高锌胁迫对八棱海棠幼苗锌积累、分配与9个MTP基因表达的影响

为了研究高锌(Zn)胁迫下苹果砧木八棱海棠(Malus robusta Rehd.)Zn积累、分配及分子响应机制,以其8叶龄实生苗为试验材料,采用溶液培养法进行不同浓度(4、25、50、100μmol·L~(-1))Zn处理。试验结果表明:过量Zn胁迫严重影响植株生长及Zn的积累与分配,随着Zn处理浓度的升高,八棱海棠幼苗根系中Zn含量显著高于茎和叶;富集系数(BAF)的增大和转运系数(TF)的减小都说明Zn在根系中大量积累,以减轻对地上部的伤害。根据对9个MTP基因的相对表达量以及相关性分析,认为在高Zn胁迫下MTP基因的表达与植株内Zn含量有密切联系。MTP1在茎、叶中显著表达,具有组织特异性。MTPC2-like的相对表达量在4μmol·L~(-1) Zn处理下与根、茎、叶的Zn含量显著正相关,而在较高浓度Zn胁迫下相关性减弱,这说明MTP基因的表达具有浓度效应。

Effects of Zinc Stress on Accumulation and Distribution of Zinc and Expression of 9 MTP Genes in Malus robusta Seedlings

To investigate the responses of zinc (Zn) accumulation,distribution and molecular level to high Zn stress,the experimental materials,Malus robusta Rehd.seedlings with eight leaves,were treated with different Zn concentrations (4,25,50,100 μmol · L-1) by solution culture.The results showed that the excessive Zn stress seriously affected plant growth and the accumulation and distribution of Zn in apple seedlings.With the increase of Zn concentration,the content of Zn in roots was significantly higher than that in stems and leaves.The increase of bioaccumulation factor (BAF) and the decrease of translocation factor (TF) all indicated that Zn was accumulated in the roots to reduce the damage to the ground.According to the relative expression of 9 MTP genes,correlation analysis under high zinc stress,expression of MTP genes was closely associated with Zn content.The expression of MTP1 had tissue specificity that was significantly higher in stems and leaves than that in roots.The expression of MTPC2-like was significantly positively correlated with Zn content under the treatment of 4 μmol · L-1 Zn,but the correlation decreased under the high concentration of Zn stress,which indicated that the expression of MTP gene had effects of concentration.