Plant form and function Flashcards
What are meristems?
They are undifferentiated tissues containing cells that can constantly divide via mitosis under suitable conditions and give rise to new cells. They have dormant periods.
Define primary growth of a plant root.
Elongation of the root due to the activity of the root apical meristem (which is a primary meristem) located at the root apex.
Define the primary growth of a plant shoot.
Elongation of the shoot due to the activity of the shoot apical meristem (which is a primary meristem) located at the shoot apex.
What are intercalary meristems?
They are meristems present in some monocots like grasses, present at the base of stems and leaves, allowing for rapid regrowth of damaged leaves.
3 processes taking place during primary growth of a root.
- cell division
- cell elongation
- cell maturation due to differentiation.
What is a root cap and how is it formed?
It is the structure present in the root to protect the root apical meristem from damage due to friction when the root moves through the soil. produced by the differentiation of cells produced outwards by the meristem.
What occurs in the zone of cell maturation?
The cells will start to get specialised structurally and functionally due to differentiation, and will obtain functional maturity.
Structure of the shoot apical meristem.
It is a dome shaped mass of dividing cells located at the shoot tip.
Describe the epidermis of the dermal tissue system.
- it is the protective layer of the stems and roots of the primary plant body and leaves.
- it is a single cell layer with tightly packed cells.
- covered by a waxy cuticle in aerial parts.
- some specialised epidermal cells are present.
Function of hair-like trichomes
To reflect excess light and reduce water loss
Function of glandular trichomes
Produces chemicals that provides defense against insects, pathogens and herbivores.
Explain the ground tissue system.
Fills the gap between the vascular and dermal tissue system
composed of pith and cortex
has cells that function in storage, photosynthesis, support and short distance transport (radial transport)
Functions of different cell types in xylem tissue.
Xylem vessel elements and tracheids = conducting cells.
Fibres = give mechanical strength
Parenchyma = storage and radial transport.
What are the structures present in the end walls of xylem vessel elements?
perforation plates
Significance of the cell wall of xylem vessel elements being thickened with lignin.
To provide support, and prevent collapse under the tension of water transport.
