Abstract: As an important turfgrass and forage grass， perennial ryegrass （Lolium perenne L.） is frequently constrained by high temperature stress during its growth. To explore the effects of PvPCF5 gene functional repression on heat tolerance of perennial ryegrass and its correlation with photosynthesis， wild-type （WT）， PvPCF5 functional repression （PvPCF5-SRDX）， and overexpression （PvPCF5-OX） plants were used as experimental materials and divided into 2 groups with or without heat acclimation， followed by heat stress treatment at 42℃ for different durations. The results showed that under high temperature stress， PvPCF5-SRDX plants exhibited superior physiological performance compared with WT ones， with significantly higher relative water content， and significantly lower electrolyte leakage and malondialdehyde content （P<0.05）. Meanwhile， the photosynthetic pigment contents of PvPCF5-SRDX plants were significantly higher than those of PvPCF5-OX ones （P<0.05）， accompanied by the highest net photosynthetic rate， stomatal conductance and transpiration rate， as well as the lowest intercellular CO₂ concentration. In conclusion， repression of PvPCF5 gene function can effectively improve the photosynthesis of perennial ryegrass and thereby significantly enhance its high temperature tolerance. This study provides a theoretical basis for breeding new heat-tolerant perennial ryegrass varieties.

Key words: High temperature, Perennial ryegrass, PCF5, Photosynthesis

摘要： 多年生黑麦草（Lolium perenne L.）作为一种重要的草坪草和牧草，其生长常受高温胁迫制约。为探究PvPCF5基因功能抑制对多年生黑麦草高温耐受性的影响及其与光合作用的关系，本研究以野生型植株（WT），PvPCF5功能抑制型（PvPCF5-SRDX）和过表达型（PvPCF5-OX）植株为材料，设置热锻炼与无热锻炼两组，并于42℃高温下处理不同时间。结果表明，在高温胁迫下，PvPCF5-SRDX的多年生黑麦草较WT表现出更优的生理状态：叶片相对含水量显著更高，电解质渗漏和丙二醛含量显著更低（P<0.05）。同时，PvPCF5-SRDX植株的光合色素含量显著高于PvPCF5-OX植株（P<0.05），并具有最高的净光合速率、气孔导度和蒸腾速率，以及最低的胞间二氧化碳浓度。综上所述，抑制PvPCF5基因功能可通过有效改善多年生黑麦草的光合作用，显著增强其对高温的耐受性。本研究为利用PCF5基因培育耐热型多年生黑麦草新品种提供了理论依据。

关键词: 高温胁迫, 多年生黑麦草, PCF5, 光合作用