Time-separated seed collections with a separation period of 12–18 years were used to study recent changes in germination traits and the role of climate factors in seven tropical dry forest (TDF) woody species in Zambia, southern Africa. In all the species, peak and final germination were lower in recent (2016–2021) seed collections than in historic (1998–2005) seed collections during the first germination season. However, in species with seed dormancy, both peak and final germination after one year burial were higher in recent seed collections than in historic seed collections. Three monthly climate factors had significant effects on final germination in the different species and the timing of most of these factors was during seed development and ripening that suggest that these factors operated through mother plants. In species with seed dormancy, post-first-year germination of buried seeds responded to climate factors in the regeneration niche. Climate factors that significantly affected germination included those that changed over the separation period between historic and recent seed collections. This indicates that short-time climatic changes may have the potential to impact germination in TDF woody species of southern Africa. The germination responses to climate factors were both positive and negative and it is not clear whether these are adaptations or not. Further research is required to assess the adaptive significance of these changes in germination traits in TDF species of southern Africa.

中文翻译：

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赞比亚中部干燥森林物种不同时间种子收集的发芽性状差异以及气候的潜在作用

使用分离期为 12-18 年的时间间隔种子收集来研究南部非洲赞比亚的七种热带干燥森林 (TDF) 木本物种的发芽性状的最新变化以及气候因素的作用。在所有物种中，在第一个发芽季节，最近（2016-2021）种子收集的峰值和最终发芽率低于历史（1998-2005）种子收集的峰值和最终发芽率。然而，在种子休眠的物种中，最近收集的种子在埋藏一年后的峰值和最终发芽率均高于历史种子收集。三个月的气候因素对不同物种的最终发芽有显着影响，并且大多数这些因素发生的时间是在种子发育和成熟期间，这表明这些因素通过母体植物发挥作用。在种子休眠的物种中，埋藏种子的第一年发芽对再生生态位中的气候因素做出了反应。显着影响发芽的气候因素包括在历史和最近种子采集之间的间隔期间发生变化的气候因素。这表明短期气候变化可能会影响南部非洲 TDF 木本物种的发芽。发芽对气候因素的反应既有积极的也有消极的，目前尚不清楚这些是否是适应。需要进一步的研究来评估南部非洲 TDF 物种发芽性状变化的适应性意义。