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Lab1

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What are the 2 basic systems found in vascular plants?
1) Shoot
2) Root
Define PHYLLOTAXY.
-the arrangement of leaves along the stem showing certain well defined patterns
What are the 5 classificatiosn in Phyllotaxy?
1)Opposite
-2 leaves are attached at a node on opposite sides of the stem

2)Decussate
-successive pairs are at right angles to one another

3)Whorled
-if three or more leaves are found at a node

4)Helical
-if the leaves stand single at the nodes, it will be found that they are arranged in an ascending helix along the axis

5)Distichous
-refers to teh pattern with only one leaf per node, but where all the leaves are arranged in only 2 vertical rows, usually 180deg apart

**pg.7**
Define MERISTEMATIC
-embryonic tissue in plants that have the potential to continually increase in length
What is the SHOOT APICAL MERISTEM?
-AKA the PROMERISTEM
-the embryonic regino at the apex of a shoot
-produces the tissues of the stem and a succession of leavs in a repetitive fashion
Define LEAFLETS
-the leaf like things on a compound leaf
Define STIPULES
-outgrowths at the bae on either side of the leaf
-is believed to be part of the leaf because its vascular supply is derived from that which serves the leaf
How does shoot expansion occur?
-leaves are initiated by the meristem are very close together vertically
-the spreading of leaves of a typical long shoot is accomplished below the apical meristem by the process of INTERNODAL ELONGATION
-thuis the meristem is responsible for the initiation of the stem and leaves, but much of the actual growth is accomplished in the maturing region below the meristem
Define LONG SHOOTS
-has long internodes
Define SHORT SHOOTS
-has short/no internodes
List the different types of shoot modifications. eg: vines.
1) vines
2) runners
3) rhizomes
4) tubers
5) corms
6) flattened or leaflike stems
7) tendrils
8) thorns
How does shoot branching occur?
-branching in the seed plants occurs by the production of LATERAL BUDS
-the developement of these axillary buds is controlled by ian internal hormonal mechanism in the plant
What are some unique characteristics about leaves?
-although it is a distinct organ, it is not sharply set off from the stem (ie: can't precisely tell where the tissue of the leaf ends and that of the stem begins)
-a DETERMINATE ORGAN (ie: does not retain a meristem at the tip, but grows for a definite time and then stops and matures completely)
-an axillary bud only occurs where the petiole of a leaf meets the stem (ie: at the node); at the base of a leaflet, therefore, an axillary bud is lacking
What are the 2 separable portions on a leaf?
1) Petiole/Leaf Stalk
2) Blade/Lamina
What is a SESSILE LEAF?
-the blade is attached directly to the stem (ie: no petiole)
Define SIMPLE LEAF
-a leaf with one blade per axis/petiole
Define COMPOUND LEAF
-a leaf having 2 or more LEAFLETS attached to a common axis/petiole

-can either be PINNATELY(feather like fashion) or PALMATELY(arise from a common point and flop over, like a palm tree) compound
-compound leaves may be compounded twice or rarely thrice

**pg.11**
What are the 3 tissue systems found in plants?
1) Dermal
2) Vascular
3) Ground/Fundamental
What components make up the DERMAL TISSUE SYSTEM?
1) Epidermis
-contains STOMATA
-a surface layer of cells which are tightly fitted together and whose outer, thickend walls are impregnated with...

2) Cutin
-a fatty substance related to waxes, which retards water loss

3)Cuticle
-a surface layer of cutin ouside the epidermal cells
What components make up the VASCULAR TISSUE SYSTEM?
1)Xylem
-conducts water and dissolved mineral salts
-includes TRACHEIDS, VESSEL ELEMENTS, PARENCHYMA & FIBRES

2)Phloem
-transports organic solutes like sugar and also some minerals
-includes SIEVE TUBE ELEMENTS, COMPANION CELLS, PARENCHYMA & FIBRES

**These two tissues always occur together in land plants with the phloem peripheral to the xylem, although internal phloem may also be found in some cases.**
Define PLASMODESMATA
-clusters of submicroscopic holes which are penetrated by delicate strands of cytoplasm which connect the adjacent cell protoplasts throughout the plant body
What are some characteristics of PARENCHYMA CELLS?
-often called the basic cell type of the plant body
-living at maturity
-have primary walls only
-function as metabolic cells and as storage depots
What are some characteristics of TRACHEIDS & VESSEL ELEMENTS?
-dead cells at maturity
-have thickened cell walls containing LIGNIN
-has primary and secondary walls
-secondary wall may be ANNULAR, HELICAL, SCALARIFORM

-vessel elements are believed to ahve been derived from tracheids in evolution and are found only in the angiosperms and in a few other isolated groups among the vascular plants
-vessel elements are arranged end to end in a vertical series to form vessels which may have an overall length of many feet in some large trees
-end walls of vessel elements are occupied by PERFORATION PLATES (may have a number of openings or it may have one very large opening so that the vessel element is like a barrel wich both ends knocked out
What are the 4 types of secondary wall formation on Tracheids?
1) Annular
-series of separate rings

2) Helical
-one or more helices

3)Scalariform
-ladder like pattern

4)Reticulate
-netted pattern
What are FIBRES?
-supportive cells in the vascular system
-have thick secondary walls with a few small pits only and are usually dead at maturity
-purely mechanical in function and do not conduct
-they are placed in the general category of SCLERENCHYMA
What are some characteristics of SEIVE TUBE ELEMENTS?
-they are conducting elements of phloem
-they are living cells containing cytoplasm when mature, but their protoplasm is highly altered and the nucleus and most other organelles have disappeared
-the wall is soft and relatively thin
-end walls between adjacent sieve tuve elements within a sieve tube are called SIEVE PLATES
-recognition of sieve tubes is done in the presence of a carbohydrate material called CALLOSE (super blue in aniline blue)
-callose is for sealing off
-side walls contain SIEVE AREAS where there are intercellular connections smaller than those of the sieve plate

COMPANION CELLS
-small
-living cells with nuclei which have a common origin (arise as sister cells)
-believed to supply the sieve tubes with metabolites necessary for transport of materials into and out of them
What are SIEVE CELLS?
-different then SIEVE TUBE ELEMENTS
-found in phloem of gymnosperms
-cells are long, tapered elements like tracheids in shape but like sieve tube elements in cytology
-have no sieve plates, but have sieve areas like those of the side walls of sieve tubes
-no companion cells but have parenchyma cells called ALBUMINOUS CELLS
What 2 tissues make up the FUNDAMENTAL/GROUND TISSUE SYSTEM?
1)CORTEX
-between the epidermis and the vascular cambium

2)PITH
-the centre of the stem, internal to the vascular system
-pith rays between the bundles are also included
-lacking in lower plants and tough to differentiate in MONOCOTS
Define LEAF TRACE
-a vascular bundle which extends into a leaf
-a leaf may have one to many traces depending upon the spps
-when a leaf trace changes its course and diverges towards a leaf, the portion of the vascular ring above the divergence which it would have occupied, had it not diverged is filled parenchyma, this region is called a LEAF GAP
Define EUSTELE
-the bundles of the stem are in a ring as in most dicotyledons
Define ATACTOSTELE
-vascular bundles are scattered through the entire central region of the axis
-as found in monocots
What are VEINS?
-term used for vascular bundles when they are in the leaf
Define ANASTOMOSE
-term meaning run together
-useful in describing patterns of veins
What is PINNATE VENATION?
-a main vein from which smaller veins arise in a feather like pattern
What is PALMATE VENATION?
-several branching veins arising from a common point along the midvein, near the lamina base
Describe the GROUND TISSUE SYSTEM of the leaf.
you know this:
-palisade and spongy mesophyll
-intercellular spaces
-etc.
Describe the DERMAL TISSUE SYSTEM of the leaf.
-consists of the epidermis which is composted of tightly fitted cells covered by a cuticle
-has STOMATA which allows for gas exchange
-openings are surrounded by 2 GUARD CELLS (come from a common parent cell; leave an opening when they are turgid, close the opening when they are flaccid)
Summarize all tissue systems and cell types...
-no way, too lazy

**look at pg 17&18**
What is CHLORENCHYMA?
-parenchyma with chloroplast
-found under the epidermis if present
What are 3 types of UNDERGROUND STORAGE STRUCTURES SHOOT MODIFICATIONS?
1)Corm
-an underground tuber like base of a vertical stem that has stored food
-eg: gladiolus, crocus

2)Bulb
-a very short underground stem with fleshy bulb scales (leaves) thickened with stored food
-eg: onion

3)Tuber
-a short, much enlarged portion of stem containing food reserves
-the eye's of the potatoe tuber are the nodes, they are coposed of bestigial leaves and axillary buds, each eye is capable of producing a new plant

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