蓝莓根系复合共生体及其根区土壤中AM真菌调查

蓝莓Vaccinium uliginosum是欧石南菌根（ericoid mycorrhiza,ERM）真菌典型的寄主植物,但同时也可与丛枝菌根（arbuscular mycorrhiza,AM）真菌和深色有隔内生真菌（dark septate endophytes,DSE）共生形成复合共生体。本研究旨在调查和评价不同栽培体制下蓝莓成年树花果期根系共生体发育状况及其根区土壤中AM真菌资源分布状况,以期为优质蓝莓栽培管理提供理论依据和技术基础。从青岛佳沃蓝莓基地采集暖棚、冷棚和露地3种方式栽培的9-10年生‘蓝丰’、‘奥尼尔’和‘公爵’蓝莓的根系及根区土样,观察测定根系共生体着生数量、根区土壤中AM真菌孢子数量和菌种组成。结果表明,所有栽培方式下供试品种蓝莓根系均形成ERM、AM和DSE结构及其复合共生体;其中,AM着生数量最多,其次是ERM,DSE侵染率最低;复合共生体中则呈现ERM+AM>ERM+DSE>ERM+AM+DSE;蓝莓复合共生体着生数量、AM真菌侵染率、丛枝着生率及孢子数量等不同种植方式下呈现暖棚>冷棚>露地,不同品种呈现‘蓝丰’>‘公爵’>‘奥尼尔’,而ERM和DSE侵染率也呈现上述变化趋势。依据AM真菌形态特征,供分离鉴定获得5属11种AM真菌,以暖棚栽培条件下分离获得的AM真菌数量最多,‘蓝丰’根区土壤中分布的AM真菌属种最多。暖棚内成年树花果期蓝莓根系共生体发育健全,AM真菌种类和孢子数量较多,可能有利于提高蓝莓的产量、改善果实品质和抗逆性。

Investigation on the root multiple symbionts and rhizosphere soil AM fungi of blueberry

Vaccinium uliginosum is one of typical host plants of ericoid mycorrhizal (ERM) fungi, which also can be colonized with arbuscular mycorrhizal (AM) fungi and dark septate endophytic fungi (DSE) to form multiple symbionts. The purpose of the present study was to determine and evaluate the root symbiont development status of various cultivars of blueberry adult trees grown under different cultivation systems in flowering and fruiting stages, and the distribution of AM fungi in root zone soil in order to provide theoretical and technical bases for high quality cultivation management technology. Root and root zone soil samples from nine- to ten-year-old plants of Bluecrop, Duke and OʹNeal blueberry grown under plastic cover in the early spring and later autumn, open field and solar greenhouse in Jiawo blueberry production base of Qingdao were collected to observe and measure the quantity of root symbionts, number of AM fungal spores, and AM fungal species distribution. The results showed that ERM, AM, and DSE structures, and their multiple symbionts formed on roots of blueberry trees. Among them, AM gave the largest colonization percentages, followed by ERM, and DSE the lowest; while the colonization of multiple symbiont showed ERM+AM> ERM+DSE>ERM+AM+DSE. The multiple symbiont colonization quantity, AM fungal infection rate, arbuscule colonization percentage, and spore number of AM fungi showed greater in solar greenhouse as compared with those in plastic cover in the early spring, however, they showed decline in open field in later autumn. Different cultivars showed difference in quantity of root symbionts and AM fungal infection rate, manifesting progressive increase order of Bluecrop>Duke>OʹNeal, and ERM and DSE also gave the similar changing trend. Based on the morphological characters of AM fungal spores, totally eleven species in five genera of AM fungi were isolated and identified. More species were isolated from solar greenhouse from the root zone soil of Bluecrop plants. It is concluded that the root symbiont in the flowering and fruiting stage of the blueberry adult trees grown under solar greenhouse is well developed, and it is probably beneficial to the yield, quality and stress resistance of blueberry trees.