摘要
水培条件下,以生菜(Lactuca sativa L.)种子为供试材料,研究0、5、10、20、40 mg/L镉(Cd2+)处理对生菜种子萌发及幼苗生理特性的影响。结果表明,低浓度Cd2+(5 mg/L)胁迫对生菜种子萌发具有明显的刺激作用,其中种子的发芽势较没有Cd2+胁迫处理的增加63.64%;发芽指数和活力指数均达到最大值,分别为40.30和119.29;而随着营养液中Cd2+浓度的进一步升高,种子的萌发表现出明显的抑制作用,发芽势、发芽率显著降低,发芽指数和活力指数逐步减小,且处理浓度越高种子发芽的抑制作用越明显。与没有Cd2+胁迫的处理相比,低浓度Cd2+(5 mg/L)胁迫对生菜幼苗生长也具有促进作用,根长、芽长、鲜质量增幅分别为16.04%、11.61%和11.59%,且生菜幼苗叶片中叶绿素a含量、叶绿素b含量以及叶绿素总量的水平均显著升高;当Cd2+浓度>10 mg/L时,生菜幼苗生长明显受到抑制,且叶绿素a含量、叶绿素b含量以及叶绿素总量的水平均显著降低。相比较而言,Cd2+胁迫对生菜幼苗根生长的抑制作用大于对地上部的抑制作用,Cd2+胁迫对生菜幼苗叶片叶绿素a的影响作用小于对叶绿素b的影响。此外生菜幼苗根组织中丙二醛含量随Cd2+浓度的增大而显著增加。
Effects of cadmium stress on seed germination and physiological characteristics of lettuce seedling were studied under five Cd^2+ concentrations (0,5,10,20,40 mg/L) with solution culture.The results showed that low Cd^2+ concentration stress (5 mg/L)significantly promoted the seed germination.The germination energy was increased by 63.64 % compared with the treatment with no Cd^2+.Both the germination index and the vigor index reached the maximum of 40.30 and 119.29,respectively.The seed germination was significantly inhibited with the increase of Cd^2+ concentration.The germination energy and the germination rate significantly decreased.The germination index and vigor index decreased gradually.The higher Cd^2+ concentration,the more obvious inhibition of seed germination.The growth of lettuce seedling was promoted over 5 mg/L Cd^2+ concentration compared with the treatment with no Cd^2+.The increasing amplitude of root length,bud length and fresh weight was in the order of 16.04%,11.61% and 11.59%.The contents of chlorophyll a,the chlorophyll b and the total chlorophyll increased significantly.With increase of Cd^2+ concentration (Cd^2+〉10 mg/L) in nutrient solution,the seedling growth was depressed greatly.The contents of chlorophyll a,the chlorophyll b and the total chlorophyll decreased dramatically.Cd^2+ had a stronger inhibiting effect on the growth of root than on the aerial part of seedling.The effects of Cd^2+ on chlorophyll was lower than that on chlorophyll b.The content of MDA of seedling roots increased significantly with the increase of Cd^2+ concentration.
出处
《湖北农业科学》
北大核心
2014年第20期4892-4896,共5页
Hubei Agricultural Sciences
基金
嘉兴市科技计划项目(2012AY1046)
嘉兴学院博士科研启动基金(70611027)