unit 5 Flashcards
plants
3 main functions of plants
- photosynthesis, cellular respiration
- absorption of water and minerals
- transporting substances throughout the plant
shoot system?
made up of stems and leaves
- leaves: preforms photosynthesis
- stems: structural support
root system
roots
- anchors plant to soil
- absorb water and mineral nutrients
3 plant cells
- parenchyma cells
- flexible, thin-walled cells throughout most plants
- basis for many plant structure (storage, photosynthesis, gas exchange, protection)
- spherical shaped, cell walls packed tightly when together - schlerenchyma cells
- provide support for plants
- thick secondrary cell walls that contain ligin to make walls tough and strong
- dead at maturity - collenchyma cells
- long strands or cylinders that provide support for surrounding cells
- can elongate and expand
- allows plants to bend without breaking
plant tissues
- meristematic tissue: where new cells are produced
(where cells mature and become specialized)
- plants growth results are from cell produced by meristematic tissues - Dermal tissue: forms outer covering of plant (epidermis, periderms)
- ground tissue:
- makes up inside of plant (contains 3 plant cells)
- photosyentheis - vascular tissue:
- tube system that runs lenghthwise through the stem connecting roots to leaves
- transports water, minerals, and other substances throughout plant (xylem and ploem)
epidermis vs peridermis
epidermis: single layer covering (for non woody plants)
peridermis: outer layer that replaces epidermis in woody plants
3 types of specialized epidermal cells
- gaurd cells
- pair of cells that surround and control stoma
- co2 diffuses in and O2 and water vapors diffuse out - trichomes
- tiny growth on leafs and stems (fuzzy/wooly)
- keeps surface cool and reduces evaporation - root hairs
- extension of root surface
- increase surface area for absorbing water and nutrients
vascular tissue for woody/non-woody plants
non woody: flowering plants have groups of vascular tissue called vascular bundles scattered around ground tissue
woody: flowering plants have vascular bundles arranged in rings
xylem vs phloem
xylem: transports water and minerals from roots to leaves
phloem: transports nutrients such as sugars to areas needed for growth and metabolism or roots for storage
for a plant to function 2 transport processes
- sugars and carbohydrates that are made in the leaves must be transfered through water moving up and down the tube
- water and dissolved nutrients in ground must be taken up roots and transported to cells in leaves
osmosis, diffusion, active transport
diffusion: particles move from area of high concentration to low concentration
osmosis: diffusion of water molecules
active transport: moving from low concentration to high concentration using energy
transport in xylem
water moves up roots using osmosis since root cells have higher concentration than the soil
- water enters the xylem and is transported up through the roots to the stem
- xylem carries water and dissolved nutrient to leaves through veins
transpiration: water is evaporated through stomata
what is root pressure:
mechanism that pushing water up the plant
cohesion-tension model in water transport
cohesion: the attraction between wateer molecules that helps them keep together in xylem
adhesion: water molecules attraction to walls that keeps them together without breaking
transpiration: when water is lost from stomata in leaves, the negative pressues pulls water from roots to balance.
transport in phloem
- the sugars that are made through photosynthesis are being transported through the ploem (called translocation)
- the phloem takes the sugar to source to sink
source: any part of plant entering the phloem tube
sink: storage
pressure flow model
- as the storage in roots increases in pressure with sugars it has to spill out solouion to any other areas where sugar is used
- can flow in both ways
- pressure mist be balanced between source and sink
3 functions of roots
- taken in water adn dissolved minerals to transport
- anchor plant
- store carbohydrates/sugers created photosynthesis
structure of roots
- the tip of the roots is covered by s root cap
- has the apical meristem which produces root tissues that keep growing into soil
roots are covered in dermal disuse
- this is created by epidermal cell which produce root hairs
- cortex of roots lies beneath the epidermis and vascular tissue of roots (stores water, minerals, food)
- endodermis: layer between cortex and vascular tissue
–> creates barrier that forces water and dissolved minerals to cross instead of moving around (controls what enters the vascular system
(endodermis contains vascular tissues (xylem +phloem) )
leaf structure
cuticle: prevents water loss
epidermal cells/layer(creates cuticle)
palisade mesophyll: where photosynthesis occurs
(chloroplast) (parenchyma cells)
vascular bundle: xylem and phloem
spongy mesophyll: allows O2, CO2, H2o to move around
- epidermal cells +cuticle
stomata + gaurd cells: releases water and bring in co2
type of root systems
- taproot
- stores food
- grows deep into soil with water
- thick root with small materal branching roots - fibrous root
- small branching roots
- all same size that grow from one point
- do not grow deep
monocots vs dicots
monocots: parallel ventilation (grass)
- veins run parallel
dicots: palmate or pinnate
- palmate have veins tht branch off from a point
- pinnate have veins that branch of a common vein
what do plant hormones do
- to signal and stimulate growth activity in plant
- growth regulators
- 5 main:
auxin
cytokinins
gibberellins
ethylene
abscisic acid
auxins
- stimulates elongation of plant cells
- produces in apical meristems
- Apical domincance: when a plant mostly grows upward
(removing apical meristems can promote growth in side branches)
(weed killes contain so they die quickly without food)
cytokinins
- promotes cell division and differentiation
- delays aging of leaves and fruit
- (if combined with auxins can promote rapid cell division and rapid growth)
gibberellins
produced in apical meristem but transported in vascular tissue
- stimulates plant growth but stopping dormancy in seeds
- promotes growth of taller and stronger plants
(used to increase fruit size and increase fruit yield)
ethylene
- gaseous hormone
- found in tissues of ripening fruits, drying leaves, flowers
- weakens cell walls of unripe fruits and breaks down complete carbohydrates into simple sugars
- speeds up ripening process when shipping
abscisic acid
- created in mature green leaves, fruits, and roop caps
- block CO2 intake by controlling leaf stomata
- can block actions of growth-promoting hormones
nastic response
- plants movement in the response to a stimulus that is not related to the direction of stimulus (once down they return and can be repeated)
growth response
a response to a stimulus that can cause a plant to growth toward or away from it called tropic response
tropism
- if a plant grows towards the stimulus = positive tropsim
- if a plant grows away from stimulus = negative tropism
tropic responses
- phototropism:
- growth response to light (more in direction of light) cased by unequal distribution of auxin
- less auxin on the side of the light source sends more auxin to the other side
- creates curve - gravitropism
- growth response to gravity
- grow downward into soil to anchor plant - thigmotropism
- growth response to mechanical stimuli (contact with an object or smth)
- ex: vines around a fence
soil factors that affect plat growth
macronutrients for greater amounts for plant growth
- nitrogen, pottasium, calcuim
micronutrients for smaller amounts for plant growth
- chlorine, iron, copper
Soil PH:
- most plants: pH 6-7
- fewer: pH 7-8
ecological disturbance?
when eevents change the entire structure of the biological community and destorys all active organisms
- forest fires
- floods
- volcanoes
primary succession
- following ecological disturbance
- establishment of a community in an area that does not have top soil
- plants will be the first to populate the area with bacteria and algea
–> called pioneer species
then more diversity comes and more plants and soil grow
–> intermediate stages
the final late comers
–> climax community
secondary succession
- recolonization of an area after ecological disturbance where soil is intact
- eg: forest fires
same stages as primary succession
