Leaf Anatomy Flashcards
What is the stomata?
Located mostly under the leaf and regulates water loss in a plant
What are the tissues present in a leaf?
Ground, dermal, vascular
What is the cuticle?
Wax like covering on the outside of the leaf
What is the bundle sheath?
Holds both the xylem and phloem
What is mesophyll
Parenchyma cells
What is the role of guard cells?
keep toxins out
What is the role of the stomata?
Regulate water loss and allow for the movement of CO2 and O2
Where are spongy mesophyll located?
Closest to the stomata
What percent of the leaf surface is covered with stomata?
1 - 2%
Why is there so few stomata on the surface?
Too much water would be lost
What percent of water escapes through the stomata?
98%
How ma y stomata might be found in 1 cm2
1000 - 1.2 million
What is the rest of the leaf covered with besides stomata?
Suberin
How is the stomata designed?
Radially oriented cellulose microfibrils
What is the role of the vacuole?
Store water
When does the guard cell open? When does it close?
Open- cell in turgid state
Closed- cell in flaccid state
_________ ions create negative water potential
Potassium
What is the source of K+ ions?
Neighboring cells
K+ entry into guard cells depends on what?
H+ pump
The absorption of K+ causes the water potential to become more _________ and water moves (in or out) of the cell
Negative
In
As water enters the cell, the guard cells become __________
Turgid
How do you “close” stomata
Turn off proton pump
______ allows water to enter the cell into the vacuoles
Potassium
What are the stimuli for stomatal opening and closing? 4
- Stomata opening in the day triggered by light (blue light)
- CO2 depletion within leaf air spaces (stomata OPEN)
- Drought stress (stomata CLOSED)
- Circadian rhythms “internal clocks”