We reviewed the status of orthodox seed collections of globally threatened plants conserved in − 20 °C long-term storage at the Millennium Seed Bank, Royal Botanic Gardens, Kew, UK in terms of their geographic and bioclimatic representativeness, taxonomic and genetic diversity, quality and physiological status. The comprehensive dataset used spans over 45 years of worldwide conservation effort across various organisations. The data provides evidence-based results and future directions for the represented globally threatened flora that are of relevance to all plant conservation and seed banking organisations across the globe. The reviewed sample includes 523 collections and represents a wide geographic range, originating from 67 countries, from all nine bio-geographic continents. The majority of collections originated from temperate climates and from habitats with no dry seasons but experiencing warm summer periods. The taxonomic composition of the collections highlighted a substantial diversity, with 303 taxa (four extinct in the wild; 56 critically endangered; 105 endangered; and 138 vulnerable) represented by 297 species, 199 genera and 74 families. Almost four fifths of the collections were harvested from wild habitats. Whilst wild-origin collections can harbour useful genes not available in the cultivated gene pool, for threatened plants both collections and taxa are likely to suffer from low genetic diversity as a low number of individual plants, populations and/or potentially viable or usable seeds were sampled at the original harvest. Large numbers of empty and infested seeds in the original harvest have significantly affected the quality of collections in terms of availability of potentially viable or usable seeds in collections. As a result, just over one third of taxa and one fifth of collections consisted of ≥ 5000 potentially viable or usable seeds. Viable seeds exhibited a sound physiological status in terms of germinability and viability at the initial round of germination tests after storage, but on average, relative germination and viability achieved were below 85%. A decline in germinability during their variable time of storage was evident for 16% of the 78 collections analysed for longevity. According to a set of criteria, suitable germination protocols for propagation of plants from seeds were identified for 165 taxa. Given the apparent differences between wild species, especially those that are rare and threatened, and domesticated crops, the quality and physiological status of reviewed collections are reasonably sound. The characteristics we observed for collections, the challenges we identified for conserving them and the germination protocols we suggested for propagation of plants from seeds have the scope to be noted, integrated and used globally across various conservation activities and policies.

我们从地理和生物气候代表性，生物分类学和遗传多样性，质量方面，回顾了在英国邱园皇家植物园的千年种子库中长期保存于− 20°C的全球濒危植物的正统种子收藏的状况。和生理状态。所使用的综合数据集横跨各个组织超过45年的全球保护工作。数据为与全球所有植物保护和种子库组织相关的代表全球受威胁植物提供了基于证据的结果和未来方向。审查的样本包括523个馆藏，代表了来自九个生物地理大洲的67个国家的广泛地理区域。大部分藏品来自温带气候和没有干燥季节但经历温暖的夏季的栖息地。这些集合的生物分类组成突出了多样性，共有297个科，199个属和74个科的303个分类单元（在野生环境中已灭绝4个；濒临灭绝的56个；濒临灭绝的105个；以及138个易受害的）。几乎五分之四的收藏品均来自野生栖息地。尽管野生来源的收集物可以包含栽培基因库中无法提供的有用基因，但是对于濒临灭绝的植物，由于单个植物，种群和/或潜在的可行或可用种子数量少，收集物和分类单元都可能遭受低遗传多样性的困扰。在原始收获时取样。原始收成中大量的空种子和出没过的种子在收集中潜在可行或可用种子的可用性方面显着影响了收集的质量。结果，超过三分之一的分类单元和五分之一的集合体由≥5000种潜在可行或可用的种子组成。在储存后的第一轮发芽试验中，就可发芽性和生存力而言，活种子表现出良好的生理状态，但平均而言，获得的相对发芽和生存力低于85％。在经分析的78个寿命长的集合中，有16％的细菌在不同的储存时间内可生性下降了。根据一组标准，针对165个分类单元确定了适合从种子繁殖植物的发芽方案。考虑到野生物种之间的明显差异，特别是那些稀有和受威胁的物种与驯化的作物之间的差异，经过审查的馆藏的质量和生理状况是合理的。我们观察到的特性，我们为保护它们而面临的挑战以及我们建议的从种子繁殖植物的发芽方案在各种保护活动和政策中都应予以注意，整合和全球使用。