HORT 2003 Exam 3 Study Guide

Botanically what makes a fruit different from a vegetable

Fruit: comes from the seed-bearing structure of a flowering plant

Vegetable: edible parts of a plant, such as roots, stems, and leaves

Native plant

Indigenous terrestrial and aquatic species that have evolved and occur naturally in a particular region, ecosystem, and habitat

Invasive plant

A plant outside of its native range, introduced or accidental, that displace native plants and disrupt the ecosystem

Adapted plant

Plants that are adapted and do best or thrive in a particular region based upon the environmental conditions of soil and weather

Centers of origin

Where crop plants originated naturally. Area of greatest genetic diversity (provenance)

Center of domestication

Where crop plants were domesticated

Horticulture vs agriculture

Agriculture: diverse, but typically fewer crop types. Dry harvest and long-term storage

Horticulture: very broad-includes fruits, vegetables, ornamentals, trees. Shorter shelf life. Higher moisture content

Father of American Horticulture

Liberty Hyde Bailey: Co-founder of the American Society for Horticultural Scientists

Binomial System of Nomenclature and who created it

Carl Linnaeus

• Two part Latin scientific name. Based naming system on reproductive plant parts

How to properly hand-write a scientific name: underline if handwritten

Genus species

Simple Tissues

Undifferentiated cells. Immature plant cells that are actively dividing and responsible for growth

Parenchyma, Collenchyma, Sclerenchyma

Three types of simple tissues

Complex tissues

Nondividing differentiated cells

• Mature, specialized cells that have lost the ability to divide and perform specific functions like support, transport, and storage

Phloem

Transports food substances throughout the plant (up and down)

Xylem

Transports water and minerals UP from the roots to the aerial parts of the plant

Monocot

• 1 cotyledon (single seed leaf)

• Large endosperm for food storage

• Fibrous roots system

• Vascular bundles run side-by-side

• Veins are usually similar in size

• Parallel leaf venation

  • Corn, Wheat, Rice, Grasses, Palms

Dicot

• 2 cotyledons (two seed leaves)

• Food stored in cotyledons

• Taproot system

• Net-like venation

  • Beans, sunflower, peas, oak

Meristematic tissues

Apical meristem: region of cell elongation both in roots and stem

Lateral meristem: found in the stems and roots of woody plants responsible for growth and girth in diameter

Intercalary meristem: characteristic of grasses and many monocots, where they are located at the bases of leaves or internodes and allow rapid regrowth after grazing or mowing

Types of root systems

• Tap root

• Fibrous root

• Prop root

• Adventitious root

Bulb

Fleshy leafy storage stem

Corm

Storage organ for overwintering

Rhizome

Continuously, laterally growing underground stems

Tuber

Modified underground storage stem

Stolon

Horizontal, extending above-ground stem or runner that takes root along points on its length to form new plants

Anther

Male part of the flower where sperm (pollen) are produced by meiosis

Filament

Supports the anther

Ovary

A flower structure that encloses and protects ovules and seeds as they develop

Ovule

A structure that develops within the ovary of a seed plant and contains the female gametophyte

Petal

A modified leaf of a flowering plant. Petals are the often colorful parts of a flower that advertise it to insects and other pollinators

Sepal

A modified leaf in angiosperms that helps enclose and protect a flower bud before it opens

Stamen

The pollen-producing reproductive organ of a flower, consisting of an anther and a filament

Stigma

The top of the central female part of a flower, where pollen is received

Style

The narrow elongated part of the pistil between the ovary and the stigma

Radial symmetry

A flower that can be divided into equal halves through multiple planes passing through the center

Bilateral symmetry

A flower that can be divided into equal halves through only one plane

Perfect flower

Both staminate and pistillate (male and female) parts in the same flower

Imperfect flower

Either staminate or pistillate flowers (separate male and female flowers) on the same plant or separate plants

Complete flower

Contains all four whorls of multiple parts (pistil, stamen, sepal, petal)

Incomplete flower

Missing one or more of the whorls (pistil, stamen, sepal, or petal)

Monoecious plants

Male and female flowers on the same ONE plant

Dioecious plants

Separate (divided, two) male and female flowering plants

Flower function

Reproduction

Preservation of genetic diversity

Three types of fruit

• Simple fruit: single fruit emerging from a single flower

• Aggregate fruit: multiple ovaries and fruitlets within a single flower structure

• Multiple fruit: adjacent multiple flowers in an inflorescence which form a single fruit structure

C3

Most common form of photosynthesis where carbon dioxide is directly fixed into a 3-carbon compound using the enzyme Rubisco

C4

A more efficient adaptation, particularly in hot climates, where carbon dioxide is initially fixed into a 4-carbon compound before being transferred to the Calvin cycle, allowing for a higher concentration of CO2 around Rubisco and minimizing photorespiration

CAM

Special type of C4 plant

• CO2 is stored as malic acid in vacuoles, which makes the plant more acidic at night and basic during the day

• Stomata open at night and are closed during the day

• Take up CO2 during the night and convert it to a form that can be stored until day

Light Quality

Photons of shorter wavelength and higher frequency BLUE light have more “energetic” potential than photons of red light

• Lighting must provide rich amounts of blue and red light for maximum photosynthesis

Light intensity

• The unit of measure for the intensity of photosynthetic light is micromoles per square meter per second

• Light intensity will affect photosynthesis rates. However, the effect of light intensity varies among different plant species

  • Sun-loving plants = high light intensity needed

  • Shade-loving plants = grow best under low intensity

  • Intermediate plants = in-between the other two categories

• Light compensation point = minimum light a plant needs to survive

• Light saturation point = maximum light a plant can use efficiently for photosynthesis

Light duration

Longer photoperiod usually = greater photosynthetic activity

Genotype

The plant’s genetic makeup, describing what alleles it carries

Phenotype

The observable traits of a plant, including height, leaf shape, or fruit taste

Disjunct populations

Groups of organisms from the same species that are separated by geographic distances and lack a continuous range of suitable habitat between them

Allopatric speciation

The formation of a new species from an ancestral population due to geographic isolation

Sympatric speciation

The formation of a new species from an ancestral species that remains in the same geographic area, often driven by ecological divergence, sexual selection (e.g., mate preference, or polyploidy (in plants), which reduce geneflow and lead to reproductive isolation

Benefits of polyploidy

1. Bigger plants and flowers

   1. Larger cells = larger leaves, fruits, and blooms

2. Seedless fruits

   1. Triploids can’t divide chromosomes evenly = sterile

3. Crop improvement

   1. Combines traits like stress tolerance, disease resistance, and yield

4. New plant species

   1. Polyploidy can create instant speciation

Ecotypes

A locally adapted population within a species. They show genetic differences that fit them to their environment

Morphogeneiss

Creation of form and structure (shape and pattern formation)

Differentiation

Specialization of cells and tissues in structure and function. (cells becoming xylem, phloem, epidermis)

Indeterminate growth form

A pattern where flowers form on side buds while the main stem keeps growing, so the plant can keep producing fruit for a long time

Determinate growth form

A growth pattern where the main stem stops growing and all the top buds flower at the same time, so the plant blooms in a short period

5 stages of plant growth

1. Seed

2. Juvenile

3. Transition

4. Maturity

5. Senescence

Juvenility vs maturity

Juvenile plants are unable to produce reproductive structures, meaning that they cannot produce flowers or seeds

• Plants tend to be more vining, have different leaf form, thorns, ease of root cuttings at this stage

Photoperiodism

Daylength is stable, reliable, and replicable

• Short day plants: produce flowers when the daylength is less than or shorter than some critical photoperiod

• Long day plants: produce flowers when the daylength is more than or longer than some critical photoperiod

• Day neutral plants: do not use photoperiod as a means of floral timing: rely on plant age and size only

Vernalization and chill hours

Chilling hour requirement: A requirement of exposure to temperatures below 45 degrees Fahrenheit for a certain duration of time, usually measured in hours

Auxins

Plant hormones that regulate cell elongation, apical dominance, vascular differentiation, root formation, and directional growth responses such as photoperiodism and gravitropism

Gibberellins

Plant hormones that stimulate stem elongation, seed germination, bolting, flowering, and fruit development

Cytokinins

Plant hormones that promote cell division, delay leaf aging (senescence), and stimulate lateral bud growth

Abscisic Acid (ABA)

A plant hormone that inhibits growth, promotes seed dormancy, and helps plants respond to stress such as drought by closing stomata

Ethylene

A gaseous plant hormone that regulates fruit ripening, leaf abscission, and plant responses to stress

Plant hormones

Naturally occurring organic substances that affect plant growth and development and function at very low concentrations

Trophism

The growth or movement of a plant in response to an external stimulus

Photropism

Growth or movement of a plant in response to light, usually toward the light source

Geotropism (gravitropism)

Growth or movement of a plant in response to gravity, with roots typically growing downward and shoots growing upward

Thigmotropism

Growth or movement of a plant in response to touch or physical contact with a solid object

Endogenous dormancy

A type of dormancy caused by internal factors within the seed, such as undeveloped embryos or the presence of growth-inhibiting hormones

• Physical dormancy

• Chemical dormancy

• Mechanical dormancy

• Morphological dormancy

Types of exogenous dormancy

• Physiological dormancy

• Morphophysiological dormancy

Types of endogenous dormancy

Exogenous dormancy

A type of dormancy caused by external factors outside the seed, such as hard seed coats, temperature, or water-impermeable layers that prevent germination

Physical dormancy

Dormancy caused by a hard of impermeable seed coat that prevents water and gases from entering the seed

Overcome via scarification (scratching, nicking, or soaking seeds)

Chemical dormancy

• Dormancy caused by the presence of chemical inhibitors within the seed that prevent germination until they are removed or neutralized

• Overcome via: leaching (soaking seeds in water to wash out inhibitors). Removing pulp, then leaching

Mechanical dormancy

• Dormancy caused by a seed coat or surrounding structures that physically restrict the embryo from expanding and growing, even if water an oxygen are available

• Overcome via: mechanical scarification (cracking or filing the seed coat)

Morphological dormancy

• Dormancy in seeds with underdeveloped or immature embryos that require time to grow before germination can occur

• Overcome via: warm/cold stratification

Physiological dormancy

• Dormancy caused by internal physiological factors, such as growth-inhibiting hormones, that prevent germination even when conditions are favorable

• Overcome via:

  • Stratification: cold or warm treatment to change hormone balance

  • After-ripening: dry storage for a period

  • Gibberellic acid application: shift internal hormonal balance

Morphophysiological dormancy

• Dormancy in seeds that have both an underdeveloped embryo and physiological inhibitors, requiring both embryo growth and overcoming internal inhibitors before germination

• Overcome via: time and stratification or temperature treatments

Combinational dormacny

• Both physical dormancy (hard seed coat) and physiological dormancy inside the embryo

• Overcome via: scarification + stratification or other treatments

Invasive plant

A non-native organism whose introduction causes or is likely to cause economic or environmental harm, or harm to human, animal, or plant health

Characteristics of invasive plants

• Broad ecological amplitude - widely distributed in a diversity of ecosystems and habitats

• Grow very fast

• Leaf out early in the year

• Lack natural predators & diseases

• Seeds: high production, high germination rate, and often a long-lived seed bank

• Adept at competing for resources

• Chemical warfare (allelopathy)

Macronutrients

Essential chemical elements required in relatively large quantities for healthy plant growth, development, and reproduction

Micronutrients

Essential trace elements required in small quantities for critical functions like photosynthesis, enzyme activation, and structural integrity

Major macronutrients

• Nitrogen (N)

• Phosphorus (P)

• Potassium (K)

Nitrogen (N)

• Essential for leaf and stem growth

• Key component of chlorophyll —> drives photosynthesis

• Mobile

Phosphorus (P)

• Critical for energy transfer (ATP)

• Promotes root development

• Important for flowering and fruiting

• Mobile

Potassium (K)

• Regulates water movement and stomatal function

• Improves stress tolerance (drought, disease, cold)

• Mobile

How to read a fertilizer bag

Listed as N-P-K

• Measured by total weight %

• 20-20-20 = 20% N, 20% P, 20% K, and 40% inert material

Soil

A natural mixture of minerals, organic matter, water, air, and living organisms that forms the upper layer of the Earth’s surface and supports plant growth

Potting media

A soilless or partially soilless growing medium designed to provide plants in containers with proper aeration, moisture retention, and nutrients for healthy root development

Five factors that form soil

1. Parent material

2. Climate

3. Topography

4. Organisms

5. Time

1. parent material

Originates in rock — as rock weathers it produces tiny fragments that are combined with remains of plants and animals in various stages of decomposition