卤代阻燃剂和镉对旱稻种子萌发和生长的影响

Effects of halogenated flame retardants and cadmium on the germination and seedling growth of rice

为探讨卤代阻燃剂四溴双酚A(TBBPA)和得克隆(DP)与重金属镉污染土壤对旱稻种子萌发及生长的影响,选用原旱稻3号种子为模式材料,采用土壤染毒法进行种子萌发试验。结果表明DP、TBBPA和镉对原旱稻3号种子萌发和幼苗生长具有抑制作用,且存在明显的剂量-效应关系,DP、TBBPA和镉对根伸长的EC50分别为250.40、124.75 mg·kg^-1和133.41 mg·kg^-1,对芽伸长的EC50分别为645 265.53、244.52 mg·kg^-1和81.80 mg·kg^-1。卤代阻燃剂和镉增强了本品种种子根系的活力;TBBPA、DP、镉和三者复合污染处理脯氨酸分别比对照增加了51.03%、4.91%、42.52%和86.35%;TBBPA和DP具有促进植物可溶性蛋白质生成的作用,比对照分别增加了36.55%和5.86%,镉和复合污染均抑制了水稻幼苗可溶性蛋白质的生成,抑制率分别为28.86%和15.09%;镉具有抑制水稻体内可溶性糖生成的作用,抑制率为8.41%,而阻燃剂和复合污染具有促进水稻体内可溶性糖生成的作用。原旱稻3号幼苗对镉具有一定的积累作用,而两种阻燃剂在幼苗中残留量较低。研究表明DP、TBBPA和镉对原旱稻3号种子萌发和幼苗生长均具有一定的抑制作用,而幼苗通过调节细胞中脯氨酸、可溶性糖和可溶性蛋白质等物质的含量来提高对胁迫的耐受性。

The study investigated the effects of halogenated flame retardants[tetrabromobisphenol A(TBBPA)and dechlorane plus(DP)]and cadmium(Cd)on the germination and seedling growth of rice. A seed germination test was conducted using the soil application method with the seeds of No.3 Yuanhan rice. DP, TBBPA, and Cd inhibited the germination and seedling growth of rice, and there was a significant dose–effect relationship. The EC50(concentration for 50% of maximal effect)of DP, TBBPA, and Cd for root elongation was 250.40, 124.75 mg·kg^-1, and 133.41 mg·kg^-1, respectively, and that for shoot elongation was 645 265.53, 244.52 mg·kg^-1, and 81.80 mg·kg^-1, respectively.Halogenated flame retardants and Cd enhanced the root activity of rice. Compared with that in the control, the proline content in seedlings treated with TBBPA, DP, Cd, and combination of pollutants was increased by 51.03%, 4.91%, 42.52% and 86.35% compared with the control, respectively. The soluble protein content in rice seedlings treated with TBBPA and DP was increased by 36.55% and 5.86% compared with the control, respectively. Furthermore, the formation of soluble proteins in rice seedlings treated with Cd and combination of pollutants was inhibited by 28.86% and 15.09%, respectively. The soluble sugar content in rice seedlings was reduced(8.41%)by Cd, but increased by the flame retardants and combination of pollutants compared with the control. The seedlings of No. 3 Yuanhan rice accumulated Cd to a certain level, whereas the residual level of the two flame retardants was very low in the seedlings. The results indicated that DP, TBBPA,and Cd could inhibit the germination and seedling growth of No. 3 Yuanhan rice, and that the seedlings improve tolerance to pollutant stress by regulating the content of proline, soluble sugars, and soluble proteins in cells.