botany = plant science agronomy - field crops, wheat, corn, soybeans horticulture - fruits, veggies,...
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Botany = Plant Science
Agronomy - field crops, wheat, corn, soybeans
Horticulture - fruits, veggies, woody ornamentals and floriculture crops
Forestry - wood and pulp production, recreation, wildlife and watershed management
Weed science - deal with controlling and management of unwanted plants.
Major Uses of Plants as FOOD
Grains – wheat, corn, oats, rye, barley, millet and grain sorghum
Starchy Foods – potatoes, sweet potato, cassava, yam, banana
Vegetables - sweet corn, snap bea, pea, bean, lettuce Fruits – apples, strawberries, blueberries, raspberries,
watermelon Sugar Crops – sugar beets, sugar cane, (corn syrup) Oil Crops – soybean, sunflower, peanut, corn,
cottonseed, olive Nuts - Walnut, Pecan; Spices – Vanilla, Pepper, Allspice, Oregano;
Beverages – Coffee, Chocolate, Tea
Nonfood Uses of Plants
Fiber Crops Cotton and Flax
Natural fibers have been replaced with synthetics. Nylon, rayon, polyester
Common to see a blend of natural and synthetic fibers Cotton/polyester blend
Timber, Fuel and Pulp Aesthetic Uses
Cut flowers, turf grasses, green foliage
Careers in Plant Science - (with a high school diploma)
Greenhouse caretaker Plant propagator Orchard Care Taker Pesticide Applicator Groundskeeper Tractor Operator Combine harvester
Careers in Plant Science with a 2-year (associate's) degree
Greenhouse manager Golf course manager Pesticide dealer Crop supply salesperson Greenhouse supply
salesperson
4-year degree job opportunities in Plant Science
Crop marketing specialist Crop production specialist Fertilizer technologist Erosion control scientist Soil conservationist Seed technologist Turf grass specialist
Graduate level careers in Plant Science
Plant geneticist Plant breeder Biotechnologist Genetic engineer Plant pathologist Plant physiologist Statistician Weed scientist
Plant Classifications Angiosperm: produces seeds enclosed in a fruit
Ex: corn, deciduous trees 1. Monocot: one seed leaf (cotyledon)
ex. Corn, grass 2. Dicot: two seed leaves
ex. Beans, trees
Gymnosperms: produces seeds enclosed in cones Ex: evergreen and pine trees
Root Functions
Absorption of water and nutrients (root hairs take up oxygen and water and
it is transported through the xylem tissue in the plant)
Transportation of water and nutrients to stem
Anchor plant to maintain stability Stores food and water
Root System
Primary root: short-lived, develops from embryo
Secondary root: branches from primary root, fibrous root, becomes primary root
Root hairs: extensions reach between soil particles; absorbs water and nutrients; needs care when transplanting
Parts of Roots
Root hairs - site of absorption, one-celled, white, fuzzy hair-like growths that develop near the end of the root branches
Root tip - where the root grows in length (4 to 6 cm of the “free end”)
Root cap - provides protection for the root tip Epidermis - the outermost layer of cells Cortex: - undifferentiated plant tissue from which
new cells arise at the tips of roots (under root cap)
Parts of Roots
Growing point - just back of the root cap where active cell division
Vascular tissue - is within the cortex, contains cells which transport water, nutrients, and minerals to all parts of the plant.
Elongation region - where rapid growth in the length of the root takes place.
Region of maturation - lies behind the growing point and is where secondary roots emerge.
Types of Root Systems
1. Taproots: primary roots; reach deep into soil ex. Carrot, dandelions, oak
2. Fibrous: no real primary roots; many fine roots, spread out at soil surface ex. Annuals, grasses, shrubs
3. Fleshy: become food reservoirs, store surplus food ex. Carrots, turnips, beets
Function of Stems
Attachment point for leaves, flowers, fruit
Support Leaves have to
have access to light and air
Function of Stems
Transport FOOD, WATER,
MINERALS Through Capillary Action Vascular System:
Xylem = water and nutrients taken from roots to leaves
Phloem = manufactured food distributed to all parts of the plants
Storage = of water, nutrients, waste
Vascular Systems
Monocot: bundles scattered throughout stem
Dicots: segregated into circular pattern; separated by cambium layer (produces new xylem & phloem cells)
Dicot Stem
Epidermis Bundle Cap
Xylem
Phloem
Cambium Layer
Vascular bundles in a circular arrangement
Woody = accumulated dead xylem cells
Herbaceous = nonwoody - succulent (corn, weeds, beans, annual flowers)
Stem Structure:
Terminal bud = tip of stem, point of elongation (cut it off and it’ll get a bushy plant)
Auxillary bud = located above each leaf Node = where the leaf is attached Internode = region between nodes
Stem Growth
Growth in LENGTH = meristematic cells = active cell division Apical meristems = tips
Growth in DIAMETER = cambium layer (rings) Cells divide between xylem and phloem Stem grows in diameter when: cambium layer divides on inner side of stem =
new xylem and on outer side of stem = new phloem
Trees in dormant seasons add different colors to the growth layers = rings
Function
To absorb sunlight for the manufacturing of plant sugars
Photosynthesis Flattened surfaces present a large area for
absorption of light energy To make food used by plants for growth
& reproduction
Types of Leaves
Scale leaves - small, leathery, protective leaves, enclose & protect buds
Seed leaves - cotyledons, are modified leaves (storage organs).
Spines and tendrils - modified leaves that protect or assist in supporting stems
Types of Leaves
Storage leaves - found in bulbs and succulents, serve as food storage
Bracts - which are often brightly colored (poinsettia)
Conifers,(pines, firs, spruce)needles- waxy cuticles with sunken stomata resin canals on sides of vascular system
to guard against insect damage
Dicot Parts of a Leaf
Blade - broad, thin part of leaf Petiole - thin stem attaching leaf to stem Sessile - leaves with no petiole Midrib - large, central vein Margin - edge of leaf Secondary vein - branches from main vein Apex or tip - top of leaf Base - bottom of leaf
Monocots
Sheath - portion of leaf blade surrounding stem
Ligule - “collar” extension of sheath curving around stem
Auricles - appendages that surround stem at junction of blade and sheath
Cross-Section of A Leaf Epidermis - protection of leaf tissue Cuticle - waxy substance (cutin) protects leaf from
dehydration Guard cells - open and close, regulate passage of
H2O, O2, and CO2 Stoma - openings in leaf surface Mesophyll - middle layer of leaf, where
photosynthesis occurs Palisade layer - dense upper layer Spongy mesophyll - lower layer air space
Chloroplasts - actual sites of photosynthesis
Leaf Characteristics
Simple - one blade per leaf ex: grass, oak, apple
Compound - several leaflets ex: sumac, locust 2 Types:
Palmate Pinnate
Leaf Arrangement along a Stem
Rosulate - basal leaves form a rosette around stem
Alternate - leaves occur at alternate spots on stem; single leaf at each node oak, beech
Opposite - leaves occur two at a node on opposite sides of stem maple, ash, dogwood
Whorled - 3 or more leaves at each node
Venation - arrangement of veins
Parallel - from base to tip in parallel lines ex. Grasses/monocots
Net-veined - veins branch from main midrib(s) and subdivide to finer veinlets more resistant to tearing Pinnate - veins are lateral from midrib to edge Palmate venation - principal vein extends
outward, like ribs of a fan ex. Dicots, apple, maple leaves
Purpose of Flowers
POLLINATION = Plant Sexual Reproduction Brightly colored & fragrant to attract bees,
insects, birds Pollination occurs by animals, wind,
human activity
Flowers
Dicots - typically have four or five sepals and/or petals, or multiples thereof
Monocots - typically come in threes or multiples of three
Flowers Contain 4 Parts
Sepals: small, green, leaflike structures located at the base of a flower - protects opening bud and flower; supports petals; also called a calyx
Petals: highly colored portions of a flower to attract pollination
Stamen: male part of the flower Pistil: female part of the flower
Female Part of the Flower (PISTIL) Stigma: pollen-collecting
structure at top of pistil Style: support structure
connecting ovary and stigma Ovary: enlarged base of the
pistil contains ovules (eggs), if an egg is fertilized, the ovule develops into a seed.
Pollination: pollen is collected at stigma, travels down style and reaches the ovary
Male parts of the flower
Stamen: Anther: pollen sac - located
at top of structure...Contains pollen
Filament: stalk supporting anther, holds the anther in position, making the pollen available for dispersement by wind, insects, or birds
Types of Flowers
Complete/Perfect: flower with all four parts Incomplete/Imperfect: flower missing any
of the four parts
Corn plant: male and female parts in different places on one plant Male part = tassel Female part = ears
Incomplete FlowerIncomplete Flower
Has ONLY male parts or female parts Has ONLY male parts or female parts Male flower – sepals, petals & stamens but Male flower – sepals, petals & stamens but
no pistilno pistil Female flower – sepals, petals, & pistil, but Female flower – sepals, petals, & pistil, but
no stamensno stamens Examples: Kiwi, GinkgoExamples: Kiwi, Ginkgo
Plants are classified by reproduction life spans
Annual: completes life cycle in one year Ex: bedding plants, vegetables, corn, wheat
Biennial: 2 year life cycle. Grows vegetation in one year. Flowers and dies off second year Ex. Celery, asparagus, wild carrot
Perennial: life span of 2 + years Ex. Trees, shrubs
Tomato Reproductive Cycle
Developing Buds Immature Flowers Mature Flower
Fertilized Flower Developing Fruit
Immature Fruit Mature Fruit
Sexual & Asexual Reproduction
Sexual: Propagation is by seed
Asexual: Propagation is the increase of plants by vegetative methods.
Sexual Reproduction
Advantages more economical easier longer storage time
Disadvantages do not breed true slow growth do not produce viable seeds
How do pollen grains fertilize the ovules?
Pollen grains are carried by wind, water, or animals
Pollen lands on stigma, pollen tubes move toward ovary
Fertilization happens in ovary Embryo is formed Embryo grows outward and forms fruit or
seed
Sexual Reproduction Self-fertilization, pollen and ovules are made by the
same plant. Repeated self-fertilization results in inbreeding. Inbred plants
often show reduced vigor and make fewer fruits and seeds. Cross-fertilization, pollen and ovules come from
genetically different plants. Cross-fertilization often leads to vigorous, highly productive
plants, an effect called hybrid vigor. Cross-pollination is useful in plant breeding
Can be done by removing anthers from a plant before pollination, so that the grower can supply pollen from another selected plant
Some plants cannot self-pollinate. Some plants have distinct male and female individuals.
Asexual Reproduction
Vegetative reproduction is asexual a= without
Three types of cuttings: Tip cutting Leaf section, leaf petiole, or cutting veins Cutting of roots
Ensure new plants are identical to parent plants
Maintain desirable species
Common types of asexual propagation
Cuttings - portion of plant removed and forms roots (shrubs/houseplants)
Grafting - shoot removed from parent plant and placed on another (apple/fruit trees)
Budding - bud removed from parent plant and placed on stock (fruit trees/ornamentals roses)
Division - clumps of plants dug up and separated (hostas, mums, lilies)
Rhizomes - rhizomes dug up, cut into sections and planted (iris)
Stolon - new plants root at nodes (strawberries
Sexual Reproduction
Requires flowers to form, pollination & fertilization to occur, seeds develop and grow
Pollen from anther falls on stigma of pistil from anther of stamen
Fertilization occurs in ovary Ovary develops into fruit and ovules
become seed
Parts of the Seed
Seed Coat Protective outer covering of the seed Helps transport seeds and keep them
viable (alive) Endosperm
Stores plant food (starch & protein) Feeds the growing embryo during
germination
Parts of the Seed
Cotyledon Seed leaf - first leaves seen on a plant. Feeds
the plant during first growth Dicots = 2 Monocots = 1
Embryo New plant that develops as a result of fertilization Epicotyl - forms all plant parts above the first
node of the stem. Hypocotyl - forms the lower stem and roots
Seeds
Angiosperm— flowering plants, seeds are born in an enclosed ovary (some 250,000 species)
Gymnosperm— seeds of gymnosperms are born naked with no ovary (pines, spruces, and ginkgo 700 species)
Germination
1. Seed coat softened by water
2. Favorable temperatures must exist
3. Endosperm feeds growing plant
4. Epicotyl - grows away from gravity
5. Hypocotyl - grows toward gravitational attraction
Cotyledons
Monocots - (grasses); remains inside seed for a longer period
Dicots - push up through the soil at germination and act as true leaves
Fruit Consists of:
Fertilized and mature ovules = SEEDS Ovary wall
Fleshy, as in the apple, or dry and hard as in a maple fruit
Seeds enclosed within the ovary apples, peaches, oranges, squash, cucumbers
Seeds situated on outside of fruit tissue corn, strawberry
Types of Fruit - Simple
Develop from a single ovary Cherries and peaches (drupe), pears and
apples (pome), and tomatoes (berries) Tomatoes are a botanical fruit since they
develop from the flower, as do squash, cucumbers, and eggplant
DRY: (fruit wall becomes papery and hard) Peanut (legumes), poppy (capsule), maple
(samara), and walnut (nut)
Types of Fruit - Aggregate
Come from a single flower which has many ovaries
Ovaries are fertilized separately and independently
Strawberry and blackberry have an edible, enlarged receptacle