plants unit

characteristics of plants

• domain: eukarya

• cell type: eukaryotic

• number of cells: multicellular

• nutrition: autotrophs (by photosynthesis)

• cell wall: made of cellulose

• method and reproduction: asexual and/or sexual

eukaryotic

nucleus and other membrane bound organelles

chloroplasts

in leaf cells, where photosynthesis happens

central vacuole

storage of water, nutrients, and waste

cell wall

for structure/rigidity

main things in plant cells

• chloroplasts

• central vacuole

• cell wall

• eukaryotic

photosynthesis

plants use energy from sunlight to make sugar, happens in chloroplast

nonvascular plants

• no specialized vascular tissue

• no true roots, leaves, or stems (no veins or tubes)

• low lying

• ex: mosses, hornworts, liverworts

vascular plants

• specialized vascular tissue (xylem and phloem) used to move food, water, exchange gases throughout the plants

• contain roots and shoots (leaves and stems)

• can grow tall/grow upwards

• ex: trees, ferns, conifers

shoot system

• plant stem, leaves, buds

• contain vegetative and reproductive parts of plants

vegetative

do not participate in sexual reproduction

root system

• anchors plant

• absorbs nutrients and water

• typically underground

plant transport

• food production occurs within the leaves of the shoot system via photosynthesis

• sugars travel from leaves to the stem through phloem

• absorption occurs in the root system

• water and minerals are absorbed from the soil and moved from the roots to the shoots through the xylem

xylem

• one way flow (from the ground up)

• only transports water and stuff dissolved in it

phloem

• two way flow

• transports sugars and nutrients

vascular bundle

• xylem and phloem stacked on top of each other in leaves

• xylem cells are on the upper side of the leaf vein

• phloem cells are on the underside of the leaf vein

transpiration

• movement of water from inside plants to the atmosphere

• water is carried through plants from roots to upper side of leaves

• transforms into water vapor and is released into the atmosphere

  • pulls water that’s still in the plant upwards with it while it evaporates

  • all of the water molecules in the plant are all connected so they all get pulled upwards

evaporation

movement of water as it changes from liquid to vapor form

guard cells

regulate the opening and closing of stomata via osmosis

• when guard cells are full of water they swell and expand to open the stomata

• when the guard cells shrink they cover the stomata to close it

stomata

• tiny pores in leaf

• control exchange of gases (oxygen and carbon dioxide)

• mostly found on the bottom of the leaf

• open stomata = increased rate of transpiration

• closed stomata = decreased rate of transpiration

sexual reproduction

• requires male and female parts

• offspring are genetically different than parent

  • Self-pollination IS a form of sexual reproduction because gametes that have undergone meiosis produce a zygote.

• all plants can do this

asexual reproduction

• All plants are capable of producing sexually, but can also produce asexually

• reproduction doesn’t require gametes

• offspring are genetically identical to parent (clone)

  • spores in some plants (seedless)

  • vegetative budding (vascular plants)

• new plant grows from a part of a single parent plant

• ex:

  • Bulbs

  • Cuttings (shoots with leaves attached)

  • Roots or tubers

  • Runners (side stems)

runner

• side stems that grow outwards from a parent plant

• create a clone of the parent

• parent provides nutrients until the clone can support itself

• ex: spider plant (house plant)

tuber

• enlarged structure on a plant that stores nutrients

• can be planted to grow a clone

• ex: potatoes

asexual reproduction pros

• one parent saves time and energy to produce a new generation

• can occur quickly and produce high numbers

asexual reproduction cons

• offspring is identical, which disfavors unstable environments

• overcrowding can occur

reproduction of vascular plants (seedless)

• sexual

• ferns, horsetails, club mosses

• use spores to reproduce

• sori (sorus)

  • cluster of spores

  • lightweight and disperse easily in the wind

reproduction of vascular plants (seeds) types

• sexual

• angiosperms

  • flowering plants with fruit, seeds surrounded by an ovule

• gymnosperms

  • no flowers of fruit, seeds found in scales such as pinecone

angiosperm

• produce flowers that contain male and female parts

• ovaries of a fertilized flower develop into fruit, where seeds are housed

• fruit protect seeds and help disperse the seed

stamen

• male part of flower

• anther

• filament

• petal

pistil

• female part of flower

• stigma

• style

• ovary

gymnosperms

• do not have flowers of fruits

• seeds are developed in cone-like structure

• cones have scales which protect that seeds

  • eventually open to deposit seeds when conditions are right

angiosperm sexual reproduction

• male part produces pollen

  • pollen produces sperm cells

• sperm cells stick to stigma and travels down the style to the ovary, where fertilization occurs

  • this makes seeds

ways flowers can fertilize

• self fertilization (if flower has both parts)

• bee pollination

• pollen carried on wind from other plants

flowering plants

• monocot

• dicot

cotyledon

• embryonic leaf

• first to appear from a growing seed

monocot

• angiosperms with seeds that contain one cotyledon

• leaves are long and narrow with parallel veins

• vascular bundles are scattered

• floral parts in multiples of 3

dicot

• angiosperms with seeds that contain two cotyledons

• leaves are broad with a network of veins

• vascular bundles are in a ring

• floral parts in multiples of 4 or 5

gymnosperm sexual reproduction

• use separate male and female cones to reproduce

  • male are smaller and toward the bottom of the tree

  • female are larger and toward the top of the tree

  • some plants have both

• encourages pollen from male cones of other trees to blow in from wind and fertilize female cones

  • rather than male pollen falling on top (self-fertilization)

hormones

• plant growth and development is regulated by these

• send chemical messages

• help plants respond to their environment

tropism

plants response to an environmental stimulus

gibberellins

• growth hormones that stimulate rapid increase in size

  • makes stems longer

• play a role in flowering and fruit ripening

cytokinins

promote cell division in plants and prevent aging in leaves and fruits

auxins

• lengthens the cells found in the tips of plants

• control many forms of tropism

ethylene

• gas that promoted ripening of fruits

• known as the “ripening” and “death” hormone

abscisic acid

• inhibits shoot and leaf growth

• closes stomata to prevent water loss

• keeps dormant

phototropism

• the tendency of plants to grow towards light

• controlled by auxin

• positive or negative

  • positive - growing towards the light

  • negative - growing away from light

how phototropism works

• auxin is produced in tips of plant

• auxin diffuses away from sunlight

• auxin elongates the plant on the side where the sun does not shine, causing a bend

• plant bends toward the light

thigmotropism

• a plants response to touch

• ex: climbing plants and vines raveling around a fence or wire

• plants growing in the direction of the wind

• auxin plays a role in this

limiting factors to plant growth

• temperature

• humidity

• nutrients

  • nitrogen needed to make chlorophyll

  • make amino acids and nucleic acids like DNA

• light

• carbon dioxide

• water

plant uses

• food

• medicine

• perfumes

• dyes

plants as food source

• 1 in 7 jobs in canada are involved in agriculture

• Maple syrup and maple sugar products are big contributors to Canada’s gross income, around 600 million yearly.

3 sister plants

• important part of indigenous agriculture

• corn - acts as vertical structure for beans to climb (thigmotropism)

• bean - plant decays, providing nitrogen for corn and squash

• squash - grows horizontally along the ground, protects corn and beans from dehydration, weeds, pests

plants medicinal uses

• indigenous people have been using plants as medicine for a long time

• 1600 and 1700s they helped european explorers treat scurvy (vitamin c deficiency)

  • boiled bark and needles from pines to produce tea rich in vitamin c

• 25% of prescription medicine is created from plant biochemicals

peppermint species

• menthol

• local anesthetic

• treat sore throats

opium poppy

• morphine

• most effective pain reliever

deadly nightshade

• atropine

• to open patients pupils during eye exams

yams species

• diosgenin

• used in birth control pills