Plant Transports Flashcards
(35 cards)
What are the properties of Monocots
Single Cotyledon,
Long narrow leaf,
Veins are parallel
Vascular bundles scattered
Flower part in multiples of 3
What are the properties of dicots?
Two cotyledons
Broad leaf
Network of veins
Ring of vascular bundles
Flower part in multiples of 5
What is the Casparian strip
a water-impermeable, waxy suberin layer,
What is the cortext in the plant?
The cortex consists of parenchyma cells.
These large, thin-walled cells have leucoplasts to store starch and large vacuoles to store water and dissolved sugars and
Intercellular spaces between parenchyma cells facilitate the movement of water
Parenchyma in xylem contains tamins, which are bitter and help deter herboviores from eating the plant.
What is The stele, or vascular cylinder
Consists of the pericycle, phloem, cambium and xylem.
What is the endodermis?
It is the innermost layer of the cortex. It consists of tightly-packed, modified parenchyma cells.
The radial and transverse cell walls are thickened with a water-impermeable, waxy suberin layer, known as the Casparian strip. This layer helps to regulate the flow of water from the cortex into the stele. To aid in directing water, there are also thin-walled passage cells in the endodermis, directly opposite the xylem, allowing water to move into the xylem rapidly.
What is the xylem tissue?
it is responsible for transporting water and
dissolved mineral salts to the xylem tissue of the stem and leaves. These cells are strengthened with lignin for support. The pits in the cell walls allow for the lateral movement of water.
What is Turgidity in refrence to plant cells
Turgidity, or turgor pressure, refers to the water content of cells and how this lends structural support to the plant. When cells absorb water, the vacuoles fill up and the cytoplasm increases, pushing against the cell membranes, which in turn push against the rigid cell walls. This makes the cells rigid, or turgid.
Why is transpiration important for the plant?
Cooling of the plant: the loss of water vapour from the plant cools down the plant when the
weather is very hot.
The transpirational pull: when the plant loses water through transpiration from the leaves, water and mineral salts from the stem and roots moves, or is `pulled’, upwards into the leaves. Water and is therefore taken up from the soil by osmosis and finally exits the plants through the stomata.
Plant structure: young plants or plants without woody stems require water for structural support. Transpiration helps maintain the turgidity in plants.
how does the transpiration pull occur?
Results from the evaporation of water from the surfaces of the mesophyll layer in the leaf to the atmosphere, through the stomata.
What four parts make up the Phloem?
Phloem fibres
Phloem parenchyma
Sieve tubes
Companion cells
What are the two ways water can move through the plant?
Apoplast and Symplast
What is apoplast?
Water moving through the cell wall/intracellular fluid, it is quick but doesn’t have much control due to it being simple diffusion
What is Symplast?
It is when water moves continuously through the cytoplasm, it is very slow but is controllable.
Describe how water moves in and out of the plant.
Water enters the roots via osmosis, then travels through the cells by apoplast or symplast to reach the xylem, then due to cohesion/ the water column being under tension, the water moves up the xylem. Then it enters the leaves where it evaporates and leaves through the stomata.
What are Vascular bundles.
Vascular bundle: bundles of tissue containing
both xylem and phloem
What is the Vaculoar route?
Water passes through tonoplast and then
through vacuoles of cells
What is the Protoxylem?
First xylem to develop behind root and shoot tips; lignin added in rings or spirals
Metaxylem?
More mature xylem where the walls are fully lignified
What is the Secondary xylem?
Formed from ring of cambium
New secondary xylem formed annually: secondary thickening, tree rings
What are Tracheids?
Elongated cells with tapering ends
Not as well adapted as the xylem
Water has to pass between cells from pit to pit
Xylem includes fibres for support and parenchyma as packing
How does Humidity effect transpiration
Humidity: increase in humidity reduces water potential gradient between air spaces and atmosphere, rate of transpiration decreases
How does wind speed effect
Wind speed: low wind speed, water vapour
accumulates around stomatal pores, reduces
water potential gradient, rate of transpiration
decreases
How does temperature effect
Temperature: increasing temperature,
increasing KE water molecules, increased
diffusion and increase in number of water
molecules that can be held in air, rate of
transpiration increases
