Botanic Garden Meise, Nieuwelaan, Meise, Belgium.
Royal Botanic Gardens, Kew, Wakehurst Place, Ardingly, West Sussex, UK.
Ann Bot. 2018 Mar 5;121(3):405-413. doi: 10.1093/aob/mcx147.
Photoinhibition of seed germination, known to occur notably in species growing in dry and hot habitats, is considered an adaptation to avoid germination at the soil surface after unpredictable rainfall events during the dry season. Hence, the association of this ecophysiological response with plant life histories and the natural environment was investigated in Lilioid monocots, a group of plants where photoinhibition has been pre-eminently observed.
A data set including germination in light and darkness of about 150 monocots was compiled. Habitat preference, local climate conditions, seed traits and temperature conditions used during germination experiments were retrieved. Factors driving the evolution of photoinhibition were analysed within a phylogenetic framework.
Significant phylogenetic signal was found in germination response (λ between 0.76 and 0.80) and photoinhibition (D = 0.406). Photoinhibition was mainly related to plant traits, namely seed coat colour, seed mass and plant height. A relationship with habitat light and moisture was also evident, but the association with climate as well as temperature conditions during incubation was rather poor.
Whilst photoinhibition is prevalent in open habitats, the relationship with habitat moisture conditions and hot and dry climate is weak. Indeed, photoinhibition is also commonly observed in temperate and alpine climate geophytes growing in habitats that are much less susceptible to drought. Hence, phylogenetic inertia, probably mediated by seed morphological traits such as seed coat colour, may explain why temperate climate species have retained photoinhibition inherited from their Mediterranean ancestors.
光抑制种子萌发是一种普遍存在于干旱和炎热生境中的现象，被认为是一种适应策略，可以避免在旱季不可预测的降雨事件后在土壤表面萌发。因此，本研究调查了光抑制这种生理生态响应与植物生活史和自然环境之间的联系，研究对象为百合类单子叶植物，该类群的植物中已明确观察到光抑制现象。
本研究编制了约 150 种单子叶植物在光照和黑暗下的萌发数据。检索了栖息地偏好、当地气候条件、种子特性以及萌发实验中使用的温度条件。在系统发育框架内分析了驱动光抑制进化的因素。
在萌发反应（λ值在 0.76 到 0.80 之间）和光抑制（D = 0.406）方面均发现了显著的系统发育信号。光抑制主要与植物特性有关，即种皮颜色、种子质量和植物高度。与栖息地光照和水分的关系也很明显，但与气候以及孵化期间的温度条件的关联较差。
尽管光抑制在开阔生境中很普遍，但与栖息地水分条件和炎热干燥气候的关系较弱。事实上，光抑制也常见于生长在不易受干旱影响的温带和高山气候地区的中生植物中。因此，可能由种皮颜色等种子形态特征介导的系统发育惰性可以解释为什么温带气候物种保留了其地中海祖先遗传的光抑制。
