胡麻残茬水提液化感自毒作用研究

Allelopathy autotoxicity of aqueous extracts of oil flax stubble

为探讨胡麻不同器官残茬的自毒作用,明确残茬根、茎及叶中的主要自毒物质,分别制备水提液,以蒸馏水为对照,设置不同浓度梯度水提液,用于胡麻种子萌发及幼苗生长实验,通过测定发芽势、发芽率、株高及根重等指标确定自毒效应,利用气相色谱-质谱(GC-MS)技术分析胡麻残茬根、茎及叶中的主要自毒物质。结果显示,胡麻残茬根、茎及叶水提液对自身种子萌发和幼苗生长总体上表现为"低促高抑"作用,且存在浓度效应。随着水提液浓度增加,胡麻残茬叶水提液最先到达临界浓度,其次为茎水提液,最后为根水提液。综合效应显示,胡麻不同残茬器官水提液化感自毒作用强弱关系为:残茬叶>残茬茎>残茬根。胡麻残茬根、茎及叶水提液中分别鉴定出8种、21种和14种化合物,主要包括酸类和酯类,含量最多的自毒物质为棕榈酸和邻苯二甲酸二丁酯。胡麻残茬根、茎及叶水提液对种子萌发及幼苗生长具有显著的化感自毒效应,可能是导致胡麻连作障碍的主要原因之一。

In order to investigate the allelopathy autotoxicity of oil flax stubble and identify the organic compounds responsible for its autotoxicity,aqueous extracts of stubble root,stem and leaf were prepared respectively.Different concentrations of gradient aqueous extracts were set for seed germination and seedling growth experiments.The autotoxic effects were determined by measuring germination potential,germination rate,seeding length and root weight,etc;and the main autotoxic chemical substances of the stubble root,stem and leaf were analyzed by gas chromatography-mass spectrometry(GC-MS).The results showed that the stubble root,stem and leaf aqueous extracts of oil flax inhibited the seed germination and seedling growth in a dose-dependent manner.With the increase of aqueous extract concentration,the aqueous extract from the stubble leaves reached the critical concentration first,followed by the aqueous extract of stubble stem,and finally the aqueous extract of the stubble root.The synthesis effect showed that the relationship between the aqueous extract of different stubble organs and the autotoxicity is that stubble leaf > stubble stem > stubble root.Eight,twenty-one and fourteen compounds were identified in aqueous extracts of root,stem and leaf,respectively,including acids and esters.The most abundant autotoxins was palmitic acid.These results showed that aqueous extracts of oil flax stubble significantly affected seed germination and seedling growth,which could be one of the main cause of continuous cropping obstacles of oil flax.