重铬酸钾对大蒜根尖细胞有丝分裂的影响

Effects of Potassium Dichromate(K_2Cr_2O_7) on the Mitosis of Root Tip Cells of Garlic

[目的]研究不同浓度的重铬酸钾溶液对大蒜根尖细胞有丝分裂的影响,为探讨铬离子对植物体的细胞毒性和遗传毒性提供参考。[方法]用12.5、25.0、50.0、100.0、200.0 mg/L重铬酸钾溶液分别处理大蒜根尖24、48、72 h,设蒸馏水为对照组;应用常规染色体压片技术,观察铬对大蒜根尖细胞有丝分裂指数和染色体畸变现象的影响;应用Tamhane多重比较进行差异性分析。[结果]当重铬酸钾的浓度为0～25.0 mg/L时,无论处理时间长短,大蒜根尖细胞有丝分裂指数均呈上升趋势;当重铬酸钾浓度大于25.0 mg/L时,有丝分裂指数则呈下降趋势。Tamhane多重比较表明:用不同浓度的重铬酸钾培养大蒜根尖24h,较高浓度(200.0 m∥L)与较低浓度(0、12.5、25.0 mg/L)处理组间存在极显著差异(P<0.01);培养大蒜根尖48 h,较高浓度(200.0 mg/L)与较低浓度(12.5、25.0、50.0 mg/L)处理组间存在极显著差异(P<0.01);培养大蒜根尖72 h,则大部分处理组间都存在极显著差异。各处理组均有染色体畸变现象。[结论]重铬酸钾对大蒜根尖细胞的毒害作用与其浓度和作用时间有关。在一定时间内,较低浓度的重铬酸钾促进大蒜根尖细胞的有丝分裂,较高浓度的重铬酸钾则抑制大蒜根尖细胞的有丝分裂,说明铬具有二重性。

[ Objective ] The research aimed to study the effects of potassium dichromate （ K2 Cr2O7 ） on the mitosis of root tip cells of garlic, and provide references for exploring the cytotoxic and genotoxic effects of chromium ions on plants. [ Method] Different concentration K2Cr2O7 solutions were used separately to treat the root tip of garlic for 24,48,72 h,and the control was distilled water. Conventional chromosome pressing technology was employed to observe the effects of chromium on mitotic index and chromosome aberration of root tip cells of garlic, and multiple comparison method Tamhane was employed to analyze the variations and differences. [ Result ] When the garlic root tip was treated with increasing concentration of K2 Cr2 O7 （0 -25.0 mg/L）, the mitotic index showed a increasing trend after treatment. However,when the concentration was higher than 25.0 mg/L,the mitotic index showed a decreasing trend. After treated 24 hours with various concentration of K2Cr2O7 ,Tamhane analysis showed that there were significant differences（P 〈0.01 ） in mitotic index between higher concentration（200.0 mg/L） treatment and lower concentration（0,12.5,25.0 mg/L） treatments. If treated for 48 hours, the differences were significant （ P 〈 0.01 ） between higher concentration （200.0 mg/L） treatment and lower concentration（ 12.5,25.0,50.0 mg/L） treatments. If treated for 72 hours,there were had significant differences among most treatments. Chromosome aberration existed in all treatments. [ Conclusion ] The results showed that the effects of K2Cr2O7 on the root tip cells of garlic was related to its concentration and time. In a certain time,the low concentration of K2Cr2O7 promoted the garlic root tip cellg mitosis,while the high concentration of K2Cr2O7 suppressed the garlic root tip cellg mitosis, h turned out K2Cr2O7 has two sides.