plant cell types

How is plant development influenced?

Totipotency, meristems, cell walls, vacuoles

What are the functions of cell wall?

Mechanical strength, controls cell expansion, provides protection, regulates transport, store food reserves

What is the structure of cell wall?

Surrounding plasma membrane

Layers of primary and secondary walls

Middle lamellar composed of cellulose, hemicellulose and pectin

What is primary cell wall?

Thin, flexible layer

Forms while cell is growing, allowing for expansion and growth

What is the secondary cell wall?

Derived from primary cell wall by thickening and inclusion of lignin

Specialised cell: tracheary elements, fibers

What is the function of secondary cell wall?

Provides structural support, protection, and rigidity to plant cells, especially in cells that have stopped growing and are no longer capable of expansion

Do all plants have a secondary wall?

No, but all plant cells have a primary cell wall, only specialised cells develop a secondary cell wall after primary cell wall is formed

What are the 3 types of plant cells?

Parenchyma, collenchyma, sclerenchyma

What is the structure of parenchyma cells?

Thin, flexible primary cell wall, lack secondary wall. Large central vacuole

Where are parenchyma cells present?

In mesophyll of leaves, and cortex and pith of stems and roots

What are the role of parenchyma cells?

In photosynthesis in leaves and storage (e.g. starch in roots, protein in fruits), wound healing and regeneration

Give examples of parenchyma cells

Aerenchyma, chlorenchyma

What is the structure of collenchyma cells?

Pectin deposition at the corner, thicker cell wall, elongated cell

Where are collenchyma cells present?

In stem cortex and leaf petiole

What is the role of collenchyma cells?

Support and flexibility to non woody stems and leaf petiole

What is the structure of sclerenchyma tissue?

Thick secondary wall. Most cells undergo apoptosis

What is the role of sclerenchyma tissue?

Support

Where are sclerenchyma tissue present?

In regions where plant has stopped growing growth

What are the 2 types of sclerenchyma tissue?

Fibers: long, slender cells with tapered ends

Sclereids: short, irregular, or branched cells

What is the function of dermal tissue?

Outer protective tissue - to prevent water loss and protection

Controls interactions with the plant’s surroundings

What are the 2 plant parts of dermal tissue?

Non-woody parts: epidermis

In woody parts and root: periderm

What can epidermal cells differentiate into?

Stomata guard cell, trichomes, root hair, secrete cuticle

What are meristems?

Regions of undifferentiated cells where cells are able to divide

What is primary growth?

Extension of the plant body -? Primary plant body

What is secondary growth?

Thickening of the stem and roots -? Secondary plant body (wood and bark)

What are phloem made up of?

Sieve-tube elements

Associated to a companion cell connected by plasmodesmata

What are the conducting cells of xylem?

Tracheids and vessel elements

What is xylem made up of?

Thick walls of cellulose and lignin

What does xylem do?

Provide mechanical support to the plant

What are apical meristems?

Found at tips of roots and shoots

What are secondary lateral meristems?

Found along the sides of stems and roots

What is the main function of root apical meristems?

Anchoring, uptake of water and mineral ions

What are the 4 main zones in the root tip?

Root can

Zone of cell divison: root apical meristem (cells divide and differentiate)

Zone of cell elongation

Zone of maturation

Root tip have overlapping zone of cell division, elongation and maturation

Which plants commonly undergo secondary growth?

Some edicts, especially in roots and stems

What tissues are produced during secondary growth?

Secondary xylem (wood)

Secondary phloem (part of bark)

What are the 2 types of lateral meristems?

Vascular cambium

Cork cambium

Where is the vascular cambium located?

Between primary xylem and primary phloem

Explain the development of woody stems

Vascular cambium cell divides and produces secondary xylem (inwards) and secondary phloem (outwards)

Breaking of the epidermis and cortex

Formation of cork cambium → secondary dermal tissue: periderm