目标:岛屿社区,他们漫长的海岸线和对海平面上升的脆弱性增加,提供令人信服的机会来调查沿海植物的耐盐性。种子通常比其他植物阶段更容易受到增加的胁迫。这项研究的目的是描述在夏威夷群岛沿海社区中发现的来自14个植物科的21种不同植物库的发芽过程中的耐盐性,以增加我们对沿海植物生态学的一般理解,以进行保护和恢复。
方法:将每个物种的种子暴露于未过滤/未处理的海水(总盐度35ppt)和两种盐度处理(10和20ppt),其中海水用蒸馏水稀释,将发芽百分比和时间与蒸馏水对照中的种子进行比较。然后测试未发芽的种子的恢复发芽。我们量化并比较了发芽率,时间,以及物种之间和盐分水平的恢复,并测试与种子大小相关的异质性,休眠类,习惯,威胁地位。
结果:尽管不同物种的耐盐性差异很大,盐度暴露通常会减少和延迟发芽。在较高的盐度水平下检测到最大的影响。对于暴露于较高盐度的种子,恢复发芽总体较高。除了种子质量外,我们探索的所有因素都没有成为耐盐性的预测因素,在较高的盐度下倾向于增强发芽。
结论:物种对盐度暴露的反应表明,沿海系统对盐度胁迫的脆弱性很高,物种之间的变异性可能导致海平面上升下群落聚集和组成的变化。这些结果可以帮助指导面对气候变化的沿海生态系统保护和恢复管理决策。
Islands, with their long coastlines and increased vulnerability to sea level rise, offer compelling opportunities to investigate the salinity tolerance of coastal plants. Seeds are generally more vulnerable than other plant stages to increased stressors. The aim of this study was to characterize salinity tolerance during germination across a diverse pool of 21 species from 14 plant families found in coastal communities throughout the Hawaiian Islands in order to increase our general understanding of coastal plant ecology for conservation and restoration.
Seeds of each species were exposed to unfiltered/untreated seawater (35 ppt total salinity) and two salinity treatments (10 and 20 ppt) in which the seawater was diluted with distilled water, and germination percent and timing were compared to seeds in a distilled water control. Non-germinated seeds were then tested for recovery germination. We quantified and compared germination percent, time and recovery among species and across salinity levels and tested for heterogeneity related to seed size, dormancy class, habit and threatened status.
Although salinity tolerance varied considerably among species, salinity exposure generally reduced and delayed germination. The greatest effects were detected at higher salinity levels. Recovery germination overall was higher for seeds that had been exposed to higher salinity. None of the factors we explored emerged as predictors of salinity tolerance except seed mass, which tended to enhance germination at higher salinity.
Species responses to salinity exposure indicate high vulnerability of coastal systems to increased salinity stress, and variability among species could lead to shifts in community assembly and composition under sea level rise. These results can help guide coastal ecosystem conservation and restoration management decisions in the face of climate change.