Leaves Survive Desiccation

Biological Strategy

Spanish moss

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Protect From Loss of Liquids

Water is essential to life. Liquids, mostly water, make up 70 to 90% of all living systems, and the loss of even a small percentage can mean the difference between life and death. Living systems must maintain a proper liquid balance, which is especially difficult in dry conditions. To do so, they must control the movement of liquids across their boundaries. Living systems do this using structures or waterproof materials to prevent or slow liquid movement. For example, when humans receive a cut, they must limit blood loss. Scattered throughout the bloodstream are lens-shaped structures that serve to plug the wound.

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Capture, Absorb, or Filter Liquids

The most common liquid used by living systems is water, which they require to survive. But there are many other liquids that provide nourishment, play a role in defense mechanisms, or serve other purposes. Water varies in its availability; it is sometimes plentiful and sometimes very scarce or only available as fog or mist. To minimize the energy required to capture, absorb, or filter liquids, living systems have strategies that take advantage of the unique properties of the given liquid. For example, water moves from a gaseous to liquid state when it encounters a surface colder than the air. Plants in forests that experience fog and clouds more than rain have strategies that condense liquid water from moist air.

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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 Spanish moss absorb water and have slow water loss because they are covered in dense scales.

“Almost all the members of the Tillandsia subfamily are epiphytic. The exceptions are a number of thin-leaved species that grow on the forest floor. The epiphytic species mostly have well-developed tanks that function in the same way as those of the epiphytes of the Bromelia subfamily, and once again the roots are for attachment only. Some species of Tillandsia have much-reduced tanks, but Spanish moss (T. usneoides) has gone to the extreme and given them up entirely. It has also given up roots and, with its small leaves and many branches, drapes itself over twigs and branches like some lichens. The surfaces of this curious plant are densely covered with overlapping scales that avidly absorb water when it rains and slow water loss during drought. At times, this Tillandsia dries up almost completely but revives when it rains, so it is a resurrection plant.” (Dawson and Lucas 2005:43)

Last Updated September 14, 2016

References

Book

The Nature of Plants: Habitats, Challenges, and Adaptations

01/02/2005 | John Dawson

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