Abstract: To investigate the effects of root application of arbuscular mycorrhizal fungi（AMF）and strigolactone（SL） on the growth，chlorophyll fluorescence parameters，ion balance，and antioxidant enzyme system of Lolium perenne under salt alkali stress，five concentrations（0，0.2，0.4，0.8，1.6 μmol/L）of SL were applied to the roots of perennial ryegrass under 150 mmol/L salt alkali stress，inoculated with AMF Rhizophorus intrapradices or not vaccinated（CK），to explore the mechanisms by which both alleviate saline alkali stress in L.perenne.The results showed that root application of SL could promote AMF infection in L.perenne.The highest AMF infection rate was 62.7% at a concentration of 0.4 μmol/L of SL，and the maximum number of vesicles was 22.3.At a root application concentration of 0.4 μmol/L of SL，compared with CK，the total biomass and root shoot ratio of L.perenne treated with AMF increased by 18.7% and 13.2%，respectively，and the chlorophyll a and chlorophyll b contents increased by 21.1% and 13.4%，respectively；The maximum photochemical efficiency（Fv/Fm），potential activity（Fv/Fo），and actual photochemical quantum efficiency（Φ_PSⅡ） of PS Ⅱ were increased by 4.7%，8.7%，and 32.9%，respectively，while the non photochemical quenching coefficient（NPQ）decreased by 19.3%.The synergistic effect of AMF and SL could reduce the accumulation of Na⁺ in the upper and root systems of L.perenne，increase K⁺ content and K⁺/Na⁺ to improve plant ion balance. Under the treatment of SL concentration of 0.4 μmol/L，compared with CK，the relative expression levels of PAL and P5CS genes in L.perenne inoculated with AMF increased by 43.4% and 36.0%，PAL and P5CS activities increased by 26.8% and 26.7%，while the relative expression level of PPO gene decreased by 22.9% and PPO activity decreased by 15.6%.In addition，inoculation with AMF increased the soluble protein and proline content of L.perenne，while reduced the rate of superoxide anion production and hydrogen peroxide content.In summary，SL can promote the infection and development of AMF.Among them，the inoculation of AMF combined with root application of SL at a concentration of 0.4 μmol/L improves best the growth status of L.perenne，maintains chlorophyll fluorescence and antioxidant system，and significantly enhances salt alkali resistance.

Key words: Lolium perenne, Arbuscular mycorrhizal fungi, Strigolactone, Chlorophyll fluorescence, Ion balance, Antioxidant system

摘要： 为探究盐碱胁迫下根施丛枝菌根真菌（Arbuscular mycorrhizal fungi，AMF）和独脚金内酯（Strigolactone，SL）对多年生黑麦草（Lolium perenne）生长、叶绿素荧光参数、离子平衡以及抗氧化酶系统的影响，在150 mmol/L盐碱胁迫下对多年生黑麦草根施5个浓度（0、0.2、0.4、0.8、1.6 μmol/L）SL时，分别设接种AMF根内根孢囊霉（Rhizophagus intraradices）和不接种（CK）处理，以探明两者缓解多年生黑麦草盐碱胁迫的机制。结果表明，根施SL能促进AMF侵染多年生黑麦草，0.4 μmol/L SL处理下AMF侵染率最高（62.7%），泡囊数最多（22.3个）。与CK相比，根施0.4 μmol/L SL处理下接种AMF的多年生黑麦草总生物量和根冠比分别提高18.7%、13.2%，叶绿素a含量以及叶绿素b含量提高21.1%、13.4%；PSⅡ最大光化学量子效率（Fv/Fm）、PSⅡ潜在活性（Fv/Fo）以及PSⅡ实际光化学量子效率（Φ_PSⅡ）分别提高4.7%、8.7%、32.9%，非光化学淬灭系数（NPQ）下降19.3%。AMF和SL二者协同可降低多年生黑麦草地上部和根系中Na⁺含量，提高K+含量以及K⁺/Na⁺值，改善植物体离子平衡。与CK相比，0.4 μmol/L SL处理下接种AMF的多年生黑麦草苯丙氨酸解氨酶（PAL）、吡咯啉-5-羧酸还原酶（P5CS）基因的相对表达量分别提高43.4%、36.0%，PAL、P5CS活性分别提高26.8%、26.7%，多酚氧化酶（PPO）基因的相对表达量下降22.9%，PPO活性下降15.6%。接种AMF还提高了多年生黑麦草可溶性蛋白以及脯氨酸含量，降低了超氧阴离子自由基（O₂·^-）产生速率以及过氧化氢（H₂O₂）含量。综上，SL能促进AMF侵染发育，其中，接种AMF配合根施0.4 μmol/L SL改善多年生黑麦草生长状况、维持叶绿素荧光以及抗氧化系统，最终提高植物抗盐碱胁迫的效果最为显著。

关键词: 多年生黑麦草, 丛枝菌根真菌, 独脚金内酯, 叶绿素荧光, 离子平衡, 抗氧化系统