Lotus flowers heat themselves, and their leaves shed water like glass
Lotus leaves are so water-repellent that droplets touch them at a single tiny point and roll away at the slightest tilt, a phenomenon now called the lotus effect. The flowers also generate their own heat through an unusual chemical pathway, and nobody is certain why.
The genus Nelumbo, usually called lotus, consists of water plants with big, striking blooms. It looks like the water lilies but is only distantly related to them, and it has nothing to do with the land plant genus also named Lotus. The lineage is ancient, with dozens of fossil species going back to the Early Cretaceous, yet only two survive. Nelumbo nucifera grows wild across East, South and Southeast Asia and probably Australia, and is widely farmed for food and traditional Chinese medicine. Nelumbo lutea is native to North America and the Caribbean. Gardeners have crossed the two, even though they never meet in the wild.
The water repellence matters because the leaves float. Most plants keep their breathing pores, the stomata, on the underside of the leaf, but a floating lotus leaf has them on top, where rain, mist or splashing water could clog them. Dense bumps called papillae, each tipped with small waxy tubules, cut the contact area for water to almost nothing. Droplets merge quickly and slide off, leaving the pores free for gas exchange.
Heat comes from the alternative oxidase pathway, a cyanide-resistant route for electrons in the mitochondria that bypasses the usual cytochrome complexes. The plant lowers its levels of ubiquitin during this process, which lets the enzyme keep working without being broken down. Only the receptacle, stamens and petals warm up, and each does so independently.
Several explanations compete. Warm flowers may attract insects that rest inside to heat up, picking up and dropping pollen as they do. The warmth may suit pollinator mating, help release scent over open water, or act as a signal for heat-sensing insects in the dark. None of these ideas has yet been shown to be more likely than the rest.
Source: Nelumbo
