摘要
为揭示石漠化地区桑树对丛枝菌根(arbuscular mycorrhiza,AM)真菌介导土壤氮变化的适应性,选择AM真菌两种优势菌种摩西管柄囊霉(Funneliformis mosseae,Fm)和根内根孢囊霉(Rhizophagus intraradices,Ri)接种于桑树根系,分析接种和未接种处理下石漠化土壤剖面和桑树器官C、N含量变化及生态化学计量比和内稳性大小.结果显示:土壤总有机碳(total organic carbon,TOC)含量和C:N比值随剖面增加而降低,但相比CK,接种Fm和Ri使TOC含量和C∶N比值显著提升了0.93％-5.00％(P＜0.05)和 1.81％-16.20％(P＜0.05);对于土壤总氮(total nitrogen,TN)而言,其含量随土壤深度增加而增加,但相比CK,接种Fm和Ri使TN含量显著降低了 1.49％-9.48％(P＜0.05).桑树叶片C含量与C∶N比值低于根和茎秆,N含量却高于根系和茎,接种AM真菌使叶片C含量和C∶N比值显著增加1.30％-3.64％(P＜0.05)和1.78％-14.51％(P＜0.05).桑树不同器官不同元素及计量比的内稳性存在差异,未接种时桑树根系和茎N、C∶N不具有内稳性,接种Fm使根系N内稳性增强(内稳性指数2.94),却使叶片C∶N内稳性降低(内稳性指数2.32),接种Ri使桑茎N内稳性增强(内稳性指数1.69).综上所述,接种AM真菌调节不同剖面石漠化土壤C、N变化,其中TOC含量增加、TN含量降低,C:N变化符合"缓慢分解"假说;同时,AM真菌促进桑树根系吸收N并将其转运至地上叶片部位,但对根系、茎和叶片N、C:N内稳性的调节受菌种类型影响.(图3表1参39)
Abstract
Ecological stoichiometry is a pertinent theory to reveal the adaptability of mulberry-inoculated arbuscular mycorrhizal fungi to rocky desertification areas.Two sets of experiments were performed,one in which Funneliformis mosseae(Fm)and Rhizophagus intraradices(Ri)were inoculated and the other in which uninoculated plants were used as controls.After four months,soil and mulberry organs were sampled.Total carbon(C)and total nitrogen(N)were measured and the ecological stoichiometric ratio and stoichiometric homeostasis indices were calculated.With increasing soil depth,soil total organic C(TOC)content and the C∶N ratio decreased,but the total N(TN)content increased.The inoculation of Fm and Ri significantly(P＜0.05)increased TOC content from 0.93％to 5.00％and C∶N ratio from 1.81％to 16.20％(both P＜0.05),and reduced TN content from 1.49％to 9.48％.C content and C∶N ratio in mulberry leaves were lower than those in roots and stems,but the N content in the mulberry leaves was higher than that in the roots and stems.Inoculation with arbuscular mycorrhizal fungi significantly(P＜0.05)increased the C content from 1.30％to 3.64％,and C∶N ratio from 1.78％to 14.51％in mulberry leaves.The stoichiometric homeostasis indices were different for N and C∶N in mulberry organs.The second experiment did not involve inoculation.The N and C∶N homeostasis indices of mulberry stems and roots were lower than those in the inoculated experiment,indicating instability.Inoculation with Fm enhanced the homeostasis indices of N in mulberry roots(H=2.94)but reduced the indices of C∶N in leaves(H=2.32).Inoculation with Ri enhanced the homeostasis index of N in the stems(H=1.69).Inoculation of arbuscular mycorrhiza fungi increased TOC content of different soil profiles,reduced TN content in rocky desertification soil,and regulated C∶N changes.These findings support the"slow decomposition"hypothesis.Arbuscular mycorrhiza fungi promoted the uptake and transfer of N in mulberry roots.However,N and C∶N stabilities of mulberry organs are regulated by the species of arbuscular mycorrhizal fungi.
基金项目
国家自然科学基金(32060377)
贵州省创新能力建设项目(黔科合服企[2022]003)
贵州省创新能力建设项目(黔农科院国基后补助[2021]53号)
NETL
NSTL
万方数据