Plant Growth Adapts to Environment

a bunch of small flowers with white petals grow against a blurry green background

Biological Strategy

Wall cress

AskNature Team

Image: Marie-Lan Nguyen / Wikimedia Commons / CC BY - Creative Commons Attribution alone

Protect From Wind

Wind subjects living systems to various forces, such as compression, twisting, turbulence, and tension. These forces put living systems at risk of losing the ability to perform life-essential functions, such as when a plant becomes uprooted. Wind can result from weather phenomena or rapid movement through the air, as when flying. Wind is typically not a constant or predictable force, so living systems must be able to function both with and without its presence by adjusting to its direction and speed. A good example is how plants’ leaves and stems are flexible so that they can align with the wind, rather than being battered by it.

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Sense Touch and Mechanical Forces in a Living System

Perceiving touch enables living systems to detect other living systems around them and environmental conditions, such as air movement, water currents, and temperature. This ability can help them sense danger as well as opportunity, as when a Venus flytrap’s hairs sense the presence of an insect to eat. Sometimes, a living system senses touch or mechanical forces at a coarse scale; other times, at a sensitive scale that detects very subtle differences. For example, a human elbow is not nearly as sensitive to textures as human fingertips. Fingertips have dermal ridges and many nerve endings that increase sensitivity, enabling them to explore the environment in detailed ways. Elbows don’t need to sense at that level of detail.

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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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Wall cress adapts to environmental conditions by sensing information through touch which triggers biochemical growth controls.

Introduction

Wall cress is a small flowering plant, often found growing as a weed on roadsides and along farm fields. Its lower leaves tend to hug the ground but the stem height can vary. Some plants stay short and sturdy while those in other locations may reach around 9 inches tall. The cress plant adapts to surrounding conditions by controlling its growth in response to touch.

The Strategy

When forces such as wind or rain impact the plant, certain genes switch on and make a called calmodulin. Calmodulin causes an increase in calcium ions, signaling the plant to change its growth patterns.

This touch-response system in plants is called thigmomorpho-genesis. It allows some plants to sense challenges to their growth and to prepare for similar challenges in the future. For example, wall cress plants growing in windy locations tend to be shorter than those in protected areas.

The Potential

This method of having form adapt to external physical pressure could drastically improve the efficiency or effectiveness of many machines and processes. Wind turbines could change shape or size depending on weather conditions. Weight-training equipment could respond to the exact force exerted by each user at each moment. Bridges or buildings could slowly reinforce themselves as needed.

This strategy was contributed by Heather Dove.

Reproductive Tissues Respond to Favorable Conditions

Rockweed seaweed

Reproductive tissues of rockweed seaweed release eggs and sperm in favorable conditions by chemically sensing calm waters.

Biological Strategy

Discharge Trigger Responds to Fish’s Chemical Cues

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The filament injection organ of Myxobolus cerebralis detects a potential fish host via receptors that recognize chemical compounds present in fish mucus.

Last Updated August 18, 2016

References

Web page

Science: Plant switches on genes in response to touch

New Scientist | Boyd, Alan

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Reference

Journal article

Rain-, wind-, and touch-induced expression of calmodulin and calmodulin-related genes in Arabidopsis

Braam J; Davis RW

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