Vascular Plant Anatomy

Flashcards for Vascular Plant Anatomy Slides

Cell

the fundamental unit of life

tissue

a group of cells consisting of one or more cell types that together perform a specialized function

organ

consists of several types of tissues that together carry out particular functions

Three basic organs evolved to facilitate efficient resource acquisition:

roots, stems, and leaves

Roots, stems, and leaves are organized into a — system and a — system

root; shoot

The shoot system includes

stems and leaves

Roots rely on — produced by — in the — system

sugar; photosynthesis; shoot

Shoots rely on — and — absorbed by the — system

water; minerals; root

A root is an organ with important functions:

• Anchoring the plant

• Absorbing minerals and water

• Storing carbohydrates

The — root is the first to emerge from the seed

primary

— — branch off from the primary root improving anchorage and water absorption

Lateral roots

Tall plants with large shoot masses generally have this type of root system

taproot system

The — usually develop from the primary root and functions in anchoring the plant in soil

taproot

absorption primarily occurs the tips of the

lateral roots

Root hairs

finger-like extensions of epidermal cells that increase the absorptive surface of the root

Absorption of water and minerals typically occurs through the — — that grow near the — —

root hairs; root tips

— increase mineral absorption in most plants

Mycorrhzial associations which are symbiotic interactions with soil fungi

Stem

a plant organ bearing leaves and buds

The stem functions to

elongate and orient the shoot to maximize photosynthesis

Stems consist of an alternating system of — and —

nodes; internodes

Nodes

the points at which leaves are attached

Internodes

the stem segments between nodes

apical bud (meaning and what does it do)

the growing shoot tip; causes elongation of a young shoot

axillary bud

a structure that has the potential to form a lateral branch, thorn, or flower

leaf

the main photosynthetic organ of vascular plants

Role of leaves

Leaves intercept light, exchange gases, dissipate heat, and defend against herbivores and pathogens

A leaf generaly consists of a flattened — and a stalk, the —, which joins the leaf to the stem

blade; petiole

Monocots and eudicots differ in the arrangement of —, the vascular tissue of leaves

veins

Most monocots have — veins

parallel

Most eudicots have —

branching

Leaf shape may be — or —

simple; compound

Roots, stems, and leaves are composed of three tissue types:

dermal, vascular, and ground tissues

Each of the three tissue types (dermal, vascular, and ground) forms a — — that is continuous throughout the plant

tissue system

— — serves as a protective outer coating

Dermal tissue

In nonwoody plants, dermal tissue is usually a single tissue layer called the

epidermis

A waxy — covers the — and protects leaves and most stems from water loss

cuticle; epidermis

periderm

a protective layer that replaces the epidermis in older regions of woody stems and roots

Guard cells

specialized dermal cells that facilitate gas exchange in shoots

Trichromes

hairlike outgrowths of epidermal cells that help reduce water loss, reflect light, and defend against insects

— — facilitates the transport of materials through the plant and provides mechanical support

Vascular tissue

— conducts water and dissolved minerals upward from roots into the shoots

Xylem

— transports sugars from where they are made (primarily leaves) to actively growing parts of the plant or storage structures

Phloem

The vascular tissue of a root or stem is collectively called the —, arrangement varies by species and organ

stele

Ground Tissue

Tissue that are neither dermal nor vascular

Pith

Ground tissue internal to the vascular tissue

Cortex

Ground tissue outside the vascular tissue

Ground tissue includes cells specialized for

storage, photosynthesis, support, and short-distance transport

During development, plant cells undergo cell differentiation:

specialization in structure and function

The major types of plant cells are:

1. Parenchyma

2. Collenchyma

3. Sclerenchyma

4. Water-conducting cells of the xylem

5. Sugar-conducting cells of the phloem

Mature parenchyma cells characteristics:

• have thin and flexible primary walls

• generally lack secondary walls

• have a large central vacuole

• perform most of the metabolic functions

• retain the ability to divide and differentiate

Collenchyma Cells characteristics

• they are grouped in strands and help support young parts of the plant shoot

• they have unevenly thickened primary cell walls

• they are living at maturity

• these cells provide flexible support without restraining growth

Sclerenchyma Cells Characteristics

• Sclerenchyma cells are rigid cells with secondary cell walls containing lignin, a strengthening polymer, for support

• many are dead at maturity; the rigid cell walls remain to support the plant

• two types of sclerenchyma cells are specialized entirely for support and strengthening: sclereids and fibers

Sclereids

Type of sclerenchyma cell that is boxy and irregular in shape and has very thick, lignified secondary walls

Fibers

long, slender, are tapered and grouped in strands

Water-Conducting Cells that are dead at maturity have — secondary cell walls for plant support

lignified

Tracheids

long, thin, tapered cells found in the xylem of all vascular plants

Vessel elements

wider, shorter, and thinner than tracheids; align end to end to form long pipes called vessels

Most —, and a few — and — — — have vessel elements

angiosperms; gymnosperms; seedless vascular plants

Sugar-conducting cells of the phloem are — at maturity, but — a nucleus, ribosomes, vacuole, and elements of the cytoskeleton

alive; lack

In seedless vascular plants and gymnosperms, sugars are transported through

sieve cells

In angiosperms, sugars are transported in — —, which are chains of cells that are made up of — —

sieve tubes; sieve-tube elements

Porous end walls between sieve-tube elements that allow fluid to flow between cells

Sieve plates

Each sieve-tube element is connected to a — — by numerous plasmodesmata

companion cell

The — and — of the companion cell also serve the sieve-tube element

nucleus; ribosomes

indeterminate growth

when a plant can grow throughout its life

Meristems

undifferentiated tissues composed of dividing cells; continuous plant growth is possible due to the activity of these

determinate growth

this happens in most animals and some plant organs; it when the growth ceases at a certain size

There are two main types of meristems:

apical meristems and lateral meristems

apical meristems (location and definition)

located at the tips of roots and shoots; their cells allow for the elongation of shoots and roots, a process called primary growth

elongation of roots and shoots

primary growth

Cells displaced from the meristem give rise to three tissue called — — that will produce mature tissues

primary meristems (protoderm, ground meristem, and the procambium)

The protoderm produces

dermal tissue

the ground meristem produces

ground tissue

the procambium produces

vascular tissue

Lateral meristems

allow the stems and roots of woody plants to grow in circumference, a process called secondary growth

secondary growth

growth of the circumference of the stems and roots of woody plants; allowed by lateral meristems

There are two lateral meristems:

• vascular cambium

• cork cambium

vascular cambium

adds vascular tissue called secondary xylem (wood) and secondary phloem

Cork cambium

replaces the epidermis with thicker, tougher periderm

Lateral meristems in woody plants also have — —, which give rise to secondary growth

stem cells

In herbaceous plants, most of the plant consists of — growth; in woody plants, only new, non-woody parts represent — growth

primary

Root cap

covers the root tip to protect the apical meristem and polysaccharide slime lubricates the passage as the root pushes through soil

Growth occurs just behind the tip, in three zones:

zone of cell division, zone of elongation, and zone of differentiation/maturation.

the primary growth of roots produces the

epidermis, ground tissue, and vascular tissue

the outermost primary meristem; it gives rise to the epidermis

protoderm

—, which are epidermal cells modified for absorption, make up 70-90% of the total root surface area

root hairs

Between the protoderm and the procambium is the — —, which produces the ground tissue

ground meristem

Ground tissue, mostly — —, makes up the region between the vascular tissue and the epidermis

parenchyma cells

Cortex

the region between the vascular tissue and the epidermis

Endodermis

the innermost layer of the cortex; it regulates passage into and out of the vascular cylinder

procambium

the innermost primary meristem; it gives rise to the central vascular cylinder

pericycle

a cell layer that surrounds the solid core of xylem and phloem in the vascular cylinder

in most —, the xylem has a starlike appearance in cross section with phloem between the “arms”

eudicots

in many —, a core of parenchyma cells is surrounded by alternating rings of xylem and phloem

monocots

Lateral (branch) roots arise from the — and destructively push through the outer tissues

pericycle

Branching is a form of

primary growth

The stem is covered by the

epidermis and a waxy cuticle

The ground tissue is composed primarily of

parenchyma cells

— & — cells strengthen and support the stem

Collenchyma; sclerenchyma

Emerging shoots do not damage stem issues unlike

lateral roots