菌根生物技术应用现状与研究进展

论述了菌根的类型、功能及其在林业上的应用现状，并指出菌根生物技术研究进展与方向，为林业生产提供参考。     

菌根与植被恢复

菌根不仅可促进植物的营养吸收、生长发育、抗病、抗逆,而且在保持良好的土壤结构、控制水土流失方面具有直接的作用。在我国西北许多地区,菌根菌与植物间的共生关系已被中断,要恢复该地区的植被,治本的方法应是重建植物与菌根菌的共生关系,形成健康的生态系统。文中还提出了菌根技术在植被恢复中的应用策略。     

甘肃省兴隆山区域丛枝菌根真菌多样性初探

本研究采用Illumina HiSeq分子测序技术,探究了兴隆山东山丛枝菌根(Arbuscular mycorrhizal,AM)真菌多样性及其在不同海拔高度的分布特征。结果表明:1)自兴隆山东山土壤分离获得AM真菌共52种,隶属于4目8科13属,其中球囊霉属(Glomus)和原囊霉属(Archaeospora)为主要物种,分别为20种和9种,共占总物种的55.77%;2)各海拔梯度AM真菌种属分布结果表明,优势属球囊霉属(Glomus)和类球囊霉属(Paraglomus)随海拔变化呈现规律性分布,其余各属均匀分布于不同海拔梯度;球状巨孢囊霉(Gigaspora margarita)、蜜色无梗囊霉(Acaulospora mellea)、白色球囊霉(Glomus albidum)、球囊霉属的Glomus sp.1和Glomus sp.4,还有弯丝硬囊霉(Sclerocystis sinuosa)仅在部分海拔梯度出现,为不同海拔特有种;3)AM真菌丰富度分析表明,从低海拔到高海拔,ACE和Chao1指数总体上表现出“单峰”变化曲线,且部分海拔间差异性显著(P<0.05)。Spearman相关性分析发现,该地区AM真菌种属分布受海拔因子影响较小,两者间不具有显著相关性。综上,兴隆山东山AM真菌资源丰富,物种繁多,具有较大的应用潜力。     

丛枝菌根真菌接种对白车轴草耐盐性的影响

丛枝菌根真菌(AMF)可与植物共生形成复杂的菌丝网络,影响植物生长及抗逆能力。目前关于AMF对白车轴草耐盐性的影响尚存争议,本研究采用盆栽试验,研究在盐胁迫条件下(NaCl浓度为150 mmol·L^-1),接种AMF对拉丁诺白车轴草耐盐性的影响。结果表明,在盐胁迫条件下,与对照相比,白车轴草的生长与生理指标均受到抑制。盐胁迫下接种AMF后,白车轴草株高、干重、PSⅡ最大光能转换效率和相对含水量均有增加,丙二醛(MDA)含量以及相对电导率有所降低,渗透调节物质均有提高,其中可溶性糖(SS)和游离脯氨酸(Pro)含量分别提高了32.03%和9.42%。说明盐胁迫抑制白车轴草的生长,接种AMF增强了白车轴草抗逆适应能力,促进白车轴草的生长,增加渗透调节物质含量,提高白车轴草耐盐胁迫的能力。     

AM真菌对加拿大一枝黄花与菌根植物和非菌根植物种间作用的影响

为明确丛枝菌根(arbuscular mycorrhizal,AM)真菌对加拿大一枝黄花Solidago canadensis与本地菌根植物和非菌根植物种间竞争格局的调控作用,采用温室盆栽试验,通过接种摩西球囊霉Glomus mosseae(GM)、根内球囊霉G. intraradices(GI)及其混合菌种(GM+GI)3种处理,分析AM真菌对加拿大一枝黄花与本地菌根植物玉米Zea mays和非菌根植物油菜Brassica campestris种间作用的影响。结果表明:与对照相比,接种AM真菌均显著提高了加拿大一枝黄花和玉米的菌根侵染率,菌根侵染率为13.720%～50.015%,且前者的菌根侵染率明显高于后者。单独种植时,与对照相比,接种AM真菌尤其是接种混合菌种显著提高了加拿大一枝黄花的株高、叶片数和总干重。在加拿大一枝黄花与玉米混合种植时,与单独种植相比,加拿大一枝黄花的株高、叶片数、根长和总干重均较低;同时,与对照相比,接种AM真菌显著提高了玉米的相对竞争强度而对加拿大一枝黄花的相对竞争强度没有显著影响。在加拿大一枝黄花和油菜混合种植时,与对照相比,接种AM真菌则显著提高了加拿大一枝黄花的株高、叶片数、净光合速率和总干重;同时,接种AM真菌促进了入侵种的竞争优势而抑制了非菌根植物油菜的生长。说明加拿大一枝黄花与本地种的竞争格局受到与之混生物种的菌根依赖性强度以及AM真菌的种类差异影响。     

松口蘑与赤松形成的外生菌根形态结构初步研究

对松口蘑菌丝与赤松根形成的外生菌根形态特征和解剖结构进行了初步研究。结果表明:感染松口蘑菌丝的赤松根呈不规则的多分支状或扫帚状,表面覆有松口蘑菌丝,但不形成由菌丝构成的菌鞘。赤松幼根感染松口蘑菌丝的部分呈暗褐色至黑色。被菌丝侵染表皮的细胞壁明显增厚,细胞内容物浓缩、变暗,皮层细胞内有明显的、淀粉粒样的大颗粒,细胞质浓缩、变暗。皮层细胞间不形成明显的“哈蒂氏网”。以上结果表明,松口蘑与赤松形成的外生菌根与典型的外生菌根明显不同。     

混合接种菌根真菌对喜树幼苗生长及喜树碱含量的影响

通过温室盆栽接种试验,研究了蜜色无梗囊霉(Acaulospora mellea)、弯丝硬囊霉(Sclerocystic sinosa)及二者混合接种(分别记为Am、Ss和Am-Ss)对喜树幼苗生长及喜树碱含量的影响.结果表明:丛枝菌根的形成促进了喜树幼苗的生长,菌根幼苗的生物量优于无菌根幼苗,混合接种Am-Ss的菌根幼苗显著高于无菌根幼苗和单接种的菌根幼苗.丛枝菌根形成影响了喜树幼苗的喜树碱代谢,菌根幼苗根、叶片和全株的喜树碱含量均显著高于无菌根幼苗,并且混合接种处理的喜树幼苗喜树碱含量最高.     

茶树接种VA菌根的生理特性研究

茶树接种VA菌根（丛枝菌根）的生理特性研究表明,茶树叶片接种VA菌根50d后,其叶绿素含量都高于未接种的。在光合有效辐射0~1200μmol/m²·s,接种VA菌根的茶树,其净光合速率、气孔导度、蒸腾速率等均有提高;而水分利用率前期快速增加,达到高峰然后下降;茶树叶片相对含水量先上升后下降,叶片的自然饱和亏逐渐降低。接种VA菌根后,随着侵染率的增加,茶树叶片的丙二醛含量越少,脯氨酸的含量先降低后升高。VA菌根能够提高茶树保护酶的活性,在生长到90d时,过氧化物酶（POD）活性达到最高值,超氧化物歧化酶（SOD）活性先升高再降低,但增加幅度均比较小;对过氧化氢酶（CAT）活性的影响一直高于未接种的。     

Arbuscular mycorrhizal fungi improve the growth and phosphorus uptake of mung bean plants fertilized with composted rock phosphate fed dung in alkaline soil environment

Abstract

Inoculation effect of arbuscular mycorrhizal fungi (AMF) on phosphorus (P) transfer from composted dung of cattle with a diet supplemented with powdered rock phosphate (RP) and their successive uptake by mung bean plants was assessed in alkaline soil. The efficacy of composted RP fed dung alone or/and in combination with AMF inoculums containing six different species were compared with SSP in six replicates per treatment in pots. The results showed that the association of AMF with composted RP fed dung had a positive effect on mung bean shoot (3.04?g) and root (2.62?g) biomass, chlorophyll (a, b), carotenoid contents and N (58.38?mg plant^?1) and P (4.61?mg plant^?1) uptake. Similarly, the percent roots colonization (56%) and nodulation of mung bean plant roots and their post-harvest soil properties were also improved by the inoculation of AMF together with composted RP fed dung. It is concluded that the combined application of AMF with composted RP fed dung has almost the same effect as SSP for improving mung bean plants growth and their nutrients uptake. Moreover, AMF inoculants can be used as a suitable biofertilizer in combination with locally available organic sources of fertilizers for improving P status and growth of plants in alkaline soils.     

Effects of nitrogen feeding for extraradical mycelium of Rhizophagus irregularis maize symbiosis incorporated with phosphorus availability

In terrestrial ecosystems, plants are frequently in symbiosis with arbuscular mycorrhizal fungi (AMF) with mineral nutrients and photosynthesis carbon exchanges in between. This research sought to identify the effects of phosphorus (P) levels on the nitrogen (N) uptake via extraradical mycelium (ERM) and the mycorrhizal growth response (MGR) of maize plants within the AMF symbiosis. Pots were separated into root compartments and hyphae compartments (HCs) with two layers of a 30‐μm mesh membrane and an air gap in between, where only hyphae could pass through, to avoid both N diffusion and root growth effects. Maize plants were inoculated with Rhizophagus irregularis with different N fertilization in HCs under two different P fertilization levels. Our results indicated that a strong increase in MGR with low‐P fertilization. The same tendency was not observed with high‐P fertilization, although both had a large increase in P concentration as a potential source of growth in shoot tissue of mycorrhizal plants. Substantial effects (10.5% more N) were observed in the case of high‐P availability for the host plants from ERM fed with N, whereas under low‐P conditions ERM may prioritize P uptake rather than N uptake. The AM fungi increase the uptake of N and P, which are most limiting in the soil with fewer forces from soil resources. In addition, there was still more P accumulated than N due to the high N for ERM with high‐P supply. Low N in HCs corresponded with a lower colonization rate in roots but with high hyphae density in HCs; this result suggest that N and P availability might change the ratio of extraradical to intraradical hyphae length.