Unit 2: Tissues Flashcards
plant tissues
composed of cells that are similar and perform a specific function.
group cells
tissues
organs
organ systems
plant tissue system
- dermal tissue
- epidermis
- periderm - ground tissues
- vascular tissue
transpiration, gas exchange and defense.
dermal tissue (skin)
- covers roots, stems, leaves, and fruits
- at the outer surface of the epidermal cells is a continuous layer (cuticle) made up of fatty material (cutin)
- Sometimes overlaid with a protective, waterproof coating of wax. Oil, resin, and salt crystals may also be deposited on the surface
___________: specialized epidermal cells, control air exchange (CO2 and O2) and water loss from plants
epidermis
stomata
functions of epidermis
- mechanical support
- protection from desiccation (drought) and against attack by virulent pathogenic organisms and insects
- gas exchange
- restriction of water loss by evaporation (transpiration) through stomates and water and mineral storage
formed during secondary growth replacing primary epidermis
periderm
cork
cork cambium
phelloderm
- inner to the dermal tissue and is compose of simple tissue like parenchyma
- store molecules (such as starch), photosynthesize (such as mesophyll cells), or support the plant.
- three types of ground tissue:
ground tissue
collenchyma, sclerenchyma, parenchyma
- consist of conducting elements xylem and phloem
- may be scattered in ground tissue or irregularly arranged forming a ring.
- in the latter arrangement, ground tissue is differentiated into _______ (outer to vascular tissue) and _____ (inner to vascular tissue)
- the ground tissue if leaves are called ________, bound by upper and lower epidermis
vascular tissue
cortex
pith
mesophyll
- plumbing system of the plant.
- allows water, minerals, and dissolved sugars from photosynthesis to pass through roots, stems, leaves, and other parts of the plant.
- It is primary composed of two types of conducting tissue: _______ and _______.
- veins on leaves
- xylem and the phloem form a structure called a ____________; in roots, this is termed the ____________ or ____________.
vascular tissue
xylem and phloem
vascular bundle
vascular stele or vascular cylinder
types of plant tissues
A. Meristematic (3)
B. Permanent
i. Simple
*parenchyma
-
-
+
+
*collenchyma
*sclerenchyma
-
-
ii. Complex
*xylem
-
-
*phloem
-
-
-
A. Meristematic
- apical
- intercalary
- lateral
B. Permanent
i. Simple
*parenchyma
- aerenchyma
- chlorenchyma
+ palliside
+ spongy
*collenchyma
*sclerenchyma
- fibers
- sclereids
ii. Complex
*xylem
- vascular cells
- bordered
*phloem
- sieve cells
- sieve-tube elements
- companion cells
-These are actively dividing cells, which are isodiametric in shape, rich in cytoplasm with small or no vacuoles.
-These cells consist of undifferentiated cells that are found at shoot tips, at root tips, in the vascular cambium, and in the cork cambium.
- differentiate into specialized tissues of three systems: dermal, ground, and vascular.
- plant regions of continuous cell division and growth.
______________ consists of plant cells that are no longer actively dividing.
meristematic
permanent tissue
- found at the tips of stems and roots and is responsible for primary growth e.g. plant length
apical meristems
- found at the basal portion of internodes and is responsible for the elongation of internodes in Poaceae members
- occur only in monocots, at the bases of leaf blades and at nodes (the areas where leaves attach to a stem). This tissue enables the monocot leaf blade to increase in length from the leaf base; for example, it allows lawn grass leaves to elongate even after repeated mowing.
intercalary meristems
- found at the vascular and cork cambium and is responsible for secondary growth
- facilitate growth in thickness or girth in a maturing plant.
lateral
- Tissues contain cells of similar structure, function and have common origin
simple permanent
- the fundamental tissue found in every part of the plant body like pith and cortex of the stem and root, mesophyll of leaves, flesh of fruits, floral parts and even in xylem and phloem
– involved in storage of starch, sucrose, protein, water, phenol derivatives and many mineral substances
– there is active respiration and protein synthesis
- usually thin-walled and vary in shape from spherical with many flat surfaces, to elongated, lobed, or folded
- compactly arranged or more commonly spaciously arranged with intracellular spaces as in cortex and pith
- cells possess dense cytoplasm and are active metabolites
parenchyma
- Intracellular spaces filled with air, are large in size and many in number
- Cells occupy a smaller area but provide the required strength to aquatic plants (for aeration and buoyancy)
aerenchyma
- Parenchyma cells that contain numerous chloroplasts, seen in leaves and sometimes in young shoots
__________: elongated and compactly arranged
__________: spaciously and irregularly arranged
chlorenchyma
pallisade
spongy
- cell walls are thickened due to deposition of pectin, narrower than parenchyma
- provide elastic support to stems & leaves due to variously thickened primary walls containing cellulose, hemicellulose, pectin & water
- usually found near the surface in the cortex around vascular bundles of leaf petioles and stems.
- primary supporting tissue in stems, leaves and floral parts of dicots, whereas in stems and leaves of monocots collenchyma is usually absent (instead, sclerenchyma is present in monocots)
- living supportive tissue that has elongated cells and an unevenly thickened primary cell wall.
- main function is the mechanical support of young stems and leaves via turgor.
collenchyma
- function in mechanical support due to thick lignified secondary walls, which contain large amounts of cellulose and lignin
- dead supportive tissue that consists of longsclerenchyma fibersor short, crystal-like.
- fibers occur in groups (bundles).
- may be branched or not and occur individually or in small clusters.
- Each cell has a uniformly thicksecondary wallthat is rich in lignin.
- main function is a support of older plant organs, and also hardening different parts of plants (for example, make fruit inedible before ripeness so no one will take the fruit before seeds are ready to be distributed).
- Fibers inside phloem are sometimes regarded as a _________________
sclerenchyma
separate sclerenchyma
- usually long and spindle shaped structures with tapering ends (with pits)
- found in water-conducting tissue (xylem) and food-conducting tissue (phloem) along leaf veins and margins, and surrounding vascular bundles in stems
fibers
- shorter than fibers that occur singly or in groups
- commonly found in fruit wall, seed coat, epidermal scales and occasionally found in cortex, pith and mesophyll
- known types are the asterosclereids, macrosclereids, osteosclereids and brachysclereids
sclereids
3 basic types of plant tissues
_____________: cell walls
_____________: intracellular spaces
_____________: cell walls within lignin
collenchyma tissue
parenchyma tissue
sclerenchyma tissue