Unit 6: Plant Systems

characteristics of plant cells

made of plant cells

cell wall, chloroplasts, central vacuole, organelles common to all eukaryotes (nucleus, ribosomes, mitochondria, etc.), multicellular organisms, photosynthesis

non vascular plants

bryophytes

types of bryophytes

mosses, liverworts, hornworts

characteristics of bryophytes

don't have tubes to move water and nutrients through the plant

osmosis

water moves from cell to cell or from areas where there is plenty of water to areas where water is needed

bryophytes

don't have true leaves, stems, and roots; have rhizoids instead

rhizoids

part of bryophyte; anchor the plant to the ground

seedless vascular plant types

ferns, club mosses, horsetails

ferns

first plants to have special tissues that carry water and food throughout a plant

plant tissue types

dermal, ground, vascular

dermal tissue

used for protection and to prevent water loss

includes epidermis (mostly) and periderm (like bark)

cuticle

a waxy layer found in dermal tissue

ground tissue

used for metabolism, storage, and support (any tissue that isn't dermal or vascular)

types of ground tissue

parenchyma, collenchyma, sclerenchyma

parenchyma

traditional plant cells

collenchyma

support, like cellulose

sclerenchyma

wooded and durable (like what makes up an apple core)

types of vascular tissue

xylem and phloem

xylem

moves water from the roots to all parts of the plant

made up of tracheids

have thick, strong cell walls

phloem

carries nutrients and food from place to place within the plant

characteristics of general plant tissues

have true roots, leaves and stems

roots

absorb water and minerals

leaves

make food by photosynthesis

stems

support the plant and connect leaves and roots

seed plant types

gymnosperms nad angiosperms

gymnosperms

aka cone-bearing plants

produce seeds directly on the surface of cones

angiosperms

aka flowering plants

produce seeds inside a tissue that protects them

gymnosperm characteristics

oldest surviving seed plants

include gnetophytes, cycads, ginkgoes, and conifers

produce seeds that are protected by a seed coat

cone does not cover the seeds - why they are called naked seed plants

angiosperm characteristics

have reproductive organs called flowers

seeds are protected

the structure that protects the seeds develops into a fruit

flowers

attract animals, which carry pollen from flower to flower

more efficient way of pollination than wind pollination (most gymnosperms)

groups of angiosperms

monocots and dicots

monocot embryos

have one seed leaf, or cotyledon

dicot embryos

have two cotyledons

differences between monocot and dicot

arrengment of veins in leaves, the number of flower petals, the structure of roots, and the arrangement of vascular tissue in the stem

reproduction in flowering plants

occurs inside the flower

inside the anthers

each cell undergoes meiosis to produce four haploid spore cells

the haploid cells become pollen grains

ovules

found inside the ovaries, where the female gametophyte develops

female gametophyte

one of four haploid cells undergoes mitosis to produce the embryo sac

egg cell

found in embryo sac

pollination

pollen is transferred from the anther to the stigma

most gymnosperms are wind pollinated; animals pollinate most angiosperms

fertilizations in the embryo sac

one sperm nucleus fuses with the egg to form a diploid zygote, which grows into the plant embryo

the other sperm nucleus fuses with two other nuclei in the embryo sac to form the endosperm, which provides food for the embryo; aka double fertilization.

plant growth

not precisely determined; follows general growth patterns that differ among species; never stops; new cells are always being made in meristematic tissue

occurs in response to environmental factors like light, moisture, gravity, and temperature

apical meristems

found at the tips of stems and roots

involved in growth

new cells later develop into specialized tissues

hormones

plant chemicals that control plant growth

a substance that is produced in one part of an organism and affects another part of the same organism

target cell or tissue

the part of the organism affected by a hormone

different kinds can respond to the same hormone

one hormone may affect two different tissues in different ways

auxins

have different effects on different tissues

make stems grow toward light and away from the pull of gravity

control plant branching by keeping the buds on the sides of the stem from growing

tropisms

phototropism, gravitropism, thigmotropism

phototropism

tendency of a plant to grow toward light

gravitropism

response of a plant to the pull of gravity

thigmotropism

tendency of a plants to grow around objects they are in contact with

plant responses to touch (does not involve growth)

caused by changes in the osmotic pressure of some cells

the pressure changes causes leaves to fold up or snap shut

photoperiodism

plants respond to periods of light and darkness

phytochromes

plant pigments that react to changes in the length of periods of light and darkness

changes cause plants to flower

cytokinins

hormones created by growing roots and developing fruits and seeds

stimulate cell division and make dormant seeds sprout

effects are usually opposite to the effects of auxins

gibberellin

substance produced by a fungus that stimulates plant growth

cause dramatic increases in size and rapid growth

ethylene

plant hormone released in response to auxins; stimulates fruits to ripen