Fruits, Seeds, Germination

Fruits, Seeds, Germination

• Fruit is defined and the parts of the pericarp include exocarp, mesocarp and endocarp

Methods of Seed Dispersal

• Wind dispersal uses dandelions and willow herb as an example
• Animal dispersal uses fleshy fruits like oranges and pears as an example
• Water dispersal uses coconuts as an example
• Gravity dispersal uses some beans and peas as an example
• Mechanical dispersal uses exploding seed pods as an example

Seed Germination

• Germination involves imbibition, activation of enzymes, and radicle emergence
• There are two types of germination: hypogeous and epigeous
• Germination is affected by water, temperature, light and oxygen

Seed Dormancy and Breaking Dormancy

• Dormancy can be physical, physiological, or a double dormancy
• Dormancy can be broken by scarification, stratification, and after-ripening

Seed Certification and Storage

• There are four levels of seed certification: Breeder's Seed, Foundation Seed, Registered Seed, and Certified Seed
• Certified seeds are important in agriculture
• Seed storage methods include cryopreservation and simple dry storage

Plant Cells and Function

• A cell is considered the basic unit of life
• Cells can be differentiated by prokaryotic and eukaryotic cells

Differences Between Plant and Animal Cells

• Plant cells have key distinguishing features like a cell wall, chloroplasts, and a large vacuole,
• Both plant and animal cells have cell membranes, nuclei, cytoplasm, and mitochondria

Cell Organelles and Their Functions

• Nucleus stores DNA, controls cell functions
• Mitochondria generates energy for the cell
• Ribosomes produce of proteins
• Golgi Apparatus packages and transports proteins
• Endoplasmic Reticulum (Smooth and Rough) – Assists in protein and lipid production
• Vacuole stores materials (larger in plant cells)
• Lysosomes break down waste (mainly in animal cells)
• Cytoplasm supports and surrounds organelles
• Cell Membrane regulates entry and exit of materials
• Cell Wall (Plants Only) provides support and protection
• Chloroplasts (Plants Only) conduct photosynthesis

Functions of the Cell Membrane

• Cell membrane acts as a "toll booth" controlling material movement through its phospholipid bilayer and embedded proteins

Energy Production in Cells

• Mitochondria are key in breaking down fats and carbohydrates
• Chloroplasts contribute to photosynthesis in plants

Cellular Storage and Waste Management

• Plant and animal vacuoles differ
• Lysosomes play a role in cellular digestion

Water Transport

• Water is important for cell function, photosynthesis, and structural support
• Water also acts as a solvent and transport medium

Plant Vascular System

• Xylem transports water and minerals from roots to shoots
• Phloem distributes photosynthetic products
• Cohesion, adhesion, and capillary action facilitate water movement

Transpiration

• Transpiration is defined as, and plays a role in, water movement
• Transpiration is explained by the cohesion-tension theory
• Factors like temperature, humidity, wind, light intensity affect transpiration rates
• Transpiration can be stomatal, cuticular, and lenticular

Regulation of Transpiration

• Stomata open and close to regulate transpiration
• Potassium ions play a role in guard cell movement
• CAM photosynthesis is an adaptation in desert plants

Mineral Requirements for Plant Growth

• Macronutrients include: Nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur
• Micronutrients include: Iron, manganese, zinc, copper, boron, molybdenum, nickel, and chlorine
• Deficiency symptoms impact plant health

Leaves

• Parts of a leaf include blade (lamina), petiole, veins, and midrib
• Leaf margins, tips, and bases vary
• Venation types can be parallel, pinnate, or palmate

Internal Leaf Structure

• Stomata regulate gas exchange
• Mesophyll layers include palisade and spongy mesophyll
• Chloroplasts play a role in photosynthesis

Leaf Functions

• Leaves facilitate photosynthesis and energy storage
• Transpiration and water regulation occur in leaves
• Gas exchange occurs via stomata
• Leaves can be modified for storage and support

Leaf Identification and Classification

• Leaves can be simple or compound
• Venation can be parallel or net
• Leaf shapes and their functions vary

Leaf Modifications and Adaptations

• Spines aid in water retention(e.g., cacti)
• Tendrils are for climbing support
• Trichomes protect against herbivores
• Floating leaves are aquatic adaptations

Economic Uses of Leaves

• Food sources include spinach, lettuce, and kale
• Medicinal plants include foxglove and St. John's wort
• Fiber production uses sisal rope
• Dyes and pigments include henna and indigo
• Building materials and barriers use bamboo and thatch

Leaf Response to Environmental Factors

• Wilting occurs due to drought
• Leaf abscission occurs in seasonal changes
• Temperature affects leaf physiology
• Air pollution affects leaf structure

Roots

• Roots absorb water and minerals
• Roots provide anchorage and stability
• Roots store carbohydrates and nutrients

Root Systems

• Taproot systems include carrots and radishes
• Fibrous root system include grasses and wheat
• Adventitious roots include banyan tree and poison ivy
• Aquatic roots include water lilies

Regions of Root Growth

• Root cap protects the growing root tip
• Region of cell division actively divides cells
• Region of elongation expands cell length
• Region of maturation differentiates cells into specialized tissues

Root Modifications

• Storage roots include beets and cassava
• Prop roots include mangroves and corn
• Contractile roots include dandelions and lilies
• Aerial roots include orchids
• Buttress roots are in tropical trees

Comparison of Monocot and Eudicot Roots

• Monocots have a fibrous root system with scattered vascular bundles
• Eudicots have a taproot system and ring-like vascular bundles

Stems

• Stems support the plant structure
• Stems transport water and nutrients (xylem & phloem)
• Stems store carbohydrates and nutrients
• Some stems conduct photosynthesis

Stem Structure and Growth

• External structures include terminal bud, node, internode, lateral bud, lenticels, and leaf scars
• Internal structures include xylem, phloem, vascular cambium, pith, and cortex
• Primary and secondary growth differ
• Cambium increases girth

Vascular Tissue Organization

• Monocot and Eudicot stems differ in arrangement
• Vascular bundle patterns are scattered in monocots and ring-like in eudicots
• Vascular cambium is important in secondary growth

Stem Classification

• Stems can be herbaceous or woody
• Stems can be monocots or eudicots
• Stems can be perennial or annual
• Stems can be vines or trees

Stem Modifications and Specialized Stems

• Rhizomes include ginger and iris
• Stolons/runners include strawberries
• Tubers include potatoes
• Bulbs include onions
• Corms include gladiolus
• Thorns, spines, and prickles are for defense

Stem Adaptations and Bark

• Bark protects woody stems
• Lenticels facilitate gas exchange
• Tree rings form and determine age
• Woody plants are important in ecosystems

This lesson covers the structure of fruits, methods of seed dispersal (wind, animal, water, gravity, mechanical), the process of seed germination including factors affecting it, types of seed dormancy and methods of breaking dormancy. It also touches on seed certification and storage.