Differential exudation of two benzoxazinoids - One of the determining factors for seedling allelopathy of Triticeae species
Differential exudation of two benzoxazinoids - One of the determining factors for seedling allelopathy of Triticeae species
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DOI：
10.1021/jf048434r
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发表时间：
2005-01-26
影响因子：
6.1
通讯作者：
Hurle, K
中科院分区：
文献类型：
--
作者：
Belz, RG;Hurle, K
苯并恶嗪类化合物(Bx)是一种天然植物毒素，在几个物种中具有化学防御化合物的功能。在小麦属植物中，完整的植物根释放的Bx与根的化感作用有关；然而，Bx的分泌物浓度对植物-植物相互作用的意义仍然是一个有争议的问题。对普通小麦(Triticum aestivum L.)、硬粒小麦(Triticum hard um Desf.)、斯佩尔塔小麦(Triticum spelta L.)和黑麦(Secale graale L.)的146个品种进行生物学筛选。在剂量-反应生物测定中，证明了根化感作用对白芥根生长的抑制具有高度的品种依赖性。只有少数品种具有显著的化感活性，通过对根系分泌物的高效液相色谱-二极管阵列检测分析表明，这些品种分泌两种Bx苷元的能力存在较大差异，即Diboa[2，4-二羟基-2H-1，4-苯并恶嗪-3(4H)-酮]和Diboa[2，4-dihydroxy-7-methoxy-2H-1，4-benzoxazin3(4H)-one].在生物测定中，Diboa和DIMBOA的总分泌量与生长抑制显著相关，统计估计对总体化感作用的贡献率为48-72%。在纯植物毒素的生物测定中，与筛选生物测定中定量的Bx浓度一致的Bx浓度对白纹伊蚊造成了有害影响，几乎复制了统计估计的贡献。在实验室条件下观察到的化感活性与Bx渗出物浓度之间的因果关联表明，这种关联可能对小麦族物种对自然植物群落的干扰具有一定的意义。
Benzoxazinoids (Bx) are natural phytotoxins that function as chemical defense compounds in several species. The release of Bx by intact plant roots associated these compounds with root allelopathy in Triticeae species; however, the significance of exudate concentrations of Bx for plant-plant interactions is still a controversial question. A biological screening of 146 cultivars of four Triticeae species (Triticum aestivum L., Triticum durum Desf., Triticum spelta L., and Secale cereale L.) demonstrated a high cultivar dependence to suppress the root growth of Sinapis alba L. by root allelopathy in a dose-response bioassay. Only a few cultivars possessed a marked high or low allelopathic activity, whereby high-performance liquid chromatography-diode array detection analysis of root exudates revealed that these cultivars differed considerably in their ability to exude the two Bx aglucones, DIBOA [2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one] and DIMBOA [2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin3(4H)-one]. The total amount of DIBOA and DIMBOA exuded showed a significant correlation to the growth inhibition in bioassay with a statistically estimated contribution to the overall allelopathic effect of 48-72%. In a bioassay with pure phytotoxins, Bx concentrations consistent with the amounts quantified in the screening bioassay caused detrimental effects on S. alba and almost reproduced the statistically estimated contribution. The observed causal association between the allelopathic activity under laboratory conditions and the exudate concentrations of Bx suggests that this association might have implications for the interference of Triticeae species in natural plant communities.