Plant Science Exam 2 Study Notes

Plant Science Exam 2 Study Notes

• Plant Uses for Water: Seed germination, transplant establishment, turgor pressure in cells, transportation of dissolved minerals and carbohydrates, photosynthesis.

• Plant Water Conduct: Water moves acropetally (up) through the xylem and basipetally (down) through the phloem.

• Transpiration: The movement of water through plants.

• Water Movement Physics: Cohesion-tension (continuous water flow) and pressure-flow (water from roots) are two theories of water movement.

• Stomata: Tiny structures on the underside of leaves, accounting for 1% of leaf area, with thickened cell walls contributing to water regulation.

• Water Content in Plants: Information is missing on the exact amount of water in plants.

Factors Affecting Transpiration

• Environmental Factors: Temperature, humidity, wind, light intensity, and leaf area impact transpiration rates.

• Plant Responses: Wilting and rolling/curling up are responses to water loss.

• Drought Avoidance: Dormancy, modified roots, and xeromorphic features (e.g., leaf size, thickness) are strategies against drought.

• Evapotranspiration (ET): A measurement that accounts for both evaporation and transpiration.

• Water Management: Plant selection, shading, anti-transpiration techniques, and irrigation strategies improve water use efficiency. Healthy roots are essential for water intake and oxygen exchange.

• Optimal Irrigation Practices: Water deeply and infrequently, preferably at night or early morning to minimize evaporation. Overwatering should be avoided.

• Effects of Over/Under Watering: Negative effects of both overwatering and underwatering on plant health.

• Hydroponics: A technique used for urban farming and local growth, as it's a soil-free method.

Hydroponics Advantages and Disadvantages

• Advantages: No soil, larger plants, higher productivity, easier harvests.

• Disadvantages: Cost, lack of soil buffer, labor intensity, and required knowledge.

Hydroponic Systems Types

• Reservoir Systems
• Nutrient Film Technique
• Aeroponics
• Ebb and Flow
• Drip Systems
• Wicking
• Aquaponics

Photosynthesis

• Equation: CO2 + H2O + light → C6H12O6 + O2

• Organic Chemistry: The study of carbon and its bonds.

• Reactions: Light and Dark reactions.

• Ingredients Light, Oxygen, Carbon, and Water.

• Effect of Light Absorption: Information regarding the effect of light absorption is needed.

Light and Dark Reactions

• Light Reaction: Occurs in grana, captures light, and generates ATP and NADPH.

• Dark Reaction(Calvin Cycle): Happens in the stroma, uses ATP and NADPH produced in the light reaction to produce carbohydrates and sugars.

C3 vs C4 Plants

• C3 Plants: Common plants, optimized for cool, wet and shady conditions, struggle with high temperatures.

• C4 Plants: Optimized for warm conditions, found in tropical regions such as Corn, Sugarcane.

Importance of Bundle Sheath

• Function: Keeps Ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCo) in the appropriate location.

Carbohydrates

• Structural and Unstructural: Can serve either structural or energy roles in plants.

• Highest Reserves: When environmental conditions are unsuitable for vegetative growth, carbohydrate reserves are highest.

• Fertility: Fertilizing plants when growth slows (eg., fall), is beneficial.

Environmental Factors Affecting Photosynthesis

• Light: Quality and quantity of incoming light.

• CO2 Availability: The amount of carbon dioxide available for photosynthesis.

• H2O Availability: Water availability is needed to open stomata in leaves.

• Temperature: Temperature influences the metabolic process of photosynthesis.

Factors Affecting Respiration

• Temperature: Temperature affects the rate of respiration in plants.

• Oxygen (O2): Oxygen is a necessary component of respiration.

• Carbon Dioxide (CO2): Carbon dioxide affects respiration rates.

• Water (H2O): Water availability affects respiration rates.

• Age of Plant: Plants in their mature stage tend to use more energy for respiration, higher respiration rates.

• Ideal Conditions for Respiration: Cold temperature, increased CO2 availability, and decreased oxygen levels.

Respiration vs. Photosynthesis

• Respiration: Releases energy
• Photosynthesis: Stores energy

Secondary Compounds

• Importance: Smell, taste, and poisonous qualities, as well as medicinal uses.

Plant Parts

• Bracts: Modified leaves, frequently colorful, that support flowers.

• Petals: Attract pollinators, protect inner flower parts.

Flower Types

• Monoecious and Dioecious:
• Complete and Incomplete
• Imperfect and Perfect

Seed Production Cycle

• Steps in Seed Production:

• Wildlife seed collection

• Field Establishment

• Seed Production

• Seed Cleaning/Testing

• Seed Storage and Use

• Repeat

• Seed Storage: Secure storage in cool, dry environments to prevent rodent damage.

• Labelling: Species/variety, weight, germination test dates, pure seed percentage, other crops/weeds, inert matter

Seed Mixtures and Blends

• Seed Mixtures: Combining different species.

• Seed Blends: Combining multiple varieties of the same species.

• Dormancy, Scarification and Quiescence: Differences in seed germination processes.

Overseeding and Interseeding

• Overseeding: Seeding into existing turf (Grass) usually cool season grass into warm-season turf.

• Interseeding: Seeding into existing crop rows.

Seed Treatments

Information on seed treatments needed.

Germination

• Important Factors: Viable seeds, optimal seed quality, sufficient water, adequate oxygen, and appropriate temperature levels.

• Emergence Mechanisms: Epigeous (below ground) and hypogeous (above-ground) emergence.

Plant Domestication, Selection, Cultigens and Landraces

• Domestication: Selection and adaptation of plants to human needs.

• Selection: Intentional choice of plants with desired traits.

• Cultigens: Plants developed through human selection.

• Landraces: Locally adapted varieties of plants.

Pollen and Fertilization

• Pollen transfer: Pollen is transferred from the anther to the stigma.

• Fertilization process: Pollen grains grow into pollen tubes, transferring sperm to the ovules, leading to fertilization.

Ploidy, Alleles, Homozygous vs. Heterozygous,

• Ploidy: Number of chromosome sets in a cell.

• Alleles: Variations of a gene at a single locus.

• Homozygous: Having two identical alleles for a gene.

• Heterozygous: Having two different alleles for a gene.

GMOs

• Pros of GMOs: Pest resistance and superior plant characteristics.

• Cons of GMOs: Pollen transfer, possible food allergies, and domination of the market by certain companies.

Asexual Propagation Methods

• Methods: Plantlets, Crown division, Cuttings, Grafting, Layering, bulbs & stems, Micropropagation, Transplanting

Reasons for Grafting

• Grafting Reasons: Information is needed on specific reasons.

Parts of a Flower

• Standard Blossom Parts: Information about parts of a flower.
• Legume Flower Parts: Information on the parts of legume flowers.

Inflorescence Types

• Inflorescence Types: List of various inflorescence types (e.g., spike, umbel, head, raceme, panicle, composite).

Parts of a Grain of Pollen

• Parts: Sperm Cells, Pollen Tubes, Vegetative Cell, Nucleoi, Pore, Intine, Exine (cell wall thickening)

• Kranz Anatomy: Specific leaf anatomy in C4 plants.

• Chloroplast Anatomy: Internal parts of the chloroplast, e.g., Lamella, Grana, Lumen, Thylakoid, Stroma, Inner Membrane, Outer Membrane.

• Dry Fruits: Grains, Achene, Nut, Samara

Prepare for your Plant Science Exam 2 with these essential study notes. This quiz covers key topics such as water uses in plants, transpiration mechanisms, and factors affecting water movement. Dive into the physics behind plant water conduct and understand the role of stomata in moisture regulation.