plant cell
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Plant Cell. Plants are: Eukaryotic Autotrophic Multicellular Cell walls of cellulose. Vocabulary: - PowerPoint PPT PresentationTRANSCRIPT
Plant Cell
Plants are:EukaryoticAutotrophicMulticellularCell walls of cellulose
Vocabulary: - vascular – refers to an internal system of tubes or vessels to transport materials throughout the plant; basis or first major division of plants into bryophytes and tracheophytes; includes:
- xylem – transports water and minerals up from the roots to the shoots
- phloem – transports sugar (food) down from the leaves to the rest of the plant
Xylem brings water up from the roots to the shoots
Phloem carries sugar (food) down from leaves throughout the plant
Bryophytes – nonvascular plantsExamples include:
Moss Hornwort
Liverworts
20 mm
Bryophytes – nonvascular plants - economically importantEx) sphagnum moss – also called peat or peat mossGrows in boggy areas called peat bogs; extremely absorbant; used in agriculture/horticulture
VocabularySeed – adaptation to terrestrial life
composed of a plant embryo, stored food, and a protective coat
Seed dispersal by edible fruit, by wind, as well as other means. The picture to the right is of a samara from a maple tree.
Which is a monocot and which is a dicot? How do you know?
Tracheophytes – vascular plants•Seedless plants –whiskferns,
horsetails, and ferns
Whisk fern horsetail fern
Seedless vascular plants:Ferns - reproduce with spores - diagram shows spores growing in clusters called sori on the back of the frond of the fern
Seedless vascular plants dominated during the Carboniferous period.
VocabularyCone – reproductive structure of gymnosperms; contains pollen in males and ovules in femalesFlower – reproductive structure of angiosperms composed of 4 sets of modified leavesFruit – mature ovary of a flower that protects dormant seeds and aids in their dispersal
Ovulate cone from a pinetree (female)
Staminate cone from a pinetree (male)
Tracheophytes – vascular plants cont.•Seed plants
•Gymnosperms – have seeds in cones; include: ginkgos, cycads, gnetophytes, and
conifers
Ginkgo Cycad
Welwitschia Gnetum Ephedra
Gymnosperms called gnetophytes; only 3 extant species
Conifers: top row: Douglas fir, Sequoia, Cypress; bottom row: juniper, Australian pine tree; not shown: yew, spruce, other pines
Tracheophytes – vascular plants cont
* Seed plants•Angiosperms – flowering plants - have
flowers, fruits, and seeds
Grasses are flowering plants, too. So are trees.
Grass flowers
Flowerpistil (female)(male)
Ovaries with ovules become fruits with seeds after the ovule (egg) is fertilized by sperm from the pollen
Pollen grains contain sperm. They are produced in the anthers of the flowers in angiosperms.
Pollination - by many vectors, including:
WindWater
Animals
Fruit or VeggieHumans eat lots of different plant parts. A fruit is the ripened ovary and contains seeds. Therefore, tomatoes, peppers, squash, olives, and cucumbers are fruits, not vegetables.
Vegetables – the vegetative parts of the plants that we eat. Includes:•Roots – carrots, turnips,radishes•Stems – celery, bok choi, rhubarb, garlic, broccoli, onions, potatoes •Leaves – lettuce, cabbage, parsleyOther plant parts that we eat: Seeds – pinto beans, peas, sunflower seeds, corn, pepper corns, rice, pecans, coconut Flowers – anise flowers (licorice), basil; http://homecooking.about.com/library/weekly/blflowers.htm
Good rule of thumb: if you didn’t get it at the store, DON’T EAT IT!
We don’t just eat plants, we also wear them, build with them, and use them for
medicines!
Plant Structure & Function
Each plant part - root, stem, leaf - has a specific role in keeping the plant alive through photosynthesis
Monocots & Dicots
Cotyledons – nonphotosynthetic leaves of an immature plant; provide source of nutrients until plant can produce its own food
Leaves - site of photosynthesis - cross section
- epidermis – adaptation for terrestrial life - waxy cuticle - stomata - transpiration
Leaf
Leaf structure supports its function as the primary organ for photosynthesis
Leaves - composed of blade, veins, petiole - simple or compound (see identifying leaves ppt)
- pinnately or palmately compound - alternate or opposite if compound - pinnate or palmate venation
Overview of movement of photosynthesis reactants and products through a plant
StemsSupport and transportContains xylem and phloemModified:
Strawberry runners onionpotatoe
s
Define plant type: herbaceous, shrub, vine, tree
Stems
Herbaceous plant shrub vine
Stems – cross sections through a dicot and a monocot
RootsFunction – absorption, storage, anchorageRoot hairs – extensions of the epidermis that increase absorption by increasing surface area; see photo
Fibrous roots – see monocot information
Tap roots – see dicot information
Root Structure
Nitrogen fixation – occurs in the roots and in the soil around the roots of plants; performed by bacteria
Plants that live in nitrogen poor soils trap and break down insects with enzymes to obtain nitrogen
Venus fly trap Pitcher plant
VocabularyPrimary growth – increase in length; stems get longer, roots grow deeperMeristem – tissue that is growingApical meristem – tissue found at the tips of roots and stems that is actively dividing/growing
Plant Responses
Plant responses are called tropisms. Tropisms can be positive or negative. They include phototropism, gravitropism, and thigmotropism.Most plant responses involve the action of hormones, including gibberellins, auxins, and ethylene.
Plant Responses
Effect of gibberellens on Thompson’s seedless grapes and on growth in a dwarf plant
Auxins make plants bushier by making more branches at nodes when the apical meristem is cut off (the tips of the existing branches)
Positive Phototropism
Effect of ethylene on the ripening of an apple.
http://plantsinmotion.bio.indiana.edu/plantmotion/movements/tropism/gravitropism/gravi1/gravitrop.html
NEGATIVE Gravitropism in Stems
Vines Illustrate Positive Thigmotropism