Seed Development, plant cell growth, fruits and ripening

Question 1

What causes the development of seeds in plants ?

Answer 1

The fertilization of flowers results in sexual reproduction and the development of seeds

Question 2

What does a seed consist of to enable a period of early heterotrophic growth ?

Answer 2

Seeds consist of small embryo plant, a supply of storage molecules to enable a period of early heterotrophic growth

Question 3

What helps facilitate a seeds dispersal ?

Answer 3

Seeds are often encased in larger structures called fruits, the structures of which can facilitate their dispersal.

Question 4

When do the double fertilization stages in seeds occur in development ?

Answer 4

Both pollen nuclei and egg cell nuclei are haploid and arise by meisosis
The fertilization event results in a diploid zygote which develops within the seed to form a new embryo plant
A second fertilization event between another pollen nucleus and two different egg nuclei produces triploid endosperm.

Question 5

What are the genetic origin of the seed components - 1- Zygote/embryo 2- Endosperm 3- Testa ?

Answer 5

1- Zygote / embryo - half maternal, half paternal and is diploid
2- Endosperm - two thirds maternal, one third paternal and is triploid
3- Testa - entirely maternal in origin and is diploid

Question 6

Define what germination is ?

Answer 6

Seed germination takes place differently in different species. All involve the breakdown of storage molecules to provide energy and nutrients during the transition from HETEROTROPHIC TO AUTOTROPHIC growth.

Question 7

What are all the plant hormones ?

Answer 7

Auxin
Gibberllins
Cytokin
Ethylene
Abscisic acid
Brassinosteriods
Strigalones