7 Adaptations of Plants in the Tundra Discussed

Adaptations of plants in the tundra are; low-height morphology, shallow root system, small leaves, dense cluster-growth pattern, dark coloration, relatively-rapid growth, and surface hairs.

This article discusses the adaptations of plants in the tundra, as follows;

1). Low-Height Morphology (as one of the Adaptations of Plants in the Tundra)

Low-height morphology is an adaptive characteristic of plants in the tundra, and results from both biotic and abiotic factors including the harsh tundra climate and low-fertility soil.

*Climate as A Factor Behind Tundra Plant-Morphology

Cold, prolonged winters, accompanied by short summer seasons, are typical of the tundra [1].

The cold temperatures impose a limitation on metabolic processes required for plant growth.

Winter in the tundra is characterized by prolonged periods of darkness with minimal solar irradiation; and deprives plants of sunlight that is needed for photosynthesis.

Summer, on the other hand, lasts for a relatively-brief period annually. This gives the plants limited time to undergo an extensive lifecycle transformation and grow to significant height. The ultimate outcome is small size, for these plants, especially in comparison to their counterparts from ecosystems with more resources; like tropical rainforests.

Low-height morphology in tundra plants may also be seen as an adaptation to withstand the pressure of high-velocity winds, which are fairly common in the biome [6].

The treeless and open nature of the tundra landscape allows such wind to travel with significant momentum, so that it can easily cause mechanical damage and dessication to plant tissues.

Multiple generations of evolution have therefore resulted in shorter individuals, that are less susceptible to such damage because they grow close to the ground.

*Soil Conditions as A Factor Behind Low-Height in Tundra Plants

As a result of slow rates of biodegradation, and continuous leaching, tundra soil is generally poor in its nutrient composition.

This deficiency is also behind the morphology of tundra plants.

Because essential nutrients like phosphorus and nitrogen are not sufficient, tundra plants have evolved to adopt growth patterns that conserve nutrients and energy by minimizing the overall rate of growth, while storing extra resources for use under acutely-deficient circumstances.

Permafrost is permanently-frozen subsoil that occurs in many tundra zones [2]. It underlies a thin layer of loose soil and limits the depth of usable earth materials for soul anchorage.

This results in shallow roots for tundra plants, which can only support shorter stems and a morphology with a wide center of gravity.

*Resource Deficiency as A Factor Behind Low-Height in Tundra Plants

As earlier stated, the morphology of tundra plants is shaped by harsh conditions that include cold temperatures, a brief growing season, intense winds, are limited resources.

The limited supply of resources in tundras contributes to plant morphology by forcing plants to allocate nutrients sparingly to their cells and organelles. This reflects as relatively-stunted stems, leaves and branches in many of these plants.

2). Shallow Root System

Shallow root system is an adaptation which is developed in tundra plants in response to environmental stimuli from organic and inorganic sources.

Here, shallow root system refers to a tundra plant attribute whereby the roots of these plants have limited vertical reach, and do not extend deep beyond the soil surface.

Rather, they tend to spread in a horizontal direction upon, or at a shallow depth beneath the surface.

*How Permafrost Contributes to Shallow Roots in Tundra Plants

Permafrost is arguably the main cause of shallow root patterns found in tundra plants.

Because it is impenetrable, permafrost only allows plant roots to grow within the thin active layer of soil that overlies it.

This restriction has caused tundra plants to grow roots that do not attempt to extend far downwards.

*Availability of Water and Nutrients in Relation to Tundra Plant-Shallow Roots

The roots of tundra plants have also adapted to the distribution and accessibility of nutrients.

Most nutrients in tundra soils are concentrated in the active, topsoil layer; where they are mostly released as inorganic byproducts of the slow decomposition of biomass [5].

To access and utilize these nutrients, the plants grow shallow roots that spread horizontally and cover significant area in the active topsoil.

The same can be said of water distribution and accessibility. Tundra plant roots are shallow to access water that occurs in the topsoil from snow-melting and summer precipitation.

3). Small Leaves (as one of the Adaptations of Plants in the Tundra)

Small leaves are among the adaptive features of tundra plants, which are influenced by the conditions of their environment.

*Water Conservation as A Driver of Small Leaf-Adaptation in Tundra Plants

Water conservation plays a key role in the leaf size of tundra plants.

Many plants in the tundra biome produce small leaves as an adaptive strategy to minimize the surface area from which evapotranspiration occurs.

Because the tundra is dry and cold, rapid loss of water from plant tissues can easily lead to dessication and death of the plants' cells.

*Tundra Plant-Leaf Size as an Adaptation for Energy Conservation

Small surface area of leaves in tundra plants is also an adaptation for energy conservation.

The rate of energy loss (in the form of heat) from tundra plants is drastically reduced by the presence of small leaves.

Given the cold temperature and prolonged winter in the tundra, conservation of energy is an essential function; which is achieved (partly) by the production of small leaves.

*Small Leaves as An Adaptation to Minimize Mechanical Damage in Tundra Plants

Snowstorms and powerful winds are not very uncommon in the tundra.

These hazardous events can damage plant tissues and cause breakage, thereby reducing overall health and survival rate of the plant population.

By having small leaves, tundra plants provide less surface area for wind impact, and minimized the risk of breakage or damage.

*Allocation of Resources and Small Leaves in Tundra Plants

Nutrient-poor soil in the tundra plays a role in the development of small leaves.

By producing small leaves, plants are able to effectively manage the limited resources available in tundra soil.

Small leaves also enable tundra plants to reach maturity in less time (and with less resources) during the brief growing season.

4). Dense, Clustered Structure

Plants in the tundra tend to grow in a unique dense or clustered pattern.

This pattern results from close proximity between organelles and individual plants in a given area, and occurs in the form of dense clusters or patches of vegetation.

*Dense Growth Pattern of Tundra Plants as A Protective Adaptation

Growing in dense clusters helps to (mechanically) fortify tundra plants against elements of the harsh climate in this biome.

Dense vegetative clusters enable plants to provide mechanical support to each other, so that they are more resilient to the impact of wind and other erosive agents.

*Microclimate Establishment from Dense Tundra-Plant Clusters

The area occupied by densely-spaced tundra vegetation usually has its own microclimatic conditions, which differ from those of the surroundings.

Heat can be trapped by clustered plants, so that a more favorable environment for plant-growth is established, with moderated conditions like warmer temperature, higher humidity and less wind.

Also, the dense vegetative structure of tundra plants enables them to effectively intercept and utilize solar radiation for photosynthesis; by creating a large surface area from numerous, closely-spaced leaves (in spite of the small surface area of individual leaves).

*Efficient Utilization of Resources as A Driving Factor for Clustered-Growth Adaptation in Tundra Plants

Dense patterns of growth, of tundra plants, enables them to utilize limited resources in an optimal manner.

These resources include sunlight, nutrients and water, which are shared effectively by dense clusters of plants, in a manner that allows each plant to obtain essential resources for its survival.

*Soil Conservation by Dense Tundra Plant-Clusters

By growing in dense clusters, tundra plants contribute to the conservation of soil and the recycling of essential nutrients.

Soil erosion and leaching by water, are reduced where the soil is covered by vegetation.

The network of intertwined, shallow roots of these plants also helps to bind soil particles and prevent (or at least minimize) displacement.

Organic material that accumulates from fallen leaves and organisms sheltered by the vegetative microhabitat; is also protected from displacement by the dense cluster of plants. This ensures that nutrients derived from such organic matter are effectively conserved and cycled.

*Dense Growth as an Adaptation for Effective Pollination in Tundra Plants

Clustered growth pattern in tundra plants can also be considered an adaptation for effective pollination.

Flowers in such dense clusters constitute a large surface area that increases the chances of pollination compared to those of single, sparsely-spaced flowers.

Insects like moths, as well as herbivorous birds, are attracted to such dense flower-clusters, from which they may displace and transfer pollen, to cause cross pollination in a manner that leads to improved diversity among plants.

Lastly, dense clustered growth helps tundra plants achieve effective dispersal of seeds, by increasing the number of seeds produced within a given area. These seeds may be transported by wind which comes in contact with the plants.

5). Dark Coloration (as one of the Adaptations of Plants in the Tundra)

Dark coloration of tundra plants results from the production and presence of darker-than-average pigments in parts of these plants such as their leaves. While it does not not occur in all plants that grow in the tundra, dark coloration is not a very uncommon tundra plant adaptation.

*Dark Coloration as an Adaptation for Improved Photosynthetic Efficiency

Tundra plants that have dark leaves tend to have higher photosynthetic capacity.

This is because the dark pigments are reinforced with carotenoids, anthocyanins and chlorophyll, all of which enhance the solar-capture efficiency of plant tissues [3].

In the tundra where growing seasons are relatively short, this is an advantageous adaptation, because it enables plants to maximize the limited amount and duration of sunlight.

*Enhanced Thermal Absorption in Dark-Colored Tundra Plants

The dark colored leaves of tundra plants act as black bodies, by absorbing and retaining significant amounts of heat, in a more effective manner than light-colored leaves.

This is a particularly beneficial capability in the tundra, given the prevalence of low temperatures and frigid conditions. With improved heat absorption, plant tissues remain warm and metabolically-active, thereby enabling the plants to survive.

*Dark Coloration for Frost-Damage Protection

The damage of plant tissues by frost can be minimized by their dark pigmentation in the tundra; which helps to speed-up the process of frost-melting.

Frost-melting around dark colored tundra plants can help moisturize the soil and prevent freezing in the active (topsoil) layer.

One of the drivers of dark-pigment adaptation in tundra plants is the short growing season, which causes plants to adopt evolutionary traits to enable them optimize their productivity and store energy.

6). Relatively-Rapid Growth

Rapid growth is another characteristic of tundra plants that is notable, and resultant of adaptive development.

Factors that influence tundra plants to grow at a relatively-rapid rate include the brief duration of growing season, and the abundance of sunlight during this period.

Tundra plants have short lifecycles relative to plants in other ecosystems, because the short growing season is their only opportunity for growth.

Also, the growing is characterized by a major, sudden increase in the availability of resources like sunlight and soil nutrients. This facilitates an equally significant boost in growth rate.

Lastly, rapid growth in tundra plants can be viewed as an adaptive strategy to be competitive, especially since the plants grow in dense clusters and have to share limited resources within their reach.

7). Surface Hairs for Insulation (as one of the Adaptations of Plants in the Tundra)

Plants in the tundra tend to grow hair-like structures on their surfaces, which may be referred to as trichomes [4].

Tundra plants that posses such hairs on their surfaces include Arctic poppy (Papaver radicatum), Arctic willow (Salix arctica), and Arctic cotton (Eriophorum scheuchzeri).

*Insulation as a Function of Surface Hairs in Tundra Plants

One of the roles played by hairs on the surface of plants in the tundra, is insulation.

Hairs on the stems and leaves of plants, create a non-conductive layer of insulation that traps air and protects the plant from heat loss due to extreme cold temperatures of the surroundings.

Other functions of hairs on tundra plant surfaces are;

1. Water-loss minimization

2. Protection from UV radiation

3. Wind impact mitigation

Conclusion

Adaptations of plants in the tundra are;

1. Low-Height Morphology

2. Shallow Root System

3. Small Leaves

4. Dense, Cluster-Growth Pattern

5. Dark Coloration

6. Relatively-Rapid Growth

7. Surface Hairs for Insulation

References

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5). Kaverin, D.; Pastukhov, A.; Lapteva, E. M.; Biasi, C.; Marushchak, M. E.; Martikainen, P. J. (2016). "Morphology and properties of the soils of permafrost peatlands in the southeast of the Bol’shezemel’skaya tundra." Eurasian Soil Science 49(5):498-511. Available at: https://doi.org/10.1134/S1064229316050069. (Accessed 20 June 2023).

6). Knowles, J. F.; Blanken, P.; Williams, M. W.; Chowanski, K. (2011). "Desiccation of Alpine Tundra Due to Persistent High Wind Speeds at Niwot Ridge, Colorado." AGU Fall Meeting, San Francisco, CA. Available at: https://ui.adsabs.harvard.edu/abs/2011AGUFMGC31A1009K/abstract. (Accessed 20 June 2023).