The genus Aesculus consists of (depending on classifications) 13-19 plant species named after the territories in which they are distributed. All of these species are trees with green leaves. At the flowering time, pink, red, or yellow flowers appear on the trees, depending on the species. For example, typical in eastern Asia, Aesculus Indica (Indian horse chestnut) has pale pink flowers. Aesculus Pavia (red buckeye) has bright red, catchy flowers; the inflorescences later give brown fruits called chestnuts.
The most common (broad area of distribution) and known to all is the horse chestnut or Aesculus hippocastanum. This species is expected in the Balkans, Europe, and North America. Other species are common in eastern Asia (China, Japan) and differ from western species in their inflorescences and leaves. These trees are common in urban environments: they grow along roads, and alleys and interact closely with cars. Often the health of these trees deteriorates due to a large amount of exhaust from vehicles (Ianovici, Latis, & Radac, 2017, pp. 12406-12408). These trees need constant supervision by botanists; otherwise, their photosynthetic abilities decline.
Aesculus hippocastanum is not picky about food and can grow for a long time in the shade and on sub-hourly soils. Clay soils are also suitable for it, “grow in different site conditions, both soil and microclimatic” (Swoczyna & Latocha, 2020, p. 575). It can tolerate steppe soils well, although excessive acidity of the earth can harm the roots. Broad leaves are well photosynthesized until they get sick and take on the color of rust instead of green (until the amount of chlorophyll A and B pigment in the leaf drops). In addition, green leaves contain xanthophyll pigment (localized in the inner membranes of chloroplasts). They photosynthesize as C3, and this process is bypassed in one stage. Chloroplast organelles store solar energy, subsequently combining ATP and NADP; at the exit, the plant receives a sugar molecule.
References
Ianovici, N., Latis, A. A., & Radac, A. I. (2017). Foliar traits of Juglans regia, Aesculus hippocastanum and Tilia platyphyllos in urban habitat. Romanian Biotechnological Letters, 22(2), 12400-12408.
Swoczyna, T., & Latocha, P. (2020). Monitoring seasonal damage of photosynthetic apparatus in mature street trees exposed to roadside salinity caused by heavy traffic. Photosynthetica, 58(SPECIAL ISSUE), 573-584.