AM真菌与氮交互作用对高粱根系侵染率及光合特性的影响

Effects of AM fungi and nitrogen interaction on root infection rate and photosynthetic characteristics of sorghum

【目的】研究AM真菌与氮添加对高粱根系侵染率及光合特性的影响,选择最适宜的氮肥和生物菌肥添加量。【方法】采用盆栽试验,设置0、150、300 kg/hm^(2)3个施氮水平(分别表示为N0、N1、N2),2个AM真菌处理(接菌处理表示为GM、不接菌处理表示为NGM),共6个处理,于高粱灌浆期调查根系侵染情况、测定光合指标。【结果】AM真菌处理和氮处理对高粱根系侵染率、叶片气孔导度、叶片蒸腾速率存在显著交互作用(P<0.05)。与未接菌处理相比,接菌处理后N0、N1、N2水平下的高粱叶片叶绿素含量分别提高10.80%、8.29%、8.78%(P<0.05),净同化速率分别提高8.86%、9.47%、4.03%(P<0.05);N0、N1水平下高粱叶片蒸腾速率分别提高24.85%、16.14%(P<0.05)。接菌处理下,与N0水平相比,N1、N2水平下高粱根系侵染率分别降低35.38%、30.77%(P<0.05),叶片气孔导度分别降低15.96%、19.54%(P<0.05)。相关性分析表明,添加AM真菌后,高粱根系侵染率与叶片叶绿素含量、气孔导度、净同化速率、蒸腾速率呈显著正相关(P<0.05)。【结论】接种AM真菌和增施氮肥150 kg/hm^(2)为降低高粱根系侵染率、提高光合特性的最佳处理。

【Objective】Study the effects of AM fungi and nitrogen addition on the root infection rate and photosynthetic characteristics of sorghum,to screen for the optimal amount of biological and nitrogen fertilizer.【Methods】Using pot experiment,6 treatments were set up including 0,150,and 300 kg/hm^(2)three nitrogen levels(N0,N1 and N2)and two AM fungal treatments(inoculation GM and non-inculation NGM).Sorghum root infection status and photosynthetic indexes at filling stage were investigated.【Results】AM fungi and nitrogen treatments had significant interactions(P<0.05)on sorghum root infection rate,leaf stomatal conductance,and leaf transpiration rate.Compared with the non-inoculation treatment,the sorghum leaf chlorophyll contents of inoculated N0,N1,and N2 levels increased by 10.80%,8.29%,and 8.78%(P<0.05),respectively,and the net assimilation rate increased by 8.86%,9.47%,and 4.03%(P<0.05),respectively.The sorghum leaf transpiration rates of N0 and N1 levels increased by 24.85%and 16.14%,respectively(P<0.05).Under the inoculation treatment,compared with N0 level,the sorghum root infection rates under N1 and N2 levels decreased by 35.38%and 30.77%,respectively(P<0.05),and the leaf stomatal conductance decreased by 15.96%and 19.54%,respectively(P<0.05).Correlation analysis showed that AM fungi addition resulted in significant positive correlation of sorghum root infection rate with leaf chlorophyll content,stomatal conductance,net assimilation rate,and transpiration rate(P<0.05).【Conclusion】AM fungi inoculation and 150 kg/hm^(2)of nitrogen fertilizer addition were the best treatments to reduce root infection rate and improve the photosynthetic characteristics of sorghum.