Basic Horticultural Botany

What is Horticulture?

• Horticulture is the art and science of growing vegetable, fruit, medicinal and ornamental plants

• Agronomy covers the food and fiber and energy crops that are grown on large acreages and are usually seed propagated

What are Horticultural Plants?

• Fruit– Tropical : mango, papaya– Subtropical: Orange, fig – Temperate: Apple, Pear

• A fruit is an enlarged ovary with seeds and attached parts

What are Horticultural Plants?

• Vegetables– Cool Season: broccoli

• Cauliflower, spinach,onion

– Warm season• New Zealand spinach

– In the grocery store language: Tomatoes, peppers and squash

• Vegetables Botanically are plant parts without ovary/seeds.

What are Horticultural Plants?

• Drugs– Plants that have medical

use: Echinacea, willow, Ginkgo

What are Horticultural Plants?

• Condiments/ spices:– Plants used to make

flavorings: mustard, curry

What are Horticultural Plants?

• Beverage Plants– Coffee, Tea, – Herbal Tisanes– Hops for beer– Agave for Tequila

What are Horticultural Plants?

• Ornamental Plants– Herbaceous – flowers

and foliage plants• Annuals• Perennials

– Woody trees and shrubs

• Ornamentals are planted for shade, beauty, Climate control, windbreaks…

Basic Botany/ plant classificationScientific names , Common namesKingdom

DivisionClass

Order Family

Genus ( pl. Genera)species( sp. or spp.)

Cultivar or variety

PlantaeTracheophytaAngiospermaeRosalesRosaceaeMalusdomestica‘Honeycrisp’

More terms used to classify plants

• Annuals- completes the life cycle in one season

• Biennial – usually takes two years to complete the life cycle ( carrots, cabbage)

• Perennial- usually lives more than 2 years– Woody – trees and shrubs• Deciduous/ evergreen

– Herbaceous• Tender/hardy

Plant Structures

• Flowering plants are divided into to large groups: monocots and dicots

• Monocot means there is one seed leaf ( Cotyledon) in the seed. Dicot means two seed leaves.

Vegetative vs reproductive

• Annual herbaceous plant• Leaves, stems and roots are vegetative but can

be used in asexual reproduction• Flowers, seeds are sexual reproductive parts

Inside a herbaceous stem

Inside a woody stem

Cell types

• Parenchyma • Schlerenchyma

• 3 year old woody twig

Modified stems- often used in propagation

• Spur• Sucker• Stolon• crown

• Rhizome• Tuber• Bulb• Corm

Leafa stem appendage with a bud at it’s base

Leaf types

Leaf margins

Leaf shapes

leaf

Buds

• Axillary• Terminal• Bud scales ( temperate)• Chilling requirements• Leaf/flower/mixed

Roots/ Function

• Absorb water and nutrients

• Anchor the plant in the soil

• Support the stem• Food storage• propagation

• First to emerge from the seed

• Positive geotaxis• No nodes• No leaves or flowers

Root vs Stem

Root cross sectionStem cross section

Roots

• Tap root ( dicot)• Fibrous roots

( monocot)• Lateral /secondary

root/branch root• Generally extend

beyond the top

Flowers

• Sexual reproduction• Built to attract

pollinators• People can be

considered pollinators

• Can be perfect (complete)

• Unisexual• Plants can be

monoecious or dioecious

Basic plant life cycle

• Dormancy: seeds or buds fail to grow when given good conditions.

• Vegetative: seedling to Juvenile

• Reproductive: when plant is large enough to flower

• Senescence: ripening of seed, and fruit, leaf drop

Dormancy

• Hormonal dormancy– Timed by hormones

many temperate plants show this ex. Apple trees

• Environmental dormancy– Cold or dryness keeps seed

from germinating

• Other types in seed dormancy

Vegetative growth

• The plant has to reach its mature stage before it can start flowering. In tomatoes this happens in 30+ days after transplant to the garden. In Apple trees it can be 5-7 years

Reproductive Growth

Primary Metabolism

• Photosynthesis– Sunlight– Chloroplasts in a live

plant– Carbon dioxide– Energy is changed from

light to chemical energy ( sugars)

– Oxygen released– Water is used and

produced

• Respiration– Energy is released from

sugars for plant energy– Oxygen is used– Water is used and

produced– CO2 is produced– Happens in dark and in

light– Occurs in all living cells

( mitochondria)

Photosynthesis

CO2+ H20 +sunlight +green plant C6H12O6 + O2+ H2O

RespirationC6H12O6 + O2+ H2O CO2+ H20 + 36 ATP

Transpiration

99 % of the water that enters the plant is used in Transpiration, 1% in metabolism

Plant growth Regulators

• Plant hormones or other chemicals that influence growth of plants.–Auxins -Gibberellins–Cytokinins -Abscisic Acid– Ethylene