利用蚕豆根观察植物的有丝分裂

洋葱因取材方便、发根条件简单、染色体数目少（2n=16）,因此常作为有丝分裂实验的首选材料。但由于菜农在采收洋葱后会喷洒一种植物保鲜剂——青鲜素（MH）,这就阻碍了洋葱的发根。根据笔者发现,春季,洋葱发根多,其他时间发根非常少,因此开展此实验,在取材时间上受到了限制,但若采用蚕豆的根尖,可避免此问题     

观察植物细胞有丝分裂的好材料—蚕豆侧根

“观察植物细胞有丝分裂”是人民教育出版社 1990年版高中《生物》4个必做实验之一。在教学实践中多数学生包括不少教师反映观察不到分裂相细胞 ,实验效果差一直困扰着实验课老师。究其原因 ,除操作技术掌握不当外 ,用于实验的材料——洋葱存在的不足可能是关键之处。为此 ,我们选用 10余种容易得到、培养方便的农作物种子作材料 ,以期筛选到适宜的实验材料。经试验摸索 ,发现蚕豆侧根是一种非常理想的观察植物细胞有丝分裂材料。现将其培养方法、操作等报道如下。1　蚕豆苗及侧根的培养选择无霉变、无虫害的蚕豆种子 ,加清水浸泡 2 4 h,取…     

硫酸铜对蚕豆根尖细胞有丝分裂的影响

以蚕豆根尖为材料,研究硫酸铜对蚕豆根尖细胞的遗传毒性效应。采用蚕豆根尖细胞的微核试验方法和染色体畸变试验方法,以不同浓度的硫酸铜为诱变剂,测定蚕豆根尖细胞的有丝分裂指数、微核率和染色体畸变率。结果表明:不同浓度的硫酸铜均能使蚕豆根尖细胞有丝分裂指数明显增加,即5个实验组的分裂指数均明显高于对照组(P<0.01或P<0.001);不同浓度的硫酸铜对蚕豆根尖细胞有丝分裂各期百分数的影响有异;能诱发较高频率的微核率,即在一定浓度范围内,其微核率随硫酸铜处理浓度的升高而增加,但随着硫酸铜浓度的进一步升高而呈下降趋势;硫酸铜还能诱导染色体产生多种类型的畸变,染色体畸变率随硫酸铜处理浓度的升高而增加,随着硫酸铜浓度的进一步升高而呈下降趋势,但均明显高于对照组(P<0.001)。结论是硫酸铜对蚕豆根尖细胞具有明显的遗传毒性效应。     

Cd2+对蚕豆根生长发育的影响

目的探明Cd^2＋对蚕豆根生长发育的影响及其规律,为培育耐Cd^2＋新品种提供一定的科学依据。方法以不同浓度的Cd^2＋处理蚕豆根,然后在不同时间检测其色泽、弯曲程度和长度变化,同时利用改良的苯酚品红染色,在显微镜下观察根尖细胞的有丝分裂。结果当Cd^2＋浓度〈10μmol／L时,它能促进根的生长和细胞有丝分裂,但对根的色泽和弯曲程度的影响不明显。在Cd^2＋的浓度〉10μmol／L后,则逐渐使根色泽加深,弯曲程度增大,细胞有丝分裂指数下降,生长减慢。结论Cd^2＋对蚕豆根生长发育有影响,其影响的程度与Cd^2＋的浓度和处理时间有关。     

一种洋葱快速生根的方法

洋葱因取材方便、发根条件简单、染色体数目少 (2n=16),因此常作为有丝分裂实验的首选材料。但在实际操作过程中,常会遇到洋葱发根难且发根少。笔者在实践中通过反复摸索,找到了一种洋葱快速发根的方法,即洋葱发根前放入冰箱的冷藏室中处理一段时期,再放入清水中发根。购买洋葱时,挑选个小、无腐烂且老根少的洋葱,发根前将洋葱放入冰箱中进行     

用大蒜做植物细胞有丝分裂实验的材料更好

植物细胞有丝分裂实验,一般都用洋葱作实验材料。可是我们在教学实践中发现洋葱作实验材料,效果不太好,为此我们改用大蒜作实验材料,大蒜比洋葱有以下几个优点: 1)生长快:在同等条件下,大蒜比洋葱生根快得多, 尤其是在温度偏低时更为明显。比如在15℃时,培养大蒜48 h,根尖可长出15 mm以上,而培养洋葱72 h根尖刚长出。     

镉离子对蚕豆根尖细胞分裂的影响

蚕豆根尖经不同浓度(0.1—10.0ppm)的CdCl_2溶液处理24～48小时后,根的生长受到不同程度的抑制.对根尖细胞分裂的毒害则表现为低毒的C-有丝分裂和高毒的染色体断裂、粘连和液化.此外,对Cd~( )的毒害机理进行了简略讨论.     

“观察植物细胞有丝分裂”的实验教学组织

1引言 “观察细胞有丝分裂并概述其过程”是高中生物学课程内容标准必修1“分子与细胞”模块中1．4“细胞的增殖”主题下的一项具体内容标准。“观察根尖分生组织的有丝分裂”是人教版普通高中课程标准教材必修1第6章“细胞的生命历程”第1节“细胞的增殖”中安排的涉及临时装片制作与显微镜观察类的实验。     

乙酸铜对蚕豆根尖细胞致畸效应

采用蚕豆根尖细胞的微核试验和染色体畸变试验方法,以不同浓度的乙酸铜为诱变剂,选择不同的处理时间,测定蚕豆根尖细胞的有丝分裂指数、微核率和染色体畸变率。结果表明：乙酸铜能诱发较高频率的微核率,处理6h、12h时微核率均随着乙酸铜浓度的升高而增加,具有明显的剂量效应;处理24h时在实验浓度范围内,其微核率随乙酸铜浓度的升高而增加,但高于一定浓度后反而呈下降趋势。不同浓度的乙酸铜在不同处理时间均使蚕豆根尖细胞有丝分裂指数增大。乙酸铜还能诱导蚕豆根尖细胞产生较高频率的染色体畸变,且产生多种类型的染色体畸变。因此,乙酸铜对蚕豆根尖细胞具有明显的致畸效应。     

蚕豆根尖细胞分裂同步化的方法

从事染色体研究工作,经常要求得到较高的细胞分裂指数,这就需要使细胞同步分裂,为此本文作者试图通过在动物细胞培养同步化过程中成功地应用的几种方法如低温、经基脉以及用于诱导植物染色体G带的放线菌素D,特别是首次在蚕豆上应用coffeine使细胞同步生长,通过实验得到结果,运用统计学处理说明这几种方法的优缺点。     

Crystalline structures in vicia faba chloroplasts

Summary Chloroplast stroma crystals similar to those reported by Perner (1962, 1963) but different from those described by other workers were demonstrat ed in Vicia faba chloroplasts. They were absent in chloroplasts isolated in no sucrose, 0.3 M sucrose or in situ material either fixed in the absence of sucrose of fixed in the presence of 0.3 M sucrose. They were present in chloroplasts isolated in 0.5 M sucrose and in situ chloroplasts fixed in the presence of 0.7 M sucrose.     

4NQO对蚕豆诱变效应的研究

本试验利用４ＮＱＯ为诱变剂处理蚕豆种子,研究其诱变效应。结果表明;４ＮＱＯ对蚕豆Ｍ１的发芽率、苗高及染色体有较强的影响,可诱发蚕豆Ｍ１细胞染色体畸变。畸变类型以微核为主,是一种有效的诱变剂。     

Isolation and characterization of polysomes and polyadenylated polysomal RNA from vicia faba meristematic root cells

Undegraded Vicia faba polysomes from meristematic root cells were obtained after homogenization in a medium of low ionic strength provided that the pH was equal to 9.0. By minimizing the shearing forces during the homogenization step, polysomes were obtained free of mitochondrial and nuclear contaminants, measured by differential spectrophotometry and CsCl gradient centrifugation respectively. Poly(A)-containing RNA was obtained by poly(U)-Sepharose chromatography and shown to be virtually free of rRNA and its average size was 13–15 S. Approximately 9% of the purified preparation was annealed by [3H]-poly(U). Sucrose gradient analysis under denaturing conditions showed that the poly(A)-containing RNA were non-degraded. This RNA was used to direct the synthesis of proteins in a heterologous cell-free system from wheat germ.     

The use of a micronucleus test to characterise adaptation ofVicia faba root tip cells to gamma-radiation

Pretreatment ofVicia faba root tip cells with low doses of⁶⁰Co γ-radiation can reduce the yield of micronuclei induced by a subsequent high dose of γ-radiation (1.5 Gy). This adaptation to γ-radiation possesses the following characteristics: (1) this phenomenon can be induced by an optimal range of low doses of γ-radiation applied acutely or fractionally; (2) the expression of this response seems to be transitory and depends on the time interval between adapting and challenging doses of γ-radiation. Communicated by T. GICHNER     

Hexavalent chromium disrupts mitosis by stabilizing microtubules in Lens culinaris root tip cells

Hexavalent chromium [Cr(VI)] is an accumulating environmental pollutant due to anthropogenic activities, toxic for humans, animals and plants. Therefore, the effects of Cr(VI) on dividing root cells of lentil (Lens culinaris) were investigated by tubulin immunofluorescence and DNA staining. In Cr(VI)‐treated roots, cell divisions were perturbed, the chromosomes formed irregular aggregations, multinucleate cells were produced and tubulin clusters were entrapped within the nuclei. All cell cycle‐specific microtubule (MT) arrays were affected, indicating a stabilizing effect of Cr(VI) on the MTs of L. culinaris. Besides, a time‐ and concentration‐dependent gradual increase of acetylated α‐tubulin, an indicator of MT stabilization, was observed in Cr(VI)‐treated roots by both immunofluorescence and western blotting. Evidence is also provided that reactive oxygen species (ROS) caused by Cr(VI), determined with the specific marker dichlorofluorescein, may be responsible for MT stabilization. Combined treatments with Cr(VI) and oryzalin revealed that Cr(VI) overcomes the depolymerizing ability of oryzalin, as it does experimentally introduced hydrogen peroxide, further supporting its stabilizing effect. In conclusion, it is suggested that the mitotic aberrations caused by Cr(VI) in L. culinaris root cells may be the result of MT stabilization rather than depolymerization, which consequently disturbs MT dynamics and their related functions.     

环磷酰胺诱发蚕豆体细胞遗传损伤的研究

利用蚕豆根尖研究环磷酰胺的遗传毒性效应, 结果表明:环磷酰胺(0.1~5.0 mg/mL)能够降低蚕豆根尖细胞有丝分裂指数, 使根尖细胞中具有微核、核出芽及核固缩的细胞明显增多, 并诱发染色体结构和行为异常, 产生染色体断片、滞后和桥。环磷酰胺处理组根尖中具有核固缩和微核的细胞数呈剂量依赖性增加, 且与作用时间呈正相关, 而分裂指数的降低也具有剂量和时间效应关系。研究结果表明, 低浓度长时间接触或高浓度短时间接触环磷酰胺均可产生遗传毒害, 因此, 有关的作业人员应注意防护。     

土荆芥挥发油对蚕豆根尖细胞的氧化损伤

土荆芥是一种入侵植物,对周围植物具有较强的化感潜力.采用培养皿土培法和培养皿滤纸法,分别模拟土荆芥挥发油通过淋溶和挥发两条途径对蚕豆根尖细胞膜脂过氧化和抗氧化酶活性的影响,并分析了挥发油诱导的细胞凋亡.结果表明:在培养皿土培和培养皿滤纸处理中,在处理前期(24 h),蚕豆根尖细胞超氧化物歧化酶、过氧化物酶和过氧化氢酶的活性均随土荆芥挥发油剂量的增大呈先升高后降低的趋势;根尖丙二醛含量随处理时间的延长和处理剂量的增大呈上升趋势.在处理中期(48 h)和处理后期(72 h),出现了典型的DNALadder条带,表明土荆芥挥发油可诱导蚕豆根尖细胞凋亡,并且随着挥发油剂量的增大和处理时间的延长,细胞凋亡程度加剧.土荆芥挥发油可以通过淋溶和挥发两种途径作用于周围植物,使受体植物的膜脂过氧化程度加剧,抗氧化酶活性受到抑制,诱导根尖细胞发生氧化损伤和细胞凋亡,从而抑制周围植物生长.而且,当挥发油以淋溶途径进入土壤时,蚕豆根尖抗氧化酶活性整体较高,DNA损伤程度较小,土荆芥挥发油通过挥发途径的化感作用大于通过淋溶途径.