From green to red: Urban heat stress drives leaf color evolution

Abstract

Prevalence of impervious surface and resulting higher temperatures in urban areas, known as urban heat islands, comprises prominent characteristics in global cities. However, it is not known whether and how urban plants adapt to such heat stress. This study focused on Oxalis corniculata , which has intraspecific polymorphism in leaf color (green and red) and examined whether the leaf color variation is associated with urban heat stress. Field observations revealed that green-leaved plants were dominant in green habitats, and red-leaved individuals were dominant in urban habitats, at local (<500 meters), landscape (<50 kilometers), and global scales. Growth and photosynthesis experiments demonstrated that red-leaved individuals performed better under heat stress, while green-leaved individuals performed better under nonstressful conditions. Genome-wide SNP analysis suggests that the red leaf may have evolved multiple times from the ancestral green leaf. Overall, the results suggest that the red leaves of O. corniculata observed in cities worldwide are evidence of plant adaptive evolution due to urban heat islands.

Habitat diversification associated with urban development has a little effect on genetic structure in the annual native plant Commelina communis in an East Asian megacity

“…No correlation between genetic distance and geographic distance or landscape was found for the UP and UR population pairs (Figures 3 and 4i,j , Figure S5b ), and the absence of IBD in urban herb populations is also reported by the previous studies (Fukano et al., 2023 ; Johnson et al., 2018 ; Lu et al., 2022 ). It was indicated that founder effects and population isolation in urban habitats did not significantly influence genetic differentiation in this study species.…”

Influence of Harvesting Stages on Phytonutrients and Antioxidant Properties of Leaves of Five Purple-Fleshed Sweet Potato (Ipomoea batatas) Genotypes

“…Sweet potato leaves (SPLs) may contain anthocyanin too low for the naked eye [ 36 ], negative −a* value indicates the presence of chlorophyll, and positive values suggest the presence of anthocyanins such as pelargonidin, peonidin, and cyanidin with a purple-red-pink colour. In some genotypes that show a slightly higher colour coordinate, leaves turn slightly purple-red under heat stress [ 37 ]. Secondary metabolites, such as anthocyanins (red pigments), may play a crucial role in adaptation.…”

“…Secondary metabolites, such as anthocyanins (red pigments), may play a crucial role in adaptation. Anthocyanins have antioxidant properties that may mitigate the damage caused by reactive oxygen species [ 37 ].…”