Horticulture Science

Modules 1-4

Horticulture

The science, tech, business, art and hobby of producing fruits, nuts, vegetables and herbs for consumption and producing flowers, ornamental plants and grasses for aesthetic, landscaping and recreational use.

Not Horticulture

Forestry: The science and tech of culturing, utilizing and improving forest tree and their products like pulps, resins, oils, etc...

Agronomy

The science and tech of culturing, utilizing and improving field crops (grains, fibers, and forage crops)

Horticultural crops

Small acreage more intensively managed

Harvest is difficult

Post harvest storage is short term and difficult

Little to no processing for human consumption

Examples: Vegetables, fruits, nuts, herbs, ornamental, and bedding plants

Agronomic crops

Large scale production

Less intensively managed

Easily harvested

Post harvest storage is easy

Requires intensive processing for human consumption

(Wheat, corn, rice, sorghum, soybeans, hay, cotton, peanuts.)

Commercial Hort (Olericulture)

Planting, harvesting, storing, processing, and marketing of vegetables and culinary herbs.

Pomology

The planting, harvesting, storing, processing, and marketing of fruit and tree nut crops.

Viticulture

Science, production, and study of grapes.

Arboriculture

Cultivation, management, and study of trees, shrubs, vines and other perennial woody plants.

Floriculture

Cultivation of flowering and ornamental plants for gardens (annual and perennial bedding plants), homes (houseplants), and the floral industry (cut flowers and potted flowering plants).

Epiphytes

Herbaceous plants that grow on the branches of trees and shrubs. Modified aerial roots or leaf rosettes collect water. (orchids and bromeliads)

Annual plants

Complete their life cycle of germination, growth, flowering, seed production, and death in a single growing season.

Seed to seed.

Summer and winter annuals

Summer: Killed by the frost or prolonged cold temps

Winter: Are killed by heat in late spring/early summer.

Biennials

Completes life cycle in two growing seasons.

1st season: Basal leaves (rosettes)

2nd season: Stems flowers, fruits, and dies (Usually requires environmental condition to trigger flowering).

Perennials

Live for more than 2 growing seasons and potentially for many years. May be evergreen or go dormant in the winter or due to heat. Can regrow from a perennial root.

Woody Perennials

Shrubs, many stems arising at/close to the ground.

trees: Usually have a single defined main stem can be deciduous or evergreen.

Deciduous

A tree or shrub that sheds its leaves annually.

Tender Perennials

Not cold hardy but under optimal growing temps they can live for many years.

Nomenclature Rules

Binomial system: Every plant species is given a unique two-part name:

Genus name (capitalized, italicized)

Specific epithet (lowercase, italicized)

Example: Quercus alba (white oak)

Genus – Capitalized, italicized (or underlined in handwriting).

Specific epithet – Lowercase, italicized.

Authority – Optional abbreviation of the person(s) who first validly published the name (e.g., L. for Linnaeus)

Example: Rosa canina L.

Italicize both genus and species in print/digital text; underline in handwriting

Live to Plant

Live to Plant

+1

.

Do not bold or capitalize beyond the first letter of the genus.

Family names (e.g., Pinaceae) are not italicized and are capitalized only at the first letter

Variety Names

Given when the mutation occurs in nature.

var. is used and placed after the specific epithet

var. is not underlined or italicized

Capitalize the first letter of variety only if it is a proper noun and italicize

Ex: Sansevieria trifasciata (Italicized) var. Laurentii (Italicize)

Cultivar Names

Given when the mutation occurs is due to human influence.

cv. is used and placed after epithet

cv. is not underlined or italicized

cv. or in single quotes

Capitalize the cultivar name

Ex: Sansevieria trifasciata (Italicized) 'Golden Hahnii'

Thallophytes

Algae

Simplest plant along with Bryophytes

Not differentiated into roots stems or leaves

Lack of conducting tissues

No cuticle.

Bryophytes

Mosses and liverworts

May be divided into leaves and stems

Have a cuticle

Lack true roots and conductive tissue

Pteridophytes

Ferns

Reproduce by means of spores

Spermatophytes

Seed bearing plants

Have true roots, stems and leaves.

Gymnosperm

Conifers and gingko

Naked seed

Often narrow leaves

Angiosperm

Flowering plants

Covered seed

Most have broad leaves

Monocots

1 Cotyledon (Flower parts in multiples of 3s) Parallel venation

Dicot

2 Cotyledons

Flower parts in multiples of 5s Network venation

Choripetalae

Flower parts separate and not fuse together (Spirea's, magnolias roses)

Sympetalae

Flower parts are fused at base (Azaleas)

Cotyledons

First "leaves" produced by a germinating seed. Often contains a store of food (obtained from the endosperm) to help the seedling become established.

Cuticle (Leaf Structure)

Outermost layer of both the upper and lower surfaces of the leaf. Clear and waxy to prevent against water loss.

Epidermis

One layer of cells that provides protection for the inner tissues. (cells are clear to allow light to reach photosynthetic tissues).

Stoma

An open aperture in the epidermis surrounded by 2 guard cells. Plural: Stomata usually more frequent on the epidermis of lower leaf surface. water vapor also passes through this and if found on some herbaceous stems, fruits and petals.

Opened when guard cells are turgid and closed when guard cells are flaccid.

Stomata are designed for gas exchange. CO2 in and O2 out for photosynthesis

CO2 out and O2 in for respiration

H20 out during transpiration.

Palisade Parenchyma

Located directly below the upper epidermis. Number of rows of cells depends on the intensity of sunlight. Contains 70-80% of the chloroplasts in the leaf.

Monocots lack Palisade layer.

Spongy Mesophyll

Located next to the lower epidermis

Contains large air spaces

Specialized for gas exchange

Allows for flexibility of lamina when it moves in the wind.

Veins

Contain the vascular tissue that is continuous with that in the stem.

Xylem carries water and minerals UP

Phloem carries dissolved food throughout the plant.

Sun Grown Leaf

Shade Grown leaf

Thicker due to a thicker palisade layer

Thinner due to thinner palisade layer (larger in size and more pliable).

Simple Leaf

Blade of the leaf occurs as one unit

Tip

Terminal point on the leaf

Blade or Lamina

Flattened, green, expanded portion of a leaf.

Margin

Edge of the leaf

Midrib

The most prominent central vein in the leaf.

Lateral veins

Secondary veins in a leaf

Petiole

The leaf stalk (Monocots lack)

Stipules

Leaf-like appendages that the base of the petiole on some leaves.

Alternate arrangement

One leaf is attached per node Left right etc. (Cascading)

Opposite Arrangement

Two leaves per node. Each pair is attached on opposite sides.

Whorled leaves

Three or more leaves grow from the same node forming a circular pattern.

Pinnate Venation

Feather like, net venation with lateral veins extending from a central middrip. (elm, oak, etc.)

Palmate venation

Finger like venation, multiple primary veins of roughly equal size emerge from a common point at the base of the leaf blade.

Parallel Venation

primary veins run parallel to each other along the length of the leaf, from the base to the apex, without forming a network. (Monocots)

Bud

An underdeveloped and unenlongated stem

Terminal bud

A bud at the tip of a stem responsible for the terminal growth.

Node

Part of the the marking the point of attachment of leaves, flowers, fruits, buds, and other stems.

Internode

The part of the stem between nodes

Lenticel

Rough areas of stems composed of loosely packed cells extending from the cortex through the ruptured epidermis (Breathing pores)

Crowns

Compressed stem Leaf and flower buds occur on the crown

Stolons

Stems that grow horizontally above the ground

Spurs

Found on the branches of woody plants stems whose growth has been severely restricted due to shortened internodes (Can resume normal growth).

Rhizomes

Underground, horizontally growing stems (most monocots)

Corms

Underground structures that are compressed and thickened stems occur only in some monocots. Not true bulbs

Vascular bundles

xylem and phloem run the length of plants stem, from root to top of the plants.

Bulb

Short stem surrounded by modified leaves

Tuber

Thick, underground stem used to store carbohydrates (potato)

Dicot roots

Tap root system

Monocot roots

Fibrous root system

Embryonic Root or Radicle

When seeds germinate the embryonic root (radicle) begins.

Tap root system: Radicle forms as primary root then adds lateral roots.

Fibrous root system: A single radicle forms but in addition several other embryonic roots (senial roots) Form just above the radical.

Root Epidermis

Outermost single layer of cells that protect from diseases and absorbs water and nutrients.

Root Hairs

Tubular extensions of epidermal cells.

Root Anatomy: Monocot, Dicot, Or Gymnosperm root (primary Growth)

Vascular tissues occur in the center

Surrounded by two rings of cells (Pericycle and endodermis)

then Cortex and epidermis

Cell walls of endodermis that are perpendicular to root surface are sealed by a Supersized band called Casparian strip.

Root hairs are extensions of the epidermal cells.

Woody Dicot or Gymnosperm Root (Secondary Growth)

Looks like the stem secondary stem growth

Difference is there is primary xylem in the center.

Dicot Stem Anatomy

Monocot Stem Anatomy

What type of plant has Secondary Growth

Dicot

Pistil

The female reproductive parts of the flower, occupies the central position of the flower. (Consists of three parts) (Stigma, Style, Ovary)

Stigma

Pollen receptive part of the flower

Style

Slender Column of tissue that rises from the ovary

Ovary

Enlarged portion located at the base of the pistil that contains the ovules (immature seeds).

Stamen

Male reproductive parts of the flower

Filaments

The stalk of the stamen

Anther

Portion of the stamen that bears pollen.

Corolla

The whorl of petals; usually thin, soft and colored to attract animals that help with pollination.

Calyx

The outer whorl of sepals; typically green (But can be petal like or petaloid n some species).

Perfect flower and Imperfect flower

Has both male (stamens) and Female (Pistils) regardless of the presence of absence of petals or sepals. Imperfect: Missing one type of sexual organ.

Complete Flower

A flower having sepals, petals, stamens, and pistils is complete. IF a flower is lacking one or more of these whorls, it is said to be incomplete.

Monoecious

Both Staminate (male) and Pistillate (female) flowers occur on the same plant.

Dioecious

Staminate (male) and pistillate (female) flowers occur on separate plants.

Solitary flowers

Form singly on upright stems or stalks.

Inflorescence

Flower made up of several florets

Entire flower displays a unique pattern of smaller flowers branching from several smaller stems.

Vary from simple and easy to recognize

Usually optimize the plants pollen dispersal.

Spike Inflorescence

Often called spike flower or line flower.

Elongated inflorescence on the main stem where flowers are sessile.

Sessile means attached directly to the main stem without pedicels.

Raceme Inflorescence

Elongated inflorescence, like a spike, except the florets are not sessile.

Each floret has its own pedicel (lateral stem)
Pedicels are usually identical lengths and sometimes very short.

Panicle Inflorescence

lose irregularly branched flower cluster

Also called a compound raceme

Most have a central stem with pedicels that are also branched.

Corymb Inflorescence

Has main stem with a pedicel that comes from various alternate sides of the main stem.

Pedicels are of unequal length.

Flat top or slightly rounded shape.

Cyme Inflorescence

Inflorescence that is usually broad and often flat topped.

Umbel Inflorescence

Single pedicelled flowers all arising from the top of the main stem.

Structured like the ribs of an umbrella

Flat topped, rounded or globular.

Spadix Inflorescence

Thick and swollen spike of unstalked flowers.

Florets are often deeply and densely imbedded in a fleshy column.

Spathe Bract Surrounding the spadix that is usually arching and colored. (modified leaf)

Composite inflorescence

Also known as a head flower or capitulum- short, dense cluster of florets.

Florets are generally sessile in a rounded flat pattern.

Has two different types of florets.

Disc Florets

Tiny tubular florets