低温胁迫下丛枝菌根真菌对玉米光合特性的影响

利用盆栽试验,在15℃和5℃低温胁迫下研究了丛枝菌根(AM)真菌对玉米生长、叶绿素含量、叶绿素荧光和光合作用的影响.结果表明:低温胁迫抑制了AM真菌的侵染;接种AM真菌的玉米地上部和地下部干物质量、相对叶绿素含量高于不接种植株.与非菌根玉米相比,菌根玉米具有较高的最大荧光(Fm)、可变荧光(Fv)、最大光化学效率(Fv/Fm)和潜在光化学效率(Fv/Fo)及较低的初始荧光(Fo),并且在5℃处理中差异显著.接种AM真菌使玉米叶片的净光合速率(Pn)和蒸腾速率(Tr)显著增强;低温胁迫下,菌根植株的气孔导度(Gs)显著高于非菌根植株;而胞间CO2浓度(Ci)显著低于非菌根植株.表明AM真菌可通过提高叶绿素含量及改善叶片叶绿素荧光和光合作用来减轻低温胁迫对玉米植株造成的伤害,提高玉米耐受低温的能力,进而提高玉米的生物量,促进玉米生长.

Effects of arbuscular mycorrhizal fungi on photosynthetic characteristics of maize under low temperature stress

A pot experiment was conducted to study the effects of arbuscular mycorrhizal (AM) fungus Glomus etunicatum on the growth, relative chlorophyll content, chlorophyll fluorescence, and photosynthesis of maize (Zea mays L.)plants under low temperature (15 ℃ and 5 ℃) stress. Low temperature decreased the AM root colonization. The shoot and root dry mass and the relative chlorophyll content of AM maize plants were higher than those of non AM maize plants. AM maize plants had higher maximal fluorescence (F_m), variable fluorescence (F_v),maximum photochemical efficiency (F_v/F_m), and potential photochemical efficiency (F_v/F_o),and lower primary fluorescence (F_o), compared with non-AM maize plants, and the differences were significant under 5 ℃ condition. The photosynthetic rate (P_n) and transpiration rate (T_r) of maize inoculated with G. etunicatum increased markedly. Under low temperature stress, the stomatal conductance(G_s) of AM maize plants was significantly higher than that of non AM maize plants, while the intercellular CO₂ concentration (C_i) of AM maize plants was notably lower than that of non AM maize plants. It wassuggested that AM fungi could alleviate the low temperature damage on maize plants via improving their leaf chlorophyll content, photosynthesis, and chlorophyll fluorescence, and enhance the low temperature tolerance of maize plants, resulting in the promotion of host plant growth and the increase of host plant biomass.