樟根生产法培育的苗与常规苗的丛枝菌根真菌多样性

以湖南省林业科学院龙伏实验基地的3年生樟根生产（root production method,RPM）苗和同龄常规技术培育的苗木（以下简称常规苗）为研究对象,采集两种苗木的根系和根际土,观察根系上菌根形态,并对其苗木样品进行高通量测序研究,探索二者根系菌根特征及根系、根际土丛枝菌根真菌（arbuscular mycorrhizal fungi,AMF）群落结构及土壤微生境差异,旨在为进行接种有效性菌根苗木来改善常规苗木的土壤微生境,进而培育高质量苗木提供理论依据。结果显示：2种樟苗木根系均显示AM菌根特征,未见外生菌根结构。测序得到属于AMF群落的有效序列共25 738条,隶属1门,2纲,3目,5科,5属,按有效序列占比从高到低依次为Acaulospora、Glomus、Diversispora、Rhizophagus和Paraglomus。根生产法（RPM）苗和常规苗的优势属均为Acaulospora和Glomus,只是RPM苗中Glomus占比高（在根、根际土内占比分别为28.04%、57.36%）而常规苗中Acaulospora占比高（在根、根际土内占比分别为99.58%、42.2%）。2种苗木均是根际土内的丰富度指数（Ace和Chao）远高于根系,并且RPM苗根际土的丰富度指数高于常规苗,但二者根系内的丰富度指数无显著差异（P<0.05）。冗余分析结果显示,土壤pH和有效磷是决定AMF群落结构的主要影响因子。不同理化因子对AMF群落的菌属影响程度也不同。

Arbuscular mycorrhizal fungal diversity of Cinnamomum camphora seedlings bred with 'root production method'and conventional method

Arbuscular mycorrhizal fungal (AMF) diversity in Cinnamomum camphora seedlings bred with root production method (RPM) and conventional technology (hereinafter as ‘conventional seedlings’) in Longfu Experimental Base of Hunan Academy of Forestry Sciences was studied. AMF samples were collected from roots and rhizosphere soil of the two kinds of seedlings, and identification was based on morphology and high-throughput sequencing. The results showed the roots of Cinnamomum camphora seedlings bred with the two methods manifested arbuscular mycorrhizal characteristics, and no ectomycorrhizal structure was found. A total of 25 738 valid sequences belonging to 1 phylum, 2 classes, 3 orders, 5 families and 5 genera of AMF was obtained. According to the proportion of valid sequence ranged from high to low the five genera were Acaulospora, Glomus, Diversispora, Rhizophagus and Paraglomus. The dominant genera in RPM seedlings and conventional seedlings were Acaulospora and Glomus, but the proportion of Glomus in RPM seedlings was higher (28.04% and 57.36% respectively in root and rhizosphere soil) and the proportion of Acaulospora in conventional seedlings was higher (99.58% and 42.2% respectively in root and rhizosphere soil). For both seedlings, the Ace index and Chao index in rhizosphere soil were much higher than those in roots. The richness index of AMF in rhizosphere soil of RPM seedlings was higher than that of conventional seedlings, however, there was no significant difference in AMF richness index in the root between the two kinds of seedlings (P<0.05). Redundancy analysis showed that soil pH and available phosphorus were the main factors affecting AMF community structure, and different physical and chemical factors had different effects on AMF community.