电子束对大麦的诱变效应研究互Ⅰ．对M_1和M_2的效应

采用１００—３００Ｇｙ辐照处理１３个大麦品种（系）的风干种子，Ｍ１代产生明显的生物学辐射损伤，表现在苗的高度降低，第一叶片长度和根的长度变短，植物存活率和结实率下降。电子束诱变的适宜剂量一般为１００—２００Ｇｙ，在此剂量范围内，Ｍ２代突变频率为０．２７６％－３．８４％，除出现多种叶绿素缺陷突变外，还出现植株生长习性、株高、叶型、穗型、穗长，芒型、早熟性及茎叶蜡质减少等形态或生理性状突变，表现电子束对大麦具有诱变类型丰富、突变谱广的特点。同一种诱变处理的Ｍ１结实率高低的不同类型还会影响到Ｍ２形态突变的类型。     

Assessment of biological changes in wheat seedlings induced by ^12C^6＋-ion irradiation

The present study was designed to evaluate the effect of 12C6 ion beam (10～80 Gy) on biological changes of wheat seedlings. Reactive oxygen species (ROS)-related biomarkers and the quantification of plant survival and growth were examined at 10 day after carbon ions irradiation (LET 30.8keV/μm). The results showed that heavy ions obviously enhanced ROSs reflected by the production of O2 and H2O2 as well as TBARS, and treatment with 20 Gy achieved the peak value, suggesting that higher mutagenic potential may occur at 20 Gy. Simultaneously, increase of SOD activity was induced by heavy ions to counteract ROS accumulation. On the other hand, higher doses at 40 and 80 Gy inhibited wheat growth and survival in comparison with the control, and reversely lower doses at 10 or 20 Gy stimulated wheat growth and survival. In conclusion, the above observations imply that a dose range of 20～40 Gy is likely promised for wheat mutation breeding.     

碳离子束对甜高梁辐射诱变的当代效应

利用兰州重离子加速器提供的中能碳离子束对甜高高粱品种BJ0601和BJ0602进行了不同剂量的辐照处理，以期选育出生物学产量高、汁液糖锤度高及抗逆性强的品种。当代田间试验结果表明：（1）甜高梁在田间的存活曲线均呈“类马鞍型”，随着剂量的增加，其存活率先降后升再下降；（2）随着辐照剂量的变化，其茎秆亩产量、糖锤度和对照相比，均发生了明显的变化；（3）经过碳离子束辐照，出现了株高、单秆重、糖锤度高、早熟、茎粗等突变类型，为进一步的品种选育和诱变机理研究奠定基础。     

Plant height revertants of Dominant Semidwarf mutant rice created by low-energy ion irradiation

Dominant Semidwarf mutant rice (Sdd) was obtained from its wild type (WT) by irradiation with a low-energy ion beam. Six tall revertants of Sdd were induced by irradiation. The revertants restored the plant height to that of WT plants. Investigation of the agronomic character and genetic analysis indicate that the revertants are similar to WT plants with putative different inherited mutations. The revertants were checked for DNA differences using the simple sequence repeat technique. Among 408 such primers used, only 2 primers detected mutation sites in the revertants, which provided the molecular evidence for the revertants induced from Sdd. This study indicates that ion irradiation may be used as a mutagen to create revertants for plant architecture studies and could be a new application.     

离子束介导外源DNA导入小麦后代变异系有关分析

离子束技术是一种有效的农作物诱变和介导转基因技术,本研究利用离子束介导转化选育到一批有价值的小麦变异材料.本文对变异材料的农艺性状、品质性状、种子醇溶蛋白图谱进行了深入分析.结果表明,变异材料的株高、主茎穗长、千粒重、叶片性状、蛋白质含量、湿面筋含量与对照相比都发生了明显的变化并达显著水平;变异材料种子醇溶蛋白谱带已发生了确切的变化,且某些材料已稳定,还有的材料醇溶蛋白谱带存在多态性,还在分离之中.研究结果表明离子束介导转基因技术可产生丰富的变异、创造新的种质资源,并为该技术在小麦育种上的应用提供理论依据.     

氮离子注入不同基因型水稻的生物学效应研究

实验结果表明：不同基因型水稻材料Ｍ１代生理损伤，Ｍ２代叶绿素、株高及抽穗期突变频率和诱变效率均存在着较大的差异；Ｍ２代苗期叶绿素缺失突变频率和诱变效率高的材料，其抽穗期、株高突变频率和诱变效率并不一定高；用早熟、半矮秆突变体为母本选育的品种在氮离子注入时不但辐射敏感性差，同时未出现更早熟突变和高秆突变。     

Flower color mutants induced by carbon ion beam irradiation of geranium(Pelargonium × hortorum,Bailey)

In an attempt to elucidate the biological effects and underlying mutations involving flower color in ornamental plants following carbon ion beam radiation,shoots of geranium were exposed at dosages of 0,10,15,30,and40 Gy,and one flower color mutant was obtained.The morphological characteristics,physiological aspects,and DNA polymorphisms between wild-type and flower color mutants were analyzed.The colors of petal,peduncle,pistil,and stamen of the mutant displayed significant differences compared to those of the wild-type.Compared to the original plants,the total anthocyanin content in the petals of the mutant significantly decreased,resulting in a light pink petal phenotype.DNA polymorphisms detected by random amplified polymorphic DNA analysis showed that the ratio of different bands between the wild-type and mutant reached up to 13.2%.The present study demonstrates that carbon ion beam irradiation is effective in inducing genomic variations,resulting in flower color geranium mutants within a relatively short period of time.Meanwhile,the developed flower-color mutants may be potentially used in future mutational research studies involving ornamental plants.     

Pigment analysis of a color-leaf mutant in Wandering Jew （Tradescantiafluminensis） irradiated by carbon ions

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.     

Investigation of the radiation hardness on semiconductor devices using the ion micro-beam

Variation of the ion beam induced charge (IBIC) pulse heights due to ion irradiation was investigated on a Si pn diode and a 6H-SiC Schottky diode using a 2 Mev He⁺ micro-beam. Each diode was irradiated with a focused 2 MeV He⁺ micro-beam to a fluence in the range of 1×10⁹–1×10¹³ ions/cm². Charge pulse heights were analyzed as a function of the irradiation fluence. After a 2 MeV ion irradiation to the Si pn junction diode, the IBIC pulse height decreased by 15% at 9.2×10¹² ions/cm². For the SiC Schottky diode, with a fluence of 6.5×10¹² ions/cm², the IBIC pulse height decreased by 49%. Our results show that the IBIC method is applicable to evaluate irradiation damage of Si and SiC devices and has revealed differences in the radiation hardness of devices dependent on both structural and material.     

12C6+重离子辐照大葱的生物学效应

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.     

碳离子束辐照对甜高粱主要性状的影响

利用兰州重离子加速器国家实验室(HIANLL)提供的100 MeV/u碳离子束对甜高粱品种BJ0601和BJ0602进行了不同剂量的辐照处理,并用SPSS13.0软件分析了碳离子束辐照剂量和甜高粱主要性状节间数、株高、茎粗、含糖量及单秆重的相关性,试验结果表明:不同的辐照剂量对甜高粱节间数、株高、茎粗、含糖量及单秆重产生了明显的影响,表现出不同程度的相关性.另外,早熟突变株BJ0601-1 M2代各节的平均含糖量高于BJ0601,说明碳离子束辐照可能引起甜高梁含糖量的提高.     

碳离子束辐照大豆当代诱变效应及褐皮突变体的初步研究

利用不同剂量碳离子束辐照大豆"合丰55"干种子,通过对表型、株高、分枝数及产量相关性状的考察以及DNA指纹图谱分析探索离子束辐照大豆的当代诱变效应。结果表明离子束诱变大豆M1代田间出现多种变异表型,辐照处理对M1代株高和分枝数有抑制作用,单株荚数、单株粒数、单株粒重及百粒重随着辐照剂量的增加呈现先降低后升高再降低的趋势,但这些变异与对照相比并未达到显著水平。大豆种子经辐照后M1代筛选到1株褐皮突变体,种皮颜色由黄色变为褐色,而且这种变异在M2代能够稳定遗传。运用随机扩增多态性(Random amplified polymorphic DNA,RAPD)技术对其DNA多态性进行研究发现,辐照后突变体DNA与对照相比扩增条带或增加或减少,相似性系数为0.9513。综合结果表明,碳离子束辐照对大豆当代产生了一定的诱变效应,不仅造成了农艺性状的变异,而且使DNA水平也发生了明显的变化。     

重离子束辐照诱变选育北冬虫夏草高产菌株

利用~(12)C~(6+)重离子束对北冬虫夏草出发菌株的菌悬液进行辐照诱变处理,采用平板分离法初筛变异菌株,通过培养子实体复筛高产菌株,并测定子实体的产量、多糖和虫草素含量。结果表明,在吸收剂量为150Gy时,出发菌株的致死率达到最高为82%;经过初筛和复筛,最终选育出3株高产子实体突变菌株G2、G5、G12,并经连续传代10次,测定子实体产量稳定在8.02~8.21 g/瓶,与出发菌株的子实体产量相比提高了52.47%~56.08%,且稳定性保持良好。研究表明,利用重离子束辐照诱变选育北冬虫夏草,可以获得高产子实体菌株。     

Assessment of DNA damage of Lewis lung carcinoma cells irradiated by carbon ions and X-rays using alkaline comet assay

DNA damage and cell reproductive death determined by alkaline comet and clonogenic survival assays were examined in Lewis lung carcinoma cells after exposure to 89.63 MeV/u carbon ion and 6 MV X-ray irradiations, respectively. Based on the survival data, Lewis lung carcinoma cells were verified to be more radiosensitive to the carbon ion beam than to the X-ray irradiation. The relative biological effectiveness (RBE) value, which was up to 1.77 at 10% survival level, showed that the DNA damage induced by the high-LET carbon ion beam was more remarkable than that induced by the low-LET X-ray irradiation. The dose response curves of “Tail DNA (%)” (TD) and “Olive tail moment” (OTM) for the carbon ion irradiation showed saturation beyond about 8 Gy. This behavior was not found in the X-ray curves. Additionally, the carbon ion beam produced a lower survival fraction at 2 Gy (SF2) value and a higher initial Olive tail moment 2 Gy (OTM2) than those for the X-ray irradiation. These results suggest that carbon ion beams having high-LET values produced more severe cell reproductive death and DNA damage in Lewis lung carcinoma cells in comparison with X-rays and comet assay might be an effective predictive test even combining with clonogenic assay to assess cellular radiosensitivity.     

重离子辐照微生物效应及诱变育种进展

重离子束作为一种高效的、典型的诱变辐射源广泛用于生物育种。不同质量数、电荷数和不同能量的重离子束作用于生物细胞有特殊的过程和作用,其先后经历物理、化学和生物学三个阶段,最终引发终点生物学效应,如辐射低剂量超敏感现象,活性氧代谢变化等。本文重点探讨重离子束辐照微生物体后出现的主要终点生物效应,以及近年来重离子辐照微生物诱变育种在工农业等方面取得的成果。     

纳秒级强脉冲电子束与Ar~＋离子束辐照作物种子后自由基产额的变化

应用多极板放电室产生的纳秒级强脉冲电子束与Ａｒ~＋离子束辐照蕃茄、黄瓜、辣椒和小麦的种子，分别测定辐照种子中的自由基产额，统计胚根根尖细胞中的染色体畸变频率和种子的萌发能力，藉以比较两种不同脉冲处理的辐照效果。实验发现：辐照处理时间的长短与自由基产额、染色体畸变率以及种子的萌发能力密切相关。辐照处理时间长，自由基产额高，染色体畸变率高，萌发生长能力低。四种作物种子的重复实验证明，电子脉冲的辐射效应明显强于Ａｒ~＋离子脉冲。     

唐菖蒲两变异株的同功酶及SDS-聚丙烯酰胺凝胶电泳的比较分析

为探讨电子束对唐菖蒲诱变的可行性及不同剂量电子束对其花性状的影响，用不同剂量电子束辐照唐菖蒲“江山美人”球茎，在40Gy和160Gy处理组分别得到了1株花色和花序变异株(M1’和M2’)。对这两变异株和对照以及其相应辐照剂量（40Gy和160Gy）处理组进行了研究。M1代植株叶片的过氧化物酶、过氧化氢酶、淀粉酶和酯酶4种同功酶电泳结果表明，40Gy和160Gy处理组的酶带与对照组的相同，变异株与对照组相比，酶带有所增减。基于同功酶谱带带型，使用SPSS11.5进行了聚类分析并得到聚类树状图。图中显示，供试材料被分成了3个组：对照组（包括40Gy和160Gy处理组与对照），M1’组和M2’组。SDS-聚丙烯酰胺凝胶电泳（SDS-PAGE）分析表明，蛋白表达明显被电子束辐照所抑制，但在这两个变异株中观测到3条特异表达的蛋白条带，分子量分别为96kDa、115.4kDa和137.2kDa，这些特异表达的蛋白可能与花色与花序的调控有关。由此表明，电子束辐照诱导花色与花形突变体是1种有效的途径。     

Preliminary results of proton beam characterization for a facility of broad beam in vitro cell irradiation

The interaction of charged particles with living matter needs to be well understood for medical applications. Particularly, it is useful to study how ion beams interact with tissues in terms of damage, dose released and dose rate.One way to evaluate the biological effects induced by an ion beam is by the irradiation of cultured cells at a particle accelerator, where cells can be exposed to different ions at different energies and flux.In this paper, we report the first results concerning the characterization of a broad proton beam obtained with our 2 MV tandem accelerator. For broad beam in vitro cell irradiation, the beam has to be stable over time, uniform over a ∼0.5 cm² surface, and a dose rate ranging from 0.1 to 10 Gy/min must be achievable. Results concerning the level of achievement of these requirements are presented in this paper for a 1 MeV proton beam.     

X射线辐射对小麦幼苗生长及一些抗氧化酶活性的影响

萌发４８ｈ的小麦幼苗用Ｘ射线处理，高剂量Ｘ射线（８Ｇｙ、１４Ｇｙ）可导致小麦幼苗生长受抑制，鲜重降低，在Ｘ射线照射后第２ｄ和第４ｄ测定幼苗内蛋白质含量、抗坏血酸过氧化物酶（ＡＳＡ－ＰＯＤ）、谷胱甘肽过氧化酶（ＧＳＨ－Ｐｘ）及谷胱甘肽巯基转移酶（ＧＳＨ－Ｔｓ）活性的变化。结果可知：Ｘ射线可引起小麦幼苗内蛋白质含量的下降，１４ＧｙＸ射线照射的样品低于８Ｇｙ照射的，照射后第４ｄ的蛋白质含量高于照射后第２ｄ的，说明Ｘ射线引起的损伤可随照射后的培养而有所恢复；高剂量Ｘ射线可引起小麦幼苗内一些抗氧化酶活性的升高，且随照射剂量的增加酶活性的升高也越明显，在照射后第４ｄ幼苗的ＡＳＡ－ＰＯＤ和ＧＳＨ－Ｐｘ活性高于照射后第２ｄ的值，ＧＳＨ－Ｔｓ活性略有下降。而低剂量（２Ｇｙ）照射与对照相比，上述指标变化不大，说明Ｘ射线处理后可通过诱导这些抗氧化酶活性的升高起到减轻伤害的作用。     

采用电离室测定重离子束的Bragg峰位

从探索定点定位诱变要求出发，提出了重离子束Ｂｒａｇｇ峰可作为一个有用手段，阐述了测量重离子束Ｂｒａｇｇ峰的原理和实验装置，采用一对电离室测定初始能量为５０ＭｅＶ／ｕ左右＾１４Ｎ＾７＋离子束在物质密度归一到小麦材料后的Ｂｒａｇｇ峰位。最终得到峰位深度约为４．８５ｎｍ，离子束的最大射程为５．５ｍｍ左右。