Plant Structure Flashcards
Plant response to land
Differentiation Plasticity (change form and structure) Acclimation Adaptation Modular indeterminant growth (can keep growing indefinitely)
Blade
Flat part of leaf
Petiole
Connection between leaf and stem
Taproot
Main part of root
Extends downward into soil
Penetrates deeply
Lateral roots
Extensions of main root
Extend outward
Node
Part of branch from which a leaf or a new stem can grow
Point at which leaf is attached to stem
Looks like a small bud
Internode
Stem segments between nodes
Axillary bud
Bud from which a branch can grow
3 main plant organs
Roots
Stem
Leaves
Adventitious roots
Roots that develop from stems or even leaves
Specialized
Root hairs
Absorption rather than anchorage
Prop roots
Soggy areas: extra support to prevent plant from falling over
Storage roots
Plants like beets use these for storage of food and water
“Strangling” aerial roots
Snakelike roots that wrap around host tree
Plant germinates in the branches of host tree
Buttress roots
Extend above soil, which is shallow
Give plant extra support
Pneumatophores
Structures that grow up from water
Obtain oxygen
Apical bud
Top budding of plant
If cut off, plant grows out instead of up
Rhizome
Horizontal shoot that grows just below the surface
Bulb
Vertical underground shoots consisting of enlarged bases of leaves that store food
Stolon
Horizontal shoots that grow along the surface
Reproduction: each outgoing can become new plant
Tuber
Enlarged ends of rhizomes or stolons that store food
Tendrils
Leaves that wrap around other things for support
Spines
Modified leaves found on desert plants
Storage leaves
CAM plants
Adapted for storing water
Reproductive leaves
Maternity plant: each little leaf along big leaf can start a new plant (asexual reproduction)
Bracts
Brightly colored leaves found on poinsettias
Attract pollinators
3 plant tissue types
Ground
Dermal
Vascular
Ground tissue
Bulk of cells
Functions: photosynthesis, storage, support
Pith
Ground tissue that is internal to vascular tissue
Cortex
Ground tissue that is external to vascular tissue
Dermal tissue
Epidermal cells, periderm (bark), cuticle (waxy part)
Functions: covers, protects, gas exchange
Includes root hair, trichomes, and guard cells
Trichomes
Leaf hairs
Provide defense against insects
Guard cells
Surround stomata- allows CO2 to go into leaf
Vascular tissue
Xylem and phloem
Functions: transport and support
Xylem
Vascular tissue that transports H2O from roots to leaves Dead at maturity Secondary cell walls Ring or spiral pattern Pits/perforation plates
Phloem
Vascular tissue that transports sugar from leaves to roots
Stele
Vascular tissue of root or stem
Vascular bundles
Separate strands containing xylem and phloem
Comprise steles of stems and leaves
Meristem
Perpetually embryonic tissue
Stem cells: can grow into any part of plant
Apical meristem
Tips of roots and shoots Tissue types arise from specific regions Primary growth (elongation)
Protoderm
Meristem region that gives rise to epidermis
Procambium
Meristem region that gives rise to phloem/xylem
Ground meristem
Meristem region that gives rise to ground tissue
Lateral meristem
Secondary growth (thickening)
Vascular cambium
Adds secondary xylem and phloem- thickening
Root cap
Protects apical meristem as root pushes through soil
Located at bottom of root
Zone of cell division
Portion of root that contains apical meristem and its derivatives
Area where new root cells are produced
Located at bottom of root
Zone of elongation
Located at midsection of root
Area where growth occurs as root cells elongate
Zone of differentiation
Located at top of root
Area where cells complete differentiation and become distinct cell types
Xylem and phloem form
Secondary growth
Secondary phloem is added to the outside of the vascular cambium and the inside of the primary phloem
Secondary xylem is added to the inside of the vascular cambium and the outside of the primary xylem
Vascular rays
Radial files of mostly parenchyma cells that connect the secondary xylem and phloem
Early wood
Wood that consists of secondary xylem cells with relatively large diameters and thin cell walls
Maximizes delivery of water to new leaves
Late wood
Wood composed of thick walled cells
Don’t transport as much water, but provide more support
Rings of trees
Layer of xylem
Show age of tree
Differences between eudicots and monocots
Roots: eudicot has xylem and phloem in the center; monocot has parenchyma in center
Stems: eudicot’s vascular bundles form a ring; monocot’s vascular bundles are scattered throughout
Central vacuole
Storage compartments of plant cells
Plasmodesmata
Channels connecting each plant cell to its neighbor
3 plant cell types
Parenchyma
Collenchyma
Sclerenchyma
Parenchyma
Least specialized of plant cell types Thin primary cell wall (no secondary) Large vacuole Photosynthesis and storage Phloem= specialized example of cell type
Collenchyma
“Strands”- celery
Thickened primary walls (no secondary or lignin)
Support for growing tissues
Sclerenchyma
Thickened secondary wall Lignin- hard, rigid polymer Cells are dead upon plant maturation Fibers (hemp) Sclerids (nut shells, gritty parts of pears) Xylem- specialized example of cell type
Tracheids
Type of xylem
Tapered, elongated cells
Found in angiosperms and gymnosperms
Vessels
Type of xylem
Long tubes that grow end-to-end
Good at conducting water
Found in angiosperms only
Sieve tubes
Long tubes in phloem of angiosperms through which nutrients are transported
Sieve plates
End walls between sieve tubes
Have pores that facilitate the flow of fluid from one tube to another
Companion cells
Connected to sieve tubes by plasmodesmata
Assist functions of sieve tubes
Layers of leaf
Upper epidermis
Palisade mesophyll (columnar and stacked side by side)
Spongy mesophyll (scattered throughout)
Lower epidermis
