DiCara Caitlin, Gedan Keryn
Department of Biological Sciences, Columbian College of Arts & Sciences, The George Washington University, Washington, DC 20052, USA.
Plants (Basel). 2023 Jul 1;12(13):2522. doi: 10.3390/plants12132522.
Species-specific variation in response to stress is a key driver of ecological patterns. As climate change alters stress regimes, coastal plants are experiencing intensifying salinity stress due to sea-level rise and more intense storms. This study investigates the variation in species' responses to presses and pulses of salinity stress in five glycophytic and five halophytic species to determine whether salinity intensity, duration, or their interaction best explain patterns of survival and performance. In salinity stress exposure experiments, we manipulated the intensity and duration of salinity exposure to challenge species' expected salinity tolerances. Salinity intensity best explained patterns of survival in glycophytic species, while the interaction between intensity and duration was a better predictor of survival in halophytic species. The interaction between intensity and duration also best explained biomass and chlorophyll production for all tested species. There was interspecific variability in the magnitude of the interactive effect of salinity intensity and duration, with some glycophytic species (, , and ) having a more pronounced, negative biomass response. For the majority of species, prolonged stress duration exacerbated the negative effect of salinity intensity on biomass. We also observed an unexpected, compensatory response in chlorophyll production in two species, and , for which the effect of salinity intensity on chlorophyll became more positive with increasing duration. We found the regression coefficient of salinity intensity versus biomass at the highest stress duration, i.e., as a press stressor, to be a useful indicator of salinity tolerance, for which species' salinity-tolerance levels matched those in the literature. In conclusion, by measuring species-specific responses to stress exposure, we were able to visualize the independent and interactive effects of two components of a salinity stress regime, intensity, and duration, to reveal how species' responses vary in magnitude and by tolerance class.
物种对胁迫反应的特异性差异是生态格局的关键驱动因素。随着气候变化改变胁迫状况，沿海植物因海平面上升和更强烈的风暴而面临日益加剧的盐度胁迫。本研究调查了五个甜土植物物种和五个盐生植物物种对盐度胁迫的压力和脉冲反应的差异，以确定盐度强度、持续时间或它们的相互作用是否最能解释生存和表现模式。在盐度胁迫暴露实验中，我们操纵了盐度暴露的强度和持续时间，以挑战物种预期的盐度耐受性。盐度强度最能解释甜土植物物种的生存模式，而强度和持续时间之间的相互作用则是盐生植物物种生存的更好预测指标。强度和持续时间之间的相互作用也最能解释所有测试物种的生物量和叶绿素产量。盐度强度和持续时间的交互作用大小存在种间变异性，一些甜土植物物种（、和）具有更明显的负生物量反应。对于大多数物种来说，延长胁迫持续时间会加剧盐度强度对生物量的负面影响。我们还在两个物种和中观察到叶绿素产量出现了意想不到的补偿反应，对于这两个物种，随着持续时间的增加，盐度强度对叶绿素的影响变得更加积极。我们发现，在最高胁迫持续时间下，即作为压力胁迫源时，盐度强度与生物量的回归系数是盐度耐受性的一个有用指标，其物种的盐度耐受水平与文献中的水平相符。总之，通过测量物种对胁迫暴露的特异性反应，我们能够直观地看到盐度胁迫状况的两个组成部分——强度和持续时间的独立和交互作用，以揭示物种反应在大小和耐受类别上是如何变化的。
