Properties and functions of the cyanogenic system in higher plants
Properties and functions of the cyanogenic system in higher plants
复制标题
高等植物氰化系统的性质和功能
作者：
P. Kakes
摘要 氰化（HCN 的产生）是所有主要类群中都存在的一个特征。考虑到植物中发现的特殊机制以及HCN生产的生理和生态功能，该系统在高等植物中尤其重要。本文讨论了氰化研究的悠久历史、氰化物质在高等植物类群中的分布、它们在植物器官中的定位及其生物合成途径。相同的主题还讨论了植物中发现的在氰化物质的分解代谢和 HCN 生产中发挥作用的特殊 β-葡萄糖苷酶。讨论了氰化系统的生理和生态功能，重点讨论了迄今为止研究的少数物种，这些物种是多态性的，即在同一种群中包含氰化和氰化个体。尽管这一领域的研究仍处于起步阶段，但很明显，氰化作用是一个复杂系统的一部分，该系统除其他外还可以针对特定食草动物群体提供保护。显然，防御系统受到某种限制，发育的，选择的，或两者兼而有之，这阻止了植物对食草动物的绝对防御。其中一个约束即。较长时间地讨论了氰化系统对生长和/或繁殖的负面影响。许多栽培物种，例如木薯（Manihot esculenta）、高粱（Sorghum spp）和利马豆（Phaseolus lunatus），都是含氰的。用于人类或牲畜消费的物种中的氰化通常被认为是一种不良特征。另一方面，低水平的氰化可能会对食草动物产生更大的敏感性，从而降低产量。显然，氰化现象是试图改良氰化物种的植物育种者感兴趣的一个特征。
SummaryCyanogenesis, the production of HCN is a trait that can be found in all the major taxa. The system is particularly important in higher plants, both in view of the specialized mechanisms found in plants and with regard to the physiological and ecological function of HCN production. The present paper discusses the long history of cyanogenic research, the distribution of the cyanogenic substances among the taxa of higher plants, their localisation in the plant organs and their biosynthetic pathways. The same topics are discussed with regard to the specialized β-glucosidases found in plants that play a role in the catabolism of the cyanogenic substances and in HCN production.The physiological and ecological functions of the cyanogenic systems are discussed with emphasis on the few species studied so far that are polymorphic, i.e. contain cyanogenic and acyanogenic individuals in the same population. Although research in this area is still in its infanthood, it is clear that cyanogenesis is part of a complex system that among others, gives protection against particular groups of herbivores. Apparently the defensive system is under some kind of constraint, developmental, selectional, or both, that prevents plants from having an absolute defense against herbivores. One such constraint viz. a negative effect of the cyanogenic system on growth and/or reproduction is discussed in some length. A number of cultivated species, i.e. cassava (Manihot esculenta), sorghum (Sorghum spp) and lima bean (Phaseolus lunatus) to mention a few, are cyanogenic. Cyanogenesis in species used for human or lifestock consumption is generally considered an undesirable trait. On the other hand low levels of cyanogenesis may cause greater susceptibility to herbivores and consequently lower the yield. Apparently cyanogenesis is a character of interest for plant breeders trying to improve cyanogenic species.