Leaves Channel Water

green leaves with prominent tips hang off a tree branch in sunlight with a blue sky

Biological Strategy

Peepul tree

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Image: Bhikku Amitha / Pixabay / Free non-commercial use

Distribute Liquids

Liquids include water, as well as body fluids such as blood, gastric juices, nutrient-laden liquids, and more. To survive, many living systems must move such liquids within themselves or between locations. Because of their properties, liquids tend to disperse unless they are confined in some way. To address this, living systems have strategies to confine fluids for transport, and to overcome barriers such as gravity, friction, and other forces. Some of these same barriers also provide opportunities. Trees and giraffes face the same challenge: how to move fluids (water and blood, respectively) upward against gravity. But their strategies are quite different. The tree moves water using capillary action and evaporation, possibly due to water’s properties of polarity and adhesion. The giraffe’s tight skin provides pressure to assist in blood circulation. and keep blood from pooling in the legs.

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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 leaves of some tropical plants channel water off their surface via unique shape, called drip tips.

The sacred fig tree is a type of ficus that grows very large, up to 30 m (98 ft.) tall, in humid areas in its native India. The heart-shaped leaves have extended tips that help channel water down the leaf surface and off the bottom of the tip. The action of these “drip tips” enables the plant to move surface water efficiently and dry off more quickly than plants that do not have drip tips on their leaves. Removing excess water from the leaf surface helps to prevent the growth of potentially harmful mildew or microorganisms, which can thrive in the hot and humid conditions that sacred figs live in.

This summary was co-contributed by EcoRise Youth Innovations.

Image: Challiyil Eswaramangalath Vipin /

Image: Eric Guinther /

Young Leaves Channel Water

Fish-pole bamboo

Young leaves of bamboo channel excess water using a combination of hydrophobic and hydrophilic surfaces.

Last Updated October 20, 2017

References

“Leaves with cutoff drip tips retained ca 2.3 times more water on their surface than those in the other two treatments (Table 1). Differences among individual plants did not explain variation in water retention (F6, 12 5 1.37, P 5 0.3). These results support the hypothesis that drip tips play a role in reducing fungi on leaves of understory trees and in facilitating efficient drainage of water from leaf surfaces.” (Ivey and DeSilva 2001:189)

“Past studies have found, as we did, that drip tips increase the rate of water shedding or leaf drying (Stahl 1893, Dean & Smith 1978, Lightbody 1985). These findings suggest that this may be a mechanism by which drip tips reduce fungal growth or colonization. Others, however, have suggested that increased rates of water shedding and leaf drying may increase transpiration rates (Stahl 1893, Leigh 1975), reduce nutrient leaching from the leaf (Edmisten 1970), and decrease reflectance of sunlight (Lightbody 1985). Drip tips also reduce the size of droplets falling from leaves, which may help minimize soil disturbance beneath a plant (Williamson 1981, Williamson et al. 1983, Rebelo & Williamson 1996) or reduce the spread of fungal pathogens among leaves within plants (J. O’Brien, pers. comm.).” (Ivey and DeSilva 2001:190)

Journal article

A Test of the Function of Drip Tips

Biotropica, 33(1):188-191 | 01/01/2001 | Ivey CT; DeSilva N

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Reference

Journal article

Behavioral and Morphological Adaptations of a Tropical Plant to High Rainfall

Biotropica, 10(2): 152-154 | 01/06/1978 | Dean JM; Smith AP

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Reference

Journal article

Distribution of Leaf Shapes of Piper sp. in a Tropical Cloud Forest: Evidence for the Role of Drip-tips

Biotropica, 17(4): 339-342 | 01/12/1985 | Lightbody JP

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