http://croptechnology.unl.edu/animationOut.cgi?anim_name=water_movement_roots.swf

This is a super Casparian Strip Animation !!!!!!!!!!!

January 24, 2010

• Mycrorrhizae are roots associated with symbiotic fungi. These absorb water and minerals in the root cortex must pass through the endodermis in order to enter the rest of the plant. Endodermis surrounds the stele
• The endodermis contains the Casparian Strip which prevents substances from going around the cells. Water and minerals must therefore pass through an endodermal cell to enter the vascular tissue

Turgor/Root Pressure- water and minerals forcing in the strip to reach vascular tissue

• Transpiration- is the loss of water vapor from leaves and other parts of the plant in contact with air
• Two ways substances pulled through plant

1. Root Pressure occurs when water flowing in from the root cortex generates a

positive pressure that forces fluid up through the xylemà positive pressure

2. Transpiration- Cohesion- Tension Mechanism- water is lost through transpiration at the leaves of the plat, and this creates a negative pressure, which draws water up through the plant. The cohesion of water due to hydrogen ions bonding (groups of 4) enables it to form a column, which is drawn up through the xylem with the help of adhesion (the fact that water molecules are attracted to the plant cell walls

• Guard cells control size of the opening in the stomata by changing shape and this regulates plant water intake
• increase size by taking up water thus swelling and sealing off the stomata opening
• influence stomata opening and closing

1. Light

2. Depletion of carbon dioxide in air spaces in leaf

3. Internal clock of guard cells

• Phloem transports organic products of photosynthesis from the leaves throughout the plant
• Sieve tubes carry food from a sugar source (leaf) to a sugar sink (all organs)
• Flow through the phloem occurs mainly as a result of bulk flow-loading sugar into cells create a high solute concentration at the source end of the sieve tube, and this lowers the water potential and causes the water to flow in the tube
• Roots can be a source in fallà summer
• Leaves can be a source in summerà fall

Glogster

Chapter 35

Plant Structure and Growth





Vascular system and plants

The three basic plant organs are roots, stems and leaves
They are organized into a root system and a shoot system

Roots rely on sugar produced by photosynthesis in the shoot system. Shoots rely on water.
Roots are multicellular organs with important functions

• anchor the plant, absorb minerals and water, and store organing nutrients.

A taproot system consists of one main vertical root that gives rise to lateral roots, or branched roots.

A stem is an alternating system of nodes. Each node contains internodes, which are stem segments between the nodes.

An axillary bud is a structure that has the potential to form a lateral shoot or branch.

An apical bud, or terminal bud, is located near the shoot tip and causes elongation of a young shoot.

• apical dominance helpts to maintain dormancy in most nonapical buds.

The leaf is the maing photosynthetic organ of most vascular plants.

• a leaf generally consists of a flattened blade and a stalk called the petiole, which joins the leaf to a node of the stem
  

passage way - vessels, vascular tissue
- xylem and phloem


Alteration of Generations






















Xylem Phloem
trachied (pit) steive tube
vessel element companion cell

Chapter 35 Preview

Ch 35 Overview:

A rather large new vocabulary is needed to name the specialized cells and structures in a study of plant structure and growth. the roots, stems, and leaves of a plant are specialized to function in absorption, support, transport, protection, and photosynthesis. Plants exhibit indeterminate growth. Apical meristems at the tips of roots and shoots create primary growth, the primary meristems produce dermal, ground, and vascular tissues. The lateral meristems, vascular cambium, and cork cambium, create secondary growth that adds girth to stems and roots. New techniques and model systems such as arabidopsis are allowing researchers to explore the molecular bases for plant growth, morphogenesis and cellular differentiation

The Plant Body

-Both genes and environment affect plant structure (720-721)

-Plants have three basic organs: roots, stems, and leaves. (721-724)

-Root System & the Shoot System and Leaves

-Plant organs are composed of 3 tissue systems: Dermal, Vascular, Ground (724-726)

-Plant tissues are composed of 3 basic cell types: Parenchyma, Collenchyma and Sclerchyma(726-728)

The Process of Plant Growth and Development

-Meristems generate cells for new organs throughout the lifetime of plant. (729-730)

-Primary growth: apical meristems extend roots and shoots by giving rise to the primary plant body(730-734)

-Secondary Growth: Lateral meristems add girth by producing secondary vascular tissue and periderm (734-738)

Mechanisms of Plant Growth and Development

-Molecular biology is revolutionizing the study of plants (738-739)

-Growth, morphogenesis, and differentiation produce the plant body (739)

-Growth involves both cell division and cell expansion (739-742)

-Morphogenesis depends on pattern formation (742)

- Cellular differentiation depends on the control of gene expression (743)

-Clonal analysis of the shoot apex emphasizes the importance of a cell's location in its development fate (743-744)

-Phase changes mark major shifts in development(744)

-Genes controlling transcription play key roles in a meristem's change from a vegetative to a floral phase (744-745)

Chapter 35 Vocabulary

apic- the tip

bienn- every two years

root system

shoot system

coll- glue

fibrous root

taproot

root hairs

fusi- a spindle

axillary bud

Terminal bud

perenni- through the year

apical dominance

phloe- the bark of the tree

cuticle

tracheids

vessel elements

pits

sieve-tube members

companion cell

ground tissue

pith

parenchyma cell

collenchyma cell

sclerenchyma cell

sclerids

sclero- hard

meristem

primary growth

secondary growth

zone of elongation

stele

trachei- the windpipe

vascula- a little vessel

vascular bundles

guard cell

cork cambium

xyl- wood

bark

Ecology Continued

Niches
Fundamental Niche - Space and resources a species population would consume with no limiting factors
Realized Niche - space and resources a species population occupies when factors such as competition and limited resources are accounted for

When a species is introduced into an environment it starts in its fundamental niche, but as competition for resources increases, they can be forced into its realized niche


Smybiosis - two species that live together in benefit
Coloration - Species often use bright colors to deter predators from consuming them. Many who employ this are poisonous or extremely bad tasting

Mullerian Mimicry - Several species may have same colors, so it easy for predators to associate these colors or patterns with a "no go" on consuming

Batesian Mimicry - Look like the poisonous species to deter predators

Succession
As succession progresses, species diversity and biomass increase. Eventually, a final successful stage of constant species composition, called the climax community. Often a natural disaster will occur, causing the cycle to repeat.

Sorry for the delay, this should have been posted prior to Daniel's last post.

ECOLOGY:
There are four major factors of ecology
1. Sucession
2.Limiting Factors
3. Carrying Capacity
4. Trophic Levels

Ecology --> Study of the distibution and abundance of organisms, their interactions with other organisms, and their interactions with their environment.
- The niche of an organism describes the biotic (living) and abiotic (nonliving) resources in the environment used by an organism.

Population Ecology:
1.Size of population
2.Density of a population
3.Dispersion, how population is distributed
-clumped
-random
-uniformed
4.Age structure...description of the abundance of individuals of each age.
5.Surviviorship curve...mortality of individuals in a species varies during their lifetime.

Biotic Potential:
Maximum growth rate of a population under ideal conditions
-unlimited resources
-no growth restrictions
Contributions to biotic potential (what to look at)
-age at reproductive maturity
-clutch size
-frequency of reproduction
-reproductive lifetime
-survivorship of offspring to reproductive maturity

Limiting Factors:
Elements that prevent a population from attaining biotic potential
Density dependent factors are those agents who's limiting effect becomes more intense as population density increases
If too dense...
-parasites
-disease
-competition for resources
-toxic effect of waste product
-predation

Independent Factors:
Fires
Hurricanes

Growth of Population:

r = (births - deaths) / N
If deaths = Births than everything is constant.
D > B = - growth rate
B > D = + growth rate

Ecology Day Two

Ecology

Gout-all the things that are wrong with people.

· As density goes up so does limiting factors. Disease is not a limiting factor yet. Flu shots- dead virus, how to predict that it’s the one we use. They don’t know for sure. It comes from China. The population is so dense they get the flu first. We make a flu shot for the Northern hemisphere. Their summer is our winter.

· Ecologists look at the limiting factor.

· Delta N/delta t =rN(K-N/K) logistic growth. S curves start as exponential, stable off then, if it dips then limiting factors have taken affect.

Types of growth- exponential, logistic,

Population cycles are fluctuations in populations size in response to varying effects of limiting factors. Since many limiting factors are density dependent they will have a greater affect when the population size is greater compared to when it is small.

Instead of limiting the cockroaches, whipping them all out then allowing them to thrive.

K-selected species- is one whose population size remains constant at the carrying capacity, K. Species of this type such as humans, produces a small number umber of relatively large offspring that require parental care until they nature. Reproduction occurs repeatedly during their lifetime.

S curve characters, K-selected species are not the ones to come in stabilize they come in second, they come in to an established community. They have small clutch sizes. They need time to mature and parental care. They hover at the carrying capacity. They stabilize the population. A lot older reproductive maturity, takes them years to reproduce. Old reproductive age, small clutch size, years in frequency reproduction, old reproductive lifetime, long survivorship of offspring to reproduce maturity.

R curve- Rapid reproductive maturity set the exponential curve. Large clutch size. They have young reproductive age, large clutch size, short in frequency reproduction, young reproductive lifetime, short survivorship of offspring to reproduce maturity.

Reduction in disease, Advances in medicine, such as the discoveries of antibiotics, vaccines, proper hygiene, reduced the death rate and increased the birth rate.

Reduction of wastes water purification and sewage systems, health hazards from human wastes were reduced. Increased waste collected more exponential population growth. Expansion of habitat- better housing warmer clothing, easy access to energy for heating, cooling, and cooking, for example, allowed humans to occupy environments that were previously unsuitable.

Community Ecology- is concerned with the interaction of populations. Interspecific competitions (between different species), the following concepts are how the competition is resolved: Intra- same species.

The competitive exclusion principle (Gause’s Principle), When two species compete for exactly the same resource or they occupy the same niche and they both need the smaller seed, one is more likely to be successful, One species outcompetes the other and eventually the second species is eliminated.

The other goes and finds another niche. If they are smart enough tto do that.

Resource partitioning: Some species cexist in spite of the apparent competiton for the same resources. They occupy different niches. By pursuing slightly differently resources or securing their resources in slightly diffecrnt ways, individuals, minimize competions and maximize success. Dividing up the resources in this manner is called resource partioning.

Harter displacement (niche shift) As a result of resource partitioning , certain characteristics may enable individuals to obtain resources in their partitions more successfully. Selection for these characteristics or characters reduces competition with individuals in other partitions and leads to a divergence of features, or character displacement.