钒在不同品种玉米幼苗中的亚细胞分布和动态变化

Subcellular Distribution and Dynamic Changes of Vanadium in Different Maize Varieties Seedlings

为了阐明V在玉米作物的富集特性和毒性机理,分析植物耐受性和亚细胞分布的内在联系,通过水培试验结合差速离心技术,研究了不同钒(V)质量浓度(0、5、15、30 mg·L^-1)胁迫4、8和12 d,两个品种甜玉米幼苗中V的亚细胞分布和动态变化。结果表明,不同品种玉米幼苗中V含量分布均为:根远大于茎叶,玉米幼苗吸收的V主要积累在根部,美甜糯一号根占总量的73.91%-98.65%,益甜608为63.75%-98.82%。两个品种玉米不同器官中,V的亚细胞分布主要以细胞壁(F1)和细胞可溶部分(F4)为主。美甜糯一号和益甜608玉米根中F1和F4的分配比例之和分别为76.25%-85.98%和72.35%-83.75%,茎叶中分别为71.94%-86.55%和75.84%-82.34%,在细胞核(F2)和线粒体叶绿体(F3)分配较少,说明细胞壁和细胞可溶性组分是V在玉米幼苗亚细胞中的主要结合位点。随着V胁迫浓度和胁迫时间的增加,不同品种玉米幼苗中,V在F1的分配比例增加,F4的分配比例减少,美甜糯一号和益甜608玉米根系的F1分配比在30.31%-62.15%和22.05%-57.11%,F4分配比在45.94%-23.82%和50.30%-26.64%。两种玉米对V胁迫表现出不同的抗性作用机理,美甜糯一号主要依靠细胞壁的沉积作用,而益甜608则是可溶性组分的区隔化起主要作用,细胞壁固持和液泡区隔化可能是玉米植物应对V胁迫的主要耐性机制。

In order to clarify the enrichment characteristics and toxicity mechanism of vanadium in sweet maize,and to analyze the intrinsic relationship between plant tolerance and subcellular distribution of vanadium,the subcellular distribution and dynamic changes of V in the two varieties of sweet maize seedlings were investigated by hydroponic test combined with differential centrifugation,with different vanadium(V)stress concentrations(0,5,15,30 mg·L^-1)for 4,8 and 12 days.The results showed that the distribution of V content in the two maize varieties was in sequence as follows:root>shoots,and the V absorbed by maize seedlings was mainly accumulated in the roots.It accounted for 73.91%-98.65%of the total in Meitian No.1,and 63.75%-98.82%in Yitian 608.The subcellular distribution of different organs of the two varieties of maize is mainly on cell wall(F1)and cell soluble components(F4).The distribution ratios of F1 and F4 was 76.25%-85.98%and 72.35%-83.75%,respectively in roots of Meitian No.1 and Yitian 608,71.94%-86.55%and 75.84%-82.34%in shoots.V is less distributed in the nucleus(F2)and mitochondrial chloroplast(F3),indicating that the cell wall(F1)and cell soluble components(F4)are the major binding sites of V in the sub-cells of maize seedlings.With increasing V concentration and stress time,the distribution proportion of V in F1 increased,but decreased in F4 for the two maize seedlings.They were 30.31%-62.15%and 22.05%-57.11%in F1,45.94%-23.82%and 50.30%-26.64%in F4,respectively,in the roots of Meitian No.1 and Yitian 608.Both maize showed different mechanisms under V stress:It is mainly cell wall retention in Meitian No.1,but partitioning of soluble components in Yishen 608.Cell wall retention and vacuolar partition may be the main tolerance mechanism of maize plants to V stress.