Exam Review 4

Alternation of Generations

a pattern of reproduction occurring in the life cycles of lower plants. the generations are alternately sexual and asexual (as in ferns)

Apical Meristem

a region of cells capable of division and growth in the root and shoot tips in plants.

What characteristics do charophytes share with land plants?

both contain carotenoids and chlorophyll a and b

both store carbohydrates as starch.

What are examples of derived traits in plants?

alternation of generations

multicellular dependent embryos

walled spores produced in sporangia

multicellular gametangia

apical meristems

What are the four extant phyla of gymnosperms?

Coniferophyta, Cycadophyta, Gnetophyta, Ginkgophyta

Characteristics of Coniferophyta

Perennial woody plants with secondary growth

Cone bearingC

Characteristics of Cycadophyta

Resemble palms but have cones

Large compound leaves

Slow growing, found in tropical regions

Sago palm, cycas, zamia

Characteristics of Gnetophyta

Very diverse (though small) phylum

Only gymnosperms with vessels in their xylem

Vessel elements resemble angiosperms, but DNA analysis suggests relatedness to conifers

Ephedra viridis - Mormon tea, gnetum gnemon, welwitschia mirabilis

Characteristics of Ginkgophyta

Ginkgo biloba - only living species

Male and female reproductive structures form on different trees

High resistance to pollution

Characteristics of Angiosperms

Have flowers or fruits to protect seeds

Characteristics of Gymnosperms

Have no flowers or fruits, “naked seeds”

Came before angiosperms

Characteristics of Monocots

One cotyledon (an embryonic leaf in seed-bearing plants, the first leave(s) to appear from a germinating seed)

Parallel veins in leaves

Scattered stem in vascular tissue

Network of fibrous roots

Monosulcate pollen (a pollen grain with one groove or furrow)

Flower parts come in threes or multiples of three

Monocots do not produce true wood (hard structural tissue).

Instead produce grasses, palms (herbaceous)

Characteristics of Eudicots

Two cotyledon

Network veins in leaves

Ring pattern stem vascular tissue

Tap root with many lateral roots

Trisculate pollen

Four, five, multiple of four or five and whorls flower parts

Produce true wood

Secondary growth

Remember all plants have primary growth at the apical meristems (roots and shoots)

Secondary growth deals with expanding girth and creating wood. Wood is proliferating xylem

Moss Life Cycle

Fern Life Cycle

Microphyll

a leaf (as of a club moss) with single unbranched veins and no demonstrable gap around the leaf trace.

Importance of symbiotic fungi

plants would not have been successful in the move onto land without them

Which type of plant has the haploid gametophyte as the most important form?

non-vascular plants

Difference between sporophytes and gametophytes

Sporophytes are 2n (diploid) and gametophytes are n (haploid)

megasporangia

produce megaspores which produce female gametophytes

microsporangia

produce microspores which produce male gametophytes

Example of plant adaptions to life on land

seeds and pollen grains

dispersal of sperm no longer dependent on water

Female parts of the plant

collectively called the pistil

Stigma

The part of the pistil where pollen germinates

Style

a long, slender stalk that connects the stigma and the ovary. The stigma is at the top of the style and is a sticky platform where pollen is deposited

Ovary

The enlarged basal portion of the pistil where ovules are produced.

Ovule

the organ that forms the seeds of flowering plants

Male parts of the plant

Stamen

consists of a long slender stalk, the filament, with a two-lobed anther at the tip

Anther

the part of a stamen that produces and contains pollen.

Filament

a stalk-like structure that attaches to the base of the flower and supports the anther

Characteristics of fleshy fruits

the pericarp and accessory parts develop into succulent tissues, as in eggplants, oranges, and strawberries

Characteristics of dry fruits

the entire pericarp becomes dry at maturity, as in grains, nuts, rice, wheat

Complete flower

one that contains all the reproductive (stamens and pistil) and non-reproductive (petals and sepals) parts

staminate flowers (incomplete)

also known as androecious flowers

unisex flowers that bear stamens only and produce pollen grains only

lack carpels

carpellate flowers (incomplete)

also known as gynoecious flowers

unisex flowers that bear carpels only and produce egg cells only

lack stamens

shoot system

Vegetative (non-reproductive) parts of the plant, such as the leaves and the stems

Reproductive parts of the plant, which include flowers and fruits.

root system

Supports the plants and absorbs water and minerals.

Usually underground

Lateral meristems

cells found at the margins of stems and roots. They are an essential component in the process of the stems and roots expanding in width and diameter

What are the parts of a stem?

Nodes, internodes, axillary buds, apical bud

Nodes

points of attachment for leaves, aerial roots, and flowers

Internodes

regions between two nodes

Axillary bud

usually found in the axil—the area between the base of a leaf and the stem—where it can give rise to a branch or a flower

Apical bud

The apex (tip) of the shoot contains the apical meristem

Petiole

stalk that extends from the stem to the base of the leaf is the petiole

Parenchyma cells

the most common plant cells

have the potential to become other cell types

have all the organelles and thin primary cell walls

Collenchyma cells

tissue strengthened by the thickening of cell walls, as in young shoots

elongated like column with thick walls

Sclerenchyma cells

provide support to the cells

Dead at maturity

Lots of lignin

Made of fibers and sclereids

Dermal tissues

Mostly epidermis

Woody plants have bark

Leaves have guard cells as part of stomata and trichomes

Epidermis

the epidermis on above ground organs (leaves and stems) is involved with gas exchange

the epidermis on below ground organs (roots) is involved with water and ion uptake

Vascular tissues

transport water, minerals, and sugars to different parts of the plant

xylem

carries water and ions from the roots to stems and leaves

phloem

carries dissolved sugars from leaves to other parts of the plant

Tracheids

a type of water-conducting cell in the xylem which lacks perforations in the cell wall

Vessel elements

An elongated, water-conducting cell in xylem, one of the two kinds of tracheary elements

Sieve-tube cells (also called sieve-tube elements)

arranged end to end to make up a long sieve tube, which transports organic substances such as sugars and amino acids. 

Sugars flow from one sieve-tube cell to the next through perforated sieve plates, which are found at the end junctions between two cells. 

Companion cells

found alongside the sieve-tube cells, providing them with metabolic support. 

The companion cells contain more ribosomes and mitochondria than the sieve-tube cells, which lack some cellular organelles.

Primary growth

arises from apical meristems

Secondary growth

stem increases in thickness and due to lateral meristems

Ground tissues

responsible for metabolism, storage, and support activities

includes leaves, stems, and roots

leaf (called mesophyll)

uses the energy in sunlight to synthesize sugars in a process known as photosynthesis

stem (called pith and cortex)

develops support cells to hold the young plant upright

root (also called cortex)

often stores energy- rich carbohydrates

What are rhizomes, bulbs, corms, stolons, and tubers?

modified stems

What is wood?

Wood is secondary xylem

Tap root system

A taproot is a large, central, and dominant root from which other roots sprout laterally. Typically a taproot is somewhat straight and very thick, is tapering in shape, and grows directly downward

Fibrous or Adventitious root system

A fibrous root system is the opposite of a taproot system. It is usually formed by thin, moderately branching roots growing from the stem.

A fibrous root system is universal in monocotyledonous plants and ferns

Roots have area of maturation, elongation, and cell division

The zone of elongation is where the newly formed cells increase in length, thereby lengthening the root. Beginning at the first root hair is the zone of cell maturation where the root cells begin to differentiate into special cell types. All three zones are in the first centimeter or so of the root tip.

Dicot root

taproot structure, meaning they form a single thick root, with lateral branches, that grows deep into the soil.

Monocot root

has a ring of vascular tissue:  note contrasts with randomness in stems

Stele

  inner vascular tissue of root

Pericycle

area lateral roots emerge from

Casparian strip

a barrier to the apoplastic flux, forcing ions to pass through the selectively permeable plasma membrane into the cytoplasm, rather than move along the cell wall.

Types of roots

strangling roots and Cypress “knees”

Strangling roots

when tree roots encircle a tree's trunk

Cypress “knees”

formed on the upper surface of these roots by the vascular cambium, the meristematic layer that produces xylem and phloem, the tissues that transport water and nutrients through the plan

Leaf structure (external)

1. Tip
2. Lamina
3. Petiole
4. Midrib
5. Veins

phyllotaxy

the arrangement of leaves around the stem.

Leaf forms

1. Simple: banana leaf
2. Pinnately compound: feather-like appearance; the leaflets are arranged along the middle vein
3. Palmately compound: leaflets radiating outwards from the end of the petiole, like fingers off the palm of a hand
4. Doubly compound: the leaflets are arranged along a secondary vein, which is one of several veins branching off the middle vein.

internal structure of leaf

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1. Spongy parenchyma in mesophyll
2. Palisade parenchyma in mesophyll
3. Upper and lower epidermis
4. Stomata flanked by guard cells

What are needles?

leaves adapted for dry climates

What is solute potential?

Solute potential (ψ s) s the same as the osmotic potential and is related to dissolved materials

What is pressure potential?

Pressure potential (ψ p) is the physical pressure or turgor pressure on a solution

Transpiration

Loss of water from the plant via evaporation at the leaf surface; ideally an unbroken line of water molecules and all passive

Evapotranspiration

the process by which water is transferred from the land to the atmosphere by evaporation from the soil and other surfaces and by transpiration from plants.

Flaccid

Flaccid corresponds to a cell lacking turgidity.

They are not plump and swollen but floppy or loose, and cells have drawn in and pulled away from the cell wall.

It takes place when plant cells are in isotonic solutions.

turgid

Plant cells become "turgid" when they are put in dilute solutions.

Turgid means swollen and hard.

The pressure inside the cell rises, eventually the internal pressure of the cell is so high that no more water can enter the cell.

cohesion

Water is attracted to water

adhesion

Water is attracted to other substances

What part of the plant controls the rate of transpiration?

the stomata

translocation

the movement of materials from one area to another. In plants, plant translocation involves the movement of sugars from sources to sinks.

Photomorphogenesis

development of form and structure in plants which is affected by light, other than that occurring for photosynthesis.

Photoperiodism

the response of an organism to seasonal changes in day length.

Phototropism

the orientation of a plant or other organism in response to light, either toward the source of light ( positive phototropism ) or away from it ( negative phototropism ).

phytochromes

red (R)/far-red (FR) light photoreceptors that play fundamental roles in photoperception of the light environment and the subsequent adaptation of plant growth and development.

Phototropins

plant-specific blue light receptors for phototropism, chloroplast movement, leaf expansion, and stomatal opening

Horizons are layers of soils

O is leaf litter

A is topsoil

B is subsoil

C is the soil base

Horizon O

The O horizon has freshly decomposing organic matter—humus—at its surface, with decomposed vegetation at its base.

Horizon A

The A horizon consists of a mixture of organic material with inorganic products of weathering, and it is therefore the beginning of true mineral soil

Horizon B

The B horizon is an accumulation of mostly fine material that has moved downward, resulting in a dense layer in the soil. In some soils, the B horizon contains nodules or a layer of calcium carbonate.