Study Guide 3

Simple fruit

A fruit derived from a single carpel or several fused carpels of one flower one ovary, one flower

S alleles

Self incompatibility alleles - many in a population

gametophyte

The stage in the life cycle of a plant in which the plant produces gametes, or sex cells.

sporophyte

The stage in the life cycle of a plant in which the plant produces spores.

dehiscent

a subcategory of simple, dry fruit splits open at maturity

Be able to draw the angiosperm life cycle. Label where mitosis and meiosis occur. Label whether each structure is haploid or diploid.

check!

Please explain the ABC model for flower development, using diagrams if you like. How will a flower appear if the A, B, or C class genes are mutated?

check!

Try to visualize the parts of a flower that develop into the parts of a fruit. Keep in mind that as the ovary develops into the fruit, the ovary wall can take many forms (e.g. dry versus fleshy; multiple layers; dehiscent versus indehiscent).

check!

Outcrossing

cross pollination between individuals of SAME species Big advantage: genetic diversity amongst your offspring, better chance to adapt to change in conditions for that population

megagametophyte

female gametophyte, embryo sac

Seed

fertilized ovule seed coat = developed from integuments endosperm = triploid, nutrition for embryo/ cotyledons embryo = diploid

Cotyledons

first leaf or first pair of leaves produced by the embryo of a seed plant 2 cotyledons - dicot 1 cotyledon - monocot

micropyle

minute opening in the wall of an ovule through which the pollen tube enters

ABC model

A: sepal A+B: petal B+C: stamen C: carpel B A C

sporophytic self-incompatibility

bits of tapetum (diploid) are stuck to pollen grain If either allele matches alleles of stigma(top of carpel) (2n) it will be rejected signal transduction pathway - pollen does not hydrate so it cant grow a tube cell so wont be able to reach fertilization, callose blocks pollen and or stigma takes up water.

How many cells compose an immature male gametophyte in flowering plants? How many cells compose a mature male gametophyte? When does the male gametophyte become mature? How many cells compose a female gametophyte in flowering plants? How many nuclei? Diagram a female gametophyte within an ovule, and label the parts.

immature male gametophyte is the tube cell and generative cell, so two cells. mature male gametophyte has the tube cell and the generative cell that splits into two sperms cells so three cells. it becomes mature when the tube cell starts growing. ............................................................................................................. 7 cells in a female gametophyte which is the embryo sac, and 8 nuclei. check!

microgametophyte

male gametophyte, pollen grain

multiple fruit

many ovaries, many flowers

aggregate fruit

many ovaries, one flower (raspberry)

double fertilization

occurs when the pollen tube discharges two sperm into the female gametophyte within an ovule, fertilizing the 2 polar nuclei making triploid endosperm and fertilizing the egg a diploid zygote

Why is outcrossing beneficial? When might selfing be beneficial? What are some methods plants use to promote outcrossing? Can you describe the differences between gametophytic and sporophytic self-incompatibility?

outcrossing is beneficial because since it is cross pollination between individuals from the same species, it has more genetic diversity and can better adapt to certain environments Selfing might be beneficial when there is no other flowers around as it only needs itself to reproduce and also if its genes are strong then its great! ............................................................................................................. imperfect flowers are the BEST method that plants use to promote outcrossing. some methods plants use to promote out crossing is having stamens and carpels mature at different times be self incompatible = the rejection of pollen by the stigma of the same plant. ............................................................................................................. gametophytic self-incompatibility is when the s alleles in the pollen recognize the alleles of the stigma, it blocks fertilization from happening sporophytic self-incompatibility is when bits of tapetum is attached to the pollen, if either alleles match to the carpel allele then it will be rejected

megasporangia

produce megaspores that give rise to female gametophytes

Selfing

self fertilize pollinate same flower, or other flowers on same plant Advantage with this one too, only needs to be one individual to reproduce so if you have no one around you, you can still reproduce. If alleles are great then you don't need diversity cuz you're all good, but if your alleles are not strong then you're screwed.

gametophytic self-incompatibility

the S-allele in the pollen(haploid) genome governs the blocking of fertilization If allele matches either allele of stigma, it will be rejected RNAse destroys RNA in growing pollen tube so it can't keep growing. Says nope!

Radicle

the part of a plant embryo that develops into the primary root

pollen

the tiny granules that contain the male gametophyte of seed plants

genetic self-incompatibility

- recognizes self so it rejects fertilization Two types 1. gametophytic 2. sporophytic

Microsporangia

4 pollen sacs in the anthers the inner layer is where the tapetum is located(parenchyma cells), serve as nourishment for the male gametophytes - produces microspores that give rise to male gametophytes

microspore (mother cell)

A diploid cell in plants that divides by meiosis to give rise to four haploid microspores

Fruit

A mature ovary of a flower that protects dormant seeds and aids in their dispersal.

Coleoptile

Covers and protects the shoot as it grows upward in monocots

ovary

In flowers, the portion of a carpel in which one or more ovules are present

What are the parts of a typical flower? Contrast complete and incomplete flowers, bisexual (perfect) and unisexual (imperfect) flowers, monoecious and dioecious plants. Can a flower be both incomplete and perfect?

Sepals, petals, stamens, carpels ............................................................................................................. Complete flowers have all four parts of the flower Incomplete flowers are missing one or more of the four basic floral organs or nonfunction. ............................................................................................................. Bisexual (perfect) flowers have both stamen and carpels. Unisexual (imperfect) flowers have either stamens or carpels ............................................................................................................. monoecious= female and male flowers on same plant dioecious= female and male flowers on different plants (so plant has only male flowers or only female flowers) ............................................................................................................. Yes a flower can be both incomplete and (bisexual) perfect. Just maybe the stamen or carpel or stamen or petals are non functional.

accessory fruit

contains other floral parts in addition to ovaries, like the receptacle seen in pome

ovule

contains the megaspore mother cell female reproductive structure of a seed plant where the haploid egg develops

Try to visualize the embryo within a seed as it grows into a seedling. Where does the plant obtain its nutrition during these early stages of growth? How do dicots and monocots (such as grasses) protect the shoot apical meristem of the seedling as it emerges from the soil?

from the endosperm monocots protect their shoot apical meristem by their coleoptile, it grows first and emerges through the soil. dicots protect their shoot apical meristem with their seed coat.

apomixis

Asexual Reproduction - make seed without fertilization - embryo develops from diploid cell in ovule fragmentation, its a clone - seedless bananas are propagated asexually

Hypocotyl

Part of the developing embryo that will become the lower part of the stem and roots

Epicotyl

Part of the embryo in a seed that becomes the upper part of the stem and leaves

embryo sac

The female gametophyte of angiosperms, formed from the growth and division of the megaspore into a haploid 7 cell, 8 nuclei with two polar nuclei in central cell

flower

The reproductive structure of an angiosperm sex organ

pollination

The transfer of pollen from male reproductive structures(anther) to female reproductive structures (stigma) in plants

indehiscent

a subcategory of simple, dry fruit which are closed at maturity usually with one seed per ovary where more than one ovule may be present

What are the advantages of asexual reproduction, and how do plants achieve this? How do we take advantage of plant asexual reproduction for commercial applications?

advantages of asexual reproduction is that it produces clones of itself without needing to be fertilized. through fragmentation, budding, etc - seedless bananas are propagated asexually - more uniform plants

What is the difference between an ovule and a seed? What are the products of double fertilization? What is the difference between pollination and fertilization?

an ovule is an immature seed, once mature and fertilized it turns into a seed. ............................................................................................................. sperm fertilizes two polar nucleui producing endosperm (triploid) sperm fertilizes egg cell producing a zygote (diploid) ............................................................................................................. pollination is when pollen is transferred from anther to stigma, doesn't mean it will fertilize as the s alleles can reject the pollen fertilization is when the pollen grows its tube cell down to the ovule and enters through the micropyle and synergid cells.

megaspore (mother cell)

divides by meiosis to form 4 haploid megaspores

How might the diversity of flowers be associated with pollination? How might the diversity of fruit types be associated with plant dispersal?

through the S alleles in pollen, they can reject if an allele matches the stigma and prevent fertilization of same flower so more diversity. ?