Ca~（2＋）对蚕豆种子萌发及根生长的影响

目的]研究不同浓度Ca2＋对蚕豆种子萌发、根长以及根尖细胞有丝分裂的影响。方法]用不同浓度的CaCl2溶液培养蚕豆种子,以蒸馏水培养为对照,统计不同处理下蚕豆种子萌发率;测量根长;根尖固定、染色、压片后进行观察,计算有丝分裂指数。结果]1.0～5.0 mmol/L Ca2＋对蚕豆种子萌发没有影响,当Ca2＋浓度超过10.0 mmol/L后,随着Ca2＋浓度的增高,蚕豆种子萌发速率降低,但对最终萌发率没有影响;1.0～10.0 mmol/L Ca2＋能不同程度地促进蚕豆根生长和细胞分裂,其中5.0 mmol/L Ca2＋处理的蚕豆根长和有丝分裂指数最高,之后随着Ca2＋浓度的继续增高,根生长和细胞分裂速度开始下降,甚至受到抑制。结论]Ca是植物体生长的必需元素,但Ca2＋浓度过高不利于植物生长发育,这为合理施用钙肥提供了科学依据。

Effects of Ca2+ on the Germination and Root Growth of Vicia faba

Objective]To study the effects of Ca2+ on seed germination,root length,and mitotic index of root tip cells of Vicia faba.Method] Vicia faba seeds were cultured with CaCl2 solutions at different concentration using distilled water treatment as CK.Germination rates were counted;root lengths were measured;and the root tips were fixed,dyed and squashed for microscopic examination,and mitotic index of its root tip cells were calculated.Result] There was no effect on germination of Vicia faba seeds treated with 1.0-5.0 mmol/L Ca2+.The speed of germination decreased when the seeds were treated with Ca2+ above 10.0 mmol/L,but at last there was no effect on the rate of germination.The root length and mitotic index of root tip cells were increased after the treatment with Ca2+ at concentration of 1.0-10.0 mmol/L.When the root tips were treated with Ca2+ at higher concentration,the root length and mitotic index decreased,and even the growth of root and cell division were inhibited.Conclusion] Ca2+ is an essential element for plants,but the application of excessive Ca2+ would generate toxicity.This study provides scientific evidence for rational application of calcium fertilizer.