城市绿化植物-凋落物-土壤系统碳氮磷化学计量特征研究

Ecological Stoichiometric Characteristics of Plants,Litter and Soils of Urban Green Plants

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 urban 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 ornamental plants of different organs was differ, which showed leaf〉stem〉root. （2） The nitrogen absorptivity 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〉 arbors, 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 annual 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 significant 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 correspondence 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 microbial 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.