高温胁迫下丛枝菌根真菌对玉米光合特性的影响

Effect of Arbuscular Mycorrhizal Fungi on Photosynthetic Characteristics in Maize Plants under High Temperature Stress

利用盆栽试验研究了高温胁迫下丛枝菌根(AM)真菌对玉米生长、相对叶绿素含量、光合作用和叶绿素荧光的影响。结果表明,高温胁迫下,与非菌根玉米相比,菌根玉米具有效高的相对叶绿素含量。高温胁迫降低了所有玉米叶片净光合速率(Pn)、气孔导度(Gs)和蒸腾速率(Tr),增加了叶片胞间CO2浓度(Ci)。但接种丛枝菌根真菌的玉米Pn、Gs和Tr高于不接种植株,而Ci低于不接种植株。高温胁迫下,玉米叶片初始荧光(Fo)升高,而可变荧光(Fv)、最大荧光(Fm)、最大光化学效率(Fm/Fv)和潜在光化学效率(Fv/Fo)均下降。40℃条件下,菌根玉米叶片Fm和Fv高于非菌根植株。在所有温度处理中,接种真菌的玉米叶片Fm/Fv和Fv/Fo均高于不接种植株。结果表明,AM真菌能够通过提高叶绿素含量,改善植物叶片叶绿素荧光和光合作用,来减缓高温胁迫对玉米植株造成的伤害,提高植株耐受高温的能力。

The effect of arbuscular mycorhizal（AM）fungus Glomus etunicatum on characteristics of the growth,relative chlorophyll content,photosynthesis and chlorophyll fluorescence in maize（Zea mays L.）plants was studied in pot culture under high temperature stress.Under high temperature stress,mycorrhizal maize plants had higher relative chlorophyll content compared to non-mycorrhizal plants.High temperature stress decreased the photosynthetic rate（Pn）,stomatal conductance（Gs）and transpiration rate（Tr）of all maize plants,but increased the intercellular CO2 concentration（Ci）.The Pn,Gs and Tr of mycorrhizal maize leaves were higher than those of non-mycorrhizal plants,and the Ci of mycorrhizal plants was lower than that of non-mycorrhizal plants.Under high temperature stress,the primary fluorescence（Fo）was increased,and maximal fluorescence（Fm）,variable fluorescence（Fv）,maximum photochemical efficiency（Fv/Fm）and potential photochemical efficiency（Fv/Fo）were decreased regardless of mycorrhizal and non-mycorrhizal maize plants.Compared with non-mycorhizal plants,mycorrhizal plants had higher Fv/Fm and Fv/Fo at all temperature conditions,but Fv and Fm were higher only at 40 ℃ condition.The results showed that AM fungi is capable of alleviating the damage caused by high temperature stress on maize plants by means of improve leaf chlorophyll content,photosynthesis and chlorophyll fluorescence,and enhancing the high temperature tolerance ability of maize plants.