采用营养液培养法,研究了不同质量浓度 Pb-Cu 复合胁迫对马蔺[ Iris lactea Pall. var. chinensis ( Fisch.)Koidz.]幼苗 生 长 和 一 些 生 理 指 标 的 影 响。 结果表明, 处理 35 d 后, 在 50. 00 mg· L^-1 Pb 与 0. 10、 1. 00、 10. 00mg· L^-1 Cu 组成的 3 个复合胁迫处理组中,马蔺幼苗的株高、根长、地上部分和地下部分的鲜质量和干质量、叶片叶绿素 a(Chla)和叶绿素 b(Chlb)的含量均低于对照组(0. 00 mg· L^-1 Pb-0. 01 mg· L^-1 Cu),叶片 SOD 和 POD 活性则显著高于对照组;其中,50. 00 mg· L^-1 Pb-10. 00 mg· L^-1 Cu 处理组幼苗的株高、根长、Chla 和 Chlb 含量及 SOD 和POD 活性均最高,地上部分和地下部分的鲜质量和干质量也较高。 在 100. 00 mg· L^-1 Pb 与 0. 10、1. 00、10. 00mg· L^-1 Cu 组成的 3 个复合胁迫处理组中,100. 00 mg· L^-1 Pb-0. 10 mg· L^-1 Cu 处理组幼苗的株高、根长、地上部分和地下部分的鲜质量及干质量、Chla 和 Chlb 含量以及 SOD 和 POD 活性基本上都显著高于对照组,100. 00 mg· L-1Pb^-1. 00 mg· L^-1 Cu 处理组中幼苗的株高、地上部分鲜质量和干质量以及叶片的 SOD 和 POD 活性也均显著高于对照组;而在 100. 00 mg· L^-1 Pb-10. 00 mg· L^-1 Cu 处理组中幼苗的株高、根长以及地上部分和地下部分的鲜质量和干质量均最低,Chla 和 Chlb 的含量则显著低于对照组。 研究结果表明, 50. 00 mg· L^-1 Pb 与较高质量浓度 Cu(10. 00 mg· L^-1 )复合处理可在一定程度上缓解 Pb 胁迫对马蔺幼苗的伤害;而 100. 00 mg· L^-1 Pb 与较低质量浓度Cu(0. 10 mg· L^-1 )复合处理不但能减轻 Pb 胁迫对马蔺幼苗的伤害,还有一定的刺激生长的作用;但较高质量浓度的 Pb-Cu 复合胁迫则加剧了对马蔺幼苗的生长和生理代谢的抑制作用。

Effect of Pb-Cu combined stress with different concentrations on growth and some physiological indexes of Iris lactea Pall. var. chinensis ( Fisch.) Koidz. seedling was studied by nutrient solution culture method. The results show that in three combined stress treatments of 50. 00 mg· L^-1 Pb with 0. 10, 1. 00, 10. 00 mg· L^-1 Cu, seedling height, root length, fresh and dry weights of above- and under-ground parts, contents of chlorophyll a (Chla) and b (Chlb) in leaves all are lower, but activities of SOD and POD in leaves are significantly higher than those in the control (0. 00 mg· L^-1 Pb-0. 01 mg· L^-1 Cu) after treated for 35 d. In which, seedling height, root length, Chla and Chlb contents and activities of SOD and POD in treatment of 50. 00 mg· L^-1 Pb-10. 00 mg· L^-1 Cu all are the highest, and fresh and dry weights of above- and under-ground parts are also higher. In three combined stress treatments of 100. 00 mg· L^-1 Pb with 0. 10, 1. 00, 10. 00 mg· L^-1 Cu, seedling height, root length, fresh and dry weights of above- and under-ground parts, Chla and Chlb contents, activities of SOD and POD in treatment of 100. 00 mg· L^-1 Pb-0. 10 mg· L^-1 Cu generally are significantly higher than those in the control. And seedling height, fresh and dry weights of above-ground part, activities of SOD and POD in treatment of 100. 00 mg· L^-1 Pb-1. 00 mg· L^-1 Cu are all significantly higher than those in the control. But in treatment of 100. 00 mg· L^-1 Pb-10. 00 mg· L^-1 Cu, seedling height, root length, fresh and dry weights of above- and under-ground parts are all the lowest, Chla and Chlb contents are significantly lower than those in the control. It is concluded that the combined treatment of 50. 00 mg· L^-1 Pb with a relatively high concentration Cu (10. 00 mg· L^-1) can relieve the damage of Pb stress to I. lactea var. chinensis seedling to a certain extent, while the combined treatment of 100. 00 mg· L^-1 Pb with a relatively low concentration Cu (0. 10 mg· L^-1 ) not only reduces the damage but also has a stimulating effect on growth of seedling. But the combined treatment with a relatively high concentration Pb and Cu can aggravate the inhibition to growth and physiological metabolism of I. lactea var. chinensis seedling.