Recent polyploidy in gymnosperms is unusually scarce being present in only 9.80 % of the 714 taxa studied cytologically. Polyploid forms are represented by sporadic seedlings and individual trees, intraspecific polyploidy in cultivation or in wild and entirely polyploid species and genera. Polyploidy shows a non-random distribution in different genera being mostly prevalent in Ephedra and Juniperus, besides the classic examples of Sequoia and Fitzroya. Remarkably, both Ephedra and Juniperus show adaptive radiation by interspecific hybridization followed by polyploidy while in Ginkgo viable polyploid cytotypes are found in cultivation. Induced polyploidy has not provided any tangible results in the past but recent attempts on certain genera of Cupressaceae hold some promise of producing cultivars for horticulture trade. Lastly, various evidences derived from cytological analysis, fossil pollen, guard cells and comparative genomic studies indicating the occurrence of paleopolyploidy have been discussed.

中文翻译：

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裸子植物中的多倍体-重新评估

细胞学研究的714个分类单元中，仅9.80％的裸子植物中最近的多倍体异常稀少。多倍体形式以散生的幼苗和单株树木，栽培中或野生和完全多倍体物种和属中的种内多倍体为代表。多倍体显示出不同属的非随机分布，除了红杉和菲茨罗亚的经典例子外，在麻黄和杜松属中普遍存在。值得注意的是，在银杏叶中，麻黄和Jun属均表现出通过种间杂交然后多倍体的适应性辐射在培养中发现有活力的多倍体细胞型。诱导多倍体在过去没有提供任何实际结果，但是最近对柏科某些属的尝试为生产园艺贸易的栽培品种提供了一些希望。最后，讨论了来自细胞学分析，化石花粉，保卫细胞和比较基因组学研究的各种证据，这些证据表明古多倍体的发生。