Plant Tissue Flashcards
§ Derived from shoot and root apical meristems
§ Composed of primary tissues
§ Constitutes the herbaceous parts of a plant
Primary Plant Body
(Herbaceous Body)
A plant that never becomes woody nor covered with bark; often lives for < 1 year; consists only of a primary plant body
Herb
§ Derived from meristems other than apical meristems
§ Composed of secondary tissues: wood and bark
§ Constitutes the woody, bark-covered parts of a
plant
Secondary Plant Body
(Woody Body)
has 1° tissues at its shoot and root tips, and a seedling consists only of 1° tissues. But wood and bark (2° tissues) arise inside the 1° tissues of stems and roots after few mos.
Woody Plant
A group of cells that perform specific function
Tissues
Level of Organisation
(Plants)
Cells
Tissues
Organ
Organ System
Organism
Tissues Classifications
(Based on stage of development)
- embryonic or meristematic
- permanent
Tissues Classification
(Based on composition)
- Simple
- Complex
Meristematic Tissues
[based on initiating cells]
(Origin & Development)
- Promeristem (Primordial meristem)
- Primary Meristem
- Secondary Meristem
Meristematic Tissues
[based on position in the plant body]
(Location)
- Apical
- Intercallary
- Lateral
Meristematic Tissues
(Function)
- Protoderm (Dermatogen)
- Procambium (Plerome)
- Fundamental / Ground Meristem (Periblem)
Permanent Tissues
(Simple Permanent)
[Ground Tissue system]
- Parenchyma
- Collenchyma
- Sclerenchyma
Permanent Tissues
(Complex Permanent)
[Vascular tissue system]
- Xylem (Primary)
- Phloem (Primary)
Tissues where the cells are in the mitotic state
Meristematic
The Length (Tip)
Apical Meristem
Elongation
Intercalary Meristem
Thickness
Lateral Meristem
- 1° Vascular Tissue
(Vascular Tissue system) - Central Cylinder
Procambium
- Ground Tissue
(Ground Tissue system) - Future cortex
Ground Meristem
- Epidermis
(Dermal Tissue system) - Embryonic epidermis
Protoderm
- cells are stable, no longer dividing
- It is differentiated into 2 types
Permanent
- composed of one type of cells
- differentiates into dermal or protective and ground or fundamental
- Classified based on the nature of cell wall
Simple Permanent tissue
- composed of different kinds of cells but perform similar function
Complex permanent tissue
(Simple Permanent Tissue Types)
A mass of parenchyma cells; most common type of tissue constituting all soft parts of a plant
Parenchyma Tissue
(Simple Permanent Tissue Types)
- most common type of cell
- Has thin primary walls; large vacuole
- active metabolically and alive at maturity
- Numerous subtypes are specialized for particular tasks.
Parenchyma Cells
Parenchyma cells of geranium
Nucleus (pink
Nucleolus (red)
Cell walls
Vacuoles
(Parenchyma Cells)
- involved in photosynthesis: chloroplast
- the thinness of the wall allows light and carbon dioxide to pass through to the chloroplasts
Chlorenchyma Cells
(Parenchyma Cells)
- mediate the short-distance transport of material by means of a large, extensive plasma membrane capable of holding numerous molecular pumps
Transfer Cells
(Parenchyma Cells)
- secrete nectar, fragrances, mucilage, resins, and oils
- contain few chloroplasts but have ↑ amounts of dictyosomes and endoplasmic reticulum
Glandular Cells
(Parenchyma Cells)
- Specialized in gas exchange; large intercellular spaces
Aerenchyma
(Parenchyma Cells)
- Specialized in gas exchange; large intercellular spaces
Aerenchyma
(Simple Permanent Tissue)
- a mass of collenchyma cells
Collenchyma Tissue
(Simple Permanent Tissue)
- Unevenly thickened primary walls (thin in some areas, thick most often in the corners)
- Typically alive at maturity
- Provide plasticity, the ability to be deformed by pressure or tension and to retain the new shape even if the pressure or tension ceases.
- present in elongating shoot tips as a layer just under the epidermis or as bands located next to vascular bundles
- usually produced only in shoot tips and young petioles
Collenchyma Cells
- Masses of collenchyma cells often occur in the outer parts of stems and leaf stalks.
- Collenchyma forms a band about 8 to 12 cells thick.
- The primary wall is thicker at the corners; No intercellular spaces are present
Peperomia Stem
(Simple Permanent Tissue)
- a mass of sclerenchyma cells
Sclerenchyma Tissue
(Simple Permanent Tissue)
- has both a 1O wall and a thick 2O wall that is almost always lignified
- Many dead at maturity
- provides elasticity, the ability to be deformed, but snap back to their original size and shape when the pressure or tension is released
- Some are involve in water transport
- develop mainly in mature organs that have stopped growing (non-extending parts) and have achieved their proper size and shape.
Sclerenchyma Cells
Types of Sclerenchyma Cells
- Mechanical (non-conducting) sclerenchyma
- Conducting sclerenchyma (thacheary elements)
- More or less isodiametric; often dead at maturity.
- brittle and inflexible
- form hard, impenetrable surfaces (shells of
walnuts and coconuts or the “pits” or “stones” of cherries and peaches)
Sclereids (Stone cells)
- Long; many types are dead, other types remain alive and are involved in storage.
- Flexible; found in areas where strength and elasticity are important (wood of flowering plant, trunk and branches)
- Resists insects, fungi, pests (bark)
- Elongates as the internode increases in length
Fibers
- Long and narrow with tapered ends; contain no perfora-tions. Dead at maturity. Found in all vascular plants.
- Water conducting cell
- Movement of water is
thru thin areas called “pits” found in the secondary wall
Tracheids
- Short and wide with rather perpendicular end walls; most contain one or two perforations. Dead at maturity. Found almost exclusively in flowering plants. Among nonflower-ing plants, only a few ferns, horsetails, and gymnosperms have vessels.
- forms large hole called a perforation which greatly reduces the friction = water moves much more easily than through pits of tracheids
Vessel elements
– common source for paper and linen cloth
Philippine fibers like abaca leaves or Manila Hemp and pineapple leaves are hard fibers
Flax fibers
Parenchyma Cell shape
Isodiametric cells which are oval, spherical or polygonal in shape
Parenchyma Cell wall
Thin cellulosic cell wall
Parenchyma Cytoplasm
Abundant
Parenchyma Nucleus
Present (Living tissue)
Parenchyma Vacuole
Large Vacuole
Parenchyma Intercellular Spaces
Present
Parenchyma Occurrence
Basically packing tissue, All soft part of plant, Pith, cortex, medullary rays
Parenchyma Functions
Food storage, Photosynthesis
Collenchyma Cell Shape
Circular, oval or polyhedral
Collenchyma Cell Wall
Uneven thickening on their cell wall.
Collenchyma Cytoplasm
Present
Collenchyma Nucleus
Present (Living tissue)
Collenchyma Vacuole
Vacuolated
Collenchyma Intercellular spaces
Absent
Collenchyma Occurrence
Dicot stems, petiole and beneath the epidermis. Absent in monocot and roots
Collenchyma Functions
Provide tensile strength, Mechanical support, Photosynthesis
Sclerenchyma Cell Shape
Variable in shape. Fibres and sclereids
Sclerenchyma Cell wall
Lignified secondary cell wall present
Sclerenchyma Cytoplasm, Nucleus, Vacuoles, and Intercellular spaces
Absent (Dead Tissue)
Sclerenchyma Occurrence
Dicot hypodermis, bundle sheath, pericycle, Seed, pulp of fruits.
Sclerenchyma functions
Protection from stress and strain,
Mechanical strength
Guard + stomatal pore =
Stomata
• Outermost surface of a herbaceous stem, leaf and root.
• Encrusted with cutin (cuticle)
Epidermis
(Simple Dermal Parenchyma)
Epidermis Uses
(Simple Dermal Parenchyma)
- protection
- regulate exchange of materials
Epidermis contains..
- Guard cells
- Trichomes
- Root hairs
inhibits the entry of CO2 needed for photosynthesis = plant’s starvation → pairs of guard cells with a hole (stomatal pore) between them to permit gas entry
Cutin
Open during the daytime
Stomatal pores
serves as reservoir of water and ions
Accessory cells
(Epidermis)
longitudinal rows of vacuolated cells
Bulliform cells
for the elongation of the epidermal cell outward (trichome and root hairs)
Epidermal hair
Trichomes (Epidermal Outgrowths / Hairs)
functions
- protection from insects and excessive sunlight
- aids in nutrient uptake
- spread of seeds
- Cotton trichomes can be made into threads, which is then woven into cloth
- Plant trichomes as defense
Examples of Trichomes
Glandular trichomes
Stinging trichomes
Branching trichome
Bristle trichome
Scale
Stellate
Muntingia calabura
Aratiles
Laportea meyeniana
Lipa
Verbascumthapsus
Velvet dock
Mucuna pruriens
Lipai
Eleagnus philippinensis
Lingaro
Mallotus philippinensis
Mallotus
Greatly increase the root’s surface area and efficiency of absorption
Epidermal hair on roots
• Outer covering woody stems and roots
Cell wall impregnated with suberin
• Produced by the cork cambium (secondary
meristem
• No intercellular spaces
Cork or Phellem (simple dermal)
brings water and mineral salts from the roots to the rest of the plants.
Xylem (Complex tissue, Vascular tissue system)
moves sugar and other organicnutrients (food)
Phloem (Complex, Vascular tissue system)
- consists of tracheids, vessels,
xylem parechyma and xylem
fibres - The tracheids and vessels
help to transport water and minerals from roots to all part of the plant - Xylem parenchyma stores water and minerals.
- Fibres help in support.
Xylem
- consists of sieve tubes,
companion cells, phloem parenchyma and phloem fibres. - The sieve tubes and companion cells transport food from leaves to all parts of the plant.
- Phloem parenchyma stores food.
- Fibers help in support.
Phloem
- alive and active; vertical rows of elongated cells
- Perforated end walls serve as strainer (sieve plate)
- Walls are perforated with pits
- No nucleus
- Forms continuous connection of cytoplasm from the top to bottom
Sieve tube members
- small cells attached to the sieve cells
- Nucleated
- supply proteins to sieve tubes
- Regulate the loading and unloading of carbohydrates from the sieve tubes
Companion cells
refers to the processes by which distinct cell types arise from precursor cells and become different from each other.
Differentiation (in plants)
