草地植物凋落物浸提液对根际微生物碳源利用的影响

Effects of Litter Extracts of Grassland Plants on the Utilization of Rhizosphere Microbial Carbon Sources

通过对白羊草(Bothriochloa ischaemum)、赖草(Leymus secalinus)和扁蓿豆(Melissilus ruthenicus)凋落物浸提液的化学组成,以及不同浓度浸提液处理下植物根际土壤微生物群落碳代谢的动态及多样性变化开展研究,研究发现,3种牧草凋落物水浸提液中以醇类、酯类和酮类化合物为主。不同浓度浸提液均可影响植物根际微生物的碳源(31种)平均颜色变化率(AWCD),随着培养时间增加,微生物代谢强度的差异越显著。培养末期,根际土壤AWCD值达到最高,其中0.10g/mL白羊草浸提液、0.05g/mL赖草浸提液及0.05g/mL扁蓿豆浸提液的效果最好,分别比对照提高55.35%、21.41%及534.85%。不同浓度浸提液还可影响碳源底物(6类)的利用强度及其多样性。综上所述,不同植物凋落物浸提液的化学成分存在差异,并且其浓度变化可对其根际微生物的碳代谢强度和多样性产生不同影响。

This study was conducted to determine the chemical composition of extracts from the litters of Bothriochloa ischaemum,Leymus secalinus and Melissilus ruthenicus,as well as the dynamic changes of carbon metabolism of soil microbial communities in the rhizosphere under different concentrations of extract treatments.The results showed that alcohols,esters and ketones were the main components in the water extracts of three types of forage litter.Different concentrations of extracts could affect the average well color development(AWCD)of 31 kinds of carbon sources of plant rhizosphere microorganisms.With the increase of incubation time,the difference in microbial metabolism became more significant.At the end of incubation,the value of AWCD of rhizosphere soil reached the highest,among which 0.10g/mL of B.ischaemum extract,0.05g/mL of L.secalinus extract,and 0.05g/mL of M.ruthenicus extract had the best effects,which were 55.35%,21.41%and 534.85%higher than the control,respectively.Different concentrations of above plant extracts can also affect the utilization intensity and diversity of carbon source substrates(6 types).In conclusion,the chemical components of different plant litter extracts were different,and changes in their concentration can have different effects on the carbon metabolism intensity and diversity of rhizosphere microorganisms.