Final Horticulture Science

Foliar Feeding

Foliar feeding is the practice of applying liquid fertilizer directly to plant leaves, allowing nutrients such as phosphorus, zinc, and iron to be absorbed quickly through the cuticle and stomata for rapid correction of deficiencies. (Can bypass problems associated with Soil PH)

Macronutrients

Major nutrients in soil: Nitrogen, Phosphorus, Potassium, Calcium, Sulfur, and Magnesium

Micronutrients

Minor or trace elements. Iron, Boron, Manganese, Chlorine, Zinc, Copper, Molybdenum, Nickel

3 elements plants get from air

Carbon, Hydrogen, and Oxygen.

Ideal pH

6.3 to 6.8 (with expectations)

Tropism

Response to Stimulus

Auxin

Within shoot tips and embryos

Cell elongation of stem and roots, enlargement of fruit and tubers, cell division in cambium tissue in woody stems, tropisms.

Cell elongation

Moves from below shoot tips down.

Geotropism

Movement in response to gravity

Thigmotropic

Response to touch

Apical dominance

Determined by the apical bud, partly due to auxin produced basis of all pruning.

Fruit Set

Low concentrations of Auxin simulate pollination and fertilization and the levels of auxin that the embryo would produce.

Low Auxin concentrations cause

Fruit or flower thinning

Herbicides

Kill only dicots (auxin)

Auxin can cause

Adventitious root formation

Cytokinin

In root tips and embryos

Move from the root system up, opposite of auxin

Cell division

May delay leaf aging or abscission

May overcome dormancy or stimulate germination

Favors adventitious shoot formation

Gibberellic Acid

In shoot tips, root tips and embryos

Cell elongation better effect than auxin

Rosette or dwarf plants compact growth habit

May cause bolting in biennials

Increase size of fruits like grapes

May overcome bud dormancy or substitute for cold treatment

May speed up seed germination

Favors STAMINATE flower formation on monoicous plants.

Ethylene

In Ripening fruits, aging flowers, germinating seeds and wounded tissue.

Stimulates fruit ripening in many fruits

Triggers flowering in some bromeliads

Causes leaf abscission in some plants and causes curling and contortion of leaves in some plants

favors PISTILLATE FLOWERS on monoicous plants.

Abscisic Acid

In plastids especially chloroplasts

Triggers dormancy and leaf abscission and close stoma in a drought

Causes bud or seed dormancy

May cause leaf abscission in some plants

Causes stomata to close (Drought stress)

Functions of water (Solvent)

Dissolves solutes the cytosol of the cytoplasm is water solution of dissolved solutes

Functions of water (Reagent)

Water is used in biochemical reactions → photosynthesis

Functions of water (Translocation medium)

Water translocates solutes in xylem and phloem

Functions of water (Temperature relations)

Stabilizes plants and environment evaporation cooling, releases heat when freezes, constant temp during phase change turgor pressure and growth. T

Turgor Pressure

The positive pressure inside a cell due to water uptake. Due to osmosis. Keeps cells expanded and keeps herbaceous plants and plant parts erect. Driving force for growth is size by causing cell expansion.

Plasymolysis

Shrinkage of individual cells due to loss of turgor pressure that causes cells to become flaccid.

Wilting

Excessive water loss that causes loss of plant rigidity; caused by plasmolysis of enough individual cells to cause the organ to be limp.

Relative Humidity

Amount of water vapor in air expressed as a percentage of the amount of water vapor that could be held at saturation.

Sapwood

The lighter outer rings of wood through which all water moves up the stems

Heartwood

The inner darker rings that are clogged with resins, tannins, and other compounds that resist decay and supplies support.

Absorption

Uptake of water by roots

Translocation

Movement of water through plants mainly through xylem

Transpiration

Loss of water vapor from leaves and other above ground plant parts; mostly stomata.

Guttation

Loss of liquid water from leaves; occurs through hydathodes (stomata that don’t close)

Function of Transpiration

causes negative pressure in leaves which pulls water up the xylem.

Antitranspirants

Chemicals that close or clog the stomata

Fertilizer analysis or Grade

3 big numbers on label, Nitrogen, Phosphorus, and Potassium

Complete fertilizer

Contains N-P-K

Balanced Fertilizer

Contains equal amounts of N-P-K

Olericulture

Science of vegetable production and culture.

Greens

Lettuce, spinach, collards

Salad crops

Celery

Roots/tubers

Carrots, potatoes, beets, radishes

Bulbs

Onion, leeks

Cole

Broccoli, cabbage, cauliflower,

All different cultivars of wild mustard

Legumes

Beans and peas

Cucurbits

Melons, squash, cucumber

Solanaceous

Tomatoes and peppers

Cool season crops

(45-65 F) Germinate in cold weather and cool soils. Can withstand frost, Cold temps and or frost can improve flavor,

Brussel sprouts, Kale, Brocolli

Bolting

The premature production of a flowering stem to produce seed: increases gibberellins, response to day length, high temps in summer, drought stress. Once process has begun it can’t be stopped.

Warm season crops

(65-86 F) Frost will generally kill warm season vegetables. Chilling temps in 40s can stop growth. Cucumbers, squash and tomatoes.

Determinate Tomato

Smaller plants do most of their growing before fruit set, then stop. Mature early and ripen at the same time.

Indeterminate Tomato

Larger plants, continue growth during flowering and fruit set. Yield over entire growing season. Often set fruit later than determinate.

Vegetables and quality of water

Most vegetables sensitive to soluble salts in the soil. Saltier more water should be applied to keep salts from accumulating.

Groundwater in many parts of Colorado is getting saltier.

Conventional Agriculture

The common paradigm Minimize inputs, maximize output and or production efficiency. Success metric is yield.

Sustainable ag systems

Ecologically based ag with minimal environmental impact. Maximize system biodiversity, success metric is not yield exclusively but includes environmental impact etc.

June Bearing Strawberries

Flower set during previous fall Matures in July.

Everbearing Strawberries

Mid then late summer

Day Neutral

High temps (High vegetative growth)

Brambles

Raspberries and Blackberries

Receptacle remains on plant

Raspberry. (Blackberry the Receptacle is with the fruit)

Summer Bearing Raspberries (Floricane)

Flowers and fruits once per season on second year canes. Fruits mid-summer of second year.

Fall Bearing Primocane Raspberries

Produce flowers and fruit on floricanes the second year. However also flowers and fruit on upper portions of primocanes or first year canes in the fall.

Blueberries

Highbush and Lowbush. Needs 4.2-5.5 PH soil