秋水仙素对洋葱根尖细胞的诱变效应

通过三种浓度的秋水仙素对洋葱根尖进行控时处理,结果发现,该药剂能使洋葱根尖细胞有丝分裂指数下降,促进洋葱根尖膨大,导致染色体加倍,并产生畸变细胞。     

硫酸铜对大蒜根尖细胞产生致畸效应

为了研究硫酸铜对大蒜(Allium sativum L.)根尖细胞的毒理学效应,本实验采用不同浓度的硫酸铜溶液,处理大蒜根尖20 h。通过有丝分裂染色体制片技术,观察大蒜根尖细胞有丝分裂情况。实验表明:大蒜根尖细胞有丝分裂指数受不同浓度的硫酸铜溶液影响,低浓度时分裂指数升高,高浓度时分裂指数降低。在一定浓度范围内,微核率随硫酸铜浓度的增加而升高,但高于一定浓度后,反而下降。此外,硫酸铜也诱导了染色体产生畸变。染色体畸变率随硫酸铜浓度的升高而增加,其畸变率均高于对照组。     

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。     

褐藻寡糖抗环磷酰胺诱导蚕豆根尖的细胞遗传毒性

采用蚕豆根尖细胞的微核试验和染色体畸变试验方法,测定不同浓度的褐藻寡糖对环磷酰胺(cyclophosphamide,CP)诱导的蚕豆根尖细胞的微核率、有丝分裂指数和染色体畸变率的影响。结果表明:褐藻寡糖能有效抑制环磷酰胺诱导的蚕豆根尖细胞微核的产生,即在一定浓度范围内,微核率随褐藻寡糖处理浓度的降低而减少,但低于一定浓度后反而呈上升趋势;不同浓度的褐藻寡糖均可使蚕豆根尖细胞有丝分裂指数增大;褐藻寡糖还能有效降低蚕豆根尖细胞染色体畸变率。因此,褐藻寡糖对蚕豆根尖细胞具有明显的诱抗活性和调节细胞分裂生长的效应。     

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。     

工业废水诱发的洋葱根尖细胞有丝分裂染色体畸变与微核的测定

用工业废水对洋葱根尖染毒,对其诱发的根尖细胞有丝分裂期染色体畸变、微术是定表明,处理样品有丝分裂过程中存在着大量的畸变类型,主要表现为多极分裂、染色体桥、染色体片段、滞后染色体以及微核的产生。     

不同预处理对鹰嘴豆根尖细胞染色体制片的影响

采用常规压片法,以鹰嘴豆根尖为材料,研究了秋水仙素、对二氯苯和8-羟基喹啉等预处理剂对积累鹰嘴豆根尖细胞中期分裂相的效果,并比较了不同预处理剂对中期染色体形态的影响。结果表明,3种预处理剂均能使根尖细胞的有丝分裂停留在中期,但0.1%的秋水仙素溶液进行预处理后的中期分裂相,染色体粗短,分散度不理想;0.006 mol/L的8-羟基喹啉溶液进行预处理后的鹰嘴豆中期染色体形态不清晰,边缘缺失;对二氯苯饱和水溶液4 h处理后的根尖细胞染色体背景清晰,缢痕明显,分散度较适宜,适合核型分析。     

重铬酸钾对蚕豆根尖细胞致畸效应的研究

以蚕豆根尖为材料,研究重铬酸钾对蚕豆根尖细胞的致畸效应。采用蚕豆根尖细胞的微核试验和染色体畸变试验方法,以不同浓度的重铬酸钾为诱变剂,测定蚕豆根尖细胞的微核率和染色体畸变率。结果表明:重铬酸钾能诱发较高频率的微核率,即在一定浓度范围内,其微核率随重铬酸钾处理浓度的升高而增加,但高于一定浓度后反而呈下降趋势;不同浓度的重铬酸钾均使蚕豆根尖细胞有丝分裂指数增大;重铬酸钾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。结论是重铬酸钾对蚕豆根尖细胞具有明显的致畸效应。     

盐胁迫浓度与大麦幼苗生长分裂和遗传损伤的相关性研究

研究盐胁迫浓度与大麦幼苗生长分裂的关系, 实验结果表明:大麦幼苗生长在一定浓度的NaCl 溶液中时, 幼苗生长抑制、叶绿素含量降低, 有丝分裂指数下降, 根尖分生区细胞中具有微核和染色体畸变的细胞明显增多。统计分析结果显示:幼苗的分裂指数、遗传损伤与盐浓度间有很好的线性关系, 有丝分裂指数与处理浓度间呈负相关(p < 0.01), 微核率、染色体畸变率两项指标与处理浓度间呈正相关(p < 0.01)。研究结果表明:大麦幼根有丝分裂指数、微核率及染色体畸变率可以作为监测环境NaCl 的定量指标。     

萘乙酸对洋葱根系铜胁迫的缓解作用

以洋葱Allium cepa为材料,采用水培方式,以3μmol·L^–1硫酸铜溶液为基础,外加不同浓度萘乙酸,对洋葱根尖进行处理,探究萘乙酸对铜胁迫的缓解作用。结果表明,3μmol·L^–1硫酸铜溶液处理对洋葱根系生长抑制明显;3μmol·L^–1硫酸铜和1μmol·L^–1萘乙酸处理表现出双抑制作用,并提升细胞SOD活性和MDA含量,根尖细胞有丝分裂指数明显下降,变异率增加。10^–2或10^–4μmol·L^–1萘乙酸溶液处理对洋葱根系生长促进明显。在3μmol·L^–1硫酸铜和10^–2μmol·L^–1萘乙酸共处理下,萘乙酸对洋葱根系铜胁迫有明显缓解作用,洋葱根系生长恢复到对照水平,与3μmol·L^–1硫酸铜溶液处理对比,显著提升根尖细胞有丝分裂指数,降低了畸变率、细胞SOD活性及MDA含量。说明适当浓度萘乙酸对根系铜胁迫有明显缓解作用。     

The effects of fungicide benomyl (benlate) on growth and mitosis in onion (Allium cepa L.) root apical meristem

In this study, the effects of benomyl, a systemic fungicide were investigated in the mitotic cell division in onion (Allium cepa) root tip cells during germination. For this aim, different concentrations (1, 2, 5, 10 and 20 mM) of benomyl solutions were used. All the concentrations used caused several abnormalities in mitotic cell divisions and the mitotic frequency in the onion root tip cells decreased as the concentration of benomyl solution increased. Based on our findings, it is reported that benomyl has some negative effects on mitotic divisions in onion root tip cells.     

Mitodepressive effects ofChelidonium alkaloids on root tip cells ofAllium cepa L

A comparison of the effects of a water extract of the fresh vegetation apex ofChelidonium majus L. var.majus, with those of berberine sulphate and of chelidonine hydrochloride is reported. The water extract of fresh stems and leaves ofChelidonium majus and the berberine sulphate solution had marked mitodepressive effects on onion root tip cells. Chelidonine hydrochloride had similar but less marked effects. On the basis of the results obtained it can be assumed that the most active group of substances with cytostatic effects, hindering the cells from entering mitosis, are protoberberine bases contained in the latex ofChelidonium majus. Within the range of the investigated concentrations the extract of fresh stems and leaves was less toxic for the cells than berberine sulphate. The data ascertained provide evidence that the mechanism of the cytostatic action of chelidonine, of berberine, as well as of the extract of fresh stems and leaves ofChelidonium, majus differs from the mechanism of the action of colchicine. Of the testedChelidonium alkaloids only chelidonine produced a partial inactivation of the mitotic spindle.     

三氧化二砷（As2O3）对蚕豆根尖毒性效应的细胞遗传学研究

本文以蚕豆根尖为材料,研究不同浓度As2O3在不同的处理时间内对蚕豆胚根根尖的细胞遗传学毒性效应。结果表明：不同浓度的As2O3在不同处理时间内均能诱发较高的微核率和染色体畸变率,并能有效地积累中期分裂相,阻止其进入后期与末期。结论是As2O3对蚕豆根尖细胞具有明显的细胞遗传学毒性效应,并具有积累有丝分裂中期细胞的效应。 Abstract:The cytogenetic toxic effects of different concentration of As2O3 within different time on the cell of Vicia Faba root tip were studied.The results indicate that the different concentrations of As2O3 can induce high frequency of micronucleus and chromosome aberration.Besides,it can accumulate the metaphases in mitosis efficiently and prevent the cells from continuing their cell cycle.It shows that As2O3 has marked cytogenetic toxic effect on the root tip cells of Vicia Faba,and effect of accumulating the metaphases in mitosis.     

Autoradiographic Examination of Meristems of Intact Boron-deficient Squash Roots Treated with Tritiated Thymidine

Intact roots of boron-sufficient squash (Cucurbita pepo L.) plants, plants entering boron deficiency, and plants recovering from boron deficiency were exposed to tritiated thymidine at the end of the treatment period to label the replicating DNA of root tip cells. Using histological sections, autoradiographs of intact root meristems were prepared. The labeling pattern in +B root tips revealed the presence of a well defined quiescent center. The ability of root tip cells to incorporate label is correlated with the total root elongation during the −B treatment period. A greater amount of total root elongation during boron deficiency and recovery reflects the fact that root tip cells have retained their ability to synthesize DNA and enter mitosis for a longer time. In roots recovering from boron deficiency, cells of the quiescent center were seen to play no part in the recovery process in roots treated for as long as 20 hours in a −B nutrient solution. They were inactive before, during, and after the −B treatment. Cessation of mitosis occurs as early as 6.5 hours after boron is withheld from the nutrient solution while DNA synthesis can occur for as long as 20 hours after withholding boron. It was concluded that boron is essential for continued DNA synthesis and mitotic activity. The absence of boron results in the cessation of mitosis and DNA synthesis within 20 hours from the time boron is withheld.     

草甘膦和百草枯对毛桃幼苗根系形态及地上部生长的影响

以砧木毛桃幼苗为研究对象,通过土施草甘膦和百草枯研究2种桃园常用除草剂对毛桃营养生长、根系结构、根尖细胞分裂、叶片光合特性等的影响,为除草剂在桃生产中的安全使用提供科学依据。结果表明: 草甘膦处理显著抑制毛桃地上部和根生长,与对照相比,株高降低31.5%,总根系长度、总根表面积、总根体积和总根尖数分别降低了39.5%、39.5%、49.8%和44.6%,而百草枯处理以上指标与对照差异均不显著;草甘膦和百草枯处理后毛桃根尖细胞有丝分裂指数分别降低38.0%和35.9%,且草甘膦处理分裂中期细胞数占分裂细胞总数的比例显著低于对照和百草枯处理;毛桃根尖细胞对2种除草剂响应迅速,从处理第2天开始根尖细胞电解质渗漏率始终显著高于对照。叶片细胞电解质渗漏率则从处理5 d后开始显著升高,且草甘膦处理出现幼叶基部变黄并向叶尖蔓延,同时部分叶尖逐渐焦枯的现象;2种除草剂处理导致毛桃叶片净光合速率、气孔导度、蒸腾速率有不同程度的降低,其中草甘膦处理下降更明显。综上,使用草甘膦和百草枯均会降低毛桃幼苗根尖细胞分裂指数,提高根尖细胞电解质渗透率,总体降低叶片净光合速率。草甘膦对毛桃营养生长、叶片光合作用影响更大,而且会造成幼叶变黄、叶尖焦枯等现象。     

Effects of kinetin on cell division,with special reference to initiation and duration of mitosis

Summary Kinetin, a substance recently isolated from DNA preparations, produced polyploidy and various forms of pycnosis in meristematic cells of growing onion roots.Non-toxic concentrations of the substance changed the mean durations of mitosis and interphase as well as the relative durations of prophase, metaphase, anaphase, and telophase in onion root tip cells. It was inferred that the time of the mitotic period was increased, while the duration of interphase was decreased by addition of kinetin to the medium.The phenomena observed are interpreted to be due to (a) a trigger action of kinetin some time during interphase, resulting in premature prophase initiation, and (b) effects of kinetin on the coiling cycle of the chromosomes.It is suggested that the activity of kinetin may in some way be associated with the RNA metabolism of the nucleus.     

镉对蒜根生长的毒害及抗坏血酸、铁盐的解毒效应

蒜鳞茎在不同浓度的Ｃｄ溶液中处理２４－４８ｈ,观察到随着Ｃｄ浓度的递增或培养时间的延长,根的增长速率递减或停止,根尖细胞有丝分裂指数下降,分裂细胞异常率增 裂细胞异常主要表现为低毒时,染色体的Ｃ－有丝分裂,染色体桥以及高毒时,染色体粘连,断裂,核解体等。     

紫茎泽兰叶片水浸液对蚕豆的化感效应

外来入侵植物可以通过淋溶、自然挥发、根系分泌和植株凋落物分解等途径向周围环境释放化感物质,抑制伴生植物的生长、发育。该研究以不同浓度紫茎泽兰(Eupatorium adenophorum)叶片水浸液处理蚕豆(Vicia faba)种子,研究紫茎泽兰叶片水浸液对蚕豆根尖细胞微核、染色体畸变、细胞凋亡、蚕豆幼苗叶片叶绿素和N含量、光合生理特性、生物量的影响。结果表明:(1)紫茎泽兰叶片水浸液处理显著抑制蚕豆根尖的伸长和细胞的有丝分裂,并诱导蚕豆根尖细胞染色体畸变和细胞微核的产生,有丝分裂指数随着叶片水浸液浓度增加而减小,根尖细胞微核率随叶片水浸液浓度增加而增大,高浓度叶片水浸液处理对蚕豆根尖细胞的凋亡及坏死有明显影响。(2)紫茎泽兰叶片水浸液处理引起蚕豆幼苗叶片的叶绿素和N含量显著降低,并导致蚕豆幼苗最大净光合速率和生物量的显著下降。总之,紫茎泽兰叶片水浸液可能引起蚕豆根尖的氧化损伤和抑制根尖的伸长,且叶片水浸液的抑制作用呈现一定的剂量效应。紫茎泽兰叶片水浸液对蚕豆根尖的损伤和抑制作用可能影响了植株对氮素的吸收,进而对蚕豆幼苗光合生理表现以及生物量积累产生显著负面效应。     

Cyanamide mode of action during inhibition of onion (Allium cepa L.) root growth involves disturbances in cell division and cytoskeleton formation

Cyanamide is an allelochemical produced by hairy vetch (Vicia villosa Roth.). Its phyotoxic effect on plant growth was examined on roots of onion (Allium cepa L.) bulbs. Water solution of cyanamide (2-10 mM) restricted growth of onion roots in a dose-dependent manner. Treatment of onion roots with cyanamide resulted in a decrease in root growth rate accompanied by a decrease in accumulation of fresh and dry weight. The inhibitory effect of cyanamide was reversed by its removal from the environment, but full recovery was observed only for tissue treated with this chemical at low concentration (2-6 mM). Cytological observations of root tip cells suggest that disturbances in cell division may explain the strong cyanamide allelopathic activity. Moreover, in cyanamide-treated onion the following changes were detected: reduction of mitotic cells, inhibition of proliferation of meristematic cells and cell cycle, and modifications of cytoskeleton arrangement.     

The insensitivity of Vinca rosea to vinblastine

Root tip mitosis in both Vinca rosea and the chosen control Lepidium sativum is susceptible to the effects of colchicine at and above 5×10^–4 M. — Root tip mitosis in L. sativum is susceptible to the effects of vinblastine at concentrations equal to and greater than 10^–4 M, while root tip mitosis in V. rosea, the plant which is the source of vinblastine, is unaffected by exogenously-applied VBL at concentrations up to and including 10^–2 M. — The possible mechanisms by which this resistance of V. rosea to vinblastine might be conferred are discussed.