Bio205 Midterm

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In the Kingdom PLANTAE, what are the suffixes used for: P C SC O F: P- (-phyta)
C- (-opsida)
SC- (-edonae)
O- (-ales)
F- (-aceae)
What's the difference between MORPHOLOGY and ANATOMY?: Morphology
-the study of the external form of a plant or its parts
-deals with surface features

Anatomy
-AKA histology
-study of the internal form of the plant parts
What is the MIDDLE LAMELLA?: -the filled region between primary walls of adjacent cells
-contains pectic substances that cement walls together
-adjacent cells are connected by intercellular, cytoplasmic connections = PLASMODESMATA
-occurs in thin regions (Primary pit field) of the primary wall
What are the 2 tissues that comprises the DERMAL TISSUE SYSTEM?: 1) Epidermis
-the primary plant body

2) Periderm
-replaces the epidermis in long lived plants
-makes up part of the secondary plant body
What are the 2 Types of Epidermal Cells?: 1) Non-Specialized epidermal cells
-make up most of the epidermis
-compact, tight fitting cells
-variable outlines
-usually still living at maturity

2)Specialized Epidermal Cells
-normally much fewer in numbers
-found interspersed among the unspecialized epidermal cells throughout the epidermis
-3 types: guard cells, subsidiary cells, trichomes (*another FC)
What are GUARD CELLS?: -specialized epidermal cell
-found in pairs around a pore that forms between them
-unit (2 guard cells + pore) = stomate
-guard cells develope from the same precursor cell (=guard mother cell)
What are SUBSIDIARY CELLS?: -specialized epidermal cell
-typically in pairs surrounding guard cells in MONOCOTS
-can have multiple pairs
What are TRICHOMES?: -specialized epidermal cell
-AKA AERIAL HAIRS
-found widespread on above ground body parts
-unicellular or multicellular trichomes

*can be SECRETORY
-they secrete substances of various types (eg: volatile oils, nectar, polysaccharides)
-builds up under the cuticle

*can be NON-SECRETORY
-these form protective/defensive structure in the epidermis
-eg: defense against insect attack
What are TRICHOBLASTS?: -AKA ROOT HAIRS
-found on epidermis underground a short distance behind the tips of roots
-are long extensions of certain epidermal cells and always UNICELLULAR
-form by tip growth, possess a very large surface area
-form the absorption zone in roots
-are extremely important for plant's uptake of water and ions from soil
What is PERIDERM?: -makes up part of the secondary plant body
-formed as the outermost part of bark, at the very outside of stems, roots of long lived woody plants
-includes: cork cells (PHELLEN), cork cambium (PHELLOGEN), and PHELLODERM
What is the CORK CAMBIUM?: -AKA PHELLOGEN
-forms in a layer of cells just below the epidermis
-starts dividing to form new cells
-the largest part of the periderm consists of an outer region of cells called cork cells (PHELLEN). Compact and tight fighting. Dead at maturity after depositing SUBERIN
-cork cambium is bifacial, continually dividing and pushing new cells to outside (cork cells) and cut some cells off inward (PHELLODERM)
What are the 2 functions of SUBERIN in the PHELLEN LAYER?: 1)retain water inside of the plant body

2)prevent pathogens from entering the body
What's the difference between a SIMPLE SIEVE PLATE and a COMPOUND SIEVE PLATE?: SIMPLE SIEVE PLATE
-flat top

COMPOUND SIEVE PLATE
-slanted top
In regards to PHLOEM, whats the difference between angiosperms and non angiosperms?: -non angiosperms have specialized cells called 'SIEVE CELLS' (not sieve tube elements)
-very elongated
-lack seive plates, instead have tapered end walls

-lack companion cells; instead have small cells called ALBUMINOUS CELLS
-these do not form from the same 'PRECURSOR CELL' that forms the seive cell
What is a PHYTOMERE?: -the axillary bud, the internode above it, plus the node and its leaf
What are AXILLARY BUDS?: -buds that originate from part of the flank (peripheral) meristems
-in the axils of enlarging leaf pimordia
-responsible for the futre branching of the shoot system in certain plants like angiosprems
-in angiosperms, have a MONOPODIAL branching pattern because branching does not occur immediately, nor at the shoot apex
-instead, axillary buds are kept from developing into branches for some time (apical dominance -> auxin from the SAM of terminal bud)
-sometimes the bud forms a sharp, pointed structure called a THORN
Define STELE: -term given for the central arangement of primar vascular tissues in a stem (or root), including associated pith (if present)
-does not include secondary vascular tissues, nor leaf traces
Define BICOLLATERAL FASICLES: -have a portion of primary phloem on either side of primary xylem
Define LEAF GAP: -a break (usually consisting of parenchyma cells) in a united ring of vascular tissue associated with a departing leaf trace (see lab material and Jan.26)
What are the 4 patterns of XYLEM MATURATION?: 1)Endarch
2)Exarch
3)Centrarch
4)Mesarch

*see Jan.26*
What are ADVENTITIOUS ROOTS?: -prop roots
-roots that do not form from the primary root; instead, form from stems and leaves
What are the 2 types of ROOT SYSTEMS?: 1)TAB ROOT (eg: Dicot)
-lateral roots common
-adventitious roots here too

2)FIBROUS ROOT (eg: Monotcot)
-lateral roots common
-primary root (from radicle) is short lived
-therefore has lots of adventitious roots
What is the ROOT APEX?: -tip of the radicle of the embryo and of any othr root
-root cap protects the subterminal RAM
-cap cells often secrete mucilage
-cap cells are lost/left behind as the root apex continues to grow
-cap cells are coninually replaced by RAM
What are the 2 types of RAM?: 1)Closed
-initials are highly organized
-3 layers (HISTOGENS)
i)Dermatogen: forms the epidermis and root cap
ii)Periblem: forms the ground tissue
iii)Plerome: forms vascular cylinder

2)Open
-initials are not highly ordered (eg: onion)
What is a QUIESCENT CENTRE?: -region of the RAM that has lightly stained, slowly dividing cells
-a reserve for replacing initials that eventually deteriorate
What is the ENDODERMIS?: -usually a single cell layer thick
-innermost cell layer of the cortex
-CASPARIAN STRIP/BAND in the SUBERIN (sometimes LIGNIN)
What is the CASPARIAN STRIP?: -a hydrophobic band found in the endoderm

Provides:
APOPOPLASTIC BARRIER
-gives selectivity by the root
-includes non-living parts such as cell walls intercellular spaces, mature tracheary elements
-extracellular route

SYMPLAST BARRIER
-allows good shit into the vascular sysmetm
-living parts (eg: cytoplasm and plasmodesmata)
-intracellular route
What is the PERICYCLE?: -often a single cell layer thick
-found immediately internal to the endodermis
-outermost layer of roots stele
-give rise to LATERAL ROOTS
-in long fixed roots, pericycle is involved in origin of lateral meristems (eg: vascular cambium and cork cambium)
What are LATERAL ROOTS?: -creat new absorptive surfaces below the ground
-allows more water and ions to be taken up from the root
-pericycle undregoes periclinal cell divisions to form a bulge -> root primordium -> lateral root

*in triarch, tetrarch and pentarch, lateral roots orinante opposite the primary xylem*

*in diarch, polyarch and protosteles, the lateral root originates opposite the primary phloem*
How does INITIATION OF SECONDARY GROWTH occur in Dicots?: -arises before the end of the first year of growth, after internodes have completed their elongation
-originates from FASCICULAR CAMBIUM (the existing cambium within a fascicle)
-hormonal control initiates the cells occupying space inbetween vascular cambium to differentiate into meristemic tissue
-therefore, VASICULAR CAMBIUM = FASCICULAR CAMBIUM and INTERFASCICULAR CAMBIUM
What are the 2 TYPES OF INITIALS?: 1) FUSIFORM INITIALS
-initials are much longer (10x) than wide
-have primary walls alone -> but a distinct beaded wall appearance in the thin regions of primary wall, primary pit fields (PLASMODESMATA)
-divide to form derivatives to form tracheary elements, sievetuve elements, fibres, companion cells
-makes the AXIAL (vertical) system of the secondary vascular tissues

2) RAY INITIALS
-are approximately isodiametric
-normally occur in stacks/groups
-derivatives of the ray initials often form parenchyma cells-> Rays in secondary xylym and phloem
-derivatives of the ray initials often form the RADIAL SYSTEM (horizontal)
What is the BIFACIAL nature of the VASCULAR CAMIUM in dicots and conifers?: -most derivatives will form secondary xylem
-will form 4x-7x more xylem than it will phloem
What is WOOD?: -pretty much the secondary xylem
What is BARK?: -pretty much everything located outside of the vascular cambium
What is a FOSSIL?: -rememnant of a plant or animal body that lived in the past (must be > 10,000yrs)
-often the organism is turned to stone/rock
-often involves sedimentation
-sometimes find only fragments of the thihng rather than it in its entirety
What are the conditions that enhance fossil formations? 2: 1) Fossilization most likely if decomposition is retarded
-most organisms decompose/decay because of aeroic, saprophytic organisms (eg: fungi, bac)
-pools of standing water give good conditions
-some plants parts are less prone to decay naturally because of their chemical composition (eg: cuticle, sclerechyma, etc)

2) Need for a suitable source of sediment
-depends on particle size of the sediment
-finer sediments: yield better preserved plant material (eg: siltstone, shale)
-coarse sediments: more poorly preserved (eg: sandstone, conglomerates)
What are the 7 TYPES OF FOSSILS?: 1)Whole plant or part of the plant is the fossil
2)Compression
3)Impression (Imprint)
4)Mold
5)Cast
6)Amber
7)Petrification
What are COMPRESSION fossils?: -plant part is buried in suitable sediment, then over time gets crushed by the sheer weight of accumulated sediemtns above it
-little remains of the plant part, but a thin film/outline of carbon (black)
What are IMPRESSION/IMPRINT fossils?: -all the organic material has dissappeared, except the sediment which has hardened and hence preserves the impact
What are MOLD fossils?: -sediment covers the plant part and hardens around it, but then the plant part ddecomposes
-left with a hollow cavity
What are CAST fossils?: -if the cavity of a MOLD becomes filled with new sediments, wich then harden, this forms a cast
-3D morphology
What are AMBER fossils?: -the fossil type consists of an organism or plant that has been entrapped/entombed in sticky plant resins
-occurs in the tertiary period of the Cenozoic era
-eventually hardens into a clear resinous mass
-3D preservation
-could also section it to reveal internal structure
What are PETRIFICATION fossils?: -very important for internal structure (anatomy)
-the plant part becomes infiltrated by a mineral solution and hardens, represent a surprising detail of internal structure
-formation of coal balls: thinly sliced reveals internal structure
-can be used to determine seasonal variation with the presence or absence of growth rings (eg: present = variation, absence = equal)
Define PERIODS: -subdivisions of ERAS
Define EPOCHS: -subdivisions of PERIODS
Define ERAS.: -the largest time unit in a geological time scale
What are the 4 ERAS?: 1)Precambrian
-oldest era
-it contains all time from the creation/begining of earth (est. 4bya) to the first appearance of the trilobites

2)Paleozoic
-this era opens with appearance of trilobites, ends with appearance of dinosaurs

3)Mesozoic
-from the first appearce to the dissappearance of dinosaurs

4)Cenozoic
-our present era
-contains all time since the dinosaur
What are IDEAL INDEX FOSSILS?: Has the following factors:
-represent an animal or plant that lived in abundance and left appreciable numbers of fossils
-fossil of the organism very distinctive
-organism evolved and then dissappeared in a rather short time (eg: 1 mill years)
-fossils of the organism occur on 2 or more continents
What are ABSOLUTE GEOLOGICAL TIME SCALES?: -based on radiometric dating
-assigns actual time values to fossil layers
-uses CARBON DATING
What is CARBON DATING?: -technique useful to determine the age of relatively recent fossils only (ie: Holocene Epoch, Cenozoic Era - Quartenary Pd)
-12C carbon is very stable
-14C carbon is less stable
-because of the 2 carbons, we produce 2 types of sugars...
-when the plant dies, CO2 uptake ceases and 14C in the plant body breaks down
-half life of 14C is 5,730 yrs
-the ratio (14C/12C) is used to determine plant age
-the lower the ratio, the older the fossil
What is a FORM GENUS?: -the name applied to a fossil representing only a piece of the entire plant
-an artificial genus, used for convenience
-a form genus cannot be reliable to just one family, but can be assigned to a single order that contains the families represented by the form genus
-in some ways, form genus is non committed
-the name adopted for the entire plant is that form genus name first applied to some part of the reconstructed plant
What are the 4 types of SIDEWAYS CONNECTIONS BETWEEN ADJACENT PLANT CELLS?: 1)Primary Pit Fields

2)Sieve Area

3)Simple Pit Pairs

4)Bordered Pit Pairs
How many flower parts do MONOCOTS have per whorl? DICOTS?: Monocots
-x3's

Dicots
- x4's or x5's
What kind of root system do MONOCOTS have? DICOTS?: Monocots
-Fibrous

Dicots
-Taproots
What's the function of PARENCHYMA CELLS?: -highly actibe, metabolically
-can be involved in phsiological processes such as storage, photosynthesis, respiration, secretion, etc.
What's the function of COLLENCHYMA CELLS?: -a supportive cell type (for strength), occurring in groups
What's the function of SCLERENCHYMA CELLS?: -a supportive cell type (for strength), often occurring in groups
Where would you find COLLENCHYMA CELLS?: -often in the periphery of the cortex of stems and roots, just below the epidermis
-also common in the mid rib and petiole of leaves
What are the 2 SUBTYPES of SCLERENCHYMA?: 1)Fibres
-long but narrow
-have thick, uniformly thickened secondary walls with lignin
-pits connect adjacent fibres
-staggered alignment increases rigidity

2)Sclereids
-shorter, fatter
-rectangular or spherical
-have thick, uniformaly thickened secondary walls with lignin
-pits connect adjacent sclereids
Define COTYLEDON: -seed leaf formed during the embryonic stabge
-is not formed by the shoot apex
-in grassse, the cotyledon is also called the SCUTELLUM
Define HYPOCOTYL: -a stem segment only found in dicots
-is the portion of the stem located below the attachment point of the cotyledons
Define EPICOTYL: -found in both mnoocots and dicots
-is the portion of the stem located above the attachment point of the cotyledon
-in seeds and young seedlings, sometimes the epicotyl is also called the PLUMULE
Define MESOCOTYL: -a stem segment (an internode) only found in monocots
-located between the scutellar node and the base of the coleoptile
-will elongate, sometimes to great lengths, to push the coleoptile into the light
Define COLEOPTILE: -in grasses, the first leaf formed by the shoot apex
-is a cone shaped, hollow leaf which, in early seedling growth, will surround the shoot apex and elongating stem that eventually grow beyond the coleoptile
-is light sensitive (shows positive phototropism)
What are EPIGEAL SEEDLINGS?: -seedlings in which the cotyledon(s) always is(are) raised above the soil line

Dicot Examples:
-garden bean, castor bean, sunflower
-seedlings use a HYPOCOTYL ARCH at emergence from soil

Monocot Example:
-onion
-seedlings use a bent cotyledon at emergence from soil
What are HYPOGEAL SEEDLINGS?: -seedlings in which the cotlyedon(s) always is(are) below the soil line

Dicot Example:
-pea
-sedlings use an EPICOTYL HOOK at emergence from soil

Monocot Example:
-corn, wheat
-seedlings use a coleoptile at emergence from soil
What does the SHOOT APEX consist of?: -shoot apical meristem
-young leaf primordia
What does the SHOOT APICAL MERISTEM CONSIST OF?: -tunica
-corpus
-flank (peripheral) meristems
-pith rib (file rib) meristem

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