Botany, Ahead of Print.
Freezing as a climatic extreme can contribute to patterns of plant distribution by potentially impacting mechanisms of seed release. Therefore, the impact of freezing on samara release and seed germination in infructescences (cones) of Casuarina cunninghamiana Miq. was assessed. Cones at field moisture content were frozen (22 h) and thawed (2 h) through zero to five cycles. Freezing impaired cone dehiscence and samara release (<1% samaras released with ≥2 freezing cycles) and reduced germination from frozen samaras still in the cone (30% to 50% loss in total germination with one to five freezing cycles, respectively). Seed germination from a sample of air-dried samaras was only mildly impacted (10% drop in total germination with five freezing cycles). This vulnerability of C. cunninghamiana to freezing damage, particularly samara release, appears to be a novel finding for woody perennials with fruiting structures that are retained in the canopy during winter. Vulnerability to freezing damage also appears to be a potential factor in species persistence and invasiveness.

中文翻译：

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冷冻对木麻黄（Casuarinaceae）锥体开裂、翅果释放和种子萌发的影响

植物学，超前印刷。
冻结作为极端气候可能会通过潜在影响种子释放机制来影响植物分布模式。因此，冷冻对 Casuarina cunninghamiana Miq 果序（球果）中的翼果释放和种子萌发的影响。被评估。将田间水分含量的锥体冷冻（22 小时）并通过零到五个循环解冻（2 小时）。冷冻损害了锥体开裂和翼果释放（<1% 翼果释放，≥2 次冷冻循环释放）并减少仍在锥体中的冷冻翼果的发芽（1 到 5 个冷冻周期，总发芽损失 30% 至 50%，分别）。来自风干 samara 样品的种子发芽仅受到轻微影响（五个冷冻循环后总发芽率下降 10%）。C. cunninghamiana 易受冻害，尤其是翼果释放，对于在冬季保留在树冠中的果实结构的多年生木本植物来说，这似乎是一个新发现。对冻害的脆弱性似乎也是物种持久性和入侵性的潜在因素。