摘要
本研究以中苜一号紫花苜蓿(Medicago sativa L.cv.Zhongmu No.1)为试验材料,分别进行浓度为0、40、80 mmol/L的混合盐碱胁迫(NaCl、Na2SO4、Na2CO3 和NaHCO3 摩尔比为 1∶1∶1∶1,pH值为 9.3)处理,测定生长指标、生理指标及关键基因的表达水平,以期揭示其响应混合盐碱胁迫的机制.结果表明:随着混合盐碱胁迫程度的加剧,中苜一号紫花苜蓿幼苗的株高、光合速率、PSⅡ的有效量子产率和最大光化学量子产量均被显著抑制(P＜0.05),过氧化氢、超氧阴离子和丙二醛积累量逐渐增多,过氧化物酶活性、脯氨酸和可溶性糖含量均显著增加(P＜0.05);在80 mmol/L混合盐碱胁迫下,Na+转运蛋白的编码基因MsSOS1、MsNHX1和MsHKT1的表达量均显著提高(P＜0.05).综合分析表明,中苜一号紫花苜蓿可能主要通过以下途径响应混合盐碱胁迫:(1)高表达MsSOS1、MsNHX1和MsHKT1等Na+转运蛋白编码基因,促进Na+外排、液泡区隔化及转移,避免因Na+大量积累对植株造成离子毒害;(2)增强抗氧化酶活性,缓解由高pH值带来的氧化损伤.
Abstract
In this study,alfalfa(Medicago sativa cv.Zhongmu No.1)was used as experimental mate-rial under mixed saline-alkali stress at concentrations of 0,40,and 80 mmol/L(NaCl,Na2SO4,Na2CO3 and NaHCO3 molar ratios of 1∶1∶1∶1,pH 9.3).The growth indexes,physiological indexes and the expres-sion levels of key genes of the seedlings were measured,which provided a theoretical basis for revealing the mechanism of response to mixed saline-alkali stress.The results showed that the plant height,photosyn-thetic rate,effective quantum yield of PSⅡ photochemistry and the maximum quantum efficiency of PSⅡphotochemistry(Fv/Fm)in'Zhongmu No.1'alfalfa seedlings were significantly inhibited with the intensi-fication of mixed saline-alkali stress(P＜0.05).The accumulation of hydrogen peroxide,superoxide anion,and malondialdehyde gradually increased,while the activity of peroxidase,proline,and soluble sugar content all significantly increased(P＜0.05).Under 80 mmol/L mixed saline-alkali stress,the expression levels of Na+transporter encoding genes MsSOS1,MsNHX1,and MsHKT1 were significantly induced(P＜0.05).In summary,'Zhongmu No.1'alfalfa may mainly respond to mixed saline-alkali stress through the following pathways:(1)high expression of Na+transporter genes such as MsSOS1,MsNHX1,and MsHKT1,promoting Na+efflux,vacuolar segregation and transfer,and avoiding ion toxic-ity to plants caused by excessive accumulation of Na+;(2)enhance antioxidase activity and alleviate oxida-tive damage caused by high pH value.
基金项目
国家草业技术创新中心(筹)重大创新平台建设专项(CCPTZX2023B04)
国家林业和草原种质资源库(2005DKA21003)
NETL
NSTL
万方数据