城市绿化植物-凋落物-土壤系统碳氮磷化学计量特征研究

摘要

以福建福州市常见的15种乔木、灌木和草本绿化植物为对象,连续2年取样测定了这些植物、凋落物、立地土壤、土壤微生物量C、N、P含量,探讨城市绿化植物-凋落物-土壤系统生态化学计量特征,为中国城市绿化植物的生态功能恢复与植被重建提供科学依据.结果表明:(1)绿化植物不同器官C、N、P含量均表现为草本>灌木>乔木、C含量>N含量>P含量、叶>茎>根,呈现出叶的富集作用;绿化植物各器官化学计量比(C/N、C/P、N/P)也表现出基本一致的乔木>灌木>草本的变化趋势;各绿化植物对N的再吸收率极显著高于对P的再吸收率(P<0.01),绿化植物N和P再吸收率表现为乔木>灌木>草本,不同绿化植物对N的再吸收率差异均显著(P<0.05),对P的再吸收率差异均不显著(P>0.05).(2)绿化植物凋落物C、N、P含量基本表现为草本>灌木>乔木,其中不同绿化植物凋落物P含量差异不显著.(3)绿化植物立地土壤C、N、P含量表现为草本>灌木>乔木,但其N/P差异不显著;土壤微生物量C、N、P含量基本表现为草本>灌木>乔木,其相应的C/N、C/P、N/P差异均不显著.(4)植物-土壤-凋落物-土壤微生物量(C、N、P)均随着生长季温度的升高而降低,随着年降水量的增加而升高,P素的回归系数绝对值明显低于C素和N素;植物-凋落物-土壤的C与N含量、N与P含量、C/P与N/P、以及土壤和植物的C/N与N/P之间均呈显著正相关关系,而凋落物的C/N与N/P之间呈显著负相关关系;典范对应CCA排序中,植物高度、冠幅、茎粗、比叶面积和叶面积指数对植物-凋落物-土壤-土壤微生物量C、N、P含量和C/N、C/P和N/P具有较大影响作用,其中高度、冠幅和茎粗与比叶面积和叶面积指数呈负相关关系,与凋落物-土壤-土壤微生物量C、N、P含量呈负相关关系,与植物C、N、P含量呈正相关关系;而凋落物-土壤-土壤微生物量C、N、P含量与其C/N、C/P和N/P均具有一定的正相关关系.%This paper discusses the ecological stoichiometric characteristics of plants,litter and soils of ur-ban green plants.The results were as follows:(1 )the order of average contents of C,N and P in green plants from high to low as follows arbors>shrubs> herbs,and the contents of C,N and P in same orna-mental plants of different organs was differ,which showed leaf>stem>root.(2)The nitrogen absorptivi-ty was significantly higher than that of phosphorus absorptivity of urban green plants (P<0.01),and the nitrogen and phosphorus absorptivity showed arbors>shrubs> herbs,which the nitrogen absorptivity of arbors,shrubs and herbs had a significant difference (P<0.05)and the phosphorus absorptivity had no significant difference (P>0.05).(3)The contents of C,N and P in litter showed herbs >shrubs> ar-bors,which the content of P had no significant difference.The contents of C,N and P in soil showed herbs >shrubs> arbors,which the N/P had no significant difference.The contents of C,N and P in soil microbial biomass showed herbs >shrubs> arbors,which the C/N,C/P and N/P had no significant difference.(4)The contents of C,N and P of plants,litter,soils and soil microbial biomass decreased with the increasing of the temperature of the growing season and increased with the increasing of the annu-al precipitation,which the absolute value of regression coefficient of P was lower than that of C and N.(5) The contents of C and N in plants,litter and soils had a significant positive correlation.The contents of N and P in plants,litter and soils had a significant positive correlation.The C/N and N/P in litter had a sig-nificant negative correlation.The C/N and N/P in plants and soils had a significant positive correlation. The C/N and N/P in plants,litter and soils had a significant positive correlation.(6)Canonical correspon-dence analysis showed that the plant height,crown,stem diameter,specific leaf area and leaf area index had a large effect on the contents of C,N,P and C/N,C/P and N/P of plant,litter,soil and soil microbi-al biomass.The plant height,crown,stem diameter had a negative correlation with specific leaf area and leaf area index,and had a negative correlation with the contents of C,N,P of litter,soil and soil microbial biomass,and had a positive correlation with the contents of C,N,P of plants,while the contents of C, N,P and C/N,C/P and N/P had a positive correlation in litter,soil and soil microbial biomass.This study provides a scientific guidance for restoration of the urban green plants in China.