低温预处理对大蒜根尖细胞有丝分裂的影响

以大蒜根尖为材料，用常规压片方法制备染色体标本，研究不同低温预处理时间对根尖细胞有丝分裂的影响。结果表明：低温预处理12—42h能提高有丝分裂指数和中期分裂指数；6h和48h低温预处理会降低有丝分裂指数和中期分裂指数；低温预处理24～30h有利于根尖细胞的有丝分裂。     

蒲公英染色体核型分析

蒲公英的染色体核型国内一直未见报道 ,通过对其中期染色体形态的研究 ,得知其核型为 2n =2M 1 6m 4sm 4st=2 6。     

藏鸡的有丝分裂观察及染色体核型分析简

试验采用直接骨髓法制备林芝藏鸡染色体,通过显微自动成像系统观察藏鸡细胞有丝分裂全过程,包括间期、早前期、前期、中期、后期和末期,并分析了藏鸡有丝分裂过程染色体的形态变化规律。通过比较有丝分裂各期的形态,结果发现藏鸡有丝分裂的前期染色体伸展最长,碱基暴露最多,适合于做基因定位工作。同时进行了藏鸡染色体的核型分析,数据统计结果发现林芝地区藏鸡染色体数目2n=78,其中前5对染色体和性染色体中有3对中央着丝粒（m）染色体、1对近中着丝粒（sm）染色体、2对端着丝粒（t）染色体。与前人试验结果进行了比较,结果显示存在一定差异,原因仍需进一步试验验证。     

磷酰胺除草剂APM诱导洋葱根尖分生组织细胞异常有丝分裂和蛋白质组分变化

研究了不同浓度APM(4～6 μmol/L)和不同处理时间(4～6 h)对洋葱根尖细胞有丝分裂的影响.结果表明,当用5.6 μmol/L APM处理洋葱分生组织16 h后,中期细胞有丝分裂指数(Met.Ⅰ)从0.8(对照)分别提高至5.0、5.2.结果也同时表明,当APM浓度超过4 μmol/L时,严重影响细胞有丝分裂.在根尖细胞中,多极分裂细胞(尤其是3～4级),中期染色     

Effects of carbendazim on conidial germination and mitosis in germlings of Fusarium graminearum and Botrytis cinerea

The effects of carbendazim on carbendazim-sensitive (wild-type) and -resistant strains of Fusarium graminearum and Botrytis cinerea were compared. When treated with carbendazim, conidia and germlings of wild-type F. graminearum and B. cinerea germinated and grew to produce stunted, distorted, and abnormally branched germlings; in addition, distinct nuclei were replaced by irregularly distributed chromosome masses, and normal nuclear division was not observed. The CMI (chromosome mitosis index) values of wild-type strains rapidly increased within 60 min of treatment with carbendazim and then rapidly declined. Whereas the wild-type strains of the two fungi responded similarly, the carbendazim-resistant strains of F. graminearum and B. cinerea responded differently to carbendazim. The resistant strain of F. graminearum showed normal mitosis but produced significantly more branches and higher CMI values when treated with carbendazim than when untreated. In contrast, the carbendazim-resistant strain of B. cinerea exhibited normal morphology and mitosis after carbendazim treatment. The results suggest that the mechanism for carbendazim resistance in F. graminearum differs from that in B. cinerea and other fungi.     

空心莲子草水浸提液对蚕豆根尖细胞有丝分裂的影响

【目的】探讨空心莲子草水浸提液对蚕豆根尖细胞有丝分裂的影响,为研究空心莲子草的化感作用机制提供参考。【方法】用蒸馏水（CK）、0.025、0.050、0.075和0.1000 mg/mL空心莲子草地下部分及地上部分的水浸提液分别对蚕豆根尖进行处理,观察不同处理蚕豆根尖细胞有丝分裂的变化。【结果】与对照相比,随着空心莲子草水浸提液剂量的增加和作用时间的延长,其对蚕豆根尖细胞有丝分裂的抑制作用不断加强;空心莲子草地上部分水浸提液的抑制作用较地下部分更强。在胁迫72 h后,0.100 mg/mL空心莲子草地上部分水浸提液对蚕豆根尖细胞有丝分裂的抑制作用最强,有丝分裂指数仅1.14%。经空心莲子草水浸提液处理后,蚕豆根尖细胞细胞核出现异常,部分细胞出现微核,在0-48 h内,随着处理时间的延长,细胞微核率呈上升趋势;此外,蚕豆根尖细胞出现多种染色体畸变,如微核、染色体断片、滞后染色体、染色体桥等。【结论】空心莲子草水溶性化感物质对受体植物的遗传物质具有一定的遗传损伤效应。     

新疆苔藓植物的染色体观察

报道了进行苔藓植物细胞学研究的方法和５种新疆产的苔藓配子体生长点细胞有丝分裂中期的染色体数：（１）银藓Ａｎｏｍｏｂｒｙｕｍ ｆｉｌｉｆｏｒｍｅ（Ｄｉｃｋｓ．）Ｈｕｎｓｎ．,ｎ＝１０;（２）细叶真角藓Ｂｒｙｕｍ ｃａｐｉｌｌａｒｅ Ｌ．ｅｘＨｅｄｗ．,ｎ＝１０;（３）柔叶真藓Ｂｒｙｕｍ ｃｅｌｌｕｌａｒｅ Ｈｏｏｋ．,ｎ＝１０;（４）牛角藓Ｃｒａｔｏｍｅｕｒｏｎ ｆｉｌｉｃｉｎｕｍ（Ｈｅｄｗ．）Ｓ     

植物细胞有丝分裂实验教学材料的选择和培养

要满足大量学生实验的需要,与大多数材料相比,大蒜和蚕豆都是比较好的材料;二者相比较大蒜取得更方便,育根快捷且获得量大,根尖大小适合学生切出有效的制片体积;大蒜根尖培养液条件应为在水中加入复合水培养剂或适量氮磷钾营养剂控制电导率在0.6～1.8mS·cm-1;蚕豆用0.5%的双氧水浸泡涨满后发根,可明显有效抑制霉菌的生长。     

A proposed mechanism for loss of heterozygosity in rice hybrids

A phenomenon, loss of heterozygosity (LOH), was discovered in hybrid plants involving a selected plant (named AMR) of the Chinese rice cultivar ‘ZhongxinNo. 1’ as one parent. In these hybrids and some of their progenies, somatic variations were manifested by molecular genotypes and/or morphological phenotypes in vegetative parts of the same plant. Random amplified polymorphic DNA (RAPD) markers for the parents have been followed through the F₃ generation. RAPD markers were uniformly present or absent in all plants within some or all F₂ panicle rows derived from F₁ hybrids involving AMR. In contrast, RAPD markers segregated in the Mendelian manner for dominant markers in panicle rows derived from control hybrids. Certain F₂ panicle rows from F₁hybrids involving the special rice became fixed for all assayed RAPD markers. Genotype fixation was confirmed by molecular assays and field observations of the F₃ progenies. We propose a new biological mechanism, called ‘assortment mitosis,’ as being responsible for the observed phenomenon. The use of this mechanism in plant hybrids allows the development of uniform progenies as early as the F₂ generation. Therefore, the time required to obtain fixed non-parental type progenies for subsequent performance trials can be drastically shortened. Utilizing this mechanism in plant breeding represents a new approach and requires the modification of conventional plant breeding procedures. This revised version was published online in July 2006 with corrections to the Cover Date.