Aims Seed dispersal by endozoochory is an important process in plant regeneration and the establishment of new populations. Seeds with dormancy may especially benefit after disperser gut passage. However, the ways in which gut passage affect the germination of plant species with physiological dormancy remain unclear. Here, we experimentally assessed the mutualistic interaction between the Austral parakeet (Enicognathus ferrugineus) as a disperser of calafate (Berberis microphylla), a thorny bush inhabiting the understory of the Austral temperate forests of South America with seeds that are characterized by deep physiological dormancy. Methods Germination success and viability of calafate seeds obtained from faeces and from intact fruits were tested under four treatments: (i) digested seeds, (ii) digested seeds with faecal extract, (iii) intact seeds from fruit and (iv) intact seeds from fruit with pulp. Important Findings About 65% of the Austral parakeet droppings contained calafate seeds. Viability of seeds did not differ between treatments. However, germination was significantly higher in digested seeds than in intact seeds from fruits, while no difference was found between faecal and pulp extracts. Neither faecal matter nor fruit pulp provided seeds with any ecological advantages derived from enhancing germinability, but did confer some disadvantage in germination time. Faecal matter is expected to be completely lacking around seeds after several months under snow before germinating in the following spring, given intense washing due to persistent rain and the spring thaw in the Patagonian Andes. The higher germinability along with faster germination of digested seeds supports the hypothesis of a legitimate mutualistic interaction between Austral parakeets and calafate. We hypothesized that the passage through the disperser digestive tract might break physiological dormancy as differences in germinability between ingested and non-ingested seeds. Our results highlight the relevant role of endozoochory in plant species with physiological dormancy living in highly seasonal environments.

中文翻译：

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内源性动物打破生理休眠：南方长尾小鹦鹉（Enicognathus ferrugineus）作为巴塔哥尼亚安第斯山脉中calafate（小叶小檗）的合法分散者

目的 通过动物体内的种子传播是植物再生和建立新种群的重要过程。处于休眠状态的种子在通过分散器肠道后可能特别受益。然而，肠道通道影响生理休眠植物物种萌发的方式仍不清楚。在这里，我们通过实验评估了南方长尾小鹦鹉 (Enicognathus ferrugineus) 作为 calafate (Berberis microphylla) 的分散体之间的互惠互作，这是一种栖息在南美洲南方温带森林林下的带刺灌木，其种子具有深度生理休眠的特征。方法 在四种处理下测试从粪便和完整果实中获得的卡拉法特种子的发芽成功率和生存力：(i) 消化种子，(ii) 用粪便提取物消化的种子，(iii) 来自水果的完整种子和 (iv) 来自带有果肉的水果的完整种子。重要发现 大约 65% 的南方长尾小鹦鹉粪便含有卡拉法特种子。种子的生存力在处理之间没有差异。然而，消化种子的发芽率明显高于果实的完整种子，而粪便和果肉提取物之间没有发现差异。粪便和果肉都没有为种子提供任何源自提高发芽性的生态优势，但确实在发芽时间方面带来了一些不利因素。由于巴塔哥尼亚安第斯山脉的持续降雨和春季解冻，在下一个春天发芽之前，预计在雪下几个月后种子周围的粪便完全缺乏。更高的发芽率以及消化种子的更快发芽支持了南方长尾小鹦鹉和卡拉法特之间合法互惠互利的假设。我们假设通过分散器消化道的通道可能会打破生理休眠，因为摄入和未摄入种子之间的发芽性存在差异。我们的研究结果强调了内源性动物在生理休眠的植物物种中的相关作用，这些植物物种生活在高度季节性的环境中。