Plant BIO 310 Practical #1

What is a limiting nutrient? Which nutrients are most often limiting in agriculture? In natural ecosystems? What happens in some natural systems when limiting nutrients are added?

A limiting nutrient is essentially a nutrient or element that is most often limiting to plant growth - The nutrients that are most often limiting in agriculture are: *N, P, K* -The nutrients that are most often limiting in ecosystems are: * N and P* - In natural systems when limiting nutrients are added, an overgrowth may occur. For example, if more phosphates are dumped into a pond then alga may grow at an increased rate blotting out other life forms.

protonema

A mass of green, branched, one-cell-thick filaments produced by germinating moss spores. They contain two types of filaments: (1) *Chlorophyll containing* (2) *achlorophyllous (without chlorophyll)* -the chlorophyll containing filaments conduct photosynthesis (light and dark rxns) - the achlorophyllous filaments may be used for structure, or act as an early form of transport. However, it CAN'T photosynthesize

tonoplast

A membrane that encloses the central vacuole in a plant cell.

parenchyma cell

A relatively unspecialized plant cell type that carries out most of the metabolism, synthesizes and stores organic products (*STARCH*).

node

A section as seen in the Cara algae that creates the branches. It also connects to the internode.

internode

A segment of a plant stem between the points where the nodes are. (Think Cara).

protostele

A simple primitive arrangement of conducting tissues in the stems and roots of vascular plants. - It is essentially a vascular bundle (shares a similar arrangement in Monilophytes and lycophytes)

pyrenoid

A structure in the chloroplast of some algae that serves as a center for starch production.

Answer the following: How does a tomato plant obtain amino acids? Where do the elements in cellulose come from?

A tomato plant would obtain amino acids by breaking down of the carbon skeleton during metabolism, and through obtaining inorganic compounds. The energy provided from the breaking down process allows them to build up the amino acids. The elements in cellulose are taken up as atmospheric carbon, and water.

outgroup

Closely related group that is not part of the group being analyzed (*often branches off right before the common ancestor of the clade of interest*)

Lycopodium (club moss)

Found from the arctic to the tropics - they are herbaceous, evergreen, and usually found within small plant communities. -Roughly six genera are found in Maine. - All plants of this family are herbaceous now, but 300 MYA lycophytes were a dominant forest species. - Extinct lycophyte trees displayed secondary growth and had a branching root structure.

stalk (seta)

Found on the bryophyte sporophyte stage. The seta connects the vegetative gametophyte to the sporophyte so that the nutrients produced in the gametophyte will be passed into the sporophyte.

Polytrichum (Hairy cap moss)

Has a female calyptra sporophyte structure (Sticks up like a lamppost) - Male structure is present and looks like a brownish flower.

taxonomy

Identifying, naming, and classifying of species

lycophyll (microphyll)

In lycophytes, a small leaf with a single unbranched vein. These are also considered to be the sterile leaves as the modified *sporophyll leaves* are responsible for hosting the sporangia that bear spores.

clade

Includes a common ancestor and ALL of its descendants

rhizoids

Is a single linear line of cells (*NOT ROOTS*). This structure helps to anchor the bryophyte gametophyte to the ground. - Found in ferns and Bryophytes

Where would you find sporophylls and stroboli on a lycophyte? What are their functions and what is their part in the lycophyte life cycle?

You could find the sporophylls and stroboli on the sporophyte stage of the lycophyte specifically off of the aerial stem. The functions of these structures is to ensure that there is adequate spore dispersal via the wind or insects.

Why is Sphagnum ecologically important? Why was Sphagnum used as diapers and as a wound dressing before the days of antibiotics?

Sphagnum contains a bunch of phenolic compounds which prevent against decay and bacterium, hence due to the antiseptic properties it was once used as wound dressings. Sphagnum also has two types of cells shorter cells *which contain chloroplasts* and *larger hyoid cells which absorb water* this absorptive property is what allowed it be an affective additive for diapers. Ecologically sphagnum makes up roughly 1% of the earths surface, and stores organic carbon.

What is sporopollenin and why is it important for the survival of the zygospores in some algae and pollen and spores of plants?

Sporopollenin is a cyclic acid that allows spores, seeds, and zygotes to be extremely decay resistant, all while protecting against desiccation. Sporopollenin is important for the survival of zygospores in that it protects them from decay and desiccation before their germination process has begun.

By convention each newly described plant is required to have a type specimen that is deposited in a herbarium. Why are type specimens useful?

Type specimens are useful because they are essentially a reference species in which they contain all of the basic traits that defines a particular species. Thus, they can be used to compare to another species in question to see if they are the same species.

rhizome

horizontal stem, parallel to ground (either on surface or underground), found in lycophytes - aerial stems and adventitious roots grow off of rhizome

strobilus (strobili)

lycophyte structure, originating from heavily modified sporophylls melded and grouped together to stand at top of plant (sometimes on long stalk) - produces spores found in most N. England lycophyte genera (except Hypersia)

Antheridium

male reproductive structure in some plants that produce sperm. The antridium or sperm producing cells are protected by *sterile hair cells called paraphysis*

splash cup

structures in a moss capsule which aid in gamete dispersal (Seen on the male gametophyte) -Acts similar to that of the liverwort Gemmae.

What fraction of the dry weight of a typical plant such as garden peas consists of carbohydrates and related compounds (compounds made of only C, H, O)?

Carbohydrates are the major energy containing components of plants and roughly make up 60-96% of dry matter.

Chara, Spirogyra and their close relatives are currently believed to be the living green algae that whose ancestors were the closest to the ancestor of the plants. What characters do Chara and plants have in common?

Chara is similar to plants in that it has nodes with leaves that are connected to an internode which acts as a stem. -*chara also has a plasmodesmata similar to that of plants*

Describe the ecology of Chara including its habitat, how large it becomes, and any significance it has for animals.

Chara tends to grow in shallow temperate lakes, and can grow roughly 5cm- 1m in length. Within these lakes Chara will act as food for ducks, and will provide protective cover for young fish.

lignin

It is a secondary wall component, that is comprised of * cross-linked phenolic compounds* which make the cell walls waterproof. -it resists compression, which makes cell walls more ridged. - it is hydrophobic (water hating) and is VERY hard to break down.

adventitious roots

Roots that grow on an unusual structure such as a leaf or modified stem (ex. rhizome in lycophytes)usually form because it is adventitious for the plant to have them.

species

A group of similar organisms that can breed and produce fertile offspring.

cladogram

A hypothesis of the relationships among organisms being studied (often represented as a branched diagram) -The result of the cladistic method -uses *Shared derived characteristics*

Briefly describe how autotrophic plants meet each of the following needs: a source of energy, carbon skeletons, essential elements, complex molecules including amino acids and vitamins, and ATP.

(1) Autotrophic plants receive a source of energy by conducing photosynthetic rxn's to produce sugars for itself, and through its carbon skeleton. (2) Autotrophic plants produce its own carbon skeleton is made during photosynthesis via cellular respiration in the mitochondria. (3) Autotrophic plants uptake essential elements through its roots in the soil via its xylem, water, or atmospheric deposition. (4)*Complex molecules, amino acids*are synthesized by the carbon skeleton during photosynthesis. *ATP* is also formed by the carbon skeleton during photosynthesis.

What is the life cycle of Lycophytes and how does it differ from that of Bryophytes?

(1) Lycophytes *strobilus* has *sporophyl* leaves that are attached to a *sporangium* which undergoes *meiosis* to release haploid (1n) spores (2) The Spores then germinate into the gametophyte which can either form an archegonium or and antheridium so that gametes may be produced. (3) The Gametes then fertilize within the *Archegonium* forming a (2n) zygote. (4) The Zygote will then begin to grow into the sporophyte (which has a gametophyte section at the very bottom). (5) The sporophyte (2n) will then send out *aerial stems* that contain both *microphyll leaves* and *Strobili* thereby starting the process over again. *Differs from Bryophytes in that it doesn't utilize a Seta or a capsule for spore dispersal, instead it uses aerial stems and strobilus, also in the case of the lycophytes the sporophyte stage is dominant, while the gametophyte stage is dominant in bryophytes*

Explain alternation of generations in bryophytes. You should know the life cycle of a true moss (Polytrichum). Know the nuclear conditions (1N or 2N) of different life stages.

(1) The operculum of the capsule pops off revealing a toothy peristome which will release haploid spores (n) after it underwent meiosis in the sporangia. (2) The spores once dispersed, then germinate into the protonema which will form buds and leafy shoots. These buds will then grow into either the male or female gametophyte. (3) The male and female gametophyte will then produce gametes. Water will then be responsible for carrying over the sperm from the antheridium to the female archegonium for gamete fertilization into a diploid zygote (2n). (4) The zygote (2n) will then grow into the sporophyte will form the seta and capsule in which the sporangeous tissue will undergo meiosis to form haploid spores (n) thus repeating the cycle

Describe the method of spore dispersal from the capsule (sporangium) in the "true" mosses.

(1) The protective covering called the *Calyptra* will slide off of the mature capsule. (2) The capsule will begin to open up revealing *parastomal teeth* (3) The parastomal teeth will allow the spores to shake out of the capsule like a salt shaker when it is disturbed by the wind.

Describe some of the important functions of vacuoles in plant cells. What role does the vacuole play in cell growth? Why is saying vacuoles are big sacks of water incorrect?

* Important Functions of vacuoles are: it Allows for the cell to maintain its turgor pressure by adding water into it. The vacuole provides support to young plant tissues, helps to break down plant organelles, helps to break down/ remove toxins like tannins. Stores nutrients, pigments, sugars, amino acids, inorganic acids, and anthocyanins.* Due to the vacuoles ability to expand, when is pumped with water it allows for very fast cell growth. When the cells themselves are young there are typically multiple vacuoles within the cell. As the cell ages, there is only one vacuole within the mature cell. Saying that vacuoles are just a sack of water is incorrect because that it not its entire function, as it does far more than just act as a storage capsule for water within the plant.

Draw a cladogram that includes the following clades: Angiosperms, Bryophytes, Gymnosperms, Lycophytes, and Monilophytes and include at least one shared derived character state at each point that can be used to separate the clades.

*look at the cladogram you drew for class*

You should be able to look at a cladogram and determine positions of common ancestors, clades and look for shared derived characters among clades.

*look at the cladogram you drew for class*

lignin

- A secondary wall component, and is cross-linked phenolic (compared to a carbon molecule that has double bonds between carbons) -resists compression, makes wall more ridged - Hydrophobic, and replaces water in the cell wall (makes it harder to break down)

Both the snow algae and Spirogyra have zygotes that form resting spores with thick cell walls. Why is this important for the "life style" of each of these organisms?

- Both of these organisms probably reside within areas that loose their moisture for part of the year. Therefore, to prevent desiccation of the zygotes, these organisms have thickened their cell walls.

Name some of the derived characters that is NOT present in the green algae but is shared by the bryophytes and the vascular plants.

- Bryophytes and vascular plants utilize alternation of generations though the use of a *sporophyte* stage and a *gametophyte* stage - Bryophytes also utilize leaves (simple leaves) -Bryophytes and vascular plants utilize spores for dispersal -*Rhizoid, Cuticle, Embryo, Alternation of generations*

What methods do mosses have for dispersing their genes in the landscape? For short distances? For longer distances?

- For short distances, water will be used to bring the sperm from the male antheridium to the female archegonium so that fertilization may occur. -For long distances, Bryophytes will utilize long seta stalks with either a capsule or operculum on the top, which will catch the wind to disperse the spores a long distance.

cellulose

- Glucose molecules that are linked by β 1-4 covalent bonds - because of this β linkage, the cellulose stands can stack creating hydrogen bonds. Thus they are difficult to break down.

Name two important characters that all green algae share with plants that are unique to these two groups. Are all of the green algae and plants a monophyletic group? Is Ulva (sea lettuce) or Spirogyra more closely related to the plants? Briefly explain.

- Green algae utilize starch as a reserve for carbohydrates, similar to that of plants. Green algae also utilizes chlorophylls A and B, like that of plants. - Because green algae has two clades (Chlorophyta is considered the outgroup) while streptophyta is viewed with land plants, it would not be considered a monophyletic group. - Out of both Ulva and Spirogyra, Spirogyra would be more closely related to land plants because it resides under the (streptophyta algae clade) in which they are the ancestors to modern land plants.

hornworts

- Has a thallus-like bottom, and a horn like sporophyte -Very hard to identify without the sporophyte

Volvox (Chlorophyta)

- Is a spheroid individual with multiple daughter spheroids. - Due to the presence of daughter spheroids, the cell itself isn't hollow. - The volvox individuals are embedded in a gelatinous matrix - The volvox parent colony moves thanks to tiny flagella on the exterior when light is present, and is immobile when there is no light.

What are hornworts and liverworts? How do they differ from mosses?

- Liverworts use gemmae cups for reproduction that require water in order to splash out the genetic material. They lack a *protonema* gametophyte stage. - Hornworts are very simple in shape (*thallus-like*) and also lack a protonema gametophyte stage. They lack a leafy gametophyte that mosses have. - Can talk about how the sporophyte stage differs form liverworts and hornworts.

Moss leaves do not have stomata. Would they be able to carry out more photosynthesis if they did? Consider the path that CO2 takes to get to the chloroplast-containing cells.

- NO, the moss would not be able to conduct more photosynthesis due to the leaves thickness being only once cell thick, therefore the stomata would act as tunnels to the other side.

"true mosses"

- One of the three clades of mosses - The sporophyte stage is diploid (2n) and dependent on the gametophyte - All have sporangia inside a capsule for meiosis to occur, and produce haploid spores -Have *peristome teeth* on the capsule, to shake the spores out of the capsule like a salt shaker.

List 6 ways in which plants benefit people.

- Provide shelter - Provide food -Prevent soil erosion - Produce oxygen - Medicine - Help to balance the carbon cycle

neck canal (Archegonia)

- The archegonia itself is a *flask shaped structure* that consists of a neck, with one or more layers of cells, and a base *venture* which contains the egg. -The *neck canal* is located above the egg and disappears as the archegonium matures making a pathway for sperm to enter through.

How does the sporangium (capsule) of Sphagnum release spores? Contrast this method of spore dispersal with that of the "true mosses"

- The sporangium capsule will condense down building pressure on the operculum in sphagnum moss. Once the pressure is built, the operculum will pop off violently releasing its spores into the environment. -In true mosses they don't rely on the condensing of the sporangium, but rather on the parastomal teeth and the wind in order to disperse its spores.

liverworts

- There are two types: leafy, and thallus- like - They reproduce via the use of gemmae cups. Each gemma has two growing points, where growth occurs in the opposite directions. Therefore each gemma gives rise to two new plants. - Examples includes Marchantia and Bazzania -Utilize dichotomous branching

tracheary elements

- These elements are elongated cells that are tube-like in shape and are dead at maturity. -They have a thick cell wall containing lignin and an empty lumen (space inside the cell wall). -Their function is to conduct water and mineral nutrients. -Flowering plants have two types of tracheary elements in the stele (region @ the center of the root) (1) tracheids (2) Vessels in prepared slides the tracheary elements are typically stained bright red-to pink

Chara (Streptophyta)

- They are known to extract calcium carbonate from the water and deposit it in large amounts within their cell walls. -This algae is organized into *nodes* and *internodes*. the whorls of short branches arise @ the nodes have *determinant growth* and look-leaf like. -Larger branches have *Indeterminant growth* and arise at the nodes as well. - This algae attaches to the substrate via rhizoids

rock mosses

- They grow on different types of rock - They are photosynthetic when they are young, but turn black to red when they age - They are very small and not well studied

Describe the leaves of a "true moss" and a Sphagnum moss and how their anatomy affects their functions

- True mosses leaves are orientate around a central axis in a whorl-like pattern, they are also only one cell thick. True mosses have three types of cells in their leaves, small photosynthetic cells, hydroid cells, and Leptoid cells. The leaves alternate and whorl so that it may allow for more photosynthetic area. *DOESNT have the same water holding capacity as sphagnum* -Sphagnum mosses have branched side branches with leaves. Their leaves contain Hayline cells, and small chloroplast cells. *Allows them to fit more leaves in a smaller space to absorb more water* (*THEY BOTH HAVE SIMPLE LEAVES*)

Chlamydomonas (Chlorophyta)

- Unicellular and motile with two anterior flagella -Widely studied because they have haploid vegetative cells (this means that mutations are passed on to offspring easily) -Has pyrenoid toward the center of the organism, a nucleus towards the center, and u shaped ground cytoplasm and chloroplasts. (Also have stigma photoreceptors)

Spirogyra (Streptophyta)

- Zygotes form a thick wall that contains sporopollenin (which is a cyclic alcohol) -Has one long chloroplast that is wound within the interior, and its overall shape doesn't branch off. - it can undergo both asexual and sexual reproduction - The algae body is covered with a pectic sheath -*Pyrenoids* within the center of the chloroplasts serve as a center for starch accumulation.

xylem

- has tracheary elements that are LIGNIFIED - conducts water and minerals (Through a passive manner, as it doesn't require energy to do so)

Differentiate between rhizomes, roots, adventitious roots, and rhizoids including the structure and primary function of each and in which generation (gametophyte or sporophyte) each is found.

-*Rhizome*: horizontal underground stem which may be located on the surface, acts as structural support. (Sporophyte) -*Rhizoid*: roughly 2 cells thick on the gametophyte, acts as an anchoring agent, and may absorb some nutrients. - *Roots*: many cells thick, have protostele, in sporophytes. This is used to absorb water, and nutrients for the plant. -*Adventitious Roots*: roots arising from stems or leaves (Sporophyte). The are use to absorb water and nutrients for the plant.

hemicellulose

-A carbohydrate with a variable chemical structure. -Often found as a components within the plants primary and secondary cell walls in the form of a cross-linked cellulose fibril.

vacuole

-Allow for the cell to maintain its turgor pressure by adding water into it (requires production of cytoplasm) -The vacuole provides support to young plant tissues, helps to break down plant organelles, helps to break down/ remove toxins like tannins. -Stores nutrients, pigments, sugars, amino acids, inorganic acids, and anthocyanins. - Allow for rapid cell growth via a pumping inflow of water.

Alternation of generations

-Gametophyte generation is initiated when Meiosis occurs in the sporangia on the sporophyte and produces haploid spores (n). -These spores then grow into the gametophyte plants, which then go on to produce the gametes (eggs and sperm). -The sporophyte generation is then initiated when an egg and sperm unite in fertilization to produce a diploid Zygote. -The Zygote will then divide via Mitosis and grows into the sporophyte which will then produce more spores by meiosis to continue the cycle.

Ulva (sea lettuce) (Chlorophyta)

-Has a flat thallus shape that is only 2 cells thick. These cells are *parenchyma cells* which are considered to be the most basic cell. - It grows in temperate regions, and in intertidal/ subtidal zones off the coast of Maine, and is attached to the substrate via a holdfast. -Can have massive overgrowth due to agricultural runoffs.

Sphagnum

-Not a true moss -Diverged early from the main line of moss evolution - Have 2 types of cells:(1) slender cells with chloroplasts(2) Larger cells with large pore-holds water aka Hayline cells -cell walls contain a decay resistant phenolic compound that has antiseptic properties (keeps bacteria away) - it has branched side branches with leaves

What are some general characteristics of lycophytes? How would you distinguish them morphologically from bryophytes?

-Some general characteristics of Lycophytes are that they have a *dominant (2n) sporophyte stage that photosynthesizes*, they also have *microphyll leaves*, and *lignin* is present. Lastly some extinct and extant groups *utilize secondary growth.* -Lycophytes can be distinguished from bryophytes due to the fact that its dominant stage is the sporophyte (2n) stage as opposed to the bryophytes dominant gametophyte stage (1n). Lycophytes also have lignified tissues and are therefore taller than bryophytes. Lycophytes also have microphyll leaves (instead of simple ones).

sporopollenin

A Cyclic alcohol that is found within spores and seeds. It prevents against decay and desiccation, thereby allowing seeds/ spores to remain dormant until favorable conditions surface for them to grow.

protoplast

A cell membrane with everything enclosed within (essentially the living substance inside of the cell wall)

plasmodesmata

A channel through the cell wall that connects cells via crossing the *middle lamellae* and the primary cell wall and plasma membrane, and is composed of *cytoplasmic strands* -it allows the efficient transport of molecules from one cell to another, and can transport compounds that cant be transported across the plasma membrane like: * Sugars, amino acids, signaling compounds etc.*

derived character

A characteristic that appears in recent parts of a lineage, but is not seen in its older members.

monophyletic

A clade that includes an ancestor and ALL its descendants

genus

A classification grouping that consists of a number of similar, closely related species

Symoplast (Living protoplasm layer)

A continuum of the *protoplast* and their *plasmodesmata* - This is a pathway that allows intracellular communication that can trigger the plants defense mechanisms.

What is dodder and why can dodder seedling only live for about one week if they do not find a host

A dodder is an invasive parasitic plant also called the *Purple loosestrife*. Due to its lack of roots, ability to photosynthesize, leaves it cannot produce food for itself through autotrophy and hence needs to find a host to leech off of.

pectin

A gel-like substance made up of *hydrophilic carbohydrates* - When water is added to it, the cell wall (which contains it ) becomes more flexible.

In what kinds of habitats do green algae occur?

Algae can occur in freshwater, brackish water, sea water, and virtually anywhere there is a moist environment.

primary cell wall

All plant cells have them, and it is produced while the plant cell is still growing. -It is very pliable, and helps aid in structure, protection, turgidity, determines the cell size, and protects the protoplasts. -Composed of * cellulose, Hemicellulose, pectin, glycoproteins, enzymes, waxes, cutin, suberin, callos, and water*

Why is an outgroup used when constructing a cladogram?

An outgroup is used to identify a closely related group that is not part of the group being analyzed (*often branches off right before the common ancestor of the clade of interest*). It is often used when constructing a cladogram because it can be used to trace back a common ancestor in order to determine if a clade is monophyletic, polyphyletic or paraphyletic. *They can also be used to identify an ancestral trait*

thallus

An un-defined body of a plant. Essentially it has no real defined body plan.

hierarchical classification

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

Essential Elements

Essential for plant growth and reproduction. It leads to deficiency if they are not present.

What kinds of evidence are used to determine phylogenetic relationships? What have been used in the past and what are some problems with those data? What is convergent evolution and why could it lead to incorrect cladograms? What is an example of convergent evolution you saw in the UMaine greenhouse?

Evidence that is used to determine phylogenetic relationships is two classification methods. The first being the *traditional method*which utilizes (*Morphology and anatomy*) and the *cladistics method* which utilizes (molecular evidence, ultrastructure, morphology and anatomy, proteins and nucleic acids) -Usually in the past, strictly phenological traits, such as morphology have been used to identify species, however things that look alike are not always the same or similar species. -*Convergent evolution* is when two separate species have an independent evolutionary event which creates analogous structures that have a similar form and function, but were not present in the last common ancestor of the groups. -Convergent evolution could lead to incorrect cladograms as individuals may mistake a co-evolved trait as something that the two species share evolutionarily when they don't. -Example of convergent evolution in the UMaine greenhouse would be spines as seen on Cactus and the old world succulents.

secondary cell wall

It is found in some plants cells, and helps to add additional strength and support. -it is strong a ridged (*lignified*) , and is formed *after the cell has stopped growing* -It is secreted in layers by the *plasma membrane* and is internal to the primary cell wall - Lacks water (unlike the primary cell wall) and is composed of *Cellulose, Hemicellulose, Lignin*

Name the categories of organisms in their hierarchical order starting with the kingdom and finishing with the species. What are the characteristics of modern scientific names of a plant species?

Kingdom-> Phylum-> Class-> Order-> Family-> Genus-> Species *modern scientific names include the Genus name (which is capitalized and italicized) followed by the lowercase species name.* Prunus pumila (Sand Cherry)

middle lamella

Known as the "middle layer" and it is located in between the primary cell walls. It is VERY malleable and helps to hold adjacent cells together.

Explain why lignified cell walls are a major evolutionary advance.

Lignified cell walls are resistant to compression and other directional forces. They also help to repel water as the compound itself is hydrophobic. Lastly, lignin is a secondary wall component, that is a cross-linked phenolic (compared to a carbon molecule that has double bonds between carbons). Due to these advantages of lignin, plants were able to become stronger, and even display secondary forms of growth, adding to their success.

Sporophyte

Made up of: foot, seta, and capsule (sporangium) - The foot is the embedded apical portion of the gametophyte and serves as a nutrient transfer zone between the sporophyte and the gametophyte. - The Seta is the slender stalk that connect the foot and the capsule. -when the sporophyte is immature the capsule has a covering called the calyptra which is derived from the archegonium.

sporophyll

Modified leaves present in lycophytes that bear sporangia, produce spores

polyphyletic

NOT monophyletic, includes organisms for other lineages, but not within the same group.

Were lycophytes always herbaceous plants? What did extinct lycophytes look like?

No, Lycophytes were not always herbaceous plants. In extinct groups they were often dominant within their forested habitat approximately *300 MYA* - Extinct lycophytes displayed secondary growth, and had a branching root structure.

micronutrients

Nutrients that are needed in smaller amounts, but are just as essential as macronutrients -* Zn, B, Mn, Fe*

chloroplast

One of the three plant plastids that contains starch grains and oil bodies. *it is the main site of photosynthesis*

chromoplast

One of the three plant plastids, this one synthesizes and stores *carotenoid pigments* in oil bodies -carotenoids function to signal both pollinators , and may offer some protection.

Amyloplast

One of the three plant plastids, this one synthesizes and stores starch. - It is found in seeds and storage tissues (rice, potatoes, roots etc.)

Briefly discuss the phloem-immobile elements including their identity, and which parts of the plant show deficiency symptoms first if these elements are in short supply.

Phloem Immobile elements are elements that cannot be moved by the phloem. The phloem-immobile elements are: *B, Fe, Ca* The parts of the plant that shoe deficiency symptoms first are seen in the shoot tips.

Briefly discuss the phloem-mobile elements including their identity, how they move within the plant, and which parts of the plant show deficiency symptoms first if these elements are in short supply

Phloem mobile elements are elements that can be moved around by the phloem in vascular plants. The phloem mobile elements are * N, P, K, Mg* The parts of the plants that show deficiency first are older leaves, in which the plant moves the elements to younger leaves that are healthier and more photosynthetic.

Describe the basic structure of plant cells include its major organelles.

Plant cells have a primary cell wall that encloses a plasma membrane (which may secrete the secondary cell wall), the central vacuole, chloroplasts, nucleolus, nucleus, smooth and rough ER, ribosomes, Golgi vesicles, cytoplasm, mitochondria, along with various plastids, and starch grains for storage.

Gametophyte (1n)

The Dominant lifecycle ONLY in Bryophytes that is photosynthesizing and is haploid (1n). The Gametophyte structure is responsible for producing the sperm and the egg, which will eventually combine to form a diploid (2n) zygote.

Once a drop of sperm-containing water is splashed into the vicinity of an archegonium, how does the sperm find the egg and get to it?

The archegonium or rather the egg will release a volatile compound (pheremone) that will attract the sperm to the egg so that fertilization may occur.

sporangium (capsule)

The capsule as seen in the sporophyte stage (2n) in Bryophytes contains the sporangium in which *meiosis* is conducted to produce haploid spores (1n).

As stem tips grow they trace a more or less regular ellipse in the air. The time needed to complete an ellipse varies with the species and the temperature. In a sunflower seedling it is less than two hours. This behavior is called circumnutation and allows vines to increase their chances of finding a support. What additional method does dodder use to find its host? What are the advantages of this additional method? What evidence is there that dodder can detect suitable host plants by this method?

The dodder also senses volatile compounds (plant pheromones') as it circumnutating towards its host. The advantages to this method is that the dodder is able to find its host species relatively quickly so that it doesn't starve due to its lack of autotrophy. The evidence that the dodder can detect suitable host plants was seen in an experiment where scientists placed a cup of pheromones' into a tank with a dodder seedling and a non-pheromones' producing plant, and the dodder seedling grew towards the pheromones'.

Archegonium

The female reproductive structure in some plants, including mosses and liverworts that produces eggs and develops on the gametophyte

oogonium

The female sex organ of certain algae (like an archegonium) it is responsible for producing the oocyte (egg cell)

Which moss generation, gametophyte or sporophyte, could exist for many years through asexual reproduction? Explain why this generation can do this and the other generation cannot.

The gametophyte stage within Bryophytes can exist for many years and reproduce via asexual production due to it not only being the *dominant life stage for bryophytes* but also due to the fact that this stage is *independent and actively photosynthesizing*. - The sporophyte stage in bryophytes is dependent on the gametophyte for nutrition and is short lived.

How do the gametophytes of Lycopodium obtain carbohydrates?

The gametophytes of lycophytes are buried underground and are connected to a series of *roots* which help support it and absorb the needed essential elements to be synthesized by the sporophyte/ gametophyte into carbohydrates. -*Mycorrhiza fungi interactions, as well as photosynthesis*

phloem (Not in Bryophytes)

The living set of vascular tissue within a plant that conducts sugars throughout the plant. This process of conducting sugars, however, is not a passive process and thereby requires energy for its transport. - contains sieve cells and other cells - conducts sugars and other substances

What is the most primitive kind of stele? In which plant organs (stem, leaf, root) and in what kinds of plants could you find this stele?

The most primitive kind of stele is the *protostele*, you can find the protostele in the roots of most organisms, and sometimes even throughout its body. -the *protostele* can be found in both Monilophytes and Lycophytes. -*The xylem resides in the inside of the protostele while the phloem is on the outside*

Describe the important functions of cell walls in plants.

The plant cell wall is very pliable, and helps aid in structure, protection, turgidity, determines the cell size, and protects the protoplasts.

Where are plasomdesmata located? Explain why plasmodesmata greatly increase the movement of molecules from one cell to another.

The plasmodesmata are transport channels that are located in-between the plant cell walls. Because it is essentially an open channel, it can allow for larger particles to be transported into the plant cell, that otherwise couldn't be transported through diffusion or ion transport.

Describe the primary cell wall, including its main components and where they are located in the cell wall. Describe the basic structure of cellulose. About half of the organic carbon in the biosphere is in cellulose. Why has so much cellulose accumulated? What are hemicelluloses and pectins and what roles do they play in the primary cell wall?

The primary cell wall is a wall that is found in all plants, and is located on the exterior of the protoplasts. The cell wall is Composed of * cellulose, Hemicellulose, pectin, glycoproteins, enzymes, waxes, cutin, suberin, callos, and water* The Basic stricture of cellulose is Glucose molecules that are linked by β 1-4 covalent bonds -So much cellulose is accumulating because of its mixture of both covalent and hydrogen bonds. Therefore, it makes it incredibly difficult to break down hemicellulose A carbohydrate with a variable chemical structure. often found as a components within the plants primary and secondary cell walls in the form of a cross-linked cellulose fibril. Pectins are A gel-like substance made up of *hydrophilic carbohydrates*. When water is added to it, the cell wall (which contains it ) becomes more flexible. -*In the primary cell wall cellulose is interlinked with hemicellulose, and is surrounded by pectin*

Which process (mitosis, meiosis, fertilization, fission) produces the first cell(s) of the sporophyte generation? What about in the gametophyte generation?

The process of *Meiosis* produced the haploid (1n) spores of the sporophyte generation. For the gametophyte generation *Mitosis* occurs to produce the eggs or sperm which will then combine via *fertilization* to become a diploid zygote (2n).

Describe the location and structure of the secondary cell wall. What are its component? In terms of function, how does the secondary wall differ from the primary wall? Which components of the secondary wall are responsible for this?

The secondary cell wall is located internal to the primary cell wall and the plasma membrane (which secretes it) The Secondary cell walls function is to simply provide more support/ rigidity to the plant cell. The secondary cell wall is composed of: Cellulose, Hemicellulose, and lignin (isn't compressible and is hydrophobic)

type specimen

The specimen on which the description of a species is based. -The specimen that has *all* features of a species (essentially a go to reference).

What is the typical morphology of the sporophyte and gametophyte generation?

The sporophytes morphology is essentially a stem that is used to place the spores that are produced by the sporangia into an environment where they are more likely to disperse. The morphology of the gametophyte generation is to have an archegonium and antheridium so that production of the gametes, and fertilization may occur. Since some gametophytes actively photosynthesize they may also have some photosynthetic pigments.

systematics

The study of biological diversity and its evolutionary history. (Includes Taxonomy)

What keeps true mosses from becoming large even though some genera have water conducting cells called hydroids?

Their lack of the structural component *lignin* is what keeps bryophytes staying short and low to the ground. *Also their lack of vascular tissues keep them shorter*

What functions do chloroplasts, chromoplasts and amyloplasts have in plant cells? What is the relationship between a chloroplast and a chromoplast? What is the evolutionary origin of plastids?

These are the three main plastids within plants. Amyloplasts function to: synthesize and stores starch. It is found in seeds and storage tissues (rice, potatoes, roots etc.) Chloroplasts function to: contain starch grains and oil bodies. *it is the main site of photosynthesis* Chromoplasts function to: synthesize and store*carotenoid pigments* in oil bodies. Carotenoids function to signal both pollinators , and may offer some protection. -Both chloroplasts and chomeoplasts contain pigments, and they can interconvert between one another. -Lastly the evolutionary origin of plastids involve the *symbiogenesis theory* that plastids were once a bacterium that was engulfed by eukaryotic cells, as they still have their own DNA and reproduce vis fission.

phloem-immobile element

These elements cannot be moved around the plant phloem, and are therefore lost from the plant with shed parts. Deficiency symptoms can be found @ *shoot tips* -*B, Fe, Ca*

phloem-mobile element

They are elements that can be moved through the phloem of plants. These elements are also partially withdrawn from older *senescing leaves* to be moved to younger more photosynthetic leaves -* N, P, K, Mg*

macronutrients

They are nutrients that are needed in large amounts -*C, H, O, P, K, N, S, Ca, Mg*

carotenoid

They are pigments found in chromoplasts. -They can be yellow, orange, and sometimes red, all of which are fat soluble. -They attract pollinators, help aid in photosynthesis, and may aid in protecting the plant.

anthocyanin

They are stored in the vacuole of plant cells, and can be red or blue depending upon the pH (like and indicator) -This compound helps to function similar to that of sunscreen.

Deleterious (harmful) recessive alleles of genes that are expressed in the moss gametophyte are quickly eliminated from the population but deleterious recessive alleles that are only expressed in the sporophyte are retained. Explain why this is so.

This is due to the fact that the sporophyte is diploid and has two pairs of genes (one of which may cover the deleterious recessive gene). The deleterious dominant alleles are eliminated from the gametophyte stage because it only has one gene (1n) as opposed to two, and is then completely eliminated from the population.

paraphyletic

consists of an ancestral species and some, but not all, of its descendants

lycophytes

oldest extant vascular plant group (branched off 400mya) - those living now are herby (short, small, and small component of their environment - extinct varieties could form huge trees, and had secondary growth by using adventitious roots (=300mya) Isoetes still has secondary growth, grows sideways - dominant part of the plant is the sporophyte (2n) - has leaves comprised of multiple cell layers - meiosis occurs here and generates haploid spores (later grow into 1N gametophyte) w/ chloroplasts - mitosis produces egg and sperm w/ flagella - fertilization of egg produces 2N zygote - similar to life cycle of bryophytes w/ alternation of generations