Plant Reproduction Flashcards
How does pollination work?
Male gametophyte: pollen grain
Female gametophyte: embryo sac
Difference between a monocot and a dicot?
Monocots Dicots
One cotyledon • Two coteledons
Floral parts in 3s • in twos
Parallel leaf veins • netlike veins
Pollen grain has one pore/furrow • 3
Vascular bundles throughout stems ground tissue • arranged in a ring
Has short, fibrous roots • has a primary root and several lateral ones
What is double fertilisation? (The first part)
1• Pollen travels from the top of the stigma
2• The megaspore (original mother gamete) divides in the embryo by meiosis
=> 3 megaspores degenerate
=> mitosis occurs 3 times
=> 8 haploid nuclei are formed
(See diagram on 5th November 2014)
What is double fertilisation (second part)
1• The generative cell divides by mitosis to form 2 haploid sperm cells
2• The sperm cells enter the cytoplasm of a synergid, then the pollen tube releases them into the embryosac
3• The synergid breaks down, allowing one sperm to unite with the two central nuclei (this forms the first cell of the triploid endosperm generation => the food supply
4• The other sperm fertilises the egg, forming the zygote (this is the first cell of the diploid sporophyte generation)
What is photoperiodism?
See 9th November 2014
What is the structure of a dicotyledon seed?
See diagram on 7/11/14 and LEARN
What are the factors that affect germination?
- WATER is needed to rehydrate the seeds’ cells. Some cells contain a hormone that inhibits germination and water is needed to wash it out, plus water starts metabolic processes like aerobic respiration
- OXYGEN
- TEMPERATURE
- SEED DEPTH (for food storage reasons)
What is ABA?
Abscisic acid: plant growth regulator which prevents the stomata from opening
It triggers K+ to leave the guard cells => water follows => flaccid cell => closed stomata
This prevents stress (lack of water)
