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Flashcards in Plant Transport Deck (104)
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Why is Xylem poorly developed in Hydrophytes?

There is little need for transport tissue as the plant is surrounded by water


What is a hydrophyte?

A plant that grows submerged or partially submerged in water


Why is there little lignified tissue in hydrophytes?

The plant is supported by the water therefore not requiring the support of the lignin tissue.


Where is stomata located on hydrophytes?

On the upper surface of the leaves


How much cuticle do leaves have on hydrophytes?

Little or none


What is the function of air spaces in hydrophytes?

Stems and leaves have large air spaces which act as reservoirs for CO2 and O2. They also assist with buoyancy


What are two case study examples of a Xerophyte?

Cactus and Marram Grass


How are cacti adapted to their environment?

Cacti have succulent stems for water storage and leaves reduced to spines. Many cacti also have the ability to close the stomata during the daylight hours


How are Xerophytes adapted to their living conditions in general?

They can survive in hot, dry desert or cold regions where the soil in frozen for much of the year.


How are pine trees adapted for their environment?

Pines trees have needle leaves. This reduces the surface area over which water can be lost.


What is a mesophytes?

Plants adapted to a habitat with adequate water


Where do mesophytes survive?

Grow in well drained soil and moderately dry air


What is the cuticle like on Marram grass?

The cuticle is a thick waxy covering over the surface of the leaf which reduces water loss. The thicker this cuticle the lower the rate of cuticular transpiration.


What is the stomata like on Marram Grass?

Marram grass has sunken stomata. They are located in pits so that humid air is trapped outside the stomata. This reduces the water potential gradient between the leaf and the atmosphere and therefore reduces the rate of transpiration.


What other feature of marram grass reduces the water potential gradient?

Stiff interlocking hairs trap water vapour and reduces the water potential gradient


How does the shape of the leaves effect the characteristics of the marram grass?

The Marram grass has rolled leaves. Large thin-walled epidermal cells shrink when they lose water by transpiration causing the leaf to roll in on itself. This reduces the leafs overall area over which transpiration can occur.


What is a Xerophyte?

A plant adapted to a freshwater habitat


What are the key 5 adaptations of Xerophytes?

.Sunken stomata to create local humidity/ decreases exposure to air currents
.Presence of hairs creates local humidity next to leaf/ decreases exposure to air currents by reducing flow around the stomata.
.Thick waxy cuticle makes more waterproof/ impermeable to water.
.Stomata inside of rolled leaf creates local humidity/ decreases exposure to air currents because water vapour evaporates into air space rather than atmosphere.
.Fewer stomata decreases transpiration as this is where water is lost.


How does having a thick cuticle work?

Stops uncontrolled evaporation through leaf cells


How does having a small leaf surface area work?

Less surface area for evaporation


How does having a low stomata density work?

smaller surface area for diffusion


How does having sunken stomata work?

maintains humid air around stomata


How does having stomata hairs (trichores) work?

maintains humid air around stomata


How does having rolled leaves work?

maintains humid air around stomata


How does having extensive roots work?

Maximise water uptake


Why do plants need a transport system? (3)

1. Large multicellular organisms
2.Diffusion alone is too slow and inefficient
3.To take materials from cells to exchange surfaces and environment (ions/ sucrose/ amino acids)


What is a plant transport system similar to?

A closed animal transport system


How does a plant transport system differ to an animal system? (5)

1. Xylem and Phloem not arteries and veins
2. Water instead of blood
3. Hydrostatic pressure and evaporation instead of a pump (heart)
4. No valves


What are the two visible features of root hair cells?

1. Large surface area for H20 to enter by osmosis
2. Cellulose cell wall freely permeable to H20


Why do root hair cells have a large quantity of mitochondria?

To provide ATP for the active transport of mineral ions