The effect of stratification and shade on germination of <i>Nothofagus cliffortioides</i> (Hook.f.) Oerst seeds

Seed stratification can substantially improve germinability. In glasshouse settings, knowledge of stratification requirements is critical for allowing effective control of germination. In addition, for species that seed irregularly, understanding how to break dormancy of aged seeds is important. This study tests whether moisture is required as well as cold conditions to stratify <i>Nothofagus cliffortioides</i> (Hook.f.) Oerst. (mountain beech) seeds, and whether shading during the germination period improves germination and survival. The seeds tested had been collected during a heavy mast year and stored dry for c. 2 years at −20°C. Dry cold stratification failed to break dormancy, with average germination (3.3%) not significantly different from unstratified controls (5.3%). In contrast, average germination of moist cold stratified seeds was at least four times higher (21.7%), with most germination occurring within 30 days. Hessian covers on trays had no impact on germination or survival. These results provide useful information for growing <i>N. cliffortioides</i> from seed and raise the possibility that lengthened drought periods under future climate regimes could affect natural <i>Nothofagus</i> regeneration by reducing the effectiveness of natural winter conditions for breaking seed dormancy.层积处理可显著提升种子发芽力。在温室栽培场景中，掌握层积处理的相关要求，对实现高效的发芽调控至关重要。此外，对于结实周期不规则的物种而言，明晰如何打破老化种子的休眠状态同样意义重大。本研究旨在探究：对南山毛榉（*Nothofagus cliffortioides* (Hook.f.) Oerst.，英文俗称山毛榉）的种子实施层积处理时，是否需要同时满足湿润与低温条件，以及发芽阶段的遮阴处理能否提升发芽率与幼苗存活率。本研究所用的种子采自结实大年，并以干燥状态在-20℃条件下储存了约2年。单纯低温干燥层积处理未能打破种子休眠，其平均发芽率（3.3%）与未经过层积处理的对照组（5.3%）并无显著差异。与之相反，经湿润低温层积处理的种子平均发芽率提升至少四倍，达21.7%，且绝大多数种子在30天内完成发芽。育苗盘上覆盖粗麻布对种子发芽率与幼苗存活率均无显著影响。本研究结果可为南山毛榉的实生育苗提供实用参考，同时也提出了一种潜在可能：未来气候模式下干旱周期的延长，可能会通过削弱自然冬季条件打破种子休眠的效能，进而影响天然南山毛榉种群的自然更新。