Examples of plant adaptations

Plants have adapted to help them survive in various environments and atmospheres around the globe. Adaptations are particular features that allow plants to live in a certain habitat. These adaptations might make it very difficult for the plant to survive in a different place. This explains why particular plants are found in one place, but not in another. For example, you would not see a Cacti living in the Arctic. Nor would you see lots large trees living in grasslands.

Dessert

• Some plants, called succulents store water in their stems or leaves.

• Slower growing requires less energy. The plants don't have to make as much food and therefore do not lose as much water.

• Long root systems spread out wide or go deep into the ground to absorb water.

• Some plants have a short life cycle, germinating in response to rain, growing, flowering and dying within one year. These plants can evade drought using the avoidance strategy.

• Leaves with hair help to reduce water loss. Other plants have leaves that turn throughout the day to expose a minimum surface area to the heat.

• Spines to discourage animals from eating plants for water.

• Waxy coating on stems and leaves help reduce water loss.

• Flowers that open at night lure pollinators who are more likely to be active during the cooler night.

• Some plants have no leaves or small seasonal leaves that only grow after it rains. The lack of leaves helps reduce water loss during photosynthesis. Leafless plants conduct photosynthesis in their green stems.

Rainforest

• • Drip tips and waxy surfaces allow water to run off to discourage growth of bacteria and fungi.

  • Buttress, prop and stilt roots help to hold up plants in the shallow soils.

  • Certain plants climb on others and grow on other plants to reach sunlight.

  • Flowers on the forest floor are designed to lure animal pollinators since there is relatively no wind on the forest floor to help in fertilisation.

  • Smooth bark and smooth/waxy flowers speed the run off of rainwater.

  • Plants have shallow roots to help capture nutrients from the top level of soil.

  • Many bromeliads are epiphytes (plants that live on other plants); instead of collecting water with roots they collect rainwater into a central reservoir from which they absorb the water through hairs on their leaves.

  • Epiphytic orchids have aerial roots that cling to the host plant, absorb nutrients and to absorb water from the atmosphere.

Aquatic

• • Underwater leaves and stems are flexible to move with water currents.

  • Certain plants have air spaces in their stems to help hold the plant up in the water.

  • Submerged plants lack strong water transport systems; instead water, nutrients and dissolved gases are absorbed through the leaves directly from the water.

  • Roots and root hairs reduced or absent; as they are only needed for anchorage, not for absorption of nutrients and water.

  • Some plants have leaves that float on top of the water exposing themselves to the sunlight.

  • In floating plants, chlorophyll is restricted to upper surface of leaves and the upper surface is waxy to repel water.

  • Aquatic plants produce seeds that will float.

Tundra

• • Tundra plants are usually less than 8 cm tall; are low growing due to lack of nutrients another advantage to being close to the ground is that it helps keep the plants from freezing.

  • Plants are dark in colour; this helps them absorb long wave radiation.

  • Certain plants are covered with hair which helps conserves heat.

  • Some plants grow in colonies to protect one another from the wind and forest and cold.

  • Some plants have dish-like flowers that follow the sun, focusing long wave radiation on the centre of the flower, helping the plant stay warm.

Temperate

• • Wildflowers grow on forest floor early in the spring before trees being to produce leaves and shade the forest floor.

  • Most deciduous trees have thin, broad, light-weight leaves that can capture a lot of sunlight to produce glucose and starches for the tree in warm weather; when the weather gets cooler the broad leaves cause too much water loss and can be weighed down by too much snow, so the tree drops its leaves.

  • Trees have thick bark to protect against cold winters and other means of damage.

Camouflage

• • Camouflage is essential to the perpetuation of gymnosperm and flowering plants such as Lithops 'living stones' are true mimicry plants: their shape, size and colour cause them to resemble small stones in their national surroundings.

  • In the wild, living stones inhabit vast dry regions of southern Africa. Several areas in which these plants grow receive less than 4 cm of rainfall per month throughout the entire year. In an extreme situation of low rainfall at least one species of Lithops depends on mist or fog to provide its main source of moisture. Lithops could not survive in many areas that they are found were it not for their capacity to store water. In fact, almost the entire plant is devoted to this function.

  • Leaf Succulents: Leaves are almost entirely composed of water storage cells covered by a thin layer of photosynthetic tissue.

  • Examples: Aloe, Haworthia, Lithops and Sempervivum.

  • Stem Succulents: Fleshy stems contain water storage cells overlaid by photosynthetic tissue. Leaves are almost or entirely absent, reducing surface area to prevent evaporative loss of water.

  • Examples: Euphorbia obesa and Stapelia.

  • Root Succulents: Swollen fleshy roots store water underground away from the heat of the sun and hungry animals. Stems and leaves are often deciduous and shed during prolonged dry seasons.

  • Examples: Calibanus hookeri and Fockea edulis.

Leaf Modifications

• • A carpel may be a solitary simple carpel or part of a compounded or fused carpel. Its base forms the ovary, containing one or more ovules. The ovary, when pollinated, and the ovules successfully fertilised, culminates in a fruit whit seeds.

  • A scale is a small, thin, usually dry plant structure, such as any of the protective leaves that cover a bud or the bract that subtends a flower in a thin flake, an exfoliation of dead epidermis shed from the surface of the epidermis.

  • A bulb is an underground stem, usually globular, containing a complete embryonic plant inside, with tiny flowers, stems, leaves, and roots. The contents of the bulb are often enclosed in protective, fleshy scales; for examples include the Narcissus & Alliums.

  • The small, appendages, usually in pair that are found one on each side at the base of the petiole of many Dicotyledons and often flanking it at the node.

  • When a 'spine' originates from a stem modification and arise from the axillary or apical bud it is defined thorn. If it arises from the epidermis outside the branch it is called a prickle.

  • The podarium generally take the form of a tubercle shape. The podaria of some species have become fused into vertical ribs that cover the entire surface of the plant, for example Echinocactus grusonii.

Climbing and Rambling

· Growth of shoots is often extremely rapid.

· Searcher shoots have circumnutation and thigmotropism (rapid growth response to contact of a structure).

· Long internodes are produced for very rapid elongation; these are often sensitive to contact with any support or solid object.

· Commonly there is a long delay in enlargement of leaves until the stem or cylindrical axis becomes wrapped around a support.

· Vines produce relatively narrow stems versus leaf area and less than a shrub or tree with the same leaf area.

· Woody stems are very flexible to permit bending, twisting, and coiling. They are fairly strong if pulling on two ends but have very little strength when compressed.

· Stem flexibility is normally credited to the design of the woody stem which often has patches of soft tissue alternating with the harder tissues.