Roots Flashcards
How are root and stem tips different?
Roots have a root cap, root hairs, pericycle and endodermis
How are root and stem tips similar?
Organization of root apical meristem has same zones of growth
The same tissues are present
What is the function of the root cap?
Protect the apical meristem
What is the central tissue of the root
Xylem and phloem
Is the same central tissue present in the root also found in the central region of a herbaceous stem?
No in dicot stems (and monocots stem and root) the center contains parenchyma
In dicot roots the center contains xylem
What is the positional relationship between the primary xylem and primary phloem?
Xylem occupies the center of the root with arms extending to the pericycle
Phloem occupies the concave regions formed by xylem in young roots
Where is the cambium meristem locate with respect to the primary xylem an phloem?
Between the xylem and phloem
How is the organization of vascular tissue in roots different from the organization Of vascular tissue in stems?
In stems the vascular bundles are random in monocots and in a ring on dicots, but xylem is toward center and phloem towards the outside
In roots xylem is in an “x” in dicots and is in a ring in monocots
Explain the difference between the biotic and abiotic pathways for water movement through the root
Biotic moves through living parts and abiotic through non-living parts
What is the major chemical compound found in the Casparian strip?
Suberin
Is the compound hydrophilic or hydrophobic?
Hydrophobic
What is the function of the endodermis?
Regulate lateral movement of water and polar compounds
What cell type forms the root hairs?
Epidermis
Is the root hair a separate cell or an extension of another cell?
Extension of epidermis
What is the function of the root hair?
Increase surface area
Collect nutrients
In which growth zone are the root hairs found?
Maturation
From what tissue do lateral roots arise?
Pericycle
Do lateral roots have an apical meristem, zones of growth, and root hairs?
Yes
Compare and contrast lateral root origin to the origin of stem branches
Lateral roots come from the pericycle ad stem branches come from…
How do bacteria gain entrance into the root tissue?
Through root hairs by inducing the pericycle
Where are the bacteria found before they infect the root?
Soil
Do the bacteria fix nitrogen when they are outside the root?
Yes
What does the term anaerobic mean?
Grows in the absence of oxygen
Does the rate of nitrogen fixation increase or decrease under anaerobic conditions?
Increase
