exam 3 Botany

Dispersal mechanism

Fruit is ______ _______.

Intraspecific competition

Animals swallow the seeds in which it spreads through its feces where it can germinate

This is done to avoid ________ ______.

Endosperm (pic)

What is 1?

Embryo (pic)

What is 2?

Seed coat (pic)

What is 3?

Pericarp (pic)

What makes up 5, 6, and 7?

Endocarp

What is 5?

Mesocarp (pic)

What is 6?

Exocarp (pic)

What is 7?

Pericarp

• old ovary wall from flower becomes _____

  • Usually the edible part of a fruit

  • Can be homogenous or divided

Simple fruits

• result from a simple or compound ovary in a flower with only one pistil

Fleshy and dry

What are the two subcategories of simple fruit?

Simple fleshy fruits

Aggregate, berry, drupe, and pome are ______ _____

Berries

• Several to many seeds

• From a compound ovary

• Three kinds of _____

  • Regular

  • Pepo

  • Hesperidium

Regular berry

• thin pericarp

• Occur in many families

• Type of berry

Pepo berry

• thick hardening pericarp

• Occur in cucurbitceae (pumpkins, gourds, melons, squash)

• Type of berry

Hesperidium berry

• type of berry

• Leathery, oily pericarp

• Occur in rutaceae (the citrus fruit)

Drupe

• simple fleshy fruit

• Fleshy layer pericarp

• One seed in the middle

• Typically protected by hardened endocarp

Pome

Accessory fruit

• the ovary plus some other structure makes up the edible part

• The ovary per se is the core

  • Other edible portion derived from enlarged hypanthium

  • Apples, pears

Accessory fruit

• Some or part of the edible “fruit” is not derived from ovary tissue

• It is the receptacle part of the berry (edible)

• Each one is an ovary with a seed inside

dry fruits

Achenes, legum, follicle, and Samaras are examples of _______.

Indehiscent

Does not split open at maturity

Dehiscent

Splits open at maturity

Simple dry fruits characteristics

• Dehiscent

• One of two types of simple dry fruits

• Split open (dehiscent) to release seeds at maturity

• We tend to eat them when very immature

Legume

• from a simple ovary (1 carpel)

• Dehisces along two sutures

• Ex. Beans and peas

Follicle

• from a simple ovary (1 carpel)

• Dehisces along along one suture

• Ex. Milkweed fruits

• Dehiscent

Capsule

• from a compound ovary

• Dehisces in one of three ways

  • Septicidal

  • Loculicidal

  • Poricidial

Septicidal

Splits at carpel walls

• one of the three ways of Dehiscent

Loculicidal

Splits between carpel walls

• one of the three ways of Dehiscent

Poricidial

Develops a pore somewhere on the carpel, seeds escape through it

• one of the three ways of Dehiscent

Simple dry dehiscent fruits

Legume, follicle, capsule

Simple Indehiscent fruits

Samara, Achene, caryopis, nut

Samara

• Indehiscent

• Any fruit with a winglike growth

• Dispersed by wind

• simple dry fruit

Samara

• Indehiscent

• Any fruit with a winglike growth

• Dispersed by wind

• simple dry fruit

Nut

• thick, stony wall

• Typically of deciduous forest trees

• Ex. Acorns, pecans, walnuts, etc.

• simple dry fruit

Caryopis

• grains

• Fruits of poaceae (the true grasses)

• By far the most economically important fruit type

• Ex. Wheat, barely, rye, corn, rice

Aggregate fruits

Form from single flowers with unjoined, multiple pistils

• Each pistils forms a fruitlet (drupe, achene, etc.0

• Collectively called an etaerio

Multiple fruits

• forms from a cluster of flowers (inflorescence) but mature into a single mass

Agents of fruit dispersal

Wind, water, animals.

Wind

• winged and plumed fruits (samaras) and seeds

• Some plants that break off and are spread by the _____

  • Tumbleweed

  • Some grasses

Water

• fruits or seeds that float

• Ex. Inflated perigynia of carex coconuts

Animals

• Endozoochory- animal eats fruit, transports seed, defeecates it someplace else

  • Fruits become sweeter, larger, more sweet smelling, nutritious​

  • Becomes brightly colored

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• Ectozoochory- animal transports fruit on fur, skin, clothes, etc.

  • spines, hooks, etc.

Endozoochory

Animal eats fruit, transports seed, defecates it someplace else

• fruits become sweeter, larger, more sweet smelling, nutritious

• Becomes brightly colored

Ectozoochory

Animal transports fruit on fur, skin, clothes, etc.

• spines, hooks, etc.

Scarification

Seed coats breaks from mechanical stress

Penetration

Water enters through seed coat through _________.

Epicotyl

What is 1?

(Shoot of the plant)

Hypocotyl

What is 2?

(Includes radicle)

Radicle

What is 3?

Seed coat

What is 4?

Cotyledon

What is 5?

Embryo

What is 6?

Eudicot

This is an example of which type of seed germination?

Cotyledon (corn)

What is 1?

Coleoptile (corn)

What is 2?

Coleorhiza (corn)

What is 3?

Embryo (corn)

What is 4?

Pericarp fused with seed coat (corn)

What is 5?

Endosperm (corn)

What is 6?

Epicotyl (corn)

What is 7?

Hypocotyl (corn)

What is 8?

Radicle (corn)

What is 9?

Monocot

This is an example of what type of seed germination?

Increased crop efficiency

____________ led to thousands of technological breakthroughs

3500-10,000

Almost every plant we now use for food was domesticated ___________ years ago

Wheat, rice, corn, potato, sweet potato, manioc

80% of human calories come from 6 crops:

Alphonse De Candolle

• 1882- origin of cultivated plants

• Used a modern, consilient approach to track down the places where crop plants were native or first introduced

Nikolai Vavilov

• denoted to improvement of cereal crops for Soviet Union

• Also established many places of origin of crop plants (esp. Those of Asia and Eastern Europe)

• Soviet agronomist/geneticist

Trofim Lysenko

• Proponent of Lamarckism

• Ruthlessly used politics to stamp out those who disagreed with him

• Arrested Lysenko while on a botanical expedition in Ukraine

Intensive tillage

Leaves less than 15% of ground in-tilled per acre

• also leads to soil degradation, erosion, and nutrient runoff

Monoculture

• The cultivation of a single crop in an area

• Maximizes crop production per unit area

• Takes a LOT of preparation and maintenance

  • All other biota are regularly eliminated

  • Sometimes even down to soil microbes/nematodes

  • Energetically expensive – it takes ~9 kcal of energy to put 1 kcal on the table.

• Frequently leads to overuse of the soil

Dwarfed, disease resistance, cross-breeding-“triticale”

1940’s Borlaug developed many improved crops (3 things)

Monoculture, shuttle breeding, extensive chemical use, etc.

What techniques did Norman Borlaug develop?

Nitrogen fertilizer

Nitrogen extracted from air and converted to ammonia

• allowed humans to go beyond the limiting nutrients

Irrigation improvements

• Irrigation systems covering (usually) >3000 hectares (7,400 acres)

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• Spray or sprinkler systems covering

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• Rarely drip systems

Four tiered approach to pest management

1. Set action thresholds

2. Monitor and identify pests

3. Prevention

4. Control

Set action thresholds

Step one of four tiered approach to pest management

• identify population levels of pests which are likely to have economic impact

Monitor and identify pests

Second step of Four-tiered approach to pest management

• many insects and “weeds” are innocuous or beneficial

Prevention

Third step of Four-tiered approach to pest management

• manage crops without chemicals if possible—crop rotation, different crop varieties, etc.

Control

Last step of four tiered approach

• start with less risky approaches (pheromone treatment, etc.)

Totipotency

Plant cells that have the capacity to transform into other types of cells under specific chemical treatments

• manipulation of hormone regimes

• Especially auxins and cytokines

F.C. steward

Developed a way to regenerate entire plants from a single cell

• started by using carrot calluses in coconut water

• Laid groundwork for genetic modification

Genetic modification

A set of modern tools building off traditional selection and cross-breeding

Gene editing

Using advanced genetic techniques like CRISPR/CAS9

• to edit in specific genes (knock genes out!)

• American chestnut project

Hydroponics

Growth in a circulating nutrient bath

Aeroponics

Nutrients are sprayed directly on root systems

Aquaponics

Nutrient source is waste of large numbers of fish raised in the hydroponic water

Primary metabolites

Molecules made of all plants which are involved in growth and development

• Sugars/ polysaccharides

• Amino acids/proteins

• Fatty acids/lipids

• Nucleotides/DNA/RNA

Macronutrients

• secondary metabolites come from these pathways

  • Sugars/ polysaccharides

  • Amino acids/proteins

  • Fatty acids/lipids

  • Nucleotides/DNA/RNA

Secondary metabolites

Molecules made by posting-processing one or more primary metabolites

• highly species specific - define entire genera or families

• Involved in chemical defense

Secondary metabolites

Molecules made by posting-processing one or more primary metabolites

• highly species specific - define entire genera or families

• Involved in chemical defense

Alkaloids, phenolic, terpenoids

Three major chemical classes

Proteins and amino acids

Alkaloids are derived from

Carbohydrates (hydrophilic)

Phenolic are made up of

Fat and lipids (hydrophobic)

Terpenoids are derived of

Alkaloids

• Mostly alkaline nitrogen-containing molecules

• Structurally diverse

• Widespread in plants

True alkaloids and pseudoalkaloids

Two major group of alkaloids

True alkaloids

• Amino acid derived

• Contain N in the heterocycle

• Many major derivative groups

• Always contain a nitrogen

• Ex. Atropine, nicotine, coniine

Atropine

• pupil dilation

• Increase of heart rate

• True alkaloid

Nicotine

• vasoconstriction

• Increase of heart rate, stimulant

• Two heterocyclic ring

• True alkaloid