Ch. 35: Plant Growth, Structure, and Development Flashcards
List and explain the four major trends observed in plants as they transitioned from aqueous to terrestrial environments
1) protection and nourishment of the multicellular embryo within the body of the female
2) formation of vascular tissue to distribute water, nutrients, and carbohydrates through the plant
3) appearance of seeds: naked or fleshly; used for protection of the embryo
4) Flower: attractive to animals to disperse seeds
How are the functions of roots and shoots complimentary?
Roots: anchor, water, minerals and other micronutrients
Shoots: photosynthesis, gas exchange (O2, CO2)
- more branching, the more SA
- means more collection of nutrients/water in roots and more photosynthesis in shoots
- they work together
If a developmental mutation eliminated the production palisade mesophyll, how would the health of the plant be affected?
The palisade mesophyll is the location of the bulk of photosynthesis (chlorophyll, light rxns, ATP, NADPH)
Photosynthesis: what the plant uses to produce energy for the plant
without the palisade mesophyll, photosynthesis would not occur, meaning it is unable to produce energy or oxygen
How does the xylem function as both a vascular and structural tissue?
Xylem in vascular tissue: water conducting (dead at maturity) from roots to shoots
Xylem in structural tissue: tracheids and vessel elements
- can have 2nd xylem in dicots; helps in the formation of wood
- tracheids: long, narrow, connected by perforation plates (pits)
- vessel elements: wider, shorter with flatter perforation plates
What differences in growth rate would you predict for a plant that lost its mycorrhizae?
Mycorrhizae: help absorb mineral (N2, P, carbs); will increase SA
if lost, not as many mineral would be absorbed due to the decrease in SA
- mutualistic fungi with plants
What are the products of the vascular cambium and cork cambium?
Vascular cambium: 2nd xylem (wood, dead); 2nd phloem (live)
Cork cambium: bark (with 2nd phloem); cork cells (live) from periderm (dead) (replace epidermis) with suberin
How do plants produce “wood”? Compare heartwood with sapwood.
Vascular cambium => 2nd xylem => wood
Heartwood: additional cross-linking proteins that harden, structural, no water conduction (dense)
Sapwood: H2O conduction
If a plant lost its casparian strip, how would this affect water and solute absorption into the stele?
Casparian Strip is made up of suberin and is used as a “filter”
Steele: the central canal that everything travels down
If no casparian strip, there is no filter and harmful materials (i.e. bacteria) could enter the plant
Plants have a hierarchical organization consisting of
Organs, tissues, and cells
Different meristems generate new cells for
Primary and secondary growth
Primary growth…
lengthens roots and shoots
Secondary growth…
increases the diameter of stems and roots in woody plants
3 basic plant organs
roots
stems
leaves
Plants esp. terrestrial
- Chlorophyta
- Terrestrially
- Photosynthetic
- Cell walls
- Non-motile
Classification of plants
1) Nonvascular plants
2) Seedless Vascular
3) Seed-bearing: Gymnosperms
4) Seed and flower bearing: Angiosperms
Nonvascular plants
short
gametes/zygotes dispersed by water
water diffuses through plants
get water from below
i.e. mosses, hornworts, liverworts
Seedless vascular
Vascular: water/nutrients
need to anchor self to grow
- more elaborate root system
i.e. club mosses, ferns
Gymnosperms
seed-bearing
i.e. conifers, Ginkgo
Angiosperms
seed and flower bearing
internodes
where branches come off of
Vegetative shoot
leaves
reproductive shoot
flowers
apical bud
where mitotic growth happens
meristem: actively dividing
? end of any shoot
axillary bud
backup bud
Plants
- Eukaryotic
- Multicellular
- Sessile
- Photosynthetic
- Primarily terrestrial (basis of terrestrial food chain)
- Agricultural: nitrogen needed, fertilized soil (can add some nutrients)
Trends
1a) Protect their embryo:
embryo (sporophyte) is retained within the parent (gametophyte)
1b) Grow up and not out: increase in size, vertical = increased spore production
2) Vascular tissue: diffusion is limited, bulk flow mechanism, direct water flow, seal off epidermis and reduce desiccation
3) Appearance of seeds: protects and nourishes the embryo, lie dormant in soil (wait for optimal times), do not require water for fertilization (but rather wind pollination)
4) Appearance of flowers: increase fertilization of seeds via pollinators, fruits aid in dispersal, endosperm which nourishes early embryo (in seeds)
Plant Anatomy/Plant Body
- Roots: below ground/anchoring
- Shoots/Stems: Leaves: organs
- Branches, Buds, Flowers: Organ systems
- Shoot system
- Root system
Types of Growth
1) Reproductive: flowers, seeds, spores
2) Vegetative: everything else
Roots
- multicellular organ
- anchor
- absorptive: H2O, minerals, N2
- Taproot: straight off stem
- Lateral root: off of main stem
- Root Hairs: membrane evaginations of epidermis; off of lateral roots
- Fibrous root system: i.e. grass
Stems
- Nodes: where branch comes off
- Internodes: area between two nodes
Leaves
- Petiole
- Blade
- Vein: branch (vascular tissue)
- Parenchyma: photosynthetic: CO2 in; O2 out
- Epidermis, stoma, cuticle
Different types of leaves
1) Simple: petiole, axillary bud
Good SA/V ratio
2) Compound: leaflet, petiole, axillary bud
3) Doubly compound: leaflet on leaflet, petiole, axillary bud
- most wind tolerant since it allows air to go through easier
Tissues
1) Dermal: epidermis:
- Guard cells: can regulate diameter and form pores (stoma) in leaves
- Cuticle: Waxy substance: seal epidermis from H2O loss
- Periderm: cells that replace epidermis in “woody” plants
2) Vascular tissues:
- xylem: water conducting: dead at maturity
- phloem: sap conducting: living
- stele: vascular cylinders (xylem and phloem bundled together)
3) Ground tissue:
- cells that are not dermal or vascular
- Pith: ground tissue internal relative to vascular cylinders
- Cortex: ground tissue external relative to vascular cylinders
1) Dermal: epidermis:
- Guard cells: can regulate diameter and form pores (stoma) in leaves
- Cuticle: Waxy substance: seal epidermis from H2O loss
- Periderm: cells that replace epidermis in “woody” plants
2) Vascular tissues:
- xylem: water conducting: dead at maturity
- phloem: sap conducting: living
- stele: vascular cylinders (xylem and phloem bundled together)
3) Ground tissue:
- cells that are not dermal or vascular
- Pith: ground tissue internal relative to vascular cylinders
- Cortex: ground tissue external relative to vascular cylinders
Ground tissue cells
1) Parenchyma
2) Collenchyma
3) Sclerenchyma
Parenchyma
most common, most plant metabolism occurs
- thin walls
- somewhat flexible
Collenchyma
- Thicker cell walls
- less flexible
- support, structural role in young green parts of plants
Sclerenchyma
- thick cell walls
- reinforced with lignin: makes cells harder
- support non-growing parts of plant
- can be arranged as fibers, seeds
Meristems
- perpetually embryonic
- mitotically active
a) apical: contribute to vertical growth
b) axillary
c) lateral: 2 types
1) vascular cambium: 2nd xylem and 2nd phloem
2) cork cambium: contributes to bark
Root Cap
pushes soil out of the way
“passive” diggers
Primary Growth
elongation
apical meristems
@ root
@ stem apex
Secondary Growth
increase in diameter @ root and stem
- vascular and cork cambiums
How do trees get water from the ground to their leaves?
Transpirational pull
Transpiration: flow of H2O from roots through leaf stoma to atmosphere
