Fatty Acids Prevent Freezing

bright white puffs of cotton plants are standing against a dark background

Biological Strategy

Upland cotton

AskNature Team

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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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Modify Material Characteristics

The materials found in living systems are variable, yet often made from the same basic building blocks. For example, all insect exoskeletons consist of a material called chitin. Because material resources are limited, each material within or used by a given living system must frequently serve multiple purposes. Therefore, living systems have strategies to modify materials’ softness, flexibility, and other characteristics. To ensure survival, the benefits of these modifications must outweigh the living system’s energy and material expenditure to generate them. For example, spiders store the liquid components of spider silk in a gland, converting them into silk thread when needed. Some threads have different characteristics, such as elasticity and UV reflectance, than others.

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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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Fatty acids in cotton seedlings prevent freezing by changing the composition of the cell membranes.

Cotton plants prepare for cold nights by changing the composition of their cell membranes, reports Arnon Rikin and his colleagues at Oklahoma State University in Stillwater. At night, the concentrations of two unsaturated fatty acids in the membrane–linoleic and linolenic–increase. The double carbon bonds in the tails of these fatty acids create a “kink” that keeps fatty acid molecules from packing together too tightly. In effect, the membrane remains fluid, and s are readily able to move through. Interestingly, cotton plants exhibit this response even without light cues. That is to say, the is triggered by an internal clock, rather than by the daily light/dark cycle. (Day 1993; Rikin et al. 1993)

Last Updated August 18, 2016

References

Journal article

Correlation between the Circadian Rhythm of Resistance to Extreme Temperatures and Changes in Fatty Acid Composition in Cotton Seedlings.

Plant physiology | 01/01/1993 | Rikin A, Dillwith JW, Bergman DK.

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Reference

Journal article

How plants prepare for the cold of night

Day, S

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