Plant Structure, Growth, and Development Flashcards
What are some basic characteristics of ALL plants?
- multicellular
- photosynthetic
- adapted to land existence (vertical growth, protection from desiccation)
- share a common ancestor with green algae (charophytes) THINK CHARA
What are the two major groups of angiosperms?
monocot and eudicots
What are some characteristics of a monocot in regards to embryos, leaf venation, stems, roots, pollen and flowers?
one cotyledon
parallel veins
Scattered vascular tissue
fibrous root system (no main root)
pollen grain w/ one opening
floral organs in multiples of three
What are some characteristics of a eudicot in regards to embryos, leaf venation, stems, roots, pollen and flowers?
two cotyledons
net-like veins
vascular tissue arranged in rings
taproot (main root) usually present
pollen grain w/ three openings
floral organs in multiples of four or five
What are the three basic plant organs?
roots, stems, and leaves
What is the basic morphology of vascular plants?
organisms that draw nutrients froms the ground and above the ground.
What are the two systems that the roots, stems, and leaves are divided into?
Shoot system - leaves and stem
Root system - root
What are the functions of roots?
anchor plant
absorb minerals and water from soil
stores carbs and other reserves
What is the first root to emerge?
the primary root
What branches from the primary root? What do these do?
lateral roots
these improve anchorage and improve water absorption
What is the difference in the root system that a tall plant would have versus a smaller plant?
Tall: have a TAPROOT system that has a large taproot that prevents the plant from toppling and lateral roots that stem from it that are responsible for absorption
Short: have a FIBROUS root system which consists of adventitious roots that arise from stems or leaves, lateral roots arise from these adventitious roots
Where does most of the absorption occur in roots?
Near the tips of the roots, called the root hairs.
These help to increase the surface area of roots.
What are some specializations of roots (5)?
Prop roots - support tall, heavy plants (corn)
Storage roots - (beets)
Pneumatophores - gas exchange for plants that grow in water (mangroves)
aerial roots - climbing, capture moisture in the air or perform photosynthesis, wrap around host in some cases, killing it.
buttress roots - for plants w/ shallow root systems to help w/ support
What is a stem made up of?
This is an alternating system of nodes and internodes.
Nodes are where leaves attach and internodes are the segments between the nodes
What is the tip of the shoot that grows in an elongating direction?
The apical bud
What is an axillary bud?
this is a structure that has the potential to form a lateral branch, thorn, or flower.
What are the 3 specializations of stems?
Rhizomes (root-like) - Underground, horizontal stems
Stolons - aboveground, horizontal stem (strawberry plant), grow along surface and allow plant to reproduce asexually
Tubers - Storage stems (potatoes), enlarged ends of rhizomes or stolons that store food
What are the basic functions of leaves?
The main photosynthetic organ
exchange gases with atmosphere
dissipate heat
defend themselves against herbivores and pathogens
What attaches the leaf to the stem at an axillary bud?
petiole
What is the flattened portion of a leaf called?
the blade
Leaves have vascular tissue that run throughout them, what is the difference of the veins in a monocot and a eudicot?
monocot - parallel veins
eudicot - branching veins
What are some ways that taxonomists will classify angiosperms based on leaf morphology?
simple leaves vs compound leaves
Simple: have a single undivided blade
Compound: have multiple leaflets branching off of petiole
What are 4 specializations that leaves have?
- Spines - perform photosynthesis (cactus)
- Tendrils - support (pea plant), coils around support and brings plant closer to the support
- Reproductive leaves - some make plantlets that fall to soil and take root
- Storage - onions have modified leaves that store food
What are the three tissue systems that are continuous throughout the entire plant (from inside to outside)?
Vascular, ground, and dermal
What is the function of the dermal tissue system?
forms the outer protective covering of a plant
first line of physical defense
What are some modifications of the dermal tissue system?
epidermis - found in NONWOODY plants, epidermal cells closely packed together, exposed to air and covered w/ WAXY CUTICLE which protects them from water loss
Periderm - found in WOODY plants which replaces the epidermis in older regions of stems and roots
Root Hairs - increase surface area of root for water absorption
Trichomes - Protect plant from sun and moisture loss, also discourages herbivory
Guard Cells - control the leaf stomata
What is the basic function of the vascular tissue system of a plant?
to transport materials through the plant and provide mechanical support.
What are the two types of vascular tissue and their basic functions?
Xylem - conducts water and dissolved material upwards from roots to shoots.
Phloem - Transports sugars from where they are made to where they are needed.
What is the name for the COLLECTIVE name for vascular tissue of a root or stem?
Stele
In stems and leaves, what are the steles divided into?
What about in roots?
vascular bundles - separate strands that contain xylen and phloem.
Vascular cylinder
What is the main function of the ground tissue system?
These forms the bulk of the plant
Undergo differentiation - meaning they become specialized in their structure and function during the course of their development, some functions include storage, photosynthesis, support, and transport.
What are the two types of ground tissue, where is it located in regards to the vascular tissue?
Internal to vascular tissue is PITH
external to vascular tissue is CORTEX
What are some of the common types of plant cells that we covered in class?
Parenchyma
Collenchyma
Sclerenchyma
- Sclereids - Fibers
Xylem
- Tracheids - Vessel Elements
Phloem
- Sieve plates - Companion cells
Describe the structure and function of a parenchyma cell.
Have thin and flexible primary walls
least specialized, able to divide and differentiate
most abundant
perform photosynthesis and other metabolic functions
Describe a collenchyma cell and its structure and function.
thicker primary walls
flexible support for immature organs
grouped into strands
help support young parts of the plant shoot
STRANDS OF CELERY ARE EXAMPLE
What are the general characteristics of a sclerenchymal cell?
Describe the structure and function of the two types of sclerenchyma cells
These have thick SECONDARY walls that are strengthened with LIGNIN (an indigestible polymer)
They are NONLIVING at maturity
They support major regions of the plant
Sclereids - short and irregular shaped, have thick lignified secondary walls
fibers - long and slender and arranged into threads.
What are two types of xylem cells and some characteristics? What is their primary function?
Water-conductor cells
BOTH DEAD AT MATURITY
Tracheids - found in xylem of all vascular plants
Vessel elements - most angiosperms have this, some gymnosperms. these cells align from end to end forming VESSELS (long micropipes)
Describes the cells of the phloem and their function, describe sieve plates and companion cells.
These cells make up the SIEVE TUBES
LACK ORGANELLES (retain ribosomes and nucleus)
sugar-conducting cells have sierve tube elements (tube which things travel)
sieve-plates - porous end walls that allow for the flow of fluid between cells in sieve tube.
Every sieve tube element has a companion cell whose nucleus and ribosomes serve both cells, contents travel between cells through plasmodesmata.
What is the difference between determinate and indeterminate growth?
What are the tissues that lead to indeterminate growth?
Indeterminate growth allows for a plant to grow throughout its life while determinate growth ceases growth at a certain size.
Meristems ( tissue which cells are always dividing by mitosis)
What are the two types of meristems, their location and their main function?
Apical meristems - found in tips of roots and shoots, involved in primary growth (length)
Lateral meristems - vascular cambium and cork cambium, involved in secondary (thickness) growth
In regards to the vascular cambium (lateral meristem), what does it create when it grows?
secondary xylem (wood) and secondary phloem
In regards to cork cambium (lateral meristem), what tissue is made when it grows?
Replaces the epidermis with periderm, a thicker and tougher tissue.
LOOK AT PICTURE OF PRIMARY AND SECONDARY GROWTH IN 35.2
DO IT NOW
What are the tips of roots covered by? What are the functions of this?
Root cap - this protects the apical meristem as it pushes through the soil.
What are the three zones of growth that are behind the ROOT CAP (primary growth in roots) starting from closest to cap to furthest.?
Zone of cell division (includes apical meristem) - new root cells produced for root as well as for the cap
Zone of elongation - cells elongate (up to 10x their original length), cells also begin to specialize in this location.
Zone of differentiation - Also called zone of maturation, this is where cells complete their differentiation and become distinct.
What are the three main products of primary growth in roots?
epidermis
ground tissue
vascular tissue
In angiosperm roots, the stele (collective name of vascular tissue) is a vascular cylinder that includes the xylem, phloem and pericycle. What shape does the xylem take in eudicots? Where is the phloem located?
A “starlike” shape.
The phloem is located between the arms of the xylem.
In monocot roots (angiosperm), what does the xylem and phloem look like in the vascular cylinder?
There is a core of parenchymal cells surrounded by a ring of xylem, then a ring of phloem.
Also has pericycle surrounding this
What do we need to know about the pericycle OF ROOTS?
Lateral roots arise from the pericycle and extend through the cortex and break through the epidermis
IN ROOTS, The Cortex is the thick area that surrounds the vascular cylinder, what cells does the thick portion comprise of mostly? What is the innermost portion of the cortex called and what does it do? The cortex and the endordermis together make up what tissue layer?
Parenchymal cells
Endodermis - regulates the passage of substances from the soil into the vascular cylinder
Ground tissue
When describing the tip of a SHOOT, where do the leaves develop from? where are these located?
Leaf primordia
These are located next to the apical meristem.
At the SHOOT tip, what do the axillary buds form from?
These are made from leftover meristematic cells left at the bases of the leaf primordia.
Describe apical dominance. How can this be combated?
This is the effect that active apical buds have on axillary buds when they are in close proximity. the closer together they are the more the apical bud inhibits the growth of the axillary bud.
Axillary buds can grow if the shoot tip is removed or shaded (made inactive)
EXAMPLE OF THIS IS WHEN A BUSH IS TRIMMED AND MORE LATERAL BRANCHES GROW.
What was said in the powerpoint in regards to meristematic activity in some monocots?
Some of them have their meristematic activity located at the BASES of their stems and leaves.
In SHOOT STEM tissue organization, how would you describe the difference in vascular arrangement of eudicots vs monocots?
Eudicots - vascular bundles form a ring between the pith and the cortex.
monocots - vascular bundles are scattered throughout the ground tissue.
What are the stoma of leaves, what is their function? How is their opening and closing regulated?
Stomata are pores in leaves that allow gas exchange between the air and photosynthetic cells.
These are also the major means as to how water is lost by evaporation.
Each stomata is flanked by two guard cells that regulate its opening and closing.
What makes up the ground tissue of LEAVES?
How is it divided and what are the functions of each division?
THe MESOPHYLL
Palisade mesophyll - one or more layers of elongated parenchymal cells
Spongy mesophyll - below the palisade mesophyll, loose arrangement of parenchymal cells that allow for gases to circulate, particularly in areas near a stomata.
What are the veins of the leaf?
These are the vascular tissue bundles of the leaf and are continuous to the vascular system of the stem. Leaf veins are covered by a bundle-sheath (ground tissue)
Where does secondary growth occur?
lateral meristems in the stems and roots of woody plants (eudicots), rarely occurs in leaves, doesnt occur in monocots.
Do both monocots and eudicots undergo secondary growth?
JUST EUDICOTs
and gymnosperms
What are the two types of cambium that produce tissues for secondary growth?
vascular cambium and cork cambium
Do primary and secondary growth occur at separate times?
NO, they occur simultaneously.
Reference for secondary growth in woody plants?
35.4 picute in powerpoint.
Describe the vascular cambium and its function (secondary growth).
This is a cylinder of meristematic cells that is one layer thick.
produces the secondary vascular tissue (xylem inside and phloem outside)
Describe the cork cambium and its function (secondary growth).
Develops cork cells that accumulate to the outside of the cambium.
What is the function of cork cells?
Cork cells deposit waxy SUBERIN in their walls, then they DIE.
Cork cambium and cork cells it produces makes up the periderm.
What do lenticels in the periderm do?
these allow for gas exchange between stem or root cells and environment.
What does bark consist of?
all tissues external to the vascular cambium:
Includes secondary phloem and periderm (cork cambium and cork)
Describe how plant cell expansion works and the role of cellulose microfibrils.
The intake of water in vacuoles elongates cells, primarily along their primary axis (vertically)
cellulose microfibrils restrict the direction of the cells elongation
What is the understanding of plant phase changes (juvenile to adult) and how it typically looks on a plant.
These phases occur in the shoot apical meristem, typically you can tell between these phases in changes in morphology of the leaf size and shape.
What phase change occurs for flowering to occur? What causes this? What genes control this?
vegetative growth phase to reproductive growth phase.
Internal signals and environmental cues.
Meristem identity genes
What are the four structures of a flower and how does a primordium earn its fate?
sepal - petal - stamen - carpel
A primordiums fate is decided in the order of their emergence
Organ identity genes are responsible for the development of a floral pattern, what are the three classes of organ identity genes and which of the four flower structures they produce?
What is the rule for if A or C gene is missing?
A, B, and C
A - sepal and petal
B - peral and stamen
C - stamen and carpel
sepal - A
petal - AB
stamen - BC
carpel - C
If A or C gene is missing they will replace each other. BE ABLE TO UNDERSTAND HOW MISSING EACH OF THESE GENES WILL EFFECT THE 4 PLANT STRUCTURES
Normal - sepal - petal - stamen - carpel
