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, s unflower, peanut, corn, cottonseed, olive Nuts Walnut, Pecan; Beverages – Spices – Vanilla, Pepper, Allspice, Oregano; 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

Other Plant Products

      Medicines Drugs Perfumes Cosmetics Insecticides Industrial chemicals

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

Basic Botany

Roots Stems Leaves Flowers Seeds

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)

Root Hairs on a Tomato Plant

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:

into soil primary roots; reach deep  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

Basic Plant Parts

STEMS

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)

Monocot Stem

EPIDERMIS

BUNDLE CAP XYLEM PHLOEM Vascular bundles in a scattered arrangement

Monocot Stem

Dicot Stem

Epidermis Bundle Cap Xylem Cambium Layer Phloem Vascular bundles in a circular arrangement

Dicot Stem

 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

Basic Plant Parts

LEAVES

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

Looks compound but is actually simple

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

Tomatoes - Spiral Leaf Arrangement

Unpruned vs. Pruned

Flowers

Basic Plant Parts

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

Tomato Flower

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 Flower

    Has ONLY male parts or female parts Male flower – sepals, petals & stamens but no pistil Female flower – sepals, petals, & pistil, but no stamens Examples: 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 & 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

SEEDS

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

Seeds are living or dormant

3 parts: 1.

2.

3.

seed coat endosperm/cotyledon embryo

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.

2.

3.

4.

5.

Seed coat softened by water Favorable temperatures must exist Endosperm feeds growing plant Epicotyl - grows away from gravity Hypocotyl - grows toward gravitational attraction

Monocots vs. Dicots

Cotyledons

 Monocots (grasses); remains inside seed for a longer period  Dicots - push up through the soil at germination and act as true leaves

Monocot Growth

Dicot Growth

FRUIT

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)

Tomato

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

Types of Fruit - Multiple

 Tight cluster of separate, independent flowers on a single structure  Each flower will have its own calyx and corolla  Pineapple, fig and the beet seed