Lecture 7-seed

Question 1

Three ways to be long lived

Answer 1

1. individual long life (Bristlecone pine)
2. continually clone oneself
3. dormancy-sleep for a thousand years

Question 2

Cloning

Answer 2

many fern species, 33% dont even bother with sex
send stems laterally that rise up to produce bushes and trees
eg. Creosote bush clone, Huckleberry clone, quaking aspen (Pando)

Question 3

Old yet germinatable seeds

Answer 3

Cassia multijuga (November shower) in museums, able to germinate after 158 years
Nelumbo nucifera, sacred lotus, 1288 years old

Question 4

Gymnosperm

Answer 4

douglas-fir ovules-seed coat on outside, inside is megagametophyte made of protahllial cells and eggs.

Question 5

Prothalial cells

Answer 5

small, function is to store nutrients

Question 6

Gymnosperm fertilization

Answer 6

2 male gametes delivered by pollen into egg. one is involved in fert., other is useless. zygote formed that grows and pushes into prothallial cells

Question 7

Three developmental stages of embryo

Answer 7

1. differentiation of tissues
2. aquisition of storage products
3. acquisition of physiological abilities (dessication tolerance and cold tolerance)

Question 8

Angiosperm

Answer 8

Sherpherd’s purse ovule. Seed coat on outside, inside is embryo sac of 7 cells, one is egg cell, central (big) cell has two nuclei

Question 9

Angiosperm fertilization

Answer 9

pollen delivers 2 male gametes, both used. one fuses w/ egg to make zygote, other fuses with 2 nuclei of central cell to form endosperm

Question 10

double fert

Answer 10

2 male gametes used

Question 11

endosperm ploidy

Answer 11

triploid, stores lots of nucleic acids

Question 12

Seed size patterns

Answer 12

increases 19times for every 23 degrees towards Equator

Question 13

Enemies of seed

Answer 13

1. temperature

2. drought

Question 14

Germination at high latitudes

Answer 14

triggered only at high temp

Question 15

Germination at low latitudes

Answer 15

tripped at much lower temp

Question 16

Mediterranean germination syndrome

Answer 16

optimal temp for germination if 5-15C (low temp), cool moist frost-free winter protects from drought

Question 17

Northern Europe

Answer 17

seeds avoid germination before severe winter, require high temp to prove winter is past

Question 18

Dormancy

Answer 18

seed’s fastidiousness about germination conditions, no effect form light

Question 19

Germination

Answer 19

seed’s response when environment meets requirements

Question 20

Seeds shed early in growing season (May / June)

Answer 20

need dormancy to prevent germination in autumn

Question 21

Seeds shed late in growing season

Answer 21

do not need dormancy, outside temp low enough to prevent germination until spring

Question 22

Abscisic acid

Answer 22

prevents embryos from germinating

Question 23

Secret to eternal life

Answer 23

protection of membranes