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利用聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)技术及扩增产物序列分析方法,研究了经过4年不同植被恢复模式下呼伦贝尔沙地土壤固氮微生物的nifH基因多样性和群落结构的变化.结果表明:不同植被恢复模式间土壤固氮微生物群落组成差异显著.混播柠条+羊柴+冰草+披碱草模式(ACHE)下的土壤固氮微生物nifH基因多样性指数最高,其次为混播柠条+冰草(AC)、单播柠条(UC)、单播冰草(UA)和单播羊柴(UH)模式,对照(裸地)最低.除单播羊柴(UH)模式与对照的多样性指数差异不显著外,其余4种植被恢复模式均显著高于对照.单一恢复模式(UA、UH、UC)下,绝大多数土壤固氮微生物属于蓝藻门,结构比较单一;而混播模式(AC和ACHE)下,土壤固氮微生物组成发生明显变化,以变形菌门为主,还包含蓝藻门,其种类增加,多样性提高.不同植被恢复模式的速效磷(AP)、全磷(TP)、全氮(TN)和硝态氮(NO3--N)对固氮微生物区系的影响均达到显著水平,且AP、TP、TN和NO3--N之间均具有显著相关性.不同植被恢复模式下土壤固氮微生物区系组成的变化是不同理化因子之间相互关联、共同影响的结果.
Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and sequence analysis of amplified products were used to study the nifH gene diversity and community structure of soil-fixing nitrogen-fixing microorganisms in Hulunbuir sandy land after 4 years of vegetation restoration The results showed that there was significant difference in the composition of soil nitrogen fixing microbial community between different vegetation restoration patterns.The nifH gene diversity of soil nitrogen fixing microorganisms was the highest under the combination of Caragana korshinskii, The control (bare land) was the lowest in the combinations of Caragana korshinskii, AC, Unic, UA and UH, except unicast sheepwood (UH) The average recovery rates of the four vegetation types were significantly higher than those of the control under the single recovery model (UA, UH, UC). Most of the nitrogen fixation microbes in the soil belonged to the cyanobacteria, Under mixed-mode (AC and ACHE), the composition of soil nitrogen-fixing microorganisms changed obviously, mainly Proteobacteria, but also contained Cyanophyta, which increased in species and increased in diversity.Activities of AP in different vegetation restoration modes Phosphorus (TP), total nitrogen (TN) and nitrate nitrogen (NO3 - N) had significant effects on the colonization of nitrogen - fixing microbes, and there was a significant correlation between AP, TP, TN and NO3 - N. The changes of soil nitrogen fixing microbes in different vegetation restoration patterns were different Physical and chemical factors are interrelated, the result of common influence.