Effects Of Pb～(2+),Ca～(2+),Pb～(2+)&Ca～(2+) On Cell Division Of Root Tips Of Vicia Faba

The effects of Pb²⁺ solution of different concentrations on seed germination, root length, mitotic index, micronucleus frequency and chromosomal aberration frequency of root tip cells of Vicia faba were studied. The results show that when seeds were treated with 1×10^-4～5 × 10^-4 mol/LPb²⁺ after 1 and 2 days, the germination percentage of seeds were lightly increased. But 3 and 4 days later, there was no difference between the seeds treated Pb²⁺ and the control test. So we can say that there was no siginaficant influence on seed germination when seeds were treated with 1×10^-4～5×10^-4mol/LPb²⁺. Pb²⁺ inhibited root growth of Vicia faba. The rate of root growth decreased successively with increasing Pb²⁺ concentration. The speed of the root growth per time unit also decreased successively or stopped with increasing treatment duration. The mitotic index decreased progressively with increasing Pb²⁺ concentration and treatment duration. The different concentrations of Pb²⁺ treatments could induce micronucli and chromosomal aberrations. The frequency of micronucleus and chromosomal aberration increased progressively withincreasing Pb2* concentration.The effects of Ca2+ solution of different concentrations on seed germination, root length, mitotic index, micronucleus frequency and chromosomal aberration frequency of root tip cells of Vicia faba were also studied. The results show that there was no effect on germination of seeds treated with lX10"3⁵X10"3mol/L Ca2\ The speed of germination decreased when the seeds treated with Ca2+ above 1X 10²mol/L, but at last there was no effect oh the rate of germination. The root length and mitotic index of root tip cells were increased after the treatment with Ca2+ at concentrations of lX10^3lX10²mol/L. When the root tips were treated with Ca2+ the afore-mentioned concentrations, the root length and mitotic index decreased, and even the growth of root and cell division were inhibited. There was no significant effect on micronucli and chromosomal aberrations when the root tips were treated with lX10"3⁴X10"2mol/L Ca2\At last, the effects of Pb2* & Ca2* solution of different concentrations on seed germination, root length, mitotic index, micronucleus frequency and chromosomal aberration frequency of root tip cells of Vicia faba were studied. The results show that as seeds were treated with different combinations Ca2+ & Pb2+,within 1X1O³¹X 10²mol/L Ca2+ levels, Ca2+ could decrease and remove the toxic action of Pb2*on root length, mitotic index,micronucleus frequency and chromosomal aberration frequency, and 5 X 10³ 1X 10²mol/L Ca2+ were more obvious. But with increasing Ca2+ concentration, Ca2* increased the toxic action of Pb2\ So this clearly indicated that Pb2+ poisoning could be alleviated by the presence of Ca2t of proper concentrations.