Plant Structure and Function: Leaves, Flowers, and Growth

Simple leaves

With a single blade

Compound leaves

Blade divided into leaflets

Pinnately compound leaves

Leaflets in pairs along rachis (petiole)

Bipinnately compound leaf

Leaflets subdivided

Palmately compound leaves

All leaflets attached at same point at end of petiole

Nodes

Regions on stems where leaves are attached

Internodes

Stem regions between nodes

Phyllotaxy

Arrangement of leaves on stem

Alternate

One leaf per node

Opposite

Two leaves per node

Whorled

Three or more leaves at a node

Venation

Arrangement of veins in a leaf or leaflet blade

Pinnately veined leaves

Main midvein included within enlarged midrib; secondary veins branch from midvein

Palmately veined leaves

Several primary veins fan out from base of blade

Monocots

Primary veins parallel = Parallel venation

Dicots

Primary veins divergent in various ways = netted or reticulate venation

Dichotomous venation

Veins fork evenly and progressively from base of blade

Epidermis

Single layer of cells covering the entire surface of the leaf

Stomata

Tiny pores on lower surfaces of leaves that allow gas exchange

Guard cells

Cells that border stomata and regulate water loss by opening or closing the pore

Spongy Mesophyll

Loosely arranged parenchyma cells with abundant air spaces

Vascular bundles

Containing xylem and phloem, conduct materials between the leaf and the rest of the plant body

Xylem

Delivers water and minerals to the mesophyll cells of the leaf

Phloem

Carries away the sugar produced during photosynthesis

Chlorophylls

Green pigments in leaves

Carotenoids

Yellow pigments in leaves

Anthocyanins

Water soluble pigments that may appear red or blue

Betacyanins

Water soluble pigments that appear red

Annual plants

Cycle completed in a single season from seed germination to mature plant producing seeds

Biennial plants

Cycle completed in two growing seasons

Perennial plants

Cycle takes several to many growing seasons, or the plant produces flowers on new growth while other plant parts persist indefinitely.

Dicots

Two cotyledons, flower parts in multiples of four or five, leaves with distinct network of veins like netted or reticulate, vascular cambium and cork cambium present, vascular bundles of stem in ring, pollen grains with three apertures.

Monocot

One cotyledon, flower parts in multiples of three, leaves with parallel primary veins, vascular cambium and cork cambium absent, vascular bundles of stem scattered, pollen grains with one aperture.

Receptacle

Swollen end of peduncle or pedicel.

Sepals

Protects flower while in bud.

Petals

Attract pollinators.

Pistil

Consists of stigma, style, and ovary; ovary develops into fruit.

Ovary

Has egg cells in ovule.

Cutin

Protect epidermis.

Epidermis

Covers surface of a leaf.

Dichotomous leaves

Veins fork evenly from base.

Function of water

Invites nutrients.

Phloem

Carries food materials (sugar) throughout the plant.

Photosynthesis

Needs carbon dioxide & water to make sugar.

Superior Ovary

Makes ovules and becomes fruit, but it's more exposed.

Inferior Ovary

Same as above, but the ovary is protected inside the flower.

Inflorescence

Group of flowers.

Germination

The process by which a plant grows from a seed into a seedling.

Cotyledons

Food storage organs that function as 'seed leaves.

Embryo

Cotyledons and plantlet.

Plumule

Embryo shoot.

Epicotyl

Stem above cotyledon attachment.

Hypocotyl

Stem below cotyledon attachment.

Radicle

Tip of embryo that develops into root.

Vivipary

No period of dormancy.

Diffusion

Movement of molecules from a region of higher concentration to a region of lower concentration.

Solvent

Liquid in which substances dissolve.

Semipermeable membranes

Membranes in which different substances diffuse at different rates.

Osmosis

The movement of water through a semipermeable membrane from a place with more water to a place with less water.

mineral dissolved in water cover the root system

Turgid

Cell full of water.

Pressure Potential (Turgor Pressure)

It's the pressure inside a plant cell caused by water pushing against the cell wall.

Plasmolysis

Loss of water through osmosis.

Transpiration

Water vapor loss from internal leaf atmosphere (the process where plants release water vapor into the atmosphere, primarily through tiny pores on their leaves called stomata)

Cohesion-Tension Theory

Transpiration generates tension to pull water columns through plants from roots to leaves.

Stomatal apparatus

2 guard cells + stoma (opening).

Macronutrients

Used by plants in greater amounts: nitrogen, potassium, calcium, phosphorus, magnesium and sulfur.

Micronutrients

Needed by the plants in very small amounts: iron, sodium, chlorine, copper, manganese, cobalt, zinc, molybdenum and boron.

Active Transport

The movement of ions or molecules across a cell membrane from an area of lower concentration to an area of higher concentration, utilizing energy in the form of ATP.

Essential Elements

Essential as building blocks for compounds synthesized by plants.

Pollen

Has sperm cells; tube cells enter to the style & move the two sperm cells.

Ovule

Has two egg cells. develop into seed

Gymnosperm

Plants that produce seeds.

Angiosperms

Plants that produce flowers or fruits.

Zygote

Formed when sperm cell fuses with egg cell.

Cutin

protects epidermis

Epidermis

covers the surface of the leaf

4 parst of a flower

sepal , petal , stamen and pistil

Ovary

turn into fruit

leaf primordium

the earliest stage in the development of a flower or leaf structure.

calyx

sepal (same thing) considered the leaf

pistil

ovary, style, and stigma.

stomata

lower epidermis

stigma

pollen drops out of

Hypogeous germination

• Hypocotyl remains short and cotyledons do not emerge above surface.

Above the cotyledons

the shoot is called the epicotyl

Plasmolysis

- Loss of water through osmosis

Water potential of cell

= osmotic pressure + pressure potential

Seed Coat

breaks open the seed of germination

shoot apical meristem (primordium)

all leaves originate from

primordium

the early developmental stage of leaves or flowers in the shoot apical meristem.

apical meristem

the growing tip of a plant stem or root is responsible for primary growth.

Cycle

from seed germination to mature plant producing seeds