热带山地雨林土壤球囊霉素的分布特征

球囊霉素(GRSP)作为土壤有机碳的重要组分,对土壤质量和土壤碳库有着重要的指示作用。选择我国保存最完好的热带雨林海南尖峰岭为研究对象,通过不同海拔(300、600、900、1200 m)的样品采集,研究了热带山地雨林丛枝菌根(AM)的重要分泌物球囊霉素的空间分布特征,并结合土壤因子,进一步探讨了其分布机制,旨在阐明球囊霉素对热带山地雨林土壤碳库和土壤质量的贡献,丰富丛枝菌根的功能多样性理论基础。结果表明,4个海拔的植物都具有较高的菌根侵染水平,平均为82.92%。不同海拔间,土壤总提取球囊霉素(T-GRSP)和易提取球囊霉素(EE-GRSP)含量具有相同的变化规律,都在海拔1200 m时最高,显著高于其它3个海拔。尖峰岭T-GRSP的质量分数在1.79-3.11 mg·g^-1之间,平均2.205 mg·g^-1;EE-GRSP则为0.75-1.13 mg·g^-1,平均0.904 mg·g^-1。T-GRSP和EE-GRSP占土壤全碳比值的规律在4个海拔也一致,都是在海拔1200 m时最低。在4个海拔中,T-GRSP和EE-GRSP分别占到土壤全碳质量分数的4.33%-8.87%和1.58%-4.12%。对T-GRSP和EE-GRSP的影响因素分析则表明,土壤全碳、全氮和C/N都影响着GRSP的含量;无论是T-GRSP还是EE-GRSP都随着土壤全碳、全氮和C/N的增大而增加;三者对T-GRSP变异的解释率(63.16%、58.94%和36.05%)要远远高于对EE-GRSP变异的解释率(39.59%、32.19%和19.08%)。但土壤pH则仅影响着EE-GRSP的含量变化,全磷则对T-GRSP和EE-GRSP都没有影响。可见,热带雨林土壤中,GRSP含量较高,对土壤碳库具有重要的贡献,且受到土壤全碳和全氮及二者比例的显著影响。

Elevational Distribution of Glomalin-rated Soil Proteins in A Tropical Montane Rain Forest

Glomalin-rated soil proteins(GRSP)play an important role in regulating soil quality and soil carbon pool.In this study,we explored the elevational distribution of GRSP,important exudates from arbuscular mycorrhizas,through collecting samples at four altitudes(300,600,900,1200 m)of Mt.Jianfengling,one of the best preserved tropical rain forests in China.Further,the distribution mechanism of GRSP was discussed in combination with soil factors to clarify the effect of GRSP on soil carbon pool and soil quality of tropical mountane rain forest,which will enrich the theory of arbuscular mycorrhizal functional diversity.Our results showed that plants in all four elevations had symbiotic relationship with arbuscular mycorrhizal fungi.The average colonization rate was 82.92%.Among elevations,the content of total GRSP(T-GRSP)and easily extractable GRSP(EE-GRSP)presented the same distribution trend with the highest value at 1200-meter elevation.The content of T-GRSP changed from 1.79 to 3.11 mg·g^-1,with an average of 2.205 mg·g^-1.The content of EE-GRSP varied from 0.75 to 1.13 mg·g^-1,with an average of 0.904 mg·g^-1.The ratio of T-GRSP and EEGRSP with total soil carbon content also showed the same trend in four altitudes with the lowest in 1200-meter elevation.T-GRSP and EE-GRSP accounted for 4.33%?8.87%and 1.58%?4.12%of the total soil carbon content,respectively.The content of T-GRSP and EE-GRSP increased with total soil carbon,nitrogen and C/N.Moreover,total soil carbon,nitrogen and C/N explanted 63.16%,58.94%,and 36.05%variations in T-GRSP respectively,which were significantly higher than 39.59%,32.19%,and 19.08%variations in EEGRSP,respectively.Soil pH affected the changes of EE-GRSP than T-GRSP.Either T-GRSP or EE-GRSP was not affected by total soil phosphorus.We concluded that the content of GRSP is high in the rainforest soil,which has an important contribution to the soil carbon pool,and is significantly affected by the total carbon and nitrogen of the soil and C/N.