苍术根茎及根际土水提物生物活性研究及化感物质的鉴定

Bioactivity of extracts from rhizoma and rhizosphere soil of cultivated Atractylodes lancea DC. and identification of their allelopathic compounds

设置水(CK)、苍术根茎水提液10、50、200mgml及根际土水提液50、200、500mgml共7个处理,每处理3个重复,用作苍术自毒作用的生物学实验。在第5、7天和第14天分别测量苍术种子发芽率、胚根长及胚芽长后,利用单因子方差分析结合多重比较分析各处理组生物活性的差异;采用GCMS鉴定苍术根茎及根际土水提液中所含的有机化合物,并对根茎中含量较大的倍半萜类成分β桉叶醇进行了生物活性研究。结果表明:①500mgml根际土水提液对苍术种子发芽率无影响,虽然能稍稍抑制苍术胚根和胚芽的伸长,但未达到显著水平;②随根茎提取液浓度的增大,其对苍术种子发芽率、胚根和胚芽伸长的抑制作用增大,200mgml根茎提取液显著抑制了苍术种子发芽率及胚根和胚芽的伸长(p<0.05);③在根茎和根际土水提液中分别鉴定到20和27个化合物;④β桉叶醇对苍术种子发芽率、胚根伸长没有明显影响,但100mgl和250mgl的β桉叶醇能强烈抑制苍术胚芽伸长。提示栽培苍术连作障碍可能主要与自毒作用有关。

Atractylodes lancea plants were cultivated in pots in a greenhouse in order to study on the mechanisms of plant autotoxicity. The soil used in the experiment was freshly collected from a bare field. After 8 months, A. lancea was harvested. Treatments of H2O, 10, 50, 200 mg/ml extracts of rhizoma and 50, 200, 500 mg/ml extracts of rhizosphere soil were applied to test their effects on early development of A. lancea. Seed germination rates, extension of radicle and embryo, were recorded respectively at 5 d,：7 d and 14 d after emergence, then one-way ANOVA and multiple comparisons were conducted to test the differences between the treatments. In the follow-up studies, both rhizoma and rhizosphere soil were extracted by diethyl ether and ethyl acetate respectively, and GC-MS was conducted for the identification of the compounds in the extracts, and the similarity of the composition of compounds in rhizoma and rhizosphere soil by same extraction procedure were compared with Jaccard coefficient.β-eudesmol, which was found to be the major component in extracts of A. lancea rhizoma, was used to test the bioactivity. The experimental results showed that ① Neither 50 mg/ml and 200 nor 500 mg/ml extracts of rhizosphere soil had influences on seed germinations or the development of radicles and embryos ; ② Germination rates, lengths of radicles and embryos decreased with increasing concentration of rhizoma extracts, and 200 mg/ml rhizoma extracts reduced A. lancea growth significantly （p 〈 0.05）. Germination rates, lengths of radicles and embryos under this treatment was 11%, 32% and 23% of the Controls respectively.③ 20 compounds in rhizoma extracts and 27 compounds in rhizosphere soil extracts were identified. Many compounds, such as 2, 5-octadecadly3noic acid, methyl ester, n-Hexadecanoic acid, Pentadecanal, Tetradecanoic acid, 1- Naphthalenol, Butylated Hydroxytoluene, 2-Methoxy-4-vinylphenol, etc., were allelophathic substances and detected in both extracts of rhizoma and rhizosphere soil-β-eudesmol and Hinesol, which were the main components of essential oil in A. lancea, was found in rhizoma extracts. ④ It was found that β-eudesmol, terpene, most of which are aUelophathic substance, at all concentrations, had no effect on the germination rates and lengths of radicles, but 100 and 250 mg/1 β-eudesmol reduced embryo development significantly. In conclusion, there was autotoxicity in continuous cropping of A. lancea, which was one of the causes of problems associated with continues cropping of a single plant species.