外源褪黑素对盐胁迫下盐肤木幼苗生长和生理特性的影响

Effects of exogenous melatonin on the growth and physiological characteristics of Rhus chinensis seedlings under salt stress

以3月龄盐肤木幼苗为材料,采用叶面喷施褪黑素的方法,设置褪黑素溶液(0μmol/L、50μmol/L、100μmol/L、150μmol/L)预处理和盐溶液(150 mmol/L NaCl)处理,研究外源褪黑素预处理对盐胁迫下盐肤木幼苗生长、渗透调节物质含量、抗氧化酶活性等生理指标以及胁迫相关基因表达水平的影响。结果表明:盐胁迫显著抑制了盐肤木幼苗的生长,其株高和相对含水量显著下降;各浓度褪黑素预处理下盐害症状减轻,叶片相对含水量和株高显著增加;盐胁迫下叶片积累可溶性糖、可溶性蛋白和脯氨酸,而100μmol/L褪黑素预处理能显著促进可溶性糖和脯氨酸含量的增加;盐胁迫处理显著提高了丙二醛(malondialdehyde,MDA)和H2O2含量,而褪黑素预处理显著诱导过氧化氢酶(catalase,CAT)、超氧化物歧化酶(superoxide dismutase,SOD)和抗坏血酸过氧化物酶(ascorbate peroxidase,APX)活性的增强,降低MDA和H2O2含量;外源褪黑素预处理显著增强了盐胁迫下盐肤木叶片中RcRBOHF、RcABF3、RcRD20和RcRD22胁迫响应基因的相对表达水平。该研究表明,褪黑素预处理能够提高盐肤木对盐胁迫的抗性,为利用褪黑素提高盐肤木的耐盐性提供了理论依据,并为选育优良的耐盐品种以及盐渍化土地的开发利用提供了有益的参考。

Our experiment utilized 3⁃month⁃old Rhus chinensis seedlings as materials.Exogenous melatonin was ap⁃plied via foliar spraying,with concentrations of 0µmol/L,50µmol/L,100µmol/L,and 150µmol/L.The seedlings were pretreated with the melatonin solutions before exposure to salt stress induced by a 150 mmol/L NaCl solution.The study investigated the effects of exogenous melatonin pretreatment on the growth,osmotic regulation substance content,antioxidant enzyme activity,and the expression levels of related genes in R.chinensis seedlings under salt stress condi⁃tions.The results indicated that:salt stress significantly inhibited the growth of R.chinensis seedlings,with a notable de⁃crease in plant height and relative water content;under various concentrations of melatonin pre⁃treatment,salt⁃induced symptoms were alleviated,and leaf relative water content and plant height showed a significant increase;under salt stress,the leaves accumulated soluble sugars,soluble proteins,and proline,while pre⁃treatment with 100µmol/L mela⁃tonin could significantly promote the increase in soluble sugar and proline content;salt stress significantly increased the contents of malondialdehyde(MDA)and hydrogen peroxide(H2O2),while melatonin pretreatment significantly induced the activity enhancement of catalase(CAT),superoxide dismutase(SOD),and ascorbate peroxidase(APX),and re⁃duced the contents of MDA and H2O2;exogenous melatonin pre⁃treatment significantly enhanced the relative expression levels of salt stress⁃responsive genes RcRBOHF,RcABF3,RcRD20,and RcRD22 in the leaves of salt⁃stressed R.chi⁃nensis seedlings.This study reveals that melatonin pretreatment enhances the salt resistance of R.chinensis,providing a theoretical basis for utilizing melatonin to improve its salt tolerance,and providing useful references for breeding excellent salt tolerant varieties and the development and utilization of saline soil.