模拟氮沉降和不同外生菌根真菌侵染对樟子松幼苗生长的影响

盆栽条件下,采用单接种Suillus bovines(以下简称SB)和混合接种(Suillus luteus、Suillus grevillea、Tricholoma fulvum、Boletinus grisellus、Suillus bovinus、Leucocortinarius bulbiger、Rhizopogon luteolus、Pisolithus tinctorius 8个菌种的等量混合菌剂接种,以下简称HJ)方法对樟子松(Pinus sylvestris var.mongolica)2个月幼苗进行接种处理,幼苗生长6个月形成菌根后对樟子松幼苗进行模拟氮沉降实验,5个月后通过测定幼苗生长指标、根系形态结构和菌根侵染率,旨在探讨模拟氮沉降对樟子松不同接种处理幼苗生长的影响。结果表明:①随着氮浓度的增加,单接种乳牛肝(SB)和混合接种(HJ)菌根侵染率均呈下降趋势,且氮沉降对SB处理的菌根侵染率影响更显著。②接种显著促进幼苗地上和地下生物量积累,且混合接菌效果更好;同一接菌处理中,氮浓度增加对地上生物量的积累有抑制作用;接种和氮浓度对地径和地上生物量有显著交互作用,但对苗高和地下生物量无交互作用。③HJ处理中不施氮(CKN)和1倍氮浓度(CN)较不接菌(CK)和SB处理显著促进幼苗根系的平均直径、总根长和总表面积;氮浓度增加显著促进CK和SB处理的幼苗根系平均直径、总根长和总表面积,但是对HJ处理的根系各形态结构指标均产生抑制作用。接种和氮浓度以及两者的交互作用均极显著影响幼苗根系形态结构。

Growth Responses of Pinus sylvestris var.mongolica Seedlings under Simulated Nitrogen Deposition and Different Inoculation of Ectomycorrhizal Fungi Treatments

The growth responses of Pinus sylvestris var.mongolica seedlings in pot culture conditions were discussed under different inoculation treatments and simulated nitrogen deposition.The different inoculation treatments were performed after 2-month seedling,which included a strain inoculation of Suillus bovinus(SB)and 8 strain mixed inoculation(HJ),including Suillus luteus,S.grevillea,Tricholoma fulvum,B.grisellus,S.bovinus,Leucocortinarius bulbiger,Rhizopogon luteolus and Pisolithus tinctorius.The simulated nitrogen deposition treatments were performed for six months after mycorrhizal colonization,which included on nitrogen(CKN),1-time nitrogen concentration(CN)and 2-time nitrogen concentration(2CN)treatments.The seedling growth index,root morphology and mycorrhizal colonization rate were measured after the 5-month interaction treatments.The results showed that:①With the increase of nitrogen concentration,the mycorrhizal infection rate showed a downward trend under SB and HJ treatments.The mycorrhizal infection rate of SB inoculation was affected significantly by nitrogen deposition treatments.②The seedlings aboveground and underground biomass were accumulated significantly after inoculation treatments,which were the best effect under mixed inoculation treatment.The aboveground biomass in the same inoculation treatments were inhibited by the increase of nitrogen concentration.The seedlings ground diameter and above-ground biomass were affected significantly by interaction of inoculation and nitrogen concentration,but the seedlings height and underground biomass had no effects.③Compared with CK and SB treatments,the seedlings average root diameter,total root length and total surface area of CKN and CN treatments were promoted significantly under HJ treatment.With the increase of nitrogen content,the seedlings average root diameter,total root length and total surface area were promoted significantly under CK and SB treatments,but the morphological indexes were inhibited under HJ treatment.The seedling root morphology were affected significantly by the inoculation,nitrogen concentration,and the interaction treatments.