菌根化马尾松苗木根际土壤浸提物有效成份及其对种子萌发的影响

Active Constituents of Soil Extracts from Mycorrhizal Seedling Rhizosphere of Pinus massoniana and Their Effects on Seed Germination

【目的】对比分析接种外生菌根真菌对马尾松苗木根际土壤浸提物种类及其含量的影响,阐明根际土壤浸提物对马尾松种子萌发的影响,为菌根化育苗及马尾松天然更新研究提供科学依据和理论指导。【方法】以接种和未接种外生菌根真菌的1年生马尾松苗木为研究对象,采用乙醇和甲醇两种浸提剂分别萃取分离接种和不接种苗木根际土壤,气相色谱-质谱(GC-MS)进行物质鉴定,研究不同马尾松苗木根际土壤浸提物化学成分和含量的差异,再运用生物测定方法研究浸提物对马尾松种子的化感效应。【结果】采用乙醇浸提,接种Sl12和Sl13菌株苗木根际土壤浸提物中物质种类分别比非菌根化苗木多22和23种,其中酸类是数量最多且比例较大的一类化合物,两种接种苗木酸类所占比例分别为51.20%和48.80%,非接种苗木酸类所示比例为34.17%;采用甲醇浸提,未接种苗木根际土壤浸提物中物质种类23种,两种接种苗木物质种类分别为34和32种,其中酸类、酯类相对含量较大,两种接种苗木酸类所占比例分别为39.06%和34.86%,酯类分别为32.01%和38.91%,非接种苗木酸类所示比例为33.96%,酯类所示比例为39.59%;菌根化苗木根际土壤乙醇、甲醇浸提物均能检测出棕榈酸、硬脂酸、2,4-二叔丁基苯酚;非菌根化苗木只能检测出棕榈酸;菌根化苗木根际土壤乙醇浸提物对马尾松种子的发芽率、发芽势、活力指数、胚根长、胚轴长具有一定的抑制作用,化感效应指数为负值。【结论】接种外生菌根真菌影响苗木根际土壤中分泌物的化学组成成分,增加分泌物的种类和数量;3种苗木根际土壤浸提物对种子的萌发具有一定抑制作用。

【Objective】 This study aims to investigate the effects from ectotrophic mycorrhiza on the variety and content of the extracts from rhizospheric soil of Pinus massoniana seedlings,and elucidate the effect of soil extracts on seed germination and provides scientific basis and theoretical guidance on mycorrhizal seedlings and natural regeneration.【Method】One-year-old Pinus massoniana seedlings,inoculated ones with ECM fungi and uninoculated ones,were used to collect the rhizopheric soil extracts. Ethanol and methanol extracts were used to extract and inoculate the rhizosphere soils of the seedlings. and gas chromatography-mass spectrometry techniques was used in material identification. The variety and contents of the extracts from rhizospheric soil of different Pinus massoniana seedlings were studied,and allelopathic effects from soil extracts to seeds were also studied with bioassay method. 【Result 】 The rhizospheric soil extracts（ extracted with ethanol） of Pinus massoniana seedlings inoculated with ECM fungal strain Sl12 and Sl13 had 22 and 23 more components than those of non-mycorrhizal seedlings,respectively. Acids comprised the most abundance components of soil extracts,and accounted for 51. 20%,48. 80%,and 34. 17% of all detected components of mycorrhizal seedlings inoculated with Sl12 and Sl13 and non-mycorrhizal seedlings,respectively. Using methanol as the solvent,34,32,and 23 components were detected from the rhizospheric soil of Sl12, Sl13 and non-mycorrhizal seedlings,respectively. Acids and esters were the most abundant components of the soil extracts. Acids comprised 39. 06%,34. 86%,and 33. 96%,and esters comprised 32. 01%,38. 91% and 35. 95% of the total components of Sl12,Sl13 and non-mycorrhizal seedlings,respectively. Palmitic acid,stearic acid and 2,4-2 tertiary butyl phenol were always detected in the rhizosphere of mycorrhizal seedlings,irrelevant to the solvents; only palmitic acid was detected with non-mycorrhizal seedlings. The soil extracts（ using ethanol as the solvent） of mycorrhizal seedling rhizosphere had inhibitory effects on seed germination,vigor index,hypocotyl and radical length of P. massoniana.【Conclusion】ECM fungi reconstructed the rhizosphere through altering the profiles of rhizospheric soil extracts,and increased the types and amounts. Three kinds of seedlings of soil extracts from rhizosphere all had inhibitory effect on seed germination.