FRST 200 midterm

gymnosperms

Angiosperms

with vessel elements (specialized for transport) and fibres (specialized for support)

taxonomy

evolved as outgrowths, called enations, of the main axis of the plant.

evolved by fusion of branch systems

Taxa

reproductive isolation

• · group of populations that resemble each other
• relatively closely and other groups of populations less closely are called
• species.

· Species are reproductively isolated in most case

• offsprings cannot reproduce
• (eg. donkey x horse)

• off spring can reproduce 
• (eg. two different species of dogs)

·  closely relates species often hybridize

• ·  genetic recombination doesn’t occur in some
• organisms anyway

·  Common in trees

·  Useful to accommodate diverse habitats

• ·  Prevalent in ecologically diverse areas (eg.
• B.C.)

• bateria
• archaea
• eukarya

• Monera
• Protista
• Fungi
• Animalia
• Plantae

• Coniferophyta (conifers) 
• Anthophyta (angiosperms)

• similarities:
• vascular
• flowering plants with seeds bornes within fruits

• differences:
• monocots: with one cotyledon; no true cambial activity
• eudicots: with two cotyledons; many have true cambial activity

• coniferopytes
• ginkophytes

gymnosperm trees

angiosperm trees

controls the passage of materials in and out of the cell

gel-like consistency and contains numerous organelles and other structures

• very small particles consisting of RNA and protein
• to link amino acids together to form proteins, including enzymes

• size smaller than chloroplast
• has two membranes, inner membrane is heavily folded to increase the surface area for respiration

• a complex three-dimensional membrane system 
• function as a communications system within the cell, channeling materials such as proteins and lipids to different parts of the cell 
• Rough ER: with ribosomes attached for making protein
• Smooth ER: without ribosomes attached, function in the synthesis of other things, such as lipids

• groups of flat, disc-shaped sac 
• involved in secretion, and most plant dictyosomes secrete materials needed to build the cell walls

flexible framework comprised of microtubules and microfilaments

• disk shape, large, complex
• site of photosynthesis
• chloroplasts: chlorophyll, green
• chromoplasts: no chlorophyll, with other pigments
• leucoplasts: no pigments

long, thin cylindrical structures built of protein 

• functions, including: 
• § Assist in construction of cell wall by moving
• cellulose synthesizing enzyme “rosettes” through plasma membrane

§ Direct dictyosomes to right places

§ Pull chromosomes apart in division

§ Direct formation of the cell plate

• contractile proteins 
• function to cause cytoplasmic streaming and cyclosis

glyoxysomes: convert fats to sugar, only in plants

• peroxisomes: important in photorespiration (caused by O2 interfering with CO2 in photosynthesis. Peroxisomes assist by helping
• to reverse the “damage” caused by photosynthesis)

• a crystalline phase of cellulose 
• a non-crystalline phase (the matrix) of pectin, extensin and (often) lignin

• liquid-filled cavity bounded by a membrane called a toroplast
• to inflate the plant cell and increase its effective surface area for nutrient uptake, diffusion of gases, and light interception
• important recycling factory

division of a diploid cell into 4 haploid cells

its formation is to separate two newly divided daughter cells

diploid

• seed coat dormancy
• protecting the embryo from excessive dehydration
• deterring seed herbivory

• female gametophyte
• haploid nutritional tissue of mature seed 
• only found in gymnosperm seeds
• after being fertilized by male gamete, produce zygote then grow into embryo 
• surrounding the embryo, protecting and nourishing it

• cotyledons
• shoot apical meristem
• root apical meristem
• root cap
• suspensor

• in angiosperm seeds' early embryo development
• triploid:1 female haploid + 1 female haploid + 1 male
• haploid sperm

• only in some angiosperm seeds
• a primordial shoot with leaves above (distal to) the cotyledons prior to germination

• in monocot seeds
• a large cotyledon for absorbing food digested from the endosperm

• in monocot seeds
• protects (and guides) the plumule

• in monocot seeds
• protects radicle

supporting the early development of the embryo both through providing nutrition and growth regulators

• For seed shed in fall, not enough time to
• germinate, grow, set bud and get frost hardy before winter

• results from the levels of plant growth regulators (plant hormones)
• Breaking embryo dormancy is dependent on decreasing growth inhibitor concentrations and increasing growth promoters above some threshold.

• a required low temperature for a period of time to break the embryo dormancy
• The process is call stratification: seeds are imbibed (soaked in water), then placed in a fridge for a period of time

• stratification to meet the chilling requirement
• applying artificial growth regulator

• embryo dormancy
• seed coat dormancy
• Embryo immaturity 
• Seed coat impermeability 
• Light requirement 
• Serotiny

• require chemical inhibitors leached out by soaking in water
• require heat treatment

• 1) seeds imbibe and swell; the seed coat ruptures;
• 2) cell division occurs in the embryo and the radicle elongates and extends out of the seed;
• 3) further elongation of the radicle pushes either the cotyledons or just the epicotyl (the portion of the shoot above the 
• cotyledons) above the ground;
• 4) hormones produced in the meristems and possibly elsewhere initiate enzymatic activity, hydrolysis of stored nutrients, and movement of these nutrients to regions of growth.

grows in the direction of gravitational pull

• the cotyledons are pushed out of the ground, turn green and become photosynthetically active
• (eg. douglas fir, red alder)

• the cotyledons remain in the ground and only the epicotyl emerges
• (eg. oak)

form on the roots, and in these nodules N2 gas is fixed into NH4+, which can then be converted into amino acids. This allows red alder to 'fertilize itself'.

longitudinal growth, or growth in length

• 1) Cell division via mitosis: Daughter cells (new cells) are produced from meristematic cells (apical initials, or mother cells). 
• 2) Cell expansion: Daughter cells grow to a functional size. 
• 3) Cell differentiation and maturation: Cells develop the physical and physiological characteristics necessary to perform specialized functions.

• zones of undifferentiated perpetually juvenile
• cells capable of mitosis

• zones of active division at tips of roots; shoots;
• produce 3 types of primary meristems: protoderm, ground meristem, procambium

Protoderm (makes dermal tissues)

Ground meristem (makes ground tissues)

Procambium (makes primary vaseular tissues)

• penetrate solid
• take up require material
• exclude undesirable material
• transport water and nutrients 
• transport photosynthate
• anchor and support the shoot

• 1) Protoderm cells: (on the outside) will produce new epidermal tissues;
• 2) The procambium: in the middle will produce cells that develop into a primary vascular (=conducting) system;
• 3) Ground meristem cells: will produce the root cortex.

regulates the flow of materials into the center of the root

• primary phloem: the transport of food and other things 
• primary xylem: transports water and dissolved mineral nutrients up to the shoot 
• vascular cambium: a secondary meristem for lateral growth

The meristematic region for shoot primary growth

• A leaf plus its node and the internode below constitutes a repeating unit 
• 1 node, 1 internode, 1+ leaved, 1+ axillary
• meristems