9.4 repro in plants

Question 1

what are the three stages of sexual reproduction in flowering plants?

Answer 1

1. pollination
2. fertilisation
3. seed dispersal

Question 2

what is pollination (short defin.)

Answer 2

the transfer of pollen grains from an anther to a stigma

Question 3

what is fertilisation? (short defin.)

Answer 3

the fusion of a male gamete nuclei with a female gamete nuclei

Question 4

pollinators have a _________ relationship w flowering plants

Answer 4

mutualistic

Question 5

draw and label an animal-pollinated flower

Answer 5

-

Question 6

how do meristem cells become infloresence meristems? (short)

Answer 6

change in gene expression and differentiation of meristem cells

Question 7

what is photoperiod? (short defin.)

Answer 7

the duration of sunlight that the plant receives per day

Question 8

what is photoperiodism? (short defin.)

Answer 8

the response of the plant to relative lengths of light and darkness

Question 9

what environmental stimuli triggers flowering?

Answer 9

the duration of the absence of sunlight

Question 10

what photoreceptor detects the amount of light for flowering?

Answer 10

phytochromes

Question 11

plants that are triggered by short periods of darkness are….

Answer 11

long-day plants

Question 12

what kind of plant is triggered to flower when there is long periods of darkness?

Answer 12

short-day plants

Question 13

what are the two types of phytochromes?

Answer 13

Pr (red) and Pfr (far red)

Question 14

what kind of light does daylight have?

Answer 14

• red light
• far-red light

Question 15

when does flowering occur for short-day plants?

Answer 15

when the night length is more than a critical length

Question 16

Pr is converted to Pfr when it absorbs _________, and Pfr is converted to Pr when it absorbs ___________

Answer 16

red light, far red light

Question 17

Pfr dominates in the _______

Answer 17

daytime

Question 18

what is the active form and inactive form of phytochromes?

Answer 18

active: Pfr
inactive: Pr

Question 19

Pfr can act as an _______ and _________ of flowering

Answer 19

inhibitor, promoter

Question 20

how does night length affect short day plants in controlling flowering? (3)

Answer 20

• the night length must exceed a critical night length
• Pfr gradually converts back to inactive Pr
• thus Pfr levels fall below a critical level to stimulate flowering

Question 21

how does night length affect long day plants in controlling flowering? (3)

Answer 21

• the night length must be less than a critical night length
• sufficient Pfr remains
• thus Pfr levels accumulate to a critical level to stimulate flowering

Question 22

how do horticulturalists induce short-day plants to flower?

Answer 22

they cover the plant with a opaque black cloth for 12~ hrs a day

Question 23

why is seed dispersal important?

Answer 23

reduces competition for resources between germinating seed and parent plant

Question 24

draw the internal structure of seeds

Answer 24

-

Question 25

what are the conditions for seed germination? (4 factors)

Answer 25

oxygen, water, suitable temperature and pH