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作 者 ：覃逸明,聂刘旺*,黄雨清,王千,刘欣,周科

期 刊 ：生态学报 2009年 29卷 3期 页码：1153~1161

关键词：凤丹(Paeonia ostii T. Hong et J. X. Zhang)；自毒作用；自毒物质；作用机制；

Keywords:Paeonia ostii T. Hong et J. X. Zhang, autotoxicity, autotoxic substances, mechanism,

摘 要 ：药用牡丹的种植中存在明显的连作障碍现象，为探讨其机制，利用已萌发长根的凤丹(Paeonia ostii )种子对凤丹根际土壤和根的水浸提液进行了自毒化感检测；采用高效液相色谱法（HPLC）对种植4a的凤丹根际土壤及其根皮中的化感自毒物质进行了定性和定量分析；在此基础上, 利用外源法研究了盆栽凤丹幼苗对5种检出物质(阿魏酸、肉桂酸、香草醛、香豆素和丹皮酚)及其混合物在3种不同浓度下对植株生长的影响和生理响应。结果表明：(1)连续种植4a的凤丹根际土壤和根浸提液对已萌发种子根的生长有显著的抑制作用(p＜0.05)，显示凤丹根分泌物具有自毒化感的潜势;（2）HPLC分析表明在凤丹根际土壤中存在5种以上的酚酸类物质 (阿魏酸、肉桂酸、香草醛、香豆素和丹皮酚)，其中阿魏酸、肉桂酸、香草醛、香豆素为前人已报道的化感物质；(3)在实验室条件下，所设浓度范围内，5种物质及其混合物对凤丹幼苗的高度、根长及地下和地上生物量均有明显影响，尤其对根长和地下生物量的影响最为明显(p＜0.05)，此结果与连作移栽幼苗时，根部首先发黑死亡的现象相一致；(4)凤丹幼苗的根系活力和叶绿素含量在各处理中表现出相似性，即低浓度时根系活力和叶绿素含量高，高浓度时根系活力和叶绿素含量低，低浓度的阿魏酸和香草醛对幼苗根系活力和叶绿素合成有促进作用。此结果显示自毒物质可能是通过影响根系酶活性和叶绿素合成来影响群体中其它个体的生长。本实验的结果显示栽培4a的凤丹土壤水提液具有抑制自身种子根系生长的活性，此提示栽培凤丹连作障碍可能主要与自身分泌到土壤中的酚酸类物质的自毒作用有关。

Abstract:The obvious continuous cropping obstacles have been observed in Paeonia ostii planting. In order to understand this phenomenon, the present work studied the autotoxic potential of rhizosphere soil and root extract of Paeonia ostii on itself seedlings. Then, the extracts of rhizosphere soil and root bark of four years old Paeonia ostii were qualitatively and quantitatively analyzed with high performance liquid chromatography (HPLC). Based on the examined results, we researched the effects of five exogenous autotoxins of ferulic acid, cinnamic acid, vanillin, coumarin, paeonol and their mixture at three different concentrations and physiological responses on Paeonia ostii seedlings growth with pot-culture. The results showed that: (1) The aqueous extracts of rhizosphere soil and root could inhibit the root growth of Paeonia ostii seedlings (p＜0.05). These indicated that, under the controlled laboratory conditions, Paeonia ostii presented an allelopathic potential against itself; (2) Five phenolic compounds of ferulic acid, cinnamic acid, vanillin, coumarin and paeonol were detected and measured by HPLC in the rhizosphere soil and root bark of Paeonia ostii, and ferulic acid, cinnamic acid, vanillin and coumarin were reported previously as allelopathic substances; (3) Under controlled sand culture in laboratory, the height, root length, aboveground and underground biomass of Paeonia ostii seedlings could be affected by adding five substances and their mixtures in various concentrations. The growth indexes of seedlings were inhibited in moderate and higher concentration treatments, especially on root length and underground biomass, but ferulic acid and vanillin could stimulate seedlings growth in lower concentrations. The results were the accordant with observational phenomena in field that the root discolored and became putridity little by little when seedlings were transplanted in condition of continuous cropping; (4) The variability of root activities and chlorophyll contents of seedlings in all treatments were homologue, namely that root activities and chlorophyll contents were higher in lower concentration, inversely, they were lower when concentrations became higher, but there were stimulatory on root activity and chlorophyll contents of Paeonia ostii seedlings with lower concentration of ferulic acid and vanillin. These results revealed that the aqueous extracts from rhizosphere soil and root for 4 years could inhibit the root growth of its own seedlings, and suggested that the action of continuous cropping obstacles may relate with the autotoxic substances of phenolic compounds which come from itself exudates of root.

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