Plant Nutrition for Bachillerato Students

Theme 4: Plant Nutrition

• Focuses on the biology, geology, and environmental sciences related to how plants obtain nutrients, specifically for Bachillerato (high school) students.

Index of Topics

• Absorption of water and mineral salts
• Transport of raw sap
• Absorption of carbon dioxide
• Photosynthesis
• Transport of produced sap
• Elimination of waste products
• Relationships in plants

Review Questions

• Why are plants important to study?
• What metabolism do plants have?
• How does photosynthesis occur?
• What are the plant's conductive vessels?
• What are stomata and what is their function?

Plant Classification

• Plants are classified into vascular and non-vascular categories

Non-Vascular Plants

• Includes Bryophytes
• Lack conductive vessels
• Examples are mosses and liverworts

Vascular Plants

• Include Pteridophytes, Gymnosperms, and Angiosperms
• Possess conductive vessels

Seedless Vascular Plants

• Includes Pteridophytes
• Reproduce via spores
• Examples include ferns

Seed-Bearing Vascular Plants

• Includes Gymnosperms and Angiosperms
• Reproduce via seeds

Gymnosperms

• Lack fruits
• Exhibit non-typical flowers
• An example is conifers

Angiosperms

• Bear fruits
• Further classified into monocotyledons and dicotyledons

Role of Seeds

• Seeds protect the embryo
• Allow it to remain dormant for extended periods
• Function independently of water sources
• Contain mechanisms for broad dispersion

Plant Nutrition Overview

• Plants nourish themselves autotrophically
• Accomplish synthesis of organic molecules for growth through photosynthesis
• Energy to functions come from cellular respiration

Phases of Plant Nutrition

• Absorption of water and mineral salts
• Transport of raw sap from roots to leaves
• Absorption of carbon dioxide
• Synthesis of organic matter via photosynthesis
• Transport of formulated sap from leaves throughout the plant
• Utilization of organic matter for: growth and cellular respiration
• Elimination of waste products

Absorption of Water and Mineral Salts

• Occurs in the root system
• Specifically via the absorbent hairs on root epidermis for surface area
• Water absorption: Water penetrates the root via osmosis
• Mineral salts absorption: Active transport moves nutrient-transporting proteins that use energy
• The result: Creation of raw sap
• Xylem’s role: It transports raw sap to the rest of the plant.

Raw Sap Transport

• Raw sap travels through the xylem from the roots to the leaves against gravity
• Transpiration: Water dissipates through stomata
• Capillary Action: Cohesion between water molecules, enabling movement
• Root Pressure: Osmotic pressure helps pushing water upwards.

Carbon Dioxide Absorption

• Stomata: Pores in leaf epidermis
• Guard cells: Regulate the opening and closing of the stomata
• Lenticels: Openings on stems facilitate gas exchange
• Absorbent hairs: Absorb dissolved gases in water

Photosynthesis

• Inorganic material (CO2 and H2O) transforms into organic matter (glucose) using the sun as source of energy which produces oxygen (O2)
• Occurs mainly in the green parts of plans
• Chloroplasts and photosynthetic pigments needed for capturing sunlight in the leaves

Photosynthesis Cycle: Light Phase

• Solar energy converts to chemical energy
• Water breakdown produces hydrogen and oxygen.
• Needs light

Photosynthesis Cycle: Dark Phase

• Inorganic matter transforms into organic material
• Uses energy from the light phase
• Doesn’t need light

Factors Affecting Photosynthesis

• Light intensity: Measured by photosynthesis rate
• CO2 and O2 concentration
• Temperature

Transport of Processed Sap

• Processed/ Formulated sap moves via the phloem to leaves and parts of the plant
• Translocation: Sap moves through the plant in this process/stage
• Sources: Areas that produce like glucose and amino acids
• Sinks: Utilization or consumption areas
• Sap moves from source to sink sites explained by the pressure flow hypothesis

Elimination of Waste Products

• Secretory epidermal tissues: Used by flowers, stems and leaves through glandular hairs
• Internal secretory: Produce Taponamiento substances for protection against pathogens
• Laticiferous tubules: Secrete latex
• Resiniferous tubules: Release resins

Plant Relationship

• Plants can identify stimuli, which causes reactions
• Plant features: No sensory functions
• Possess: Chemical release
• Hormonal and internal systems in plants

Plant Stimuli

• Light
• Temperature
• Humidity
• Gravity
• Physical interactions

Plant Response

• Morphogenesis: Physiological processes to create structural organs
• Movements: tropisms and nastias

Plant Hormones

• Auxins: Stimulate growth, formation of flowers/fruit and tropisms
• Gibberellins: Facilitate growth and germination
• Cytokinins: Encourage cell division and slows down aging
• Abscisic Acid: Inhibits the growth and germination of seeds
• Ethylene: Causes fruit maturity and leaf release

Movements

• Growth in responses to stimuli is defined by tropisms
• Temporary and non-growth responses explained as nastia

Types of Tropisms

• Phototropism(light)
• Chemotropism (chemical)
• Hydrotropism (water)
• Tigmotropism (mechanical)
• Geotropism (gravity)

Types of Nastias

• Seismonasty (mechanical)
• Photonasty (light)
• Thermonastia (temperature)

Plant Morphogenesis

• Includes seed germination to flowering