摘要
[Objective] This study aimed to investigate the influence of Pb2＋ on the growth and development of broad bean roots. [Method] The effects of Pb2＋ solution of different concentrations on root length, color, bending and mitotic index frequency of root tip cells of broad bean were measured and observed. [Result] Pb2＋ at concentration lower than 20 mg/L promoted the growth and development of roots, increased the cell mitotic indexes, but had little influence on root color and bending. When the Pb2＋ concentration was higher than 20 mg/L, the root growth was inhibited; the root color gradually turned deeper; the roots bended, but the cell mitotic index was decreased. [Conclusion] Pb2＋ promoted the growth of broad bean at low concentration but inhibited the growth at high concentration, and the influence was related to Pb2＋ concentration and time.
[目的]研究不同浓度硝酸铅溶液对蚕豆种子根生长的影响。[方法]用6种不同浓度的Pb2+处理蚕豆根,每隔24h检测根的色泽、弯曲程度和根长,连续测量5次。随后将根尖固定、解离,利用改良的苯酚品红染液染色,在电子显微镜下观察根尖细胞的有丝分裂。[结果]Pb2+在浓度≤20mg/L时,能够促进蚕豆根的生长,细胞的有丝分裂指数增加,但对根的色泽和弯曲程度的影响不明显。当Pb2+浓度>20mg/L时,则抑制蚕豆根尖的生长,颜色逐渐加深,弯曲程度逐渐增加,细胞的有丝分裂指数减少。[结论]Pb2+对蚕豆生长的影响有两面性,低浓度时起促进作用,高浓度时有较明显的抑制作用。其影响的程度具有时间效应与浓度效应。
