Botany Final Exam Prep: Plant Reproduction and Fruits

Reproductive Structures

• Embryo sac (female gametophyte) consists of synergids, antipodal cells, polar nuclei, and an egg cell
• Synergids are involved in fertilization, while antipodal cells are variable in number and function
• Polar nuclei fuse to form a diploid central cell, which later becomes the endosperm
• Double fertilization occurs when one sperm fertilizes the egg, and the other sperm fertilizes the central cell

Flower Parts

• Petals: colorful, attractive structures that protect the reproductive organs
• Sepals: green, leaf-like structures that protect the flower bud
• Receptacle: the base of the flower that supports the other parts
• Stamen: composed of an anther (produces pollen) and a filament (supports the anther)
• Carpel: consists of stigma (receives pollen), style (connects stigma to ovary), and ovary (contains ovules)

Fruit

• Exocarp: outermost layer of the fruit
• Mesocarp: middle layer of the fruit
• Endocarp: innermost layer of the fruit
• Fruit types: simple, accessory, aggregate, and multiple

Seedlings

• Monocot vs. dicot: differences in cotyledon number, leaf structure, and root system
• Cotyledon: the first leaf that emerges from the seed

Root System

• Primary root: the first root that emerges from the seed
• Taproot: a main root that grows straight down
• Fibrous root: a system of branching roots
• Root hairs: increase the surface area for absorption
• Epidermis: the outermost layer of the root
• Root zones: root cap, zone of cell division, zone of elongation, and zone of differentiation
• Root types: prop roots, pneumatophores, strangling aerial roots, buttress roots, and storage roots

Shoot System

• Stem: composed of nodes, internodes, apical bud, and axillary buds
• Vascular bundle: a group of xylem and phloem tissues
• Cortex: the outer layer of the stem
• Pith: the inner layer of the stem
• Vascular cambium: produces secondary xylem and phloem tissues
• Cork cambium: produces cork tissue
• Wood (secondary xylem) and bark (secondary phloem + periderm) are produced by the vascular cambium

Stem Modifications

• Stolons: stems that produce new plants at the tips
• Tubers: swollen stems that store food
• Rhizome: a horizontal underground stem
• Bulbs: underground stems that store food
• Thorns: modified stems that defend the plant

Leaf Structure

• Blade: the flat part of the leaf
• Petiole: the stalk that attaches the leaf to the stem
• Veins: composed of xylem and phloem tissues
• Parallel veins: found in monocots
• Branched veins: found in dicots
• Cuticle: a waxy layer that prevents water loss
• Stomata: openings for gas exchange
• Guard cells: control the opening and closing of stomata
• Palisade and spongy mesophyll: layers of cells involved in photosynthesis

Leaf Modifications

• Spines: modified leaves that defend the plant
• Tendrils: modified leaves that climb
• Storage leaves: modified leaves that store food
• Reproductive leaves: modified leaves that produce new plants

Plant Tissues

• Dermal tissue: epidermis, cuticle, periderm, and trichomes
• Vascular tissue: xylem and phloem
• Ground tissue: pith, cortex, and other tissues

Plant Growth

• Determinate growth: limited growth, reaches a fixed size
• Indeterminate growth: unlimited growth, continues to grow
• Primary growth: growth in length, produced by apical meristem
• Secondary growth: growth in width, produced by vascular cambium and cork cambium
• Early wood and late wood: produced by the vascular cambium
• Annual rings: growth rings produced by the vascular cambium
• Heartwood and sapwood: areas of the stem with different functions
• Meristem: a region of undifferentiated cells that can differentiate into different tissues