Root adaptations Flashcards
What is an adventitious root?
Any root that does not originate from the radicle, or primary root system, can be considered to be an adventitious root.
These offer the plant the ability to produce roots from areas other than the seed.
Examples include the rooting of cuttings, or the support of colonisation (spread) of, for example Rubus fruticosus which spread with arching stems that produce roots where they touch the ground.
What is a pneumatophore root?
Roots that exist within wet soils, that make use of aerenchyma cells to allow for the diffusion of oxygen.
Pneumatophores sometimes float to the water surface, and have openings for gaseous
exchange, or rise out of the water, as is the case with Mangrove swamps.
Plant examples include Taxodium distichum (Please note some sources are
questioning whether this plant has true pneumatophores, however a
conclusive decision has yet to be made and so these plants can be considered
to have pneumatophores.)
What is advantageous about a fibrous root?
offering the plant the ability to absorb water and minerals over a large surface area
close to the surface of the soil, thus making use of low levels of rainfall or irrigation.
Fibrous roots can also help to reduce soil erosion preserving the root environment.
Plant examples include: any named monocotyledonous or Stipa gigantea
Impact of oxygen levels in soil on roots
The impact of reduced oxygen levels on rooting depth. This can result in raised roots in some tree species. Some roots of these species are adapted to maximise the availability of oxygen and can therefore grow close to the surface of the soil.
Plant examples include: Sorbus aria or Prunus ‘Kanzan’
What are some of the impacts of plant selection in hard landscaping or grass areas?
Raised roots can lift paving, and result in blade strike within grassed areas.
Plant examples include: Sorbus aria or Prunus ‘Kanzan’.
What effect does root adaptations have on weeds?
Some plant species are able to produce new plants (due to totipotency) from
fragments of root, examples include Taraxacum officinale, and Circaea
lutetiana
How do root adaptations affect transplanting?
The ability of plant roots to regenerate is used within horticulture with the root pruning of plants during the transplanting process.
This can include Allium porrum or the pruning of many deciduous bare root shrubs or trees
when planting, e.g. Prunus padus.
What is colonisation?
Stolons or suckering from roots Examples could include Rubus fruticosus
suckering from roots, for example Rhus typhina.
the concept of totipotency as it applies to propagation involving roots
What role do roots play in the life of a plant?
Roots help to anchor the plant in the ground.
* They absorb water and nutrients
* They actively seek out water and nutrients, this is called foraging behaviour.
* Roots will sometimes store nutrients as carbohydrates.
* In some cases, they will store water as well.
Sometimes roots absorb nutrients from other roots thru parasitic species
Roots link with mycorrhizal fungi to find more water/nutrients
Why do roots breathe?
Roots need to be able to breathe in order to respire to carry out their functions
of absorbing water and nutrients.
What is foraging behaviour of a root?
This is the ability of roots to go towards good sources of water and nutrients, which in
competitive environments (or environments with limited resources) is a very useful ability.
What is a tropism?
The growth movement in a specific direction.
a response by a plant organ to an environmental stimulus which results in
movement or growth.
Roots forage for water and nutrients through
tropic mechanisms
What is gravitropism or positive geotropism?
Seed tropism:
Downward growth - as in the radicle of the seed growing downward and embryonic shoot growing upwards.
What is a taproot? What are the advantages to a plant in maintaining a taproot throughout its life? Name ONE additional adaptation to its taproot that some plants have.
A taproot is a root that plunges straight down from the above ground part of the plant and which merges with the stem. It is derived directly from the radicle - the embryonic root which emerges from the seed – but in
dicotyledons only.
Many plants keep their tap root, as it helps anchor the plant and in some species it acts as a nutrient store – for e.g. in carrots and parsnips the tap root swells to store nutrients to enable rapid growth in the spring.
In what circumstances do adventitious roots enable a plant to spread?
When they emerge from a rhizome which is travelling horizontally, and branching. They will secure the plant in position and enable resources for shoot growth in new territory.
Also in certain species, such as willows (Salix
spp.) branches or twigs on damp ground will produce adventitious roots, effectively layering the plant.
What is a stilt root?
Stilt roots help support tall stems. They emerge from the stem just above the soil.
Example: Zea officinarum
What is a prop root?
Roots that project down from branches and function as trunks. THey do develop roots.
Fiscus elastica (rubber plant)
Ficus benghalensis (Banyan tree)