BSU Biology 192 Exam 2

Land plants

> Multicellular photosynthetic eukaryotes

> Most have reproductive, structural, and chemical adaptations for terrestrial living (distinguishes them from algae)

> Have an embryo: retained and protected for some time by parent

>> parents tissue provides nutrients and protects embryo from desiccation (drying).

Most plants have a

Vascular system

The aerial parts of most plants have a waxy coating called a ____________ that reduces__________?

cuticle, water loss.

T or F Most land plants but not all plants have a stomata

True

During the evolution of plants a transition occurred from plants where the __________ is the dominant generation to plants where the _________ is the dominant generation

gametophyte (n), and sporophyte (2n)

Within the life cycle of a plant there are multicellular stages that are ___________ and multicellular stages that are ___________.

Diploid, haploid

T or F both haploid and diploid cells can be divided by mitosis (land plants)

True

Bryophytes

Non-vascular plants

E.g. mosses liverworts and hornworts

> Small, herbaceous plants, most lack a vascular tissue, gametophyte (n) dominant generation, lack tracheids

> Life cycle includes an embryo stage

> Most live in humid environments, some able to colonize dry habitats

Vascular plants include

> Seedless vascular plants E.g. ferns, horsetails

> Gymnosperms E.g. pines, sequoia, spruce and, firs

> Angiosperms (flowering plants) E.g. corn potatoes, roses, grasses

Mosses

> Phylum Bryophyta

>Gametophyte (n) leaflike structures stem like axis rhizoids

> Rhizoids consist of several cells that anchor the moss to a substrate and absorb little water

Moss reproduction

Moss Habitat

> Humid areas

> Abundant plants in the arctic tundra

> Sometimes tolerate long periods of dehydration and can live in dry environments

Biological soil crusts

>Consists of a mixture or organisms including mosses, lichens, algae, cyanobacteria, and heterotrophic microorganisms

> Reduces soil erosion and increase soil fertility

Sphagnum peat moss

Soil addendum that improves water retention

Liverworts

Phylum Hepaticophyta

> Gametophytes tend to be flat, rhizoids are single celled

> Sexual reproduction similar to that of mosses

> Non photosynthetic sporophyte

> Asexual reproduction: gemmae fragments of the gametophyte dispersed by raindrops

> Most liverworts live in tropical forests

Hornworts

Phylum Anthocerotophyta

> Gametophyte tends to be flat

> Sporophyte is photosynthetic and has stomata and cuticle

> Sporophyte is dependent on gametophyte and is not free living

> Most live in tropical forests

Seedless vascular plants

> Dominated the worlds vegetation 360 to 290 MYA (carboniferous period)

> Coal deposits are derived that grew during carboniferous period

Lycophyta

Club mosses

>Sporophyte (2N) has photosynthetic microphylls ( leaves with one vein)

> Sporangia form at the end of stems

Pterophyta Ferns

> Most have megaphylls: Leaves with branched system of veins

> Vary in size form less than 1 cm to 25 m tall

> Asexual reproduction

: Rhizomes (underground stem)

> Live in tropics, also in temperate climates and even deserts

> Ornamental plants and i cultivation of rice

Characteristics of seedless vascular plants

> Sporophyte (2N) dominant generation

> Has vascular tissues (xylem and phloem)

> Plant can transport water, minerals, and sugars more effectively and the plants can be taller

> Aerial portions covered by cuticle and have stomata

> Sperm have flagella

Sporangium

A structure where meiosis occurs and haploid spore develop

Pterophyta Whisk ferns

> Lack leaves or these structures are very reduced

> Consist only of green stems without roots

> Rhizomes (underground stems) develop symbiotic relationship with mycorrhizae

Pterophyta Horestails

> Have non-photosynthetic leaves and photosynthetic stems

> Sporangia from at tip of reproductive stems

Azolla

Small water fern that forms a symbiotic association with cyanobacteria, which converts N2 to NH3. Present in rice paddies

Gymnosperms

> Naked seed

> About 900 living species

> Common in evergreen forests

Angiosperms

> Seeds within vessels, the seed is surrounded by other layers of plant tissue

> Have tracheids and vessels

> Flower attracts pollinators

> Fertilization is less dependent on wind pollination

> Fruit helps disperse seeds.

> Dominant vegetation

Agriculture based on angiosperms

Phylum coniferophyta

> E.g. Pines, firs, spruce, redwoods, cypress

> stems with secondary growth

>Most are evergreen ( start photosynthesis as soon as air warms up )

> Leaves are needle like with adaptations to dry conditions

> Thick cuticle, Sunken stomata( below surface of leaf)

> Ecological importance: Carbon sink, primary producers over vast areas of the world

> Economic importance of conifers: timber, paper

Cycadophyta

> Gymnosperm

> Palm Like leaves, pollen and ovule producing cones in different plants, diecious and sperm with flagella

Genetophyta

> Gymnosperm

> Welwitschia ephedra ( mormon trea) the xylem has vessels

Ginkophyta

> Gymnosperm

>Ginkgo biloba (maidenhair tree)

> Diecious. Sperm in flagella

All flowering plants belong to one phylum, the ___________

Antophyta

Most angiosperms belong to either two classes

>Monocotyledones

>Eudicots

Flower has 4 whorls

1. sepals

2. petals

3. stamens

4. carpels

Calix

Consists of sepals, which protect the flower buds

Corolla

Consists of petals, which attract pollinators and protect flower buds

Androecium

Consists of stamens. The anthers produce pollen (male gametophyte)

Gynoecium

Consists of one or more carpels, which produce ovules where the female gametophyte develops

Plant reproduction

Pollination

The transfer of pollen from the anther to the stigma

Flowers with little odor, yellow to red color, and abundant nectar atract

Birds

Flowers with large petals and fragrance attract

Bees and butterflies

Some plants are only pollinated by wind, flowers with no nectar, dull colors, odorless. Produce more pollen what are they?

Grasses, walnut, oak

Self pollination

Advantages and Disadvanatges

The transfer of the pollen to a carpel in th the same

> Advantages: fertilization can occur without plants of the same species

> Disadvantages: low genetic variation

Outcrossing

Transfer of pollen to a different plant ( promotes genetic variation among the offspring)

Outcrossing in Monoecious plants

pollen producing and ovule producing structures in different flowers or cones in the same plant E.g. pine, corn

Outcrossing in Diecious plants

pollen producing and ovule producing flowers (or cones) in different plants. E.g. willow, marijuana

Asexual or vegetative reproduction result in genetically __________ individuals

Identical

Runners

Horizontal stems over the ground

Rhizomes

Underground stems

Tuber

Tips of underground stems accumulate reserves

Suckers

Root or basal portions of the plant produce buds that can from new plants (aspens, willows)

Apomixis

Seed produce an embryo without fetalization

E.g. Citrus, dandelions

Asexual reproduction may produce individuals that are particularly well _______________________________________________________________?

suited for a particular environment.

Seed development

Food storage in plants

>Mature seed has a large endosperm

E.g: wheat, rice, barley

or

> Endosperm is absorbed during embryogenesis and most of the food reserves are stored incotyledons

E.g. pears, peanuts, sunflowers, soybeans

Mature seed

> Seed coat

> May or may not have endosperm

> Embryo

> During maturation seed loses water

> have 5 to 20% water content

> Dry stage causes cessation of growth of the embryo (quiescent state)

Germination requires

>> water

>> adequate temp

>> oxygen

Dormant seeds do not germinate under favorable conditions of ___________________?

Water, temp, and oxygen

Dormant seed have addtiional requirments

> Light (small seeds, lettuce)

> Cold temp ( plants from temperate regions, oak, pines)

> Heavy rain (some desert plants)

> Harsh conditions that break impermeable seed coats

The _______ is the first structure that emerges from the seed

Root

When the seedling reaches the light, the SAM becomes active and begins ________________?

forming leaves

Pathway of water movement

Soil --> root --> stem --> leaves --> atmophere

Most of the water enters a plant through __________________?

Root hairs and young portions of the root

Water moves in between and through the root cells until it reaches the ____?

xylem

Most of the water that enters a plant is lost via _____________?

Transpiration

Transpiration helps to

cool the leaves preventing an excessive increase in leaf temp.

In the leaves, the water evaporates into intercellular air spaces, and finally is lost through the ____________________________?

Stomata into the atmosphere

Water moves from areas of _________________________?

High to low

Adhesion

attraction between water and polar groups of other molecules

Cohesion

attraction between water molecules.

Under dry conditions, _The plant hormone abscisic acid (ABA) triggers ________________________?

Closure of stomata

Two factors that affect opening of stomata are

Light and drought

The concentration of water vapor inside the leaf is ______________ than that of the atmophere?

Higher

Water evaporates into intercellular spaces and exits mainly through the ______________________________________?

stomatal pores by diffusion

Minerals enter the roots dissolved in the ____________?

Soil solution

The plasma membrane to some extent controls the minerals that enter the _________________________?

Vascular memebrane

When minerals reach the xylem, the move to the shoot with the__________________incorporated into the ______________ of the _______________?

transportation stream, tissues, shoots

Phloem transport

>Movement of molecules is from sources to sinks. The phloem mainly transports organic molecules: Sucrose, amino acids, and some hormones

> At a particular time, movement is only in one direction

Sources

Places from where molecules are exported

E.g. Mature leaves

Sinks

Places where import of substances occurs

E.g. roots, young leaves, fruits, seeds, growing parts of the plant

Aphids

scientist decapitate aphids and through stylets, they collect the contents of the phloem

Movement of molecules through the phloem: mass flow ( Source, sinks)

Substances move by difference in hydrostatic pressure between the source and the sink

> At source, solutes are loaded into phloem. accumulation of solutes drives the movement on water into the pholem= = high pressure

>At sinks, solutes are unloaded. This decreases the concentration of solutes in the phloem. As a result water moves out and the pressure is low.

Close to their tips plants have regions known as____________?

Meristems

Meristems are the Regions of the plant that remains________?

embryonic

Meristemstemic cells divide througout the life of a plant resulting in _______________________________________?

indeterminate growth

Indeterminate growth

Through its life, a plant can keep growing

The root apical meristem produces the_______________?

Cells of the root

The Root apical meristem produces the________________? and the 3 primary meristems. The_______________, ________________, and _______________?

Root cap

protoderm

ground meristem

procambium

The root cap protects the ___________ and secretes a gel that acts as a lubricant to facilitatate _________________________________________________________________________?

Root apical meristem

Root penetration through soil

Protoderm ----->

Epidermis

Ground Meristem --->

Cortex

Procambium --->

Vascular cylinder (xylem and phloem)

The shoot apical meristem gives origin to the cells of ______________ and the ______________?

Leaves, stem

At the angle between a leaf and stem, an ______________________________________ develops?

Axillary bud

BUds can give origin to ______________, the tip of the branch has ________________________?

branches, Shoot apical meristem

The SAM produces 3 primary or deriviative meristems: _____________________, __________________, and ________________?

protoderm

ground meristem

procambium

Roots

> Anchorage of the plant body to the soil

> Absorption of water and minerals

> Conduction of food, water, and minerals

> Storage of carbohydrates

Stem

> Supports leaves

> Conducts water, minerals, and organic molecules

Functions of leaves

Photosynthesis

What plants have primary growth only

Most monocots and many eudicots