基于数据库的菌根与施肥对草地植物叶片性状影响的分析

Response to fertilization of leaf functional traits of grassland plants with different mycorrhizal status

为了探究菌根状态和施肥对草地植物叶片性状的影响,对横跨4大洲的27个全球分布的草地站点进行施肥处理,包括对照及氮(N)、磷(P)、钾(K)的全因子组合,在添加养分3~4年后测定每个地块优势物种的叶片N、P、K含量和比叶面积(specific leaf area,SLA),并根据已发表文献确定了植物的菌根状态。在此基础上,结合优势物种的构成,将草地植物分为禾本科植物和非禾本科植物,进一步分析两种植物类群对不同菌根状态和施肥处理的响应。结果表明:菌根状态是影响草地植物叶片性状的重要因素,尤其对于禾本科植物而言,非确定菌根(non-obligately mycorrhizal,NOM)植物的叶片养分含量显著高于确定形成菌根(obligately mycorrhizal,OM)的植物;对于非禾本科和草地植物而言,OM植物和NOM植物的叶片性状同样表现出差异性,但总体并不显著。施肥对草地植物叶片性状的影响主要表现为显著提高其叶片N、P、K含量,对SLA的影响较小。路径分析结果进一步表明,叶片养分含量与施肥呈显著正相关,SLA与施肥无显著相关关系。此外,草地OM和NOM植物的叶片性状均受到气候因素和处理年限的显著影响。综上,菌根状态显著影响禾本科植物的叶片性状,施肥显著提高草地植物叶片养分含量,气候因素和处理年限对草地植物叶片性状的影响同样值得引起注意。

In order to explore the effects of mycorrhizal status and fertilization on leaf traits of grassland plants,fertilization treatments were applied at 27 globally distributed grassland sites across four continents based on data made by Firn et al[25].The treatments included a control and full factorial combinations of nitrogen(N),phosphorus(P),and potassium(K).After 3-4 years of nutrient addition,the leaf N,P and K contents and specific leaf areas(SLA)of dominant species in each plot were measured,and the mycorrhizal status of plants was determined based on published literature.On this basis,combined with the composition of dominant species,the grassland plants were divided into poaceous plants and non-poaceous species,and the responses of the two plant groups to difference in mycorrhizal status and fertilization treatments were further analyzed.It was found that mycorrhizal status was an important factor affecting the leaf traits of grassland plants.Especially for poaceous plants,the leaf nutrient content of non-obligate mycorrhizal(NOM)plants was significantly higher than that of obligate mycorrhizal(OM)plants.For non-poaceous grassland plants,the leaf traits of OM plants and NOM plants also showed some differences,but these were not significant overall.The effects of fertilization on the leaf traits of grassland plants were mainly to significantly increase the contents of N,P and K in leaves,but fertilization had little effect on SLA.Path analysis further showed that there was a significant positive correlation between fertilization and leaf nutrient content,while there was no significant correlation between fertilization and SLA.In addition,the leaf traits of OM and NOM plants in grassland were significantly affected by climatic factors and differed between treatment years.In conclusion,in poaceous plants,leaf traits were significantly affected by mycorrhizal status,while fertilization significantly increased the leaf nutrient content of grassland plants.The effects of climatic factors on the leaf traits of grassland plants and differences between years also merit further investigation.