Alemanno L, Ramos T, Gargadenec A, Andary C, Ferriere N
Cirad, TA 80/02, Avenue Agropolis, 34398 Montpellier, Cédex 5, France.
Ann Bot. 2003 Oct;92(4):613-23. doi: 10.1093/aob/mcg177. Epub 2003 Aug 21.
Cocoa breeders and growers continue to face the problem of high heterogeneity between individuals derived from one progeny. Vegetative propagation by somatic embryogenesis could be a way to increase genetic gains in the field. Somatic embryogenesis in cocoa is difficult and this species is considered as recalcitrant. This study was conducted to investigate the phenolic composition of cocoa flowers (the explants used to achieve somatic embryogenesis) and how it changes during the process, by means of histochemistry and conventional chemical techniques. In flowers, all parts contained polyphenolics but their locations were specific to the organ considered. After placing floral explants in vitro, the polyphenolic content was qualitatively modified and maintained in the calli throughout the culture process. Among the new polyphenolics, the three most abundant were isolated and characterized by 1H- and 13C-NMR. They were hydroxycinnamic acid amides: N-trans-caffeoyl-l-DOPA or clovamide, N-trans-p-coumaroyl-l-tyrosine or deoxiclovamide, and N-trans-caffeoyl-l-tyrosine. The same compounds were found also in fresh, unfermented cocoa beans. The synthesis kinetics for these compounds in calli, under different somatic embryogenesis conditions, revealed a higher concentration under non-embryogenic conditions. Given the antioxidant nature of these compounds, they could reflect the stress status of the tissues.
可可育种者和种植者仍然面临着一个问题，即来自同一个后代的个体之间存在高度异质性。通过体细胞胚胎发生进行营养繁殖可能是一种在田间提高遗传增益的方法。可可的体细胞胚胎发生很困难，该物种被认为是顽拗型的。本研究旨在通过组织化学和传统化学技术，研究可可花（用于实现体细胞胚胎发生的外植体）的酚类成分及其在该过程中的变化情况。在花中，所有部分都含有多酚类物质，但它们的位置因所考虑的器官而异。将花外植体置于体外后，多酚含量发生了定性改变，并在整个培养过程中在愈伤组织中保持。在新的多酚类物质中，分离出了含量最高的三种，并通过1H-和13C-NMR对其进行了表征。它们是羟基肉桂酸酰胺：N-反式-咖啡酰-L-多巴或丁香酰胺、N-反式-对香豆酰-L-酪氨酸或脱氧丁香酰胺以及N-反式-咖啡酰-L-酪氨酸。在新鲜的未发酵可可豆中也发现了相同的化合物。在不同的体细胞胚胎发生条件下，这些化合物在愈伤组织中的合成动力学表明，在非胚性条件下其浓度更高。鉴于这些化合物的抗氧化性质，它们可能反映了组织的应激状态。
