广东省森林球囊霉素相关土壤蛋白含量及影响因素

植被和土壤组成的差异将影响土壤微生物的组成及动态,土壤微生物的动态变化将体现在微生物产物上。球囊霉素相关土壤蛋白(Glomalin-related soil protein,GRSP)被认为是唯一来源于丛枝菌根真菌(Arbuscular Mycorrhizal Fungi,AMF)的糖蛋白,是土壤碳库的稳定组分,可用于指示AMF对土壤碳固持的影响。鉴于已有GRSP相关研究多集中在样点尺度,缺乏区域水平的研究这一事实,该研究选择广东省164个代表性森林样地为研究对象,通过测定表层(0-10 cm)土壤GRSP含量、土壤理化性质,旨在了解广东省森林土壤中GRSP水平及其对土壤有机碳固持的贡献。结合土壤理化性质、植被特征探讨区域范围内GRSP的影响因素。结果表明,(1)广东省森林土壤表层土(0-10 cm)中总球囊霉素相关土壤蛋白(total GRSP,T-GRSP)质量分数为(3.26±0.11) g?kg-1,易提取球囊霉素相关土壤蛋白(easily extractable GRSP,EE-GRSP)质量分数为(1.11±0.03) g?kg-1,植被起源和植被类型对GRSP含量的影响不显著,GRSP在地带性土壤中呈现黄壤>红壤>赤红壤>砖红壤的显著变化趋势。(2)针叶林GRSP的平均水平高于常绿阔叶林,这一趋势与3种植被类型下灌木草本层生物量的趋势一致。(3)GRSP与土壤有机碳含量、阳离子交换量呈显著正相关关系,与土壤pH值呈显著负相关关系,GRSP含量随土壤细颗粒(粒径<50μm)含量的增加而增加。广东省森林土壤GRSP对土壤有机碳的绝对贡献率为2.3%,GRSP能够与土壤细颗粒结合促进土壤团聚体的形成,并提高土壤保水性能和肥力。

Patterns and Influence Factors of Glomalin-related Soil Protein in Guangdong Forests

It is well known that changes in vegetation traits and soil conditions will influence soil microbial composition and resulting in dynamics of microbial residual. Glomalin-related soil protein(GRSP) is proven to be the residual of arbuscular mycorrhizal fungi(AMF) which is crucial for soil organic carbon(SOC) accumulation and contributes to soil aggregates formation. However, most GRSP studies are site-based case study, regional studies are highly expected to reveal the ecological functions of AMF and GRSP. In this study, we investigated GRSP content from 164 forests in Guangdong Province with the ultimate goal to understand spatial patterns of GRSP in Guangdong forests and their influenced factors. The results showed that,(1) GRSP varied among forests and soil types with mean content of total GRSP(T-GRSP) as(3.26±0.11) g?kg-1 and easily extractable GRSP(EE-GRSP) as(1.11±0.03) g?kg-1 in top soil(with 10 cm in depth). Forest origin and vegetation type had no significant influence on GRSP content, while the difference of GRSP among soil types showed the trend as yellow earths>red earths>latosolic red earths>latosols.(2) Coniferous forest had higher GRSP content compared with evergreen broadleaved forest and coniferous and broadleaved mixed forest, this was consisted with the difference of the biomass and species richness of shrub and herbaceous layer. And(3) GRSP content was positively correlated with SOC content and cation exchangeable capacity(CEC), and negatively correlated with soil pH value. GRSP content was also founded increasing with the increased fine particle(with diameter<50 μm). GRSP accounted for 2.3% of SOC in the top soil in Guangdong forests, the existence of GRSP could promote soil aggregates formation by bonding fine soil particles and therefore improve soil physicochemical properties.