Plant Organ Systems. Section 2.2 Homework Pg. 76 #1-6. Quick review. How many organ systems are in a plant? Identify the organs in each of these systems. What are xylem and phloem? How are they similar? How are they different? Cross-section of a leaf:
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Plant Organ Systems
Pg. 76 #1-6
Vascular tissue allows transport between the root and shoot system.
Dead, hollow tissue
Transports water and minerals upwards from roots
Transports sugars produced by leaves, to the rest of the plant
Transport of H2O from roots to shoots through the xylem occurs by twoforces, which act in the samedirection:
1) Root pressure: The pushing force
Tiny root hairs increase the surface area of the root.
2) Capillary action: The pulling force
Cohesion and Adhesion
Both of thesefactors influence the water’sability to move up the xylemagainstgravity
Transpiration – The evaporation of water vapour from the leaf, through the stomata
Transpirational pull is felt even at the roots.
How? It is enhanced by the properties of water:
cohesion and adhesion
Allows water to move upwards by capillary action.
Two properties of water:
Guardcellscontrol when the stomata are open and closed.
When do the guard cells close?
Effect of various factors on transpiration
leaves (palisade cells - chloroplasts)
Plants photosynthesize to convert the Sun’s energy into a useable form - glucose.
CO2+ H2O + light energy glucose + O2
The energy in glucose is then accessed by cellularrespiration(in mitochondria).
glucose + O2 CO2+ H2O + energy
Cells in every part of the plantneed glucose.
Glucose must be transported to all organsof the plant.
Glucose produced in leaves
POSSIBLE FATES OF GLUCOSE
used right away by nearby cells
stored in the roots (as starch)
transportedto other parts of the plant (as sucrose); used right away
In the spring, sucrose from the roots flows upward to help nourish leaf buds.
In the summer and fall, leaves produce glucose that moves downward to be stored in the roots.