Instituto Multidisciplinario de Biología Vegetal (CONICET-UNC), Córdoba, Argentina.
Fitz Patrick Institute of African Ornithology, DSI-NRF Centre of Excellence, University of Cape Town, Rondebosch, South Africa.
Plant Biol (Stuttg). 2023 Apr;25(3):403-410. doi: 10.1111/plb.13509. Epub 2023 Feb 27.
Invasive plants displaying disparate pollination environments and abiotic conditions in native and non-native ranges provide ideal systems to test the role of different ecological factors driving flower colour variation. We quantified corolla reflectance of the ornithophilous South American Nicotiana glauca in native populations, where plants are pollinated by hummingbirds, and in populations from two invaded regions: South Africa, where plants are pollinated by sunbirds, and the Balearic island of Mallorca, where plants reproduce by selfing. Using visual modelling we examined how corolla reflectance could be perceived by floral visitors present in each region. Through Mantel tests we assessed a possible association between flower colour and different abiotic factors. Corolla reflectance variation (mainly along medium to long wavelengths, i.e. human green-yellow to red colours) was greater among studied regions than within them. Flower colour was more similar between South America and South Africa, which share birds as pollinators. Within invaded regions, corolla reflectance variation was lower in South Africa, where populations could not be distinguished from each other by sunbirds, than in Spain, where populations could be distinguished from each other by their occasional visitors. Differences in corolla colour among populations were partially associated with differences in temperature. Our findings suggest that shifts in flower colour of N. glauca across native and invaded ranges could be shaped by changes in both pollination environment and climatic factors. This is the first study on plant invasions considering visual perception of different pollinators and abiotic drivers of flower colour variation.
在原生和非原生分布区具有不同传粉环境和非生物条件的入侵植物为测试不同生态因素驱动花部颜色变异的作用提供了理想的系统。我们量化了南美长距烟草（Nicotiana glauca）在原生种群中的花色反射率，该植物在原生种群中由蜂鸟授粉，而在两个入侵区的种群中：南非，由太阳鸟授粉；巴利阿里群岛的马略卡岛，通过自交繁殖。我们使用视觉模型研究了花部颜色在每个地区的传粉者眼中是如何被感知的。通过曼特尔检验，我们评估了花色与不同非生物因素之间可能存在的联系。与原生种群相比，花色在研究区域之间的变化更大（主要在中长波长，即人类的绿-黄-红颜色）。在具有相同传粉者的南美和南非，花色更相似。在入侵区，在南非，由于太阳鸟不能将种群区分开来，花色变化较小；而在西班牙，由于偶尔来访的访客可以将种群区分开来，花色变化较大。种群间花部颜色的差异部分与温度差异有关。我们的研究结果表明，长距烟草在原生和入侵区的花色变化可能是由传粉环境和气候因素的变化共同塑造的。这是第一个考虑不同传粉者的视觉感知和花色变异的非生物驱动因素的植物入侵研究。
