Biol 145 - Plant Science - Week 3

Cells produced by stem what become what?

Meristems; shoot system with branches and leaves

Node definition

Area of stem where leaves are attached

Node Alternate or spiral looks like?

Node opposite - attached at pairs. Looks like?

Node whorled- In groups of three or more. Looks like?

Internode

Stem region between nodes

Axil

Angle between petiole and stem

Axillary bud located?

Axil

Bud scales protect?

Buds

Axillary bud located in axil will become?

Branches or flowers

Terminal bud is at?

Twig tip

Stipules

Paired, often leaflike appendages at base of leaf

Deciduous tree and shrubs (lose all leaves annually)

After leaves fall, have dormant axillary buds with leaf scars below

Apical meristem at stem tip

Contributes increase in stem length, dormant before growing season, and protected by bud scales and leaf primordia

Leaf primordia

Tiny embryonic leaves that develop into mature leaves

Apical meristem cells form 3 primary meristems: Protoderm

Gives rise to epidermis

Apical meristem cells form 3 primary meristems: Procambium

Produces primary xylem and phloem

Apical meristem cells form 3 primary meristems: Ground meristem

Produces pith and cortex, both composed of parenchyma cells

Leaf primordia and bud primordia develop into mature leaves and buds

Traces branch off from cylinder of xylem and phloem, and enter leaf or bud

Trace means?

Strand of xylem and phloem

Narrow band of cells between the primary xylem and primary phloem may become?

Vascular cambium

Cells produced by the vascular cambium become components of?

Secondary xylem toward center and secondary phloem toward surface

In many plants cork cambium (phellogen) produces?

Cork cells with suberin and phelloderm cells. (waxy coating)

Cork cambium function?

Reduce water loss and to protect against injury

Lenticels

Parenchyma cells in cork for exchange of gases

Stele

Central cylinder of primary xylem, primary phloem, and pith (if present)

Protostele

Solid core, phloem surrounds xylem

Siphonosteles

Tubular with pith in center

Eusteles

Discrete vascular bundles

Cotyledons

Seed leaves attached to embryonic stems (store food needed by young seedling)

Dicotyledons (dicots)

Flowering plants that develop from seeds having two cotyledons

Monocotyledons (monocots)

Flowering plants that develop from seeds with a single

Herbaceous dicots have?

Discrete vascular bundles arranged in a cylinder

Vascular cambium arises between?

Primary xylem and primary phloem. Adds secondary xylem and secondary phloem

Wood =

Secondary xylem

After spring wood

Fewer, smaller vessel elements in proportion to tracheids and fibers

In spring wood

Relatively large vessel elements of secondary xylem produced

Xylem ray

Part of ray within xylem

Phloem ray

Part of ray through phloem

Softwood

Wood of conifers; no fibers or vessel elements

Hardwood

Wood of dicot trees; resin canals

Resin canals

Tube-like canals scattered throughout xylem and other tissues

Bark

Tissues outside vascular cambium, including secondary phloem. Mature bark may consist of alternating layers of crushed phloem and cork

Laticifers

Ducts found mostly in phloem that have latex secreting cells. Used to make rubber, gum, and morphine

Monocots stems have neither a …

vascular cambium nor a cork cambium

Monocot stems produce no…

Secondary vascular tissue or cork

Monocot stems primary….

Xylem and phloem in discrete vascular bundles scattered throughout the stem

Monocot vascular bundle has?

Two large vessels with several small vessels. First formed xylem cells stretch and collapse.

Monocot vascular bundle also has?

Leave irregularly shaped air space. Phloem consists of sieve tubes and companion cells

The monocot vascular bundle is surrounded by what?

Sheath of sclerenchyma cells

Rhizomes

Horizontal stems that grow below-ground and have long to short internodes. EX: irises, some grasses, ferns

Runners

Horizontal stems that grow above ground and have long internodes. EX: strawberry

Stolons

Produced beneath the surface of the ground and tend to grow in different directions. EX: potato

Tubers

Swollen, fleshy, underground stem. EX: potatoes(eyes of potato are)

Bulbs

Large buds surrounded by numerous fleshy leaves, with a small stem at lower end. EX: onions, lilies, hyacinths, tulips

Corms

Resemble bulbs, but composed almost entirely of stem tissue, with papery leaves. EX: crocus and gladiolus

Cladophylls

Flattened leaf-like stems. EX: greenbriers, some orchids, prickly pear cactus

Flattened blade =

Lamina

Network of veins =

Vascular bundles

Simple leaves

Single blade

Compound leaves

Blade divided into leaflets

Pinnately compound leaves

Leaflets in pairs along rachis (petiole)

Bi-pinnately compound leaf

Leaflets subdivided

Palmately compound leaves

All leaflets attached at same points at the end of petiole

Photosynthesis

Trapping and storing of energy in sugar molecules that are constructed from water and carbon dioxide

Stomata

Tiny pores on lower surfaces of leaves. Allow carbon dioxide to enter and oxygen to diffuse out. Water vapor also escapes via stomata

Guard cells control what?

Water loss by opening or closing pores of stomatal apparatus

Guttation

Root pressure forces water out hydathodes at tip of leaf veins in some plants

Wastes is metabolic processes accumulate in leaves and…

Are disposed of when leaves are shed

Phyllotaxy

Arrangement of leaves on stem

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 blase

Dicots - Primary veins divergent in various ways =

Nettled or reticulate venation

Dichotomous venation

Veins fork evenly and progressively form base of blade

Monocots - primary veins parallel =

Parallel venation

Epidermis

Single layer of cells covering the entire surface of the leaf

Epidermis is absent of

Chloroplasts

Epidermis is coated with

Cuticle (with cutin)

Lower epidermis typically has thinner layer of

Cutin and is perforated by numerous stomata

Guard cells originate from the same

Parent cell and contain chloroplasts

Inflate

Stomata open

Deflate

Stomata close

Stomata primary functions

Regulates gas exchange between leaf interior and atmosphere. Regulate evaporation of water (changes in amount of water in guard cells cause them to inflate or deflate)

Most photosynthesis takes place in the mesophyll between the two epidermal layers. Also known as the?

Palisade Mesophyll

Spongy mesophyll

Compactly stacked, barrel-shaped parenchyma cells, commonly in two rows. Contains most of Leafs chloroplasts

Veins (vascular bundles) are scattered throughout?

Mesophyll

Veins consist of

Xylem and phloem tissues surrounded by bundle sheath of thicker-walled parenchyma

Leaves reduce loss of water by

Thick, leathery leaves, fewer stomata or sunken stomata, succulent leaves or no leaves, and dense hairy coverings

Leaves of aquatic areas

Less xylem and phloem. Transpiration does not work here. Large air spaces. Mesophyll not differentiated into palisade and spongy layers

Tendrils

Leaves curl around rigid object creating support. EX: garden peas

Spines

Leaves that reduce leaf surface and water loss and protect plant. EX: cacti

Thorns

Arising IN the axils of leaves of woody plants

Prickles

Outgrowth from epidermis of cortex

Storage leaves

Succulent leaves. Have parenchyma cells with large vacuoles

Flower-pot leaves

Leaves develop urn-like pouches that become home of ant colonies. Ants provide soil adding nitrogenous waste

Window leaves

Leaves buried in ground, except exposed end. End transparent thick epidermis and transparent water storage cells underneath. Let’s light in without dried leaves

Reproductive leaves: walking fern

New plants at leaf tips

Reproductive leaves: air plant

Tiny plantlets along leaf margins