Plant Science Exam 2

What are the functions of the root?

• Nutrient and water absorption

• Anchorage and support

• Carbohydrate storage

• Photosynthesis - aeriel roots

• Hormone synthesis

What is the zone of maturation

Cells differentiate into different types of cells

What is the zone of elongation?

Allows the root to get deeper within the soil

What happens in the meristematic region?

Rapid mitosis of undifferentiated meristematic cells

What does the root cap do?

Protects the meristematic region

Which zone has the highest absorption capacity?

Zone of maturation

Which zone has the largest vacuoles in the cells?

Zone of elongation

What is plasmodesmata?

Thin strands of cytoplasm that act as channels; cytoplasmic bridge

What is symplast?

Continuum of cytoplasm

What is apoplast?

Areas of the plant outside cell membrane (cell wall and extracellular spaces)

What is the casparian strip?

Embedded within the cell wall of endodermal cells

Serves as a boundary layer, separating apoplast of the cortex tissue from apoplast of the vascular tissue, blocking diffusion of material between the two.

This separation forces water and solutes to pass through the cell membrane via a symplastic route in order to cross the endodermis layer

What type of root systems do dicots have?

Taproot system

What type of root system do monocots have?

Fibrous root system

What is the radicle?

Primary root; usually the first structure to emerge on germination

Where does the lateral root originate from?

The pericycle

Where do adventitious roots form?

On any part of the plant other than the radicle of a germinating seed or the roots

What is the casparian strip also known as?

Endodermis

What are the functions of the stem?

• Transport

  • water - xylem

  • nutrients - nutrients

  • metabolites - phloem

• Support

• Photosynthesis

• Storage

Characteristics of herbaceous dicots

1. vascular bundles separate and distinct

2. arranged in a single circle in the stem

   1. large part of stem is cortex and pith rather than xylem or phloem

Characteristics of woody dicot perennials

• primary tissue is apical meristem

• secondary tissue is vascular cambium

Which meristem is responsible for secondary growth

Vascular cambium

What forms annual growth rings in trees?

Secondary xylem

Characteristics of monocot stems

• vascular bundles are scattered throughout parenchyma

• sclerenchyma provide principal support to stem

• no continuous cambium, no secondary growth

What is the function of bark?

• Protect the plant from mechanical damage

• resistant to entry or loss of water

• exterior to the vascular cambium

• lenticels

What are lenticels?

Pores in the bark of young twigs or small trunks tha allow diffusion of gases

What is girdling?

The complete removal of a ring of bark from around a branch of the trunk of a tree.

How does girdling kill a tree?

It severs the phloem and essentially starves the tree

What are nodes?

points of attachment for leaves, aerial roots, and flowers

What are internodes?

The stem region between two nodes

What are the different types of modified stems?

• Spur

• Stolon

• Rhizome

• Corm

• Bulb

• Tuber

What is a bulb?

A highly compressed underground stem to which numerous storage leaves (scales) are attached

• onion, lilies, tulips

What is a bubil?

A small bulb usually formed in a leaf axil

What is a tuber?

An enlarged, fleshy, terminal portion of underground stem

• potato

What is another function of the stem?

Asexual reproduction

What are the functions of leaves?

• photosynthesis

• transpiration

  • modified leaves:

  • protection

  • support

  • storage

What is the stoma and its purpose?

A pair of guard cells and a pore used for gas exchange and water loss

What is transpiration?

Loss of water from the leaf by evaporation

• provides force that draws water into and through the xylem

• helps regulate leaf temperature

What are the different types of mesopyll?

Spongy and palisade

Do dicots or monocots have palisade mesophyll?

Dicots

T/F Mesophyll contains chloroplasts for photosynthesis

True

What is the air space in leaves used for?

• Gas exchange

• Water vapor

What is the vascular bundle composed of?

Xylem and phloem

Where is the vascular bundle contained?

In leaf veins

What are the different external leaf parts?

Blade, petiole, stipule

What is a petiole?

The stalk that attaches the leaf blade to the stem

What is a sessile?

Leaf without a petiole

What type of venation do monocot leaves have?

Parallel

What type of venation do dicot leaves have?

Web-like (branching or reticulate)

What is the midrib?

The central vein of the leaf

• provides leaf additional support

• vascular system for transport of water, nutrients, and metabolites

What are the parts of a leaf blade?

Margin, tip, base

What are the three leaf arrangements

Alternate, opposite, whorled

What is a simple leaf?

One leaf

What is a compound leaf?

A leaf with 3 or more leaflets

What are the different types of modified leaves?

• Bud scale

• Floral bract

• Sepal

• Spine

• Succulents

• Tendrils

• Cotyledons

What does a bud scale do, and where would you find them?

They protect the dormant apical bud, you can find them on woody plants

What is the purpose of floral bracts?

They protect the inflorescence during development and attract pollinators

Where would you find sepals?

Under the petals

What is the function of sepals?

They protect the flower during development

What are spines?

Leaves adapted for arid conditions

What are the functions of spines?

They reduce water loss and help protect plant from predators

What is a characteristic of succulents?

They use their leaves for water storage

What are tendrils?

Climbing and supporting vines

What is the purpose of cotyledon leaves?

They store food reserves for the seed

What are characteristics of asexual reproduction?

• One parent

• No fusion of gametes

• Offspring are genetically identical to parent (clones)

What are characteristics of sexual reproduction?

• Fusion of gametes

• Offspring are genetically different from parents

What is sexual reproduction with one parent called?

Self pollination

What is sexual reproduction with two parents called?

Cross pollination

What is a flower?

Floral leaves grouped together on a stem

What is an inflorescence?

A flower cluster

What are the four parts of a complete flower?

Sepal

Petal

Stamen

Pistil

What is a sepal?

Leaf-like structure that protects the flower bud

What is a petal?

Leaf-like structure that surrounds the reproductive structures

What are sepals collectively called?

Calyx

What are petals collectively called?

Corolla

What is the stamen?

The male repro structure

What does the stamen consist of?

Filament and anther

What does the anther produce?

Pollen

What is the pistil?

The female repro structure

What does the pistil consist of?

Stigma

Style

Ovary

What is a stigma?

A receptive surface which recieves pollen

What is the style?

Tube connected to stigma and ovary

What is the ovary?

It contain one or more undeveloped ovules

What type of plant flowers in multiples of three?

Monocots

What type of plants flower in groups of four or five?

Dicots

What is a complete flower?

A flower that has all four parts - petals, sepals, pistil, stamen

What is an incomplete flower?

Missing at least one part of the flower

What is a perfect flower?

A flower with both a stamen and a psitil

What is an imperfect flower?

A flower lacking the stamen or pistil

What is a staminate flower?

An imperfect flower lacking pistils

What is a pistillate flower?

An imperfect flower lacking a staman