Northwest Indian College
description
Transcript of Northwest Indian College
ENVS 201 Spring Quarter 2012
Northwest Indian College
Welcome to Northwest Plants
Plant Parts
stems
roots
leaves
flowers
fruits
seeds
vegetative organs:
reproductive components:
Today:Stems
above ground axis of vascular plants, as well as anatomically similar below ground portions (e.g., rhizomes, bulbs & corms)trunks & branches are stemsmay be photosynthetic (e.g., cacti)may store food (in some species)etc.
Stem Features & Functions
node (region where leaves may be borne)internode (region between nodes)apical (or terminal) bud (at tip of stem)axillary (or lateral) bud (in axil, on side of stem)flower budbud scale & bud scale scarepidermis, barklenticels (in some species, also in some roots, fruits, etc.)
Stem Regions & Other Features
leafy branch (silver maple), showing nodes, internodes and buds)
silver maple with buds
apical (terminal) bud
lateral buds
flower buds (silver maple)
stems of silver maple with bud scales, bud scale scars, bark & lenticels
leaf scar (site of leaf abscission)vascular bundle scarstipular spine (in some species, e.g., black locust)
Stem Features Associated with
Leaves
silver maple leaf scar and vascular bundle scars
black locust stipular spines
stolon (runner) - aerial, horizontal, often root at nodes (e.g., strawberry)rhizome - +/- horizontal, underground (e.g., bamboo, irises, ferns)tuber - end of underground stem, fleshy, food storage (e.g., potato)corm - shortened, usu. below ground, enclosed by dry scalelike leaves (e.g., gladiolus)
Stem Modifications
stolon (Fragaria, strawberry)
rhizome (Polypodium, fern)
tuber (Solanum, potato)
corm (Gladiolus)
bulb - short, underground stem with fleshy leaf bases (e.g., onion)cladophyll (also: cladode, phylloclad) - leaflike stem (e.g., cactus)tendril - long, slender, coiling stem (e.g., grape) in climbing plants (or a leaf or other structure in other species)thorn - hard, sharp-pointed, modified branch (e.g., honey locust)prickle - sharp-pointed superficial outgrowth (e.g., Rubus)spur (spur branch/shoot, or short shoot) - short stem on a branch with very short internodes (e.g., ginkgo)
Stem Modifications (continued)
bulb (Allium, onion)
cladophyll (Opuntia, prickly pear)
tendril (Vitis, grape)
thorn (Gleditsia, honey locust)
prickle (Rubus)
spur branch or shoot
Ginkgo
Betula (birch)
vascular cambium - thin region of cells that give rise to (secondary) xylem, (secondary phloem) and parenchymacork cambium (phellogen) - thin region of cells that give rise to phellum (cork) outwardly and phelloderm inwardly
Stem Anatomy—Lateral Meristems
vascular cambium (Tilia)
cambial zone—>
cork cambium (Tilia)
<—cambial region
xylem (wood) - main water- & mineral-transporting tissue (in vascular plants)phloem - main food-conducting tissue (in vascular plants)periderm (bark) everything outside vascular cambium: phelloderm, phellogen & phellum (bark sometimes said to also include secondary phloem)
Stem Anatomy—Tissues
“sap” - edible region from vascular cambium outward, including cambial cells, phloem and possibly some phelloderm (inner layer of the bark); mainly the softest parts (e.g., of cottonwood)“inner bark” - region possibly as described above (e.g., of red cedar)
Stem Anatomy—Cultural
Considerations
stem (3-year-old, Tilia)
Questions & Comments?
Stemsarecool.
Hy’shqe!