罗布麻染色体核型分析

采用染色体常规制片法,结合显微摄影技术对罗布麻染色体进行检测分析.结果表明:罗布麻染色体数为2 n=14,核型公式是 2 n=14＝6 M 2 m 4 sm(1 SAT) 2 T,全组染色体总长度为35.92 μm,长臂总长为 21.92 μm,核型不对称系数(AS.K%)为60.97 %,总体积为15.19 μm3.     

Alterations in flower and seed morphologies and meiotic chromosome behaviors of micropropagated rhubarb (Rheum rhaponticum L.) ‘PC49’

Variations in flower and seed and meiotic chromosome behaviors were investigated in micropropagated rhubarb (Rheum rhaponticum L.) ‘PC49’. The results showed that micropropagated plants had significantly higher variations in flower and seed morphologies and chromosome behaviors than plants derived from crown division. The results demonstrated that micropropagated plants grew 2–5 stamens, 8–13 stigmas, and 2–7 seed-wing, compared to 3 stamens, 9 stigmas and 3 (rarely 4) seed-wing in crown-derived plants. Additionally, alteration in chromosome behaviors (i.e. lagging and bridging) was observed only in micropropagated plants. All the results suggest that somaclonal variation may have been involved in micropropagated rhubarb ‘PC49’.     

陕西延安蒙古牛群体的染色体研究

分析了１５头（１０♂５♀）蒙古牛的核型，Ｃ带、Ｇ带和Ａｇ－ＮＯＲｓ．结果发现，蒙古牛的核型，Ｃ带和Ｇ带与普通牛（Ｂｏｓｔａｕｒｕｓ）相同，其公平核型为６０，ｘｙ母牛为６０，ｘｘ．ｙ染色体为一小的中着丝粒染色体，认为蒙古牛为普通牛型黄牛．观察统计了５９６个细胞的Ａｇ－ＮＯＲｓ数目，每细胞平均Ａｇ—ＮＯＲｓ数为５．８１８±０．５１３，变化范围为３～１０个．     

高丹草染色体诱变株系的细胞学及SSR分析

为明确2个高丹草（Sorghum-Sudangrass hybrid）染色体诱变株系SRSCD-01和SBSCD-02的细胞遗传学特征、育性表现及DNA水平上的遗传差异,以二倍体散穗高粱（Sorghum vulgare）×红壳苏丹草、散穗高粱×黑壳苏丹草2个杂交组合F₁为对照,对其花粉可育率、结实率、染色体配对构型及SSR指纹特征进行了分析。结果表明：2个变异株系SRSCD-01和SBSCD-02的PMCMⅠ染色体数目均为40,为四倍体（2n=4x=40）,配对构型分别为19.93Ⅱ+0.04Ⅰ和19.93Ⅱ+10.06Ⅰ,染色体配对行为规则。其花粉可育率分别为92.18%和91.85%,结实率分别为72.16%和73.43%,与其二倍体杂种F₁相近。试验筛选出条带清晰稳定的3对SSR引物STWAX-2,S184和ZCT339,对4个供试材料基因组DNA进行PCR扩增共得到44个SSR位点,多态性位点39个,多态性百分率高达88.64%。每对引物扩增的SSR指纹图均可以清晰地将4个供试材料区别开来,这为高丹草四倍体株系鉴定及下一步新品种育成登记和知识产权保护利用提供了分子依据。     

Cytogenetic effects of commercially formulated atrazine on the somatic cells of Allium cepa and Vicia faba

In the present study cytogenetic effects of atrazine herbicide, were examined on the root meristem cells of Allium cepa and Vicia faba. Test concentrations were chosen by calculating EC₅₀ values of formulated atrazine against both the test systems which determined to be 30 mg l⁻¹ for A. cepa and 35 mg l⁻¹ for V. faba, respectively. For cytogenetic effects root meristem cells of A. cepa were exposed to 15, 30 or 60 mg l⁻¹ whereas V. faba to 17.5, 35 or 70 mg l⁻¹ for 4 or 24 h. Roots exposed for 4 or 24 h, after sampling, were left in water for 24 h recovery and sampled at 24 h post-exposure. A set of onion bulbs or seedlings of V. faba exposed to DMSO (0.3%) was run parallel for negative control. Treatment of atrazine significantly and dose-dependently inhibited the mitotic index (MI) and induced micronucleus formation (MN) chromosome aberrations (CA) and mitotic aberrations (MA) in both the test systems at 4 or 24 h. Root meristem cells examined at 24 h post-exposure also revealed significant (p < 0.001) frequencies of MN, CA or MA despite considerable decline. Chromosome breaks and fragments were found to be major CA whereas C-metaphase, chromosome bridges and laggards were prevalent MA. Results of our study, indicate that atrazine may produce genotoxic effects in plants. Further, both the plant bioassays found to be sensitive indicators for the genotoxicity assessment as the outcome of majority of in vivo/in vitro mammalian tests are comparable.     

山西白羊草染色体核型分析

选用山西白羊草(Bothriochloa ischaemum)种子为材料,采用根尖压片法进行细胞染色体核型分析,为白羊草的种质资源利用及育种提供细胞学依据。观察统计了30个完整的中期分裂相确定染色体数目,并选其中5个分裂相进行核型分析。结果表明,白羊草染色体数为2n=40,核型公式为K(2n)=4x=40=34m+6sm,其中中部着丝粒染色体(m)为17对,近中部着丝粒染色体(sm)为3对,核型类型为1B。核型不对称系数为58.32%。     

蜜蜂蜂毒肽对小鼠染色体的保护作用

通过对实验组小鼠的存活时间、骨髓微核试验和染色体畸变试验来评估蜂毒肽的抗辐射作用。实验结果显示,蜂毒肽能有效提高受照射小鼠的平均存活时间和存活率,当照射前24小时给小鼠腹腔注射0.8mg/kg蜂毒肽时表现最佳,可以使小鼠的存活时间提高12.4天,存活率提高52.6%;小鼠的骨髓细胞微核率较空白对照组降低了8.09‰,下降率达64%;而受试组小鼠的染色体畸变率比对照组下降了17.1%。     

微型水仙染色体C—带带型研究

用引自日本的微型水仙进行了ＣｉｅｍｓａＣ＿带带型分析，发现其４２条染色体均显带，其中除１条长染色体只在长臂上显示端带外，其余４１条染色体两臂均显端带；５条长染色体除具两个端带外，还在长臂上显出一个近端带，其中１条长染色体除显示上述带型外，还在长臂上多显示一个中间带；６条短染色体除两臂均显端带外，还显示有着丝粒带。从带型的多型性判断，该水仙可能是一个在进化过程中曾发生过染色体结构变异、基数为７的六倍体；根据中国水仙染色体显带者较少，且基数主要为１０推断，它和微型水仙的亲缘关系较远；也表明，Ｃ—带分析技术在水仙染色体组型分析、分类及起源研究中可提供有用信息。     

欧洲山杨一号染色体显微分离、原位杂交分析及特异文库的构建

 以欧洲山杨( Populus tremula) 根尖细胞为材料, 采用玻璃针分离法, 通过显微操作器成功地分离出一号染色体。将分离到的单条染色体去蛋白、Sau3A酶切, 并在染色体DNA片段两端加上Sau3A人工接头, 进行两轮PCR扩增, 得到了200～3 000 bp的DNA扩增片段。以DIG2dUTP标记的欧洲山杨基因组DNA为探针进行Southern杂交, 结果表明显微分离出的染色体扩增片段与欧洲山杨基因组DNA同源,从而证明一号染色体DNA确实已被成功地扩增。以一号染色体第2轮PCR产物为探针进行荧光原位杂交,发现荧光信号较密集的分布于一号染色体, 但同时荧光信号也出现在其它染色体的着丝粒及端粒区域。对第2轮PCR产物进行克隆, 构建单条染色体DNA文库, 经分析, 该微克隆文库包含约3 ×10⁵ 个重组子。随机挑选160个重组子进行鉴定, 证明该文库的插入片段主要介于230～2 200 bp之间, 平均800 bp。该文库的构建为欧洲山杨1号染色体特异探针的筛选、遗传图谱的构建、重要基因的克隆等研究奠定了基础。