Cytological development and sesquiterpene lactone secretion in capitate glandular trichomes of sunflower
Cytological development and sesquiterpene lactone secretion in capitate glandular trichomes of sunflower
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DOI：
10.1055/s-2005-837575
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发表时间：
2005-03-01
期刊：
影响因子：
3.9
通讯作者：
Spring, O
中科院分区：
文献类型：
--
作者：
Göpfert, JC;Heil, N;Spring, O
向日葵花药附属物头状腺毛中倍半萜内酯的分泌。通过光学显微镜和荧光显微镜以及HPLC分析观察到了菊科植物中的一种。向日葵头状花序内的花盘显示了已知的从中心到边缘的个体发育进程。在小花发育过程中，花药附属物中的毛状体将其代谢产物分泌到两个顶端细胞前的表皮下分泌物储存空间中。从分泌前期到分泌后期，形成表皮地球仪的所有阶段都可以在显微镜下观察到，同时监测分泌活动。选择已知结构的6种大环内酯和向日葵内酯进行定量分析。通过HPLC分析监测在表皮下空间延伸期间STL含量的增加。因此，STL生物合成的开始和终止被定义为与小花个体发育的其他发育阶段，特别是花粉形成有关。部分分泌的物质显示自发荧光，这可以归因于羟基-三甲氧基-黄酮，通过NMR和质谱法测定。花药腺毛在细胞学和化学上与向日葵的叶腺毛相似，代表了许多菊科植物常见的多细胞头状腺毛类型。H.结果表明，它们可为菊科植物STL和黄酮代谢研究提供有价值的模式系统。
The secretion of sesquiterpene lactones (STL) in capitate glandular trichomes from the anther appendages of Helianthus annuus L. (Asteraceae) was observed by light and fluorescence microscopy and HPLC analysis. Disk flowers within the sunflower capitulum showed the known ontogenetic progression from the centre to the margin. During development of the florets, the trichomes in the anther appendages secreted their metabolites into the subcuticular secretion storage space in front of the two apical cells. All stages of forming the cuticular globe, from the pre-secretory to the post-secretory phase, could be observed microscopically and secretory activity was simultaneously monitored. Six germacrolides and heliangolides of known structure were selected for quantitative analysis. The increase in STL content during extension of the subcuticular space was monitored by HPLC analysis. Thereby, the start and termination of STL biosynthesis was defined in relation to other developmental stages of floret ontogenesis, particularly, the pollen formation. Part of the secreted material showed autofluorescence which could be attributed to a hydroxy-trimethoxy-flavone, as determined by NMR and mass spectroscopy. The anther trichomes were cytologically and chemically similar to foliar glandular trichomes of sunflower and represent the multicellular capitate glandular trichome type common to many Asteraceae. The ease with which anther trichomes of H. annuus can be harvested and analyzed suggests that they can provide a valuable model system for investigation of STL and flavonoid metabolism in Asteraceae.