Lecture 3

Question 1

When seeds go dormant

Answer 1

Some seeds can wait years if needed

Temp and light quality (different wavelengths can penetrate the ground in different ways) and time

Question 2

Seed coat dormancy

Answer 2

No imbibition possible

Testa and micropyle is dense and sealed

Mechanical methods: nicking, abrasion, liquid N2, sulphuric acid

Question 3

Physiological dormancy

Answer 3

Seeds can not develop until embryo does

Chemical inhibitors: in seed coat, fruit or endosperm

Alternating temperatures

Light quality

Question 4

Flowering

Answer 4

triggered by environmental and internal cues

Global warming has a negative effect because some plants can not survive without their pollinators

Question 5

Modifications to aid dispersal

Answer 5

Attract animals, digest seed, inedible seed,

Animals only attracted when seed is ready

Some bitter when unripe/ poisonous

Some explode when pod us dried/ touched

Question 6

Germination

Answer 6

Appearance of radical and shoot from the seed

Question 7

Emergence

Answer 7

Appearance above soil surface

Question 8

Self fertilized

Answer 8

Fusion of male and female gametes from the same plant

You can rip open the flower to change this

Epigentic

Loss of vigour and recessive traits

Question 9

Dioecious plants

Answer 9

male and female organs on separate individuals

Question 10

Heterostyle

Answer 10

Stigma is above the style

2-3 morphs in population

Pollen transfers between different morphs

Question 11

Monecious plants

Answer 11

Anther develops at a rate that when pollen is shed the stigmas are not receptive

Question 12

Genetic incompatibility

Answer 12

Sporophytic: Blocked at stigma

Gametophytic: Blocked in style (gamete is choosing not to grow)

Question 13

Imbibition

Answer 13

Absorbing water