干旱胁迫对蒲公英渗透调节物质、酶保护系统及质膜水孔蛋白PIP2-3基因表达的影响

为了揭示蒲公英在干旱胁迫下渗透调节和酶保护系统的作用机理以及质膜水孔蛋白PIP2-3基因的表达特征,采用盆栽控水试验,研究了不同干旱胁迫RWC=(90±5)%、RWC=(75±5)%、RWC=(50±5)%下蒲公英渗透调节物质、酶保护系统以及质膜水孔蛋白基因的相关表达。结果表明:随着干旱胁迫的加重,蒲公英叶片中的可溶性糖、可溶性蛋白、游离脯氨酸的含量显著增加,超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)的活性显著提高,在轻度胁迫(MS)中呈持续上升的趋势,重度胁迫(SS)中则呈现先升高后下降的趋势(可溶性糖除外);质膜水孔蛋白PIP2-3基因的相对表达量上调,轻度胁迫(MS)显著高于重度胁迫(SS)。复水7 d后,渗透调节物质的积累以及SOD的含量下降,但仍显著高于CK,POD、CAT的含量以及质膜水孔蛋白PIP2-3基因的相对表达量恢复正常,说明在干旱胁迫条件下蒲公英通过增加渗透调节物质的积累,提高酶保护系统的活性来增强植株的抗逆性,上调质膜水孔蛋白基因的相对表达量来加强水分运输能力。

Effects of Drought Stress on Osmoregulation Substances,Enzyme Protection System and Expression of Plasma Membrane Hole Protein Gene PIP2-3 in Taraxacum mongolicum Hand.-Mazz

In order to reveal the mechanism of osmotic adjustment and enzyme protection system of dandelion and gene expression characteristics of plasma membrane aquaporin PIP2-3 under drought stress.Using pot water control experiments to study the effects of soil drought stress(RWC=(90±5)%,RWC=(75±5)%,RWC=(50±5)% on osmoregulation substances,enzyme protection system and expression of plasma membrane hole protein gene PIP2-3 in Taraxacum mongolicum Hand.-Mazz..Important findings:Under soil drought stress could significantly increase the dandelion leaf blade soluble sugar,soluble protein and free proline content,enhance the activity of SOD,POD and CAT,light stress show a tendency of gradually rising while severe stress showed a trend of first increase after decrease (except blade soluble sugar).Expression of plasma membrane hole protein gene PIP2-3 relative quantity increased significantly,and mild stress (MS) was higher than severe stress (SS).After restore water 7 d,the accumulation of osmotic regulation substances and the content of SOD decreased,but still significant in CK.The content of POD,CAT and plasma membrane hole protein gene PIP2-3 back to normal.This means that under drought stress,the dandelion can increase the accumulation of osmotic regulation substances and enhance the protective enzyme systems activities to improve plant resistance,increase plasma membrane hole relative expression of protein gene to strengthen water transport capacity.