Fernández-Pascual Eduardo, Seal Charlotte E, Pritchard Hugh W
Jardín Botánico Atlántico, Universidad de Oviedo, Avda. del Jardín Botánico 2230, 33394 Gijón/Xixón, Spain and Seed Conservation Department, Royal Botanic Gardens, Kew, Wellcome Trust Millennium Building, Wakehurst Place, Ardingly, West Sussex RH17 6TN, UK.
Jardín Botánico Atlántico, Universidad de Oviedo, Avda. del Jardín Botánico 2230, 33394 Gijón/Xixón, Spain and Seed Conservation Department, Royal Botanic Gardens, Kew, Wellcome Trust Millennium Building, Wakehurst Place, Ardingly, West Sussex RH17 6TN, UK
Ann Bot. 2015 Feb;115(2):201-9. doi: 10.1093/aob/mcu234. Epub 2015 Jan 5.
Environmental temperature regulates plant regeneration via seed in several superimposed ways, and this complex regulation will be disrupted by climate change. The role of diurnally alternating temperatures (ΔT) in terminating dormancy will be a major factor in this disruption, as its effects on seed germination are immediate.
The effect of ΔT on seed germination was modelled using two populations of the wetland sedge Carex diandra, one from a montane site and one from a subalpine site. A cardinal-temperature model was fitted to germination results obtained from a thermal gradient plate, and the model was used to simulate changes in germination under two possible future climate scenarios (RCP2·6 and RCP8·5, for representative concentration pathways) as defined by the Intergovernmental Panel on Climate Change.
Scenario RCP2·6 projected moderate increases in average temperatures and ΔT, whereas RCP8·5 projected greater warming and higher ΔT. Increasing ΔT decreased the base temperature for seed germination and the thermal time required for germination. The effect of higher ΔT together with the higher temperatures increased germination under both climate scenarios.
Carex diandra germination is highly responsive to potential changes in ΔT, and thus this study highlights the role of ΔT in seed responses to climate change. Comprehensive cardinal-temperature models, encompassing the different effects of temperature on seed germination, are needed to understand how climate change will affect plant regeneration.
环境温度通过种子以多种叠加方式调节植物再生，而这种复杂的调节将因气候变化而受到干扰。昼夜交替温度（ΔT）在打破休眠中的作用将是这种干扰的一个主要因素，因为其对种子萌发的影响是即时的。
利用湿地莎草二花苔草的两个种群模拟了ΔT对种子萌发的影响，一个种群来自山地，另一个来自亚高山地区。将一个基点温度模型拟合到从热梯度板获得的萌发结果上，并使用该模型模拟在政府间气候变化专门委员会定义的两种可能的未来气候情景（代表性浓度路径RCP2·6和RCP8·5）下萌发的变化。
情景RCP2·6预计平均温度和ΔT将适度升高，而RCP8·5预计升温幅度更大且ΔT更高。ΔT的增加降低了种子萌发的基础温度和萌发所需的热时间。在两种气候情景下，较高的ΔT与较高温度共同作用增加了萌发率。
二花苔草的萌发对ΔT的潜在变化高度敏感，因此本研究突出了ΔT在种子对气候变化响应中的作用。需要综合考虑温度对种子萌发不同影响的基点温度模型，以了解气候变化将如何影响植物再生。
