Kingdom PlantaeBotany - study of plants
Characteristics
autotrophs, some are both heterotrophic & autotrophic
ex. Venus Flytrap
multicellular
eukaryotic (has a nucleus and membrane-bound organelles)
sexual reproduction (2 haploid cells [gametes] => 1 diploid [zygote])
sessile (can't move)
Plants are put into groups based on whether or not they have vascular tissues & seeds
Nonvascular plants
ex. mosses
Vascular plants without seeds
ex. fern
Vascular plants w/ seeds:
ex. flowering - rose, maple tree
ex. nonflowering - pine tree
Flower Parts
Petals - usually brightly colored structures
Pistil - female reproductive structures
stigma - sticky top part of pistil where pollen attaches to
style - [something, will update later]
ovary
Stamen - male reproductive structure
anther - top part of stamen where sperm (pollen) is
filament - the stalk of the stamen
Sepals - protect the floral parts as they are forming
Receptacle - enlarged part of pedicle here all the rest of the flower parts are attached to
Pedicle - stalk that connects the stem to the flower
Self-pollination - pollen goes from one place on a plant to another part on the same plant; pollinates the same plant
Cross-pollination - pollen from one plant pollinates another plant
Leaves
bring in sunlight (for photosynthesis)
perform photosynthesis
provide most energy from photosynthesis (the stem provides some [has chlorophyll b/c green] but not as much as leaves)
veins = vascular tissues (carry nutrients throughout a plant)
Venation
Parallel
ex. grass, leaves on corn
Netted
Pinnate
one main/larger/central vein with smaller veins branching off
ex. oak
Palmate
several larger veins coming off one point
ex. maple
Pinnately compound
one main vein with leaflets branching off
ex. pea plants
Bipinnately compound
one main vein, smaller veins branching off, each smaller vein with leaflets
ex. honey lotus
Palmately compound
leaflets branching off a central point
ex. walnut tree, clovers, marijuana
Leaf Structure (diagram)
cuticle - waxy covering outside the upper epidermis that gives a leaf its shiny appearance; it's not actually cells but merely a secretion of cells
epidermis
upper epidermis - top layer of leaf; darker green (attributed to more chlorophyll in the next inner level [palisade mesophyll])
lower epidermis - bottom layer of leaf; lighter green (attributed to less chlorophyll in the next inner level [spongy mesophyll])
does not actually have chlorophyll in it
palisade mesophyll - column shaped cells packeted together with lots of chlorophyll in each
uniform shape allows them to be more tightly packed together and therefore more cells can fit
located under the upper epidermis
places a significant role in photosynthesis (because so much chlorophyll)
spongy mesophyll
irregularly shaped
odd shape => fewer cells b/c can't be as tightly packed together => fewer chloroplasts
in each cell, less chloroplasts (compared to palisade mesophyll)
stomata (sing. stoma) - holes in the lower epidermis
allow gases to pass through the leaf (i.e. carbon dioxide and oxygen)
also allows water vapor through
guard cells - open and close stoma
when the stoma is open, water is let in the leaf => a lot of turgor pressure
cell wall becomes very rigid and holds the shape of the cell
typically opens when sun is out because that the time that photosynthesis takes place
open during the day; close at night
close at night to conserve the water gained during the day
(exception: desert plants need to conserve water during the day so they close during the day)
sclerenchyma - thicker cell walls
help give structure and strength to the leaf
xylem - a type of vascular tissues
bigger than phloem
is dead tissue
transports nutrients from roots to plant
phloem - another type of vascular tissues
smaller than xylem
living tissue
transports from plants to roots
Different colors of leaves
caused by a lack of photosynthesis (because there is less daylight during the fall)
carotenoids (red, yellow, orange pigment) and anthocyanins (red, blue, violet) - 2 other pigments in plants that are typically overpowered by chlorophyll
less daylight = less chlorophyll => pigments of carotenoids and anthocyanins reveal themselves
Leaves fall off
abcission layer - made of cells programmed to die when the amount of daylight gets shorter
when all the cells die off, the leaf can't receive nutrients from the tree
no nutrients (i.e. water & nitrogen) => less photosynthesis (this also attributes to the changing of leaf color)
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Root Growth
2 ways roots can grow
grow in length
grow in diameter
Primary growth of a root (growth in length)
root cap = dead cells at the bottom of roots that just protect the rest of the root
meristernatic region = only part of root that actually grows; only part that goes through mitosis
elongation region = cells that "graduate" from meristernatic region get larger central vacuole and elongate to a certain extent
maturation region (carrot picture disproportional: only a small part of the entire root) = where cells are going to mature and differenciate as different tissues, forms all vascular tissue cortices
Root Tissues
Epidermis = outermost layer of the root
protect root
absorb water and nutrients from cells (?)
Cortex = made of parenchyma (Note: palisade and spongy mesophyll also made of parenchyma)
parenchyma cells do have chlorophyll, but because cortex is in the soil, doesn't do much photosynthesis
main purpose of cortex = storage
Endodermis = have connections between cells of endermis; therefore only let certain materials through
toxic material and excess material not allowed in
Pericycle = also a meristernatic region
make cork cells (= structure - dead cells)
Vascular cylinder = made up of xylem in center; arranges in different kinds of shapes then phloem surrounds/fills in xylem
Vascular cambium = vascular tissues
meristermatic tissue that will produce more xylem and phloem
cells that go through mitosis later make xylem and phloem
Plant uses for water
Photosynthesis
Maintain turgor pressure - helps to hold stemps up (i.e. daffadil)
Hydrolysis - break a complex molecule w/ H2O
Translocation of dissolved material - roots absorb water, water goes up through trunk => leaves = movement of water through roots => leaves transpiration and cohension - strate gather (sp?)
Types of Water (Note: Plants can't get to all water)
Runoff - water that is not absorbed into the soil (puddle picture)
plants can't use because roots are underneath/in soil
Gravitational - water pulled down through the soil to the water table
plants can't use because roots aren't deep enough to reach the water table
Hygroscopic water - a thin film of water around soil particles
plants can't use because water is too close to the particle ("stuck to it")
Capillary - water between all soil particles
water is not closely held to any particle of soil
if little rain, moist feel in soil would be from hygrascopic water rather than capillary
plants can use capillary water
more rain => more capillary water that plants can use
Translocation of water (moving water throughout the plant / transporting nutrients throughout the plant)
Plants need proteins and sugars (nutrients)
Without enough nutrients => plant diseases
need way for water and nutrients to traverse throughout the plant
Transpiration-cohesion theory
transpiration (part of water cycle) = evaporation of water out of leaves (water vapor leaves through stomata)
more water pulled up from soil when vapor leaves the plant through transpiration
cohesion = property of water molecules that causes them to stick together (held together by strong hydrogen bonds)
drinking straw example: force pulls continuous flow of water (not just one H2O molecule) until no water
drought problem: transpiration still occurs but there's no/little water to pull up from soil through the roots => leaves start dying
Stems
Purpose: to hold the leaves and flowers up, moves water from roots to flowers
Stem Functions:
manufactures, supports, and displays leaves
transports water and nutrients to the rest of the plants (from roots)
Sometimes more flexible (i.e. daffadil) but still has lots of turgor pressure to support the flower (?)
Tree - less flexible (obviously...)
Pine tree vs. Maple tree in ice storm:
Pine tree - just covered in snow and ice; branches weighed down
Maple tree (deciduous) - loses leaves; braches break off
Branching Patterns
Excurrent (i.e. evergreens - pine)
can see trunk of tree and follow it to the top of the tree
apical bud ( = top part of the plant) is dominant
able to distinguish branches from main stem
Deliquescent (i.e. deciduous trees - maple, oak, hickory, birch, walnut)
lateral buds ( = toward the side) are dominant
can see main trunk up to a certain point but then so many braches branch off that point that can't tell which one is the apical bud
Columnar (i.e. palm trees, flowers - daffidils)
no branches at all: just stem and leaves coming off of stem
Annual Rings
dry season - small xylem
wet season - large xylem (carries water and nutrients up roots)
=> dark line & lighter line
smaller xylem/veins because don't need to transport as much (in dry season)
larger xylem/veins because need to transport more
plants can go through multiple wet-dry periods in a year
dark line = drier season because xylem more packed together
Tropisms - growth responses to hormones
hormones located in various parts, in different quantities, and in different kinds throughout the plant
i.e. hormones cause roots and stems to growh in different directions
Phototropism - response to light
i.e. sunflower
positive = toward light
negative = away light
Examples of positive phototropism: leaves, branches, and stems
Example of negative phototropism: roots
geotropism - response to gravity
positive = same direction w/ gravity (down)
i.e. roots
negative = against gravitational pull
i.e. stems
Chemotropism - response to chemicals
hydrotropism - response to water
positive - toward water
i.e. roots grow toward water
Thigmotropism (Emma) - response to touch
i.e. ivy & grape vine
touching part = smaller cells, less growth
non-touching part = larger cells => enable to bend/curve around more, more growth
Plant Hormones
Auxins = one type of plant hormone; they help to regulate the growth of the plant
Gibberelins = cause stem of plant to grow very quickly
Abcissic acid = causes the abcission layer to form
Plants & Light
Long-day plants = need @ least 12 hours of light per day in order to form flowers and grow
i.e. sunflower
Short-day plants = need < 12 hours
i.e. corn and strawberries
Neutral-day plants grow independently of the amount of light
i.e. tomatos and beans
Dormancy = period of time when plant has little or no activity
not dead, just slowered down metabolism so much
typically winter for trees around here
could have multiple dormant periods
i.e. tulips - could bloom again after 3-4 weeks
dormant period is not always winter
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