Del Vecchio Silvia, Sharma Shivam Kumar, Pavan Mario, Acosta Alicia Teresa Rosario, Bacchetta Gianluigi, de Bello Francesco, Isermann Maike, Michalet Richard, Buffa Gabriella
Department of Environmental Sciences, Informatics and Statistics, Ca' Foscari University of Venice, Venice, Italy.
School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India.
Front Plant Sci. 2022 Aug 11;13:978205. doi: 10.3389/fpls.2022.978205. eCollection 2022.
Within-species variation is a key component of biodiversity and linking it to climatic gradients may significantly improve our understanding of ecological processes. High variability can be expected in plant traits, but it is unclear to which extent it varies across populations under different climatic conditions. Here, we investigated seed trait variability and its environmental dependency across a latitudinal gradient of two widely distributed dune-engineering species ( and ). Seed germination responses against temperature and seed mass were compared within and among six populations exposed to a gradient of temperature and precipitation regimes (Spiekeroog, DE; Bordeaux, FR; Valencia, ES; Cagliari, IT, Rome, IT; Venice, IT). Seed germination showed opposite trends in response to temperature experienced during emergence in both species: with some expectation, in populations exposed to severe winters, seed germination was warm-cued, whereas in populations from warm sites with dry summer, seed germination was cold-cued. In , variability in seed germination responses disappeared once the seed coat was incised. Seed mass from sites with low precipitation was smaller than that from sites with higher precipitation and was better explained by rainfall continentality than by aridity in summer. Within-population variability in seed germination accounted for 5 to 54%, while for seed mass it was lower than 40%. Seed trait variability can be considerable both within- and among-populations even at broad spatial scale. The variability may be hardly predictable since it only partially correlated with the analyzed climatic variables, and with expectation based on the climatic features of the seed site of origin. Considering seed traits variability in the analysis of ecological processes at both within- and among-population levels may help elucidate unclear patterns of species dynamics, thereby contributing to plan adequate measures to counteract biodiversity loss.
种内变异是生物多样性的关键组成部分，将其与气候梯度联系起来可能会显著增进我们对生态过程的理解。植物性状预计具有高度变异性，但尚不清楚在不同气候条件下，这种变异性在种群间的变化程度如何。在此，我们研究了两种广泛分布的沙丘工程物种（和）在纬度梯度上种子性状的变异性及其对环境的依赖性。比较了暴露于温度和降水梯度（德国施皮克罗格；法国波尔多；西班牙巴伦西亚；意大利卡利亚里、罗马；意大利威尼斯）的六个种群内部和之间种子对温度的萌发反应以及种子质量。在这两个物种中，种子萌发对出土期间经历的温度呈现相反趋势：不出所料，在经历严冬的种群中，种子萌发对温暖有反应，而在夏季炎热干燥的温暖地区的种群中，种子萌发对寒冷有反应。在中，一旦种皮被切开，种子萌发反应的变异性就消失了。降水少的地区的种子质量小于降水多的地区的种子质量，并且用降雨大陆性比用夏季干旱能更好地解释这一现象。种子萌发的种群内变异性占5%至54%，而种子质量的种群内变异性低于40%。即使在广泛的空间尺度上，种子性状的变异性在种群内和种群间都可能相当大。这种变异性可能很难预测，因为它仅与分析的气候变量部分相关，并且与基于种子原产地气候特征的预期部分相关。在种群内和种群间水平的生态过程分析中考虑种子性状变异性，可能有助于阐明物种动态的不明模式，从而有助于制定适当措施以应对生物多样性丧失。
