镉对豌豆根边缘细胞和早期幼根生长的毒害

Cadmium toxicity on Pea root border cells and young root growth

[目的]本文旨在探究镉(Cd^(2+))对豌豆根边缘细胞(RBC)和早期幼根的伤害。[方法]以豌豆为材料,采用根悬空培养的方法,研究了0、1、2、5μmol·L^(-1)Cd^(2+)对豌豆根边缘细胞和早期幼根生长的影响。[结果]镉对豌豆根边缘细胞和幼根产生胁迫伤害,且存在剂量效应。较高浓度的镉胁迫显著降低豌豆RBC的数量、诱导RBC凋亡。1、2、5μmol·L^(-1)Cd^(2+)胁迫,RBC数量分别比对照减少7.42%、15.42%和32.17%。RBC凋亡率分别比对照上升40.53%、160.61%和306.60%。镉胁迫诱导RBC黏胶层增厚,与对照比增加了55.40%、148.74%和248.21%;镉诱导豌豆幼根抗氧化酶POD、SOD、CAT活性升高,活性氧含量增加。1、2、5μmol·L^(-1)Cd^(2+)胁迫,幼根SOD活性分别比对照升高了39.71%、46.51%和53.91%,活性氧荧光强度分别比对照增加了12.66%、16.18%和44.37%;镉胁迫还引起豌豆幼根膜脂过氧化,细胞膜透性加大,1、2、5μmol·L^(-1)Cd^(2+)胁迫下MDA的含量分别比对照高140.67%、155.98%和161.24%,细胞膜透性分别比对照高11.22%、13.32%和31.81%。[结论]镉胁迫诱导豌豆RBC凋亡死亡,使根失去RBC的保护作用。镉进一步对根产生氧化胁迫伤害,最终抑制幼根的生长发育。

[Objective]The present study aimed to explore the toxicity of cadmium(Cd^(2+))on pea root border cells(RBCs)and early root growth.[Methods]Pea plants were used as materials,and a root suspension culture method was employed to investi-gate the effects of 0,1,2,and 5μmol·L^(-1)Cd^(2+)on the growth of young root and RBCs of pea.[Results]Cd^(2+)imposed stress and damaged on pea RBCs and young roots,exhibiting a dose-dependent effect.Higher concentrations of cadmium stress signif-icantly reduced the quantity of pea RBCs and induced RBC apoptosis.Under 1,2,and 5μmol·L^(-1)Cd^(2+)stress,the RBC quan-tity decreased by 7.42%,15.42%,and 32.17%,respectively,and the RBC apoptosis rate increased by 40.53%,160.61%,and 306.60%,respectively,compared to the control.Different cadmium stressed induced thickening of the adhesive layers of RBCs,which increased by 55.40%,148.74%,and 248.21%under 1,2,and 5μmol·L^(-1)Cd^(2+)stress,respectively,com-pared to control group.Cadmium also induced the higher activities of antioxidant enzymes such as POD,SOD,and CAT in pea young roots and increased reactive oxygen species levels.Under 1,2,and 5μmol·L^(-1)Cd^(2+)stress,SOD activity in young roots increased by 39.71%,46.51%and 53.91%,respectively,and the intensity of ROS fluorescence unit in young root in-creased by 12.66%,16.18%,and 44.37%,respectively.Cadmium stress also caused lipid peroxidation and increased cell membrane permeability in pea young roots.Under 1,2,5μmol·L^(-1)Cd^(2+)stress,MDA content increased by 140.67%,155.98%and 161.24%,respectively,and the cell membrane permeability increased by 11.22%,13.32%,and 31.81%,re-spectively.[Conclusion]These results suggested that cadmium stress induced apoptotic death of RBCs in pea,leading to the loss of their protective role in the roots.Cadmium further imposed oxidative stress damage on the roots,and eventually sup-pressed the growth and development of young roots.