Study of synergistic effects among different environmental mutagens in the stamen hairs of Tradescantia

为了研究(1)烷基化剂的致突变性及其与X射线的致突变性协同作用，(2)烷基化剂之间的致突变性协同作用，(3)促突变性及其与X射线的互致突变性，(4)促突变性剂与烷基化剂之间的互致突变性。(1)在测定n -乙基-n -亚硝基脲（ENU）、硫酸二乙酯（DES）和1,2 -二溴乙烷（EDB）的诱变性基础上，进一步测定了n -乙基-n -亚硝基脲（EMS）、甲磺酸甲酯（MMS）、硫酸二甲基（DMS）和n -甲基-n -亚硝基脲（MNU）的诱变性。ENU、DES和EDB与X射线均具有协同作用，EMS、MMS和DMS也具有协同作用。(2) MNU与EMS仅为相加作用，而MMS和EMS具有协同作用。(3)测定了邻苯二胺（PDA）、n -亚硝基二甲胺（DMN）和EDB（也是一种双官能团烷基化剂）的致突变性，发现PDA和DMN在X射线照射后与X射线发生协同作用，而在X射线照射前与X射线发生拮抗作用，类似于之前研究的马来酰肼（MH）。然而，在PDA和DMN处理期间进行X射线照射时，PDA和DMN分别与X射线协同作用和相加作用，这表明它们被过氧化物酶激活所需的时间不同。(4) MH与EMS均呈拮抗作用。

This study was carried out in 1996 to 1998, using the stamen-hair system of Tradescantia clone BNL 4430, in order to investigate (1) the mutagenicities of alkylating agents and their mutagenic synergisms with X rays, (2) the mutagenic synergisms among alkylating agents, (3) the mutagenicities of promutagens and their mutagenic interactions with X rays, and (4) the mutagenic interactions between promutagens and alkylating agents.(1) The mutagenicities of N-ethyl-N-nitrosourea (ENU), diethyl sulfate (DES) and 1 , 2-dibromoethane (EDB) were determined, adding to those determined earlier for ethyl methanesulfonate (EMS), methyl methanesulfonate (MMS), dimethyl sulfate (DMS) and N-methyl-N-nitrosourea (MNU). ENU, DES and EDB all acted synergistically with X rays, as EMS, MMS and DMS did. (2) MNU acted merely additively with EMS, differing from MMS and EMS which acted synergistically. (3) The mutagenicities of o-phenylenediamine (PDA), N-nitrosodimethylamine (DMN) and EDB (also a bitunctional alkylating agent) were determined, and PDA and DMN were found to act synergistically with X rays when treated after exposing to X rays but antagonistically when treated before exposing to X rays, similarly to maleic hydrazide (MH) studed earlier. However, PDA and DMN acted synergistically and additively with X rays, respectively, when X-rayed during PDA and DMN treatments, indicating different time periods needed for their activations by peroxidase. (4) MH and EMS were found to act always antagonistically.