Coffee (Coffea spp.) is an important tropical agricultural crop that has significant economic and social importance in the world. The ex situ conservation of plant genetic resources through seeds is not feasible due to the sensitivity of coffee seed to desiccation and low temperatures. The cryopreservation of zygotic embryos may allow for an efficient and long-term storage of coffee germplasm. This study describes the cryopreservation methods for conserving zygotic embryos of Coffea arabica L. for the long-term conservation of currently available germplasm. Zygotic embryos were successfully cryopreserved in liquid nitrogen at −196 °C under controlled environmental conditions with either droplet-vitrification or encapsulation–vitrification protocols without dehydration. Zygotic embryos had the highest regrowth (100%) following droplet-vitrification cryopreservation using the Plant Vitrification Solution 3 (PVS3) for 40 min at 23 °C. In the case of encapsulation–vitrification using PVS3 for 40 min at 23 °C, the embryo regeneration response was 78%. Plantlets were recovered following shoot multiplication using a temporary immersion system (TIS) and in vitro rooting. The prolific rooting of shoots was observed after 4 weeks of culture in the liquid medium with plugs made of the inert substrate Oasis® In vitro Express (IVE) compared to the semi-solid medium. The successful cryopreservation of coffee zygotic embryos using droplet vitrification and encapsulation–vitrification followed by micropropagation in temporary immersion culture system has not been reported earlier and together these technologies are anticipated to further facilitate the initiatives for the conservation and distribution of coffee germplasm.

中文翻译：

---

通过微繁殖和冷冻保存改善咖啡（小粒咖啡）种质的保存

咖啡（Coffea spp.）是一种重要的热带农作物，在世界上具有重要的经济和社会意义。由于咖啡种子对干燥和低温的敏感性，通过种子对植物遗传资源进行异地保存是不可行的。合子胚胎的冷冻保存可以实现咖啡种质的有效和长期储存。本研究描述了用于保存小粒咖啡合子胚胎的冷冻保存方法L. 用于长期保存当前可用的种质。在受控环境条件下，在-196°C 的液氮中成功冷冻保存了合子胚胎，采用液滴玻璃化或封装-玻璃化方案，无需脱水。使用植物玻璃化溶液 3 (PVS3) 在 23 °C 下进行液滴玻璃化冷冻保存 40 分钟后，合子胚胎的再生率最高 (100%)。在 23°C 下使用 PVS3 进行 40 分钟的封装-玻璃化，胚胎再生反应为 78%。使用临时浸入系统 (TIS) 和体外在芽增殖后恢复幼苗生根。与半固体培养基相比，在带有由惰性基质 Oasis® In vitro Express (IVE)制成的栓塞的液体培养基中培养 4 周后，观察到芽的多产生根。使用液滴玻璃化和封装 - 玻璃化然后在临时浸没培养系统中微繁殖成功地冷冻保存咖啡合子胚胎的情况尚未见较早的报道，预计这些技术将进一步促进咖啡种质保存和分配的举措。