Branches Protected From the Sun

white powder is seen on a quiver tree with a blue sky in the background

Biological Strategy

Fan aloe

AskNature Team

Image: Tom Skrinar / Flickr / Some rights reserved

Protect From Light

Access to sunlight is crucial to living systems because it’s the primary energy source for life. However, too much sunlight in the form of ultraviolet radiation (UV) can cause damage to living tissues. Therefore, living systems have strategies to filter out some or all UV radiation. For example, some plants that live in areas exposed to long periods of direct sunlight have reflective surfaces (such as white hairs or powder) that reflect UV light.

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Protect From Temperature

Many living systems function best within specific temperature ranges. Temperatures higher or lower than that range can negatively impact a living system’s physiological or chemical processes, and damage its exterior or interior. Living systems must manage high or low temperatures using minimal energy, which often requires controlling responses along incremental temperature changes. To do so, living systems use a variety of strategies, such as avoiding high or low temperatures, removing excess heat, and holding heat in. Insulation is a well-known example of managing low temperatures by retaining heat using thick layers of hair, fur, or feathers to hold warm air next to the skin.

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Flowering Plants

Clade Angiosperms (“receptacle seed”): Dandelions, oaks, grasses, cacti, apples

With 416 families containing some 300,000 known species, angiosperms are the most diverse group of plants, and they can be found around the globe in a wide variety of habitats. They are characterized by seeds that grow enclosed in ovaries, which are enclosed in flowers. The floral organs then develop into fruits of myriad kinds and dimensions, from simple seed casings on maples to elaborate fleshy growths like papayas. The oldest flower known from fossils, Montsechia vidalii, appeared during the Jurassic Period 130 million years ago. They are the primary food source for herbivorous animals, which in turn makes them the indirect food source for carnivores as well.

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The branches of a quiver tree are protected from the heat of the sun by a reflective coating of white powder.

“The quiver tree that grows in the Namib is a kind of aloe. Like the rest of its family, it has thick succulent leaves growing in a rosette, but these are hoisted twenty feet in the air, each at the end of a stumpy branch. That in itself is a way of escaping the worst of the devastating heat and reducing the amount of moisture inevitably lost by evaporation from the surface of their leaves. The branches themselves are thickly covered in a fine white powder. That too helps in keeping cool for it reflects the sun’s heat instead of absorbing it…The branches and trunk are filled with a soft fibre that can hold a great quantity of water.” (Attenborough 1995:269)