‘寒富’苹果与其同源四倍体耐盐差异研究

Differences in Salt Tolerance Between the Diploid and Autotetraploid ‘Hanfu'Apple

以含有200 mmol·L-1 NaCl的1/2 Hoagland营养液处理‘寒富’二倍体苹果及其同源四倍体幼苗8 d,分别在处理0、2、4、6和8 d时进行叶片相关生理指标及水通道蛋白相关基因表达水平的测定,比较分析两者的耐盐性差异。结果表明:盐胁迫下四倍体的形态表现优于二倍体;四倍体和二倍体的叶片相对含水量一直在下降,二倍体下降幅度大于四倍体,丙二醛含量和脯氨酸的积累随胁迫时间的延长而增加,二倍体含量始终高于四倍体;NaCl处理8 d时,二倍体的叶片相对含水量比四倍体低8%,丙二醛含量比四倍体多4.466 nmol·g-1FW,脯氨酸含量为四倍体的1.18倍;盐胁迫下两者叶片中水通道相关蛋白基因Md PIP1;1、Md PIP2;1、Md TIP1;1和Md TIP2;1的表达量均出现先下降后上升趋势,且四倍体均高于二倍体,尤其在处理24 h时差异最显著。四倍体比二倍体具有更强的耐盐性,可能与盐胁迫下四倍体相关水通道蛋白基因表达水平较高有关。

Diploid and autotetraploid‘Hanfu'apple seedlings were treated with 200 mmol · L-1 NaCl for 8 d in 1/2 Hoagland nutrient solution,and determined the physiological characteristics and the expression of aquaporin-related genes in leaves at different treatment time. The results showed that the morpholoy of autotetraploid was better than diploid. The relative water content(RWC)kept decreasing in diploid and autotetraploid leaves over time,but the latter was higher than the former in the whole process. The content of proline and the accumulation of malondialdehyde(MDA)remained higher in the diploid than the autotetraploid,with both increasing over time. The RWC of leaves in autotetraploid was 8% higher than the diploid,the concentration of MDA in autotetraploid was 4.466 nmol · g-1FW lower than the diploid and the accumulation of Pro in diploid was about 1.18 fold that in the autotetraploid by 8 d after the imposition of stress. The tendences of Md PIP1;1,Md PIP2;1,Md TIP1;1,Md TIP2;1 all showed first decreasing then increasing trend,but the expression level in autotetraploid was higher,especially for 24 h treatment. This study found that the salt tolerance of autotetraploid was strongger than the diploid,which may be associated with the higher expression of aquaporin-related genes in autotetraploid under salt stress.