Plant Tissues Flashcards
Permanent regions of growth and active cell division
Meristems
Found at the tips of roots and shoots
Apical Meristems
Roots and shoots increase in length as the apical meristems produce new cells. It is called ________
primary growth
Embryo Leaves and buds and 3 primary meristems develop where?
Apical Meristems
Primary meristems are:
Protoderm, ground meristem, procambium
Primary meristems produce primary tissues. True or false?
True
Produce secondary tissues that increase the girth of roots and stems. It includes the vascular cambium and the cork cambium.
Lateral Meristems
It is the increase of girth in stems
Secondary growth
Sometimes just known as cambium. Produces secondary tissues that function primarily in support and conduction. Composed of a thin cylinder of brick-shaped cells that extends the length of stems and roots. Cambial cylinder often branches, except at the tips.
Vascular Cambium
Individual remaining cells of the cambium are called ______, and their sister cells are called _______.
Initials; derivatives
A thin cylinder that runs the length of roots and stems of woody plants. Lies outside vascular cambium just inside the outer bark. It produces bark
Cork cambium
Grasses and related plants do not have vascular cambium nor cork cambium. Occur in vicinity of nodes (leaf attachment area) along stems. Add to stem length
Intercalary meristems
Simple tissues are composed of one type of cell. Complex tissues have two or more cell types. True or false?
True
• Thin, pliable walls
• Usually 14-sided at maturity
• Living cytoplasm, often containing large vacuoles and various secretions
• May remain alive a long time
• Have spaces between them
Parenchyma cells
Parenchyma tissue with extensive connected air spaces, usually in aquatic plants
Aerenchyma
Parenchyma cells containing chloroplasts that function in photosynthesis
Chlorenchyma
Develop irregular extensions of inner wall that greatly increase surface area of plasma membrane. For ex., nectaries of flowers
Transfer cells
• Living cytoplasm
• May remain alive a long time
• Cell walls thick, with uneven thickness
• Pliable and strong, thus provide flexible support
collenchyma cells
• Thick, tough, secondary walls, normally impregnated with lignin
• Dead at maturity
• Function in support
sclerenchyma cells
What are the two types of sclerenchyma cells?
Schlereids and fibers
- Scattered in tissue
- Cells as long as wide
- Include stone cells
Schlereids
- Found in roots, stems, leaves, and fruits
- Much longer that wide and contain lumen (tiny cavity)
- Have been used by humans for thousands of years as rope, string, canvas, textiles, etc.
Fibers
Composed of two or more kinds of cells. Include xylem and phloem, epidermis, and periderm,
Complex tissues
Transports and stores water and water-soluble nutrients in vascular plants. Chief conducting tissue for water and minerals that are absorbed by the roots. It is composed of parenchyma cells, fibers, vessels, tracheids and ray cells
Xylem
It is responsible for transporting sugars, proteins, and other organic molecules in plants. Conducts dissolved food materials produced by photosynthesis throughout plant. It is composed of sieve tube members, companion cells, fibers, parenchyma cells and ray cells
Phloem
In woody plants, most complex tissues are produced by the vascular cambium and are called what?
Vascular tissues
A protective layer covering all plant organs. It is one cell-layer thick.
Epidermis
- Comprises the outer bark of woody plants.
- Consists mainly of cork cells
- Has pockets of parenchyma-like cells
Periderm
Long tubes made of vessel elements
Vessels
• Thick secondary cell walls
• Open at both ends
• Secondary walls develop irregularly
• Perforation plate between end walls
Vessel elements; Vessels
Tapered at the ends with pairs of pits that allow water to pass from cell to cell. Dead at maturity. Has thick secondary cell walls and may have spiral thickening on cell wall
Tracheids
Areas without secondary cell
Pits
Function in lateral conduction and food storage
• Composed of long-lived parenchyma cells
• Produced in horizontal rays by ray initials of the vascular cambium
• In woody plants they radiate out from the center like spokes of a wheel
Rays
Narrow, tapered cells associated with sieve tube members
Companion cells
• Lack secondary cell walls and nuclei
• Lay end to end to form sieve tubes
• Walls have sieve plates with small pores
• Callose forms callus plug - Prevents leaking of sieve tube contents when cell injured
Sieve Tube Members
Fatty substance on the surface of outer walls of epidermis that forms cuticle
Cutin
Loosely arranged pockets of parenchyma cells formed by cork cambium that protrude through the surface of periderm. Allows for gaseous exchange.
Lenticels
