盐胁迫下外生菌根真菌与根际有益细菌互作对杨树光合特性的影响

摘要

以美洲黑杨幼苗为对象,利用盆栽试验,在100mmol/L NaCl胁迫条件下研究单接种和双接种外生菌根真菌红绒盖牛肝菌(Xerocamus chrysenteron,简称Xc)、溶磷细菌恶臭假单胞菌(Pseudomonas putida,简称JW-SX1)和菌根辅助细菌蜡状芽孢杆菌(Bacillus cereus,简称HB59)对杨树幼苗的气体交换参数、叶绿素荧光和光响应曲线参数的影响.结果表明:盐胁迫下,接种Xc、JW-SX1及HB59的杨树幼苗净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)显著增强,且均显著高于对照,而单接JW-SX1和双接Xc+JW-SX1处理的胞间CO2浓度(Ci)低于对照,但与对照相比差异不显著;各接种处理显著增强了杨树的最大光化学效率(Fv/Fm),但处理之间差异不显著性;不同接种处理杨树的实际光化学效率(φPSⅡ)与对照(CK)差异不明显,其中接种HB59和Xc+JW-SX1处理分别高于对照14.36%和19.33%;同时接种处理还明显提高了宿主的最大光合速率(Pmax)、光饱和点(LSP)、表观有效利用效率(YAQ),降低了光补偿点(LCP)和暗呼吸速率(RD),且双接种菌根真菌Xc和JW-SX1处理效果更为明显.研究发现,外生菌根真菌、溶磷细菌和菌根辅助细菌可通过改善叶片叶绿素荧光和光合参数、光响应参数来减轻盐胁迫对宿主造成的伤害,从而提高杨树的耐盐性能力.%Populus deltoides seedlings inoculated with ectomycorrhizal Fungi (EMF) Xerocamus chrysenteron Xc, phosphate-solubilizing bacteria (PSB) Pseudomonas putida JW-SX1, mycorrhiza helper bacteria (MHB) Bacillus cereus HB59 to investigate the negative effects of salt stress on photosynthesis, chlorophyll fluorescence, photosynthesis to light intensity of seedling leaves.The results showed that the photosynthetic rate (Pn) ,the stomatal conductance (Gs) and transpiration rate (Tr) of P.deltoides seedlings inoculated with X.chrysenteron, P.putida and B.cereus were higher than those of the no-inoculation under salt stress and the differences between the various treatment were significant.But intercellular CO2 concentration (Ci) of P.deltoides seedlings inoculated with the JW-SX1 and dual inoculation of Xc with JW-SX1 were lower than that of control, but no significant difference compared to the control.The inoculation plants had maximum photochemical efficiency (Fv/Fm),without difference between the inoculated treatments.The actual photochemical efficiency (ΦPSⅡ) of the P.deltoides seedling inoculated had no significant differences with that of control,the actual photochemical efficiency (ΦPSⅡ) of the P.deltoides seedling inoculated with HB59 and double inoculated with Xc and JW-SX1 were higher than that of control, with 14.36％ and 19.33％ higher respectively.The inoculation plants had maximum net photosynthetic rate (Pmax), photosynthetic light saturation point (LSP), apparent quantum efficiency (YAQ), but the respiration rate and the photosynthetic light compensation point (LCP) are lower than that of control.Dual inoculation of Xc with JW-SX1 had obvious treatment effects.It was suggested that EMF,PSB and MHB could alleviate the salt damage on P.deltoides plants via improving their photosynthesis,chlorophyll fluorescence and photosynthesis to light intensity,and enhance the salt tolerance of P.deltoides plants.