, 100, 200, 400 and 600 Gy respectively. The results showed more mutations and biocontrol charts and higher survivals were obtained under high LET(60 keV/ m)with lower dose, which was useful to screen good positive mutations. Based on the results above, it could be concluded that high LET(60 keV/ m)had obvious irradiation effects than low LET(40 keV/ m). (authors)

[en] Full text: Mutation breeding induced by irradiation with high energetic photons and ion beams is one of the important methods used to improve plant varieties, but the mutagenic effects and the molecular mechanisms are often not entirely clear. Traditional research focused on phenotype screening, chromosome aberration test and genetic variation analysis of specific genes. Recently, the whole genome sequencing technique provides a new method for understanding the comprehensive identification of mutations caused by irradiations with different linear energy transfer (LET). In this study, eleven Arabidopsis thaliana M₃ lines induced by carbon-ion beams and 10 M₃ lines induced by gamma rays were re-sequenced by using the Illumina Hiseq sequencing platform, and the substitutions and small insertion-deletions (indels) were analysed comparatively. It was found that the ratio of substitutions to indels for M₃ lines induced by carbon-ion beam was 2.58:1, whereas the ratio was 3.69:1 for gamma rays. The ratios of deletions to insertion for carbon ions and gamma rays were 4.9:1 and 2.65:1, respectively. The single base indels were more prevalent than those equal to or greater than 2 bp in both carbon-ion beams and gamma rays induced M₃ lines. Among the detected substitutions, the ratios of transitions to transversions induced by carbon ions irradiation was 0.99 and 1.27 for gamma rays; these values differ greatly from the 2.73 reported for spontaneous substitutions reported. This study provides novel data on molecular characteristics of carbon-ion beam and gamma rays induced mutations at genome-wide scale. It can also provide valuable clues for explaining the potential mechanism of plant mutation breeding by irradiations with different LETs. (author)

[en] In order to study mutagenic effects of different heavy ions irradiation on maize inbred lines, corn seeds were irradiated with ¹²C⁶⁺ and ³⁶Ar¹⁸⁺ ions. The experimental results showed that the germination rate and planting percent of maize seeds irradiated were different as dosage increasing of heavy ion irradiation in disparate maize inbred lines. The wettish seeds had higher sensibility to heavy ion irradiation. The leaf type of the plant happened visible changes in M1 generation, such as leaves broadening, crimpling, curling up and having yellow strip etc. The plant height, spike position, spike number per plant, anther color of staminate, grain texture, spike row, grain weight and resistance had changes in M₂ generation. Among them occurred some beneficial mutations. Some beneficia1 mutations could be stably inherited in M₃ generation. After irradiated by ion beams the growing period of maize was changed, and different beneficial mutations were produced. From the above we can see that heavy ions irradiation is a high performance means for improvement germplasm of maize. (authors)

[en] In order to study mutagenic effects of different heavy ions irradiation on maize inbred lines,corn seeds of Zheng58, Lu9801, Jinxiang4C-1, CSR24001, 308 and 478 were irradiated with ¹²C⁶⁺ and ³⁶Ar¹⁸⁺ ions. The experimental results showed that the germination rate and planting percent were different after irradiation. The wettish seeds had higher sensibility to heavy ion irradiation. The leaf type of the plant appeared visible changes in M₁ generation. In M₂ generation, great changes had taken place in economic traits, many of which are beneficial mutation. Some beneficia1 mutation could be stably inherited in M₃ generation. From the above, it can be predicted that heavy ions irradiation is an effective means of genetic improvement of maize. (authors)

[en] The hypocotyls and cotyledons of Medicago sativa were irradiated with original energy 100 MeV/u heavy ion beam ¹²C⁶⁺. The effects of irradiation on the growth state and the callus induction rate, the callus relative growth rate, the somatic embryogenesis rate and plantlet regeneration were studied. The results show that heavy ion beam irradiation can inhibit the callus induction of the hypocotyls and cotyledons, and the frequency of callus de- clines gradually with the increment of irradiation doses. In the course of subculture, their callus relative growth rates are higher than that of the controls, and the hurt caused by irradiation has been restored. The heavy ion beam irradiation has an influence on the somatic embryogenesis rate. The somatic embryo induced by the hypocotyls irradiated up to 30 Gy formed earlier and the number is larger while irradiated at 50 Gy there is no plant obtained. The results of RAPD (Random amplified polymorphic DNA) analysis on the control and the plants induced by the hypocotyls irradiated within 10-40 Gy suggest that eleven among twenty random primers have been amplified with different DNA polymorphism bands. Consequently, heavy ion beam irradiation could cause mutation of alfalfa genome DNA. (authors)

[en] Sweet sorghum (Sorghum bicolor (L) Moench) seeds were implantated by carbon ion for different dose (0Gy, 10Gy, 30Gy, 50Gy, 80Gy) respectively, then plant height, biomass, contents of chlorophyll, malondialdehyde (MDA) and soluble sugar of M2 seedlings were measured in order to investigate the response of M2 seedlings to heat stress. The results show that plant height and chlorophyll content are changed unobviously among all treatments. Biomasses of M2 seedlings are higher after low dose (10Gy, 30Gy) of carbon ion implantation than that of high dose (50Gy, 80Gy) treatment, while the treatment of carbon ion implantation for 30Gy enhances the heat tolerance of M2 seedlings by decreasing the content of MDA and soluble sugar. (authors)

[en] Many mutants of plant induced by heavy ion beam irradiation have been reported in recent years, but leaf anthocyan mutants induced by ion irradiation in evergreen were rarely found. In this study, a color-leaf mutant with purple leaves, stems and petals was isolated from clones of Wandering Jew irradiated by 95.8 MeV/u carbon ion beam. The concentration and histological distribution of leaf pigment were surveyed in wild type and mutant. In mutant, contents of total chlorophylls (Chl), chlorophyll a (Chl a), chlorophyll b (Chl b) and carotenoids (Car) decreased significantly, while concentration of the anthocyanins was 6.2-fold higher than that of wild type. Further composition analysis of anthocyanins by electrospray ionization mass spectrometry (ESI-MS) indicated that the purple pigmentation of leaves in mutant was caused by accumulation of petunidin anthocyanin. Microscopic examination showed that most petunidin anthocyanin accumulated in the lower epidermis, and little in vascular parenchyma of mutant, while there was no pigment in wild type. Meanwhile, in spongy parenchyma of mutant we observed little Chl, which the wild type abounds in. In conclusion, the color-leaf mutant of Wandering Jew induced by irradiation of carbon ions was improved in ornamental value, and it could be contribute to variation in level, component and distribution of foliar pigment. The possible mutation mechanisms were discussed. (authors)