Lecture 6

Question 1

what roles does a fruit play in the life cycle of an angiosperm

Answer 1

protection of seeds, dispersal of seed (abiotic and biotic)

Question 2

what is the placenta

Answer 2

portion of the ovary where ovules originate to and which they remain attached after fertilization

Question 3

what is the parietal arrangement of seeds

Answer 3

ovules borne on ovary wall or its extension

- mustard, cucumber

Question 4

what is the axile arrangement of seeds

Answer 4

ovules borne on central tissue in a partitioned ovary with as many locules (sections) as the carpels
- citrus, tomato, okra

Question 5

what is the free central arrangement of seeds

Answer 5

ovules borne on central tissue not connected to ovary wall

- bell pepper

Question 6

what is the marginal arrangement of seeds

Answer 6

placenta formed as a ridge along ventral suture of ovary. ovules borne in two rows
- beans, peas

Question 7

what is basal arrangement of seeds

Answer 7

placentation in a unilocular ovary

- sunflower

Question 8

what are cotyledons

Answer 8

embryonic leaves, different from a post germinative true leaf

Question 9

differentiate between monocots and dicot embryos

Answer 9

monocots have one cotyledons, dicots have two cotyledons

Question 10

what happens in many dicots

Answer 10

the nutritive endosperm gets used up by the developing embryo and results in large cotyledons as food stores

Question 11

what is different about endospermic dicots

Answer 11

they have thin cotyledons

Question 12

what is the epicotyl vs hypocotyl

Answer 12

epicotyl above cotyledon; is stemlike with one of more leaves, the hypocotyl is stemlike portion between the primary shoot and primary root

Question 13

what is the poaceae family

Answer 13

includes some grasses such as wheat, rice, maize

Question 14

what is the scrutellum

Answer 14

large cotyledon attached to one side of the embryo axis in poaceae
- absorbative and in contact with endosperm

Question 15

what is the radicle

Answer 15

the root pole at the lower end with sheathing coleorhiza

Question 16

what is the plumule

Answer 16

the shoot end at the upper side with sheathing coleoptile

Question 17

coleorhiza vs coleoptile

Answer 17

coleorhiza is at the radicle (root end) and coleoptile is at the plumule (shoot end)

Question 18

what is the aleurone

Answer 18

living outermost cell layer of the endosperm

Question 19

how do things like corn become a single seeded fruit

Answer 19

the testa fuses with the pericarp

Question 20

what happens to seeds in order for them to enter quiescence

Answer 20

the testa hardens, becomes impervious and looses water so the embryo exists in a highly dessicated and anoxic state

Question 21

what is quiescence

Answer 21

a state of minimal or basal activity - resting

Question 22

is quiescence the same as dormancy

Answer 22

NO!

Question 23

what makes dormancy different from quiescence

Answer 23

dormancy involves a very precise combination of factors

Question 24

what is imbibition

Answer 24

uptake of water by a seed to cause swelling and rupture of the seed coat

Question 25

what is the role of mucilage

Answer 25

plays an important role in germination and seedling establishment

Question 26

what is GA and where is it synthesized

Answer 26

gibberellic acid, regulates reserve mobilization, is synthesized in the cotyledon and embryo

Question 27

what is skotomorphogenesis

Answer 27

morphogenesis in absence of light - results in etiolated seedlings

Question 28

what is photomorphogenesis

Answer 28

morphogenesis in the presence of light - doesn't result in etiolation

Question 29

why is the hypocotyl bent during morphogenesis

Answer 29

to protect the SAM from injury

Question 30

what are phytochromes

Answer 30

light responsive pigment proteins which sense the presence, intensity, duration, direction, and quality of light - they play a huge roll in de-etiolation

Question 31

what is cryptochrome

Answer 31

absorbs UV and blue parts of the spectrum and affects the process of photosynthesis

Question 32

what is epigeal vs hypogeal

Answer 32

epigeous germination: cotyledons are lifted out of the soil as the apical hook becomes straight and epicotyl bearing foliage grows upwards (bean) hypogea's germination: cotyledons borne on the hypocotyl remain below the soil while the epicotyl emerge above (pea)

Question 33

what is the difference between monocot and dicot roots

Answer 33

monocots have multiple/fibruous roots; dicots have a single tap root with lateral extension

Question 34

what are adventitious meristems

Answer 34

non-embryonic, meristems arising in positions other than normal; supportive of vegetative growth and part of the asexual strategy of propagation

Question 35

what is an example of adventitious roots

Answer 35

the roots on the branches of ivy, roots on the babies of a spider plant (come off of a shoot)

Question 36

what is an example of adventitious shoots

Answer 36

bryophyllum leaves | - an asexual strategy occurring on the notches of the leaves ; shoots lying all around the parent plant on agave plants