Seed germination is regulated by temperature and can thus be quantified by thermal models, which can predict germination occurrence in biomes and plant survival under possible climate change scenarios. The objective of this study was to quantify germination based on thermal time and survival risk of 14 species in the Brazilian Cerrado in scenarios of future climate change. Seeds were collected in the warmer regions of the Cerrado, central Brazil, placed in incubators to germinate at constant temperatures of 10–50°C and evaluated every hour or day. Germination rate (R50), time for germination of 50% of the seeds (T50) and dent-like function were used to determine cardinal temperatures. Thermal time parameters were estimated using the Weibull model. Seed germination forecasts were made based on the International Panel on Climatic Change (IPCC) scenarios of global temperature increase. Base temperatures (Tb) ranged from 3.5 to 16.5°C, maximum temperatures (Tmax) from 35 to 50°C and optimum temperatures (To) from 30 to 35°C. Estimated thermal time varied from 484°C h to 400°C d at sub-optimal temperatures and 108°C h at 126°C d at supra-optimal temperatures. Species more distributed showed a higher thermal range of germination and are less susceptible to extinction in temperature increase scenarios. The results of this study suggest that seeds that are non-dormant after dispersal may be the most vulnerable in the future. In this context, our predictions contribute to understand how the survival of trees and shrubs will be affected in the Cerrado in the future.

中文翻译：

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基于热模型量化种子萌发以预测全球气候变化对塞拉多物种的影响

种子萌发受温度调节，因此可以通过热模型进行量化，该模型可以预测可能的气候变化情景下生物群落中的萌发发生和植物存活。本研究的目的是根据巴西塞拉多地区 14 个物种在未来气候变化情景中的热时间和生存风险来量化发芽率。种子在巴西中部塞拉多较温暖的地区收集，置于孵化器中，在 10-50°C 的恒温下发芽，并每小时或每天评估一次。发芽率 (R50), 50% 种子的发芽时间 (吨50) 和类似凹痕的函数用于确定基本温度。使用 Weibull 模型估计热时间参数。种子发芽预测是根据国际气候变化专门委员会 (IPCC) 的全球温度升高情景进行的。基础温度 (吨b) 范围为 3.5 至 16.5°C，最高温度 (吨最大限度) 从 35 到 50°C 和最佳温度 (吨○) 从 30 到 35°C。估计的热时间在次优温度下从 484°C h 到 400°C d 不等，在超优温度下在 126°C d 下从 108°C h 变化。分布更广的物种表现出更高的发芽热范围，并且在温度升高的情况下不太容易灭绝。这项研究的结果表明，散布后未休眠的种子在未来可能是最脆弱的。在这种情况下，我们的预测有助于了解未来塞拉多地区树木和灌木的生存将如何受到影响。