Institute of Biosciences and Bioresources (IBBR), Italian National Research Council (CNR), Via Ugo la Malfa 153, 90146, Palermo, Italy.
Department of Earth and Sea Sciences, University of Palermo, Via Archirafi 22, 90123, Palermo, Italy.
Sci Rep. 2024 Mar 14;14(1):6218. doi: 10.1038/s41598-024-56536-x.
Posidonia oceanica meadows are the most productive coastal ecosystem in the Mediterranean. Posidonia oceanica seeds are enclosed in buoyant fleshy fruits that allow dispersal. Many fruits eventually strand on beaches, imposing a remarkable energy cost for the plant. This study aims to assess whether stranded seeds retain functional reproductive potential under a variety of environmental conditions. First, we measured the possibility that seeds could be returned to the sea, by tagging fruits and seeds. Second, we quantified the effect of air, sun and heat exposure on the viability and fitness of stranded fruits and naked seeds. The results showed that on average more than half of fruits and seeds are returned to the sea after stranding events and that fruits significantly protect from desiccation and loss of viability. Furthermore, in fruits exposed to the sun and in naked seeds, seedlings development was slower. This study indicates that a significant portion of stranded P. oceanica fruits have a second chance to recruit and develop into young seedlings, relieving the paradox of large energy investment in seed production and apparent low recruitment rate. Additionally, we provide practical indications for seed collection aimed at maximizing seedling production, useful in meadow restoration campaigns.
波西多尼亚海草草原是地中海最具生产力的沿海生态系统。波西多尼亚海草的种子被包裹在有浮力的肉质果实中，这使得它们能够传播。许多果实最终会搁浅在海滩上，这对植物来说是一个巨大的能量消耗。本研究旨在评估在各种环境条件下，搁浅的种子是否保留了有功能的生殖潜力。首先，我们通过标记果实和种子来衡量种子是否有可能被送回大海。其次，我们量化了空气、阳光和热量暴露对搁浅果实和裸露种子活力和适应性的影响。结果表明，平均有一半以上的果实和种子在搁浅事件后被送回大海，而且果实能显著防止脱水和活力丧失。此外，在暴露于阳光下的果实和裸露的种子中，幼苗的发育速度较慢。本研究表明，相当一部分搁浅的波西多尼亚海草果实有第二次机会进行繁殖，并发育成幼株，从而缓解了在种子生产上投入大量能量而实际幼苗补充率低的悖论。此外，我们还为旨在最大限度提高幼苗产量的种子收集提供了实用建议，这对草原恢复运动很有用。
