Wolkis Dustin, Deans Susan
Department of Science and Conservation, National Tropical Botanical Garden, Kalāheo, Hawaii.
Department of Plant Science, Chicago Botanic Garden, Glencoe, Illinois.
Biopreserv Biobank. 2019 Dec;17(6):583-590. doi: 10.1089/bio.2019.0044. Epub 2019 Aug 20.
Seed banks serve the purpose of maintaining germplasm for species preservation. Herbarium vouchers may be a viable source of unique and/or additional seeds for restoration as they can sometimes be from larger and more representative populations compared with seed banks. Rapid 'ōhi'a death (ROD) has emerged as a serious threat against Hawaii's most iconic and foundational forest tree ( spp.), and seed banking has been identified as an important strategy in preserving the genetic diversity of 'ōhi'a. With respect to 'ōhi'a we ask the following: (1) what is the long-term viability of 'ōhi'a seeds stored in herbarium conditions, (2) how do herbarium curation practices affect seed viability, and (3) how long do seeds survive using conventional storage methods? We placed fresh 'ōhi'a seeds in a herbarium dryer (57°C/5% relative humidity) for 5 days, freezer (-18°C/95% RH) for 2 weeks, and dryer then freezer, and compared against fresh control seeds. Seeds were harvested from a chronosequence of herbarium specimens, withdrawn from conventional storage conditions up to 3.75 and 6.5 years before experiments began, and germination assessed. There was no difference in the proportion germinated among treatments and control testing for herbarium entry ( = 0.56). Although no seeds from herbarium specimens germinated, freshly collected dried and frozen seeds germinated at a level equivalent to the control ( = 0.76). For seeds stored using conventional storage methods at 3.75 and 6.5 years, germination was equivalent to freshly harvested seeds. This suggests that seeds can survive the extreme climate conditions necessary to enter herbaria, but lose viability after storage at ambient conditions in 4 years or less. Although 'ōhi'a seeds may be plentiful in herbaria, we recommend using seeds deposited into seed banks using conventional storage methods for orthodox seeds for postdisturbance restoration, and to combat ROD.
种子库的目的是保存种质以保护物种。植物标本凭证可能是用于恢复的独特和/或额外种子的可行来源，因为与种子库相比，它们有时来自更大且更具代表性的种群。快速 ʻōhiʻa 死亡（ROD）已成为对夏威夷最具标志性和基础性的森林树种（ ʻōhiʻa spp.）的严重威胁，种子库已被确定为保护 ʻōhiʻa 遗传多样性的重要策略。关于 ʻōhiʻa，我们提出以下问题：（1）保存在植物标本条件下的 ʻōhiʻa 种子的长期活力如何，（2）植物标本馆的保存方法如何影响种子活力，以及（3）使用传统储存方法种子能存活多久？我们将新鲜的 ʻōhiʻa 种子置于植物标本干燥器（57°C/5%相对湿度）中5天，置于冷冻箱（-18°C/95%相对湿度）中2周，以及先干燥后冷冻，并与新鲜对照种子进行比较。种子从植物标本的时间序列样本中收获，在实验开始前从传统储存条件中取出，时间长达3.75年和6.5年，并评估发芽情况。在植物标本入库的处理和对照测试中，发芽比例没有差异（= 0.56）。虽然植物标本样本中的种子没有发芽，但新鲜采集的干燥和冷冻种子的发芽水平与对照相当（= 0.76）。对于使用传统储存方法储存3.75年和6.5年的种子，发芽情况与新鲜收获的种子相当。这表明种子能够经受住进入植物标本馆所需的极端气候条件，但在环境条件下储存4年或更短时间后会失去活力。虽然植物标本馆中可能有大量的 ʻōhiʻa 种子，但我们建议使用按照传统储存方法存入种子库的正统种子用于干扰后恢复，并应对ROD。
