Transport in Plants
Card Set Information
Transport in Plants
BIO 220 Test Two
Plants don’t have a __; food is transported through the plant’s __
vascular tissue (xylem and phloem)
Three types of Transport
Gas exchange (at leaf)
: One that occurs at level of root, moving dissolved materials in and up through xylem
: movement of sugars or organic material that was made by plant that occurs through phloem
Occurs at level of __through __
Explain it in terms of guard cells
When the guard cells are turgid, the stoma is open, allowing for material to leave the plant (water, carbon dioxide, oxygen)causing material and gases to leave/ enter plant
What makes the guard cells turgd?
What opens the guard cells is an ATP proton pump
Uses energy and the proton pump
ACTIVE TRANSPORT OF POTASSIUM IONS INTO THE CELLS
When potassium enters the cells, water osmotically follows due to concentraition
under certain conditions, potassium ions are transported into guard cells
the cell BLOWS UP= TURGID
What closes stoma?
water and potassium leave
What controls opening?
Biological clock that causes them to become turgid and collapse
What controls closing?
If plant in threat of
, the stoma will not open up
If there is
a lot of carbon dioxide
in the leaf, the stoma will stay closed
Released in times of
of plant, causing it to keep stomata closed
Good Conditions for the plant
Enough water vapor
Movement of water and minerals from the soil to the leaf
Once into vascular stele, it then can move up the xylem and the xylem forms a continuous tube network from the root all the way up to the leaf
What is associated with transpiratoin?
Specialized cells in xylem that are responsible for movement of water and dissolved minerals
Tracheids and vessel elements
Dead at maturity; there’s nothing in them (no cell organelles, etc.)
What causes movement in transpiration?
: transpirational pull, root pressure, and cohesion/ adhesion properties of water
Explain transpirational pull in terms of transpiration
If stoma are opened at top at the leaves and it’s losing water vapor, its going to force the plant to want more water
; generally plays no role in large trees or bushes, but it does cause a pull at the roots because it wants to make more water in, creating a pressure that wants to get water up
Due to loss of water vapor at the top of the plant (at the stoma of the leaves)
Root Pressure in terms of Transpiration
Results from the inward
of solutes from the soil by root cells
Due to movement of solutes into the root and water osmotically follows
As more water comes in, it’ll push up those vessels and tracheids
The greater the solute concentration, the more is absorbed, the more water comes in and the more pressure is created
Force that is greater than transpirational pull, but generally weak
Cause push through cortex, up stele and into plants
Cohesion and Adhesions in terms of transpiration
Water molecules stick together (forming a continuous sheet)=
COHESIVE NATURE OF WATER
Water also adheres to the lining of tissues
Once it enters the stele, it forms a continuous flow of molecules up that xylem because it’s cohesive and adhesive
Adheres to xylem and it’s being pushed up as a continuous column of water
NOT BITS AND PIECES
In that water are the dissolved minerals
GREATEST EFFECT ON MOVING THROUGH XYLEM TO THE TOP OF THE PLANT
Movement of organic material
made by the plant through the plant that ocfurs in phloem
It is movement in all different directions
In phloem, things can move up, down, sides,
Characteristics of translocation
in terms of movement through phloem, there are the source and sink
: where the organic material was loaded into phloem
it can be the root, stem, or leaf
: where it’s unloaded
takes it out of the phloem at the sink; maybe stored in the stem and now the leaf wants it (do you see? It’s not stationary)
Unlike xylem, what are phloem?
phloem cells are alive at maturity
cells that are unique cells are
/ tube elements and
/ albuminous cells
have to be alive in order for translocation to occur
What does translocation involve?
of the organic material into the companion cells into the sieve cell
in the sink, it’s active transport out
active transport loads and unloads sugars into and out of phloem
What is in the cortex of the root?
stele (central part of the root containing the vascular tissue)
Nutrients are in __.
Absorption of minerals is based on what?
Absorption of minerals independent of rates of water absorption.
Each mineral moves into the root at a rate determined by:
1. its concentration
2. ease it can passively penetrate cell membranes or go through ion channels
3. available carriers
What does the xylem tissue contain?
tracheids and vessel elements
What do phloem cells contain?
sieve cells/ sieve tube members
companion cells/ albuminous cells