9.4 Reproduction In Plants

Question 1

Label a flower

Answer 1

Question 2

Pollination vs Fertilisation vs Seed dispersal

Answer 2

Pollination = movement of pollen (male) onto the stigma (female)

Fertilisation = union of haploid gametes to produce a diploid zygote in the ovary (seed)

Seed dispersal = the action of the seed moving from its place of origin to another site where it will grow

Question 3

Types of pollination

Answer 3

Wind

Animal - eg. bees moving pollen

Water

Question 4

Hermaphroditic

Answer 4

Plants usually are:

They have male and female sex organs

Question 5

Fertilisation

Answer 5

1. Pollen germinates on stigma
2. Goes down style
3. Enters ovary where it meets the egg of the ovule to form a zygote (diploid 46 chromies)
4. Zygote develops into a seed and the ovule develops into a fruit to protect the seed

Question 6

Plant flowering

Answer 6

Short vs Long day plants

Length of darkness (night) observed by the phytochromes

Short day plants flower in winter (shorter days)

Question 7

How plants detect light for flowering

Answer 7

FT gene produces mRNA, taken through phloem to apical meristem to form FT proteins.

FT proteins bind to transcription factors in the apical meristem cells leading to flower producing meristems.

Question 8

Phytochroms

Answer 8

Absorb sunlight with Pr and Pfr structures:

Pr = 660nm (red)

Pfr = 730nm (far red)

• Sunlight absorbed by Pr turns is back into Pfr
• Pr is converted to Pfr during the day
• At night Pfr is slowly converted back into Pr
• When there is left over Pfr during the day from the previous night, plant knows the season

Question 9

Short day vs Long day plants

Answer 9

Short day = Pfr inhibits flowering

Long day = Pfr induces flowering

Question 10

Seed structure

Answer 10

Question 11

Seed dispersal germination techniques

Answer 11