van Treuren Rob, Bas Noor, Kodde Jan, Groot Steven P C, Kik Chris
Centre for Genetic Resources, Wageningen Plant Research, Wageningen, the Netherlands.
Department of Bioscience, Wageningen Plant Research, Wageningen, the Netherlands.
Conserv Physiol. 2018 Jun 25;6(1):coy033. doi: 10.1093/conphys/coy033. eCollection 2018.
Genebanks aim to optimize their storage conditions in order to postpone seed ageing as long as possible. As most genebanks have a relatively short life history, empirical data about seed longevity during storage are almost absent. Based on seed characteristics, theoretical predictions indicate that cereal seeds can be stored without substantial loss of viability for time periods exceeding 100 years, even under temperatures of a few degrees above zero. Here we present the results of a germination study in wheat and barley, comparing genebank seed samples maintained at different temperatures for 23-33 years. Wheat and barley seed samples stored at -20°C showed a mean germination of 94% and 90%, respectively, indicating no loss of the initial viability determined for the accessions prior to introduction in the collection. Seed samples maintained at 4°C showed a mean germination of 62% for wheat and 75% for barley. In addition to the observed loss of viability, the 4°C samples also showed a loss in vigour as the time period to reach their final germination was about twice as long compared to the -20°C samples. A subset of the wheat accessions tested in 2011 were retested in 2017, showing further reduction in mean germination to 35% for the 4°C samples, while the -20°C samples remained stable at 95%. Several 4°C samples were even close to a complete loss of viability. Considering that wheat and barley are generally regarded as good maintainers, the rapid loss of seed viability observed in the present study indicates that the seed storage of genetic resources at 4°C should be treated with caution by genebanks, particularly when used for long-term conservation.
基因库旨在优化其储存条件，以便尽可能长时间地延缓种子老化。由于大多数基因库的存续历史相对较短，几乎没有关于种子储存期间寿命的实证数据。基于种子特性的理论预测表明，即使在略高于零摄氏度的温度下，谷类种子也可以储存超过100年而不会有显著的活力损失。在此，我们展示了一项针对小麦和大麦的发芽研究结果，比较了在不同温度下保存23至33年的基因库种子样本。储存在-20°C的小麦和大麦种子样本的平均发芽率分别为94%和90%，这表明在入库前测定的这些种质的初始活力没有损失。保存在4°C的种子样本中，小麦的平均发芽率为62%，大麦为75%。除了观察到的活力损失外，4°C样本的活力也有所下降，因为达到最终发芽所需的时间大约是-20°C样本的两倍。2011年测试的一部分小麦种质在2017年重新进行了测试，结果显示4°C样本的平均发芽率进一步降至35%，而-20°C样本则稳定在95%。一些4°C样本甚至几乎完全丧失了活力。鉴于小麦和大麦通常被认为是良好的种质保存类型，本研究中观察到的种子活力快速丧失表明，基因库在4°C下储存遗传资源时应谨慎对待，尤其是用于长期保存时。
