Lecture #2

Question 1

What is a Seed?

Answer 1

Sexual reproductive propagule of a flowering plant (angiosperm).

Question 2

What is a Floret?

Answer 2

A grass flower.

Question 3

What is an angiosperm?

Answer 3

A flowering plant.

Question 4

the Caryopsis is sandwiched between two floral bracts called:

Answer 4

Lemma and Palea

Question 5

define Caryopsis:

Answer 5

a small, dry, one seeded fruit. (the seed)

Question 6

a modified leaf is called a

Answer 6

bract

Question 7

The bigger, lowermost (outer) floral bract that encloses the floret is called the:

Answer 7

Lemma

Question 8

The smaller, uppermost (inner) of the two bracts enclosing the floret is called the:

Answer 8

Palea

Question 9

give an example of a type of grass that by threshing, the lemma and palea can be seperated.

Answer 9

Bermudagrass

Question 10

(Inside the Caryopsis) The outer, protective layer of the seed is called the:

Answer 10

Seed Coat

Question 11

What is the Scutellum and what does it do?

Answer 11

Single cotyledon of grass inside the seed that, after respiration begins, produces giberellins.

Question 12

Coleoptile

Answer 12

Protective sheath of the Plumule (embryonic shoot)

Question 13

define Shoot Apex:

Answer 13

The meristem where new shoots arise from

Question 14

What is the Radicle?

Answer 14

The first Seminal (primary) root to emerge from the seed.

Question 15

What is the Coleorhiza?

Answer 15

The sheeth that protects the Radicle

Question 16

what are the necessary factors for seed germination?

What are the most important ones?

Answer 16

• Water
• Proper Temperature
• Oxygen
• non-dormant seed
• Light – (Cool season grasses do not require light for germination, but some warm season grasses like crabgrass do have a light requirement.)
• _Water, Proper Temp. and Oxygen are the most important. _

Question 17

What initiates the seed germination process?

Answer 17

Water initiates process – seed absorbs or imbibes water, it swells and considerable pressure develops within it

Question 18

In the germination process, after the seed abides water, what happens next?

Answer 18

The seed coat ruptures and Aerobic Respiration occurs – requiring oxygen.

Question 19

What is the optimum temperature range for seed germination?

Answer 19

Optimum temperature range is between 25-30 degrees Celsius.

Question 20

Define what Aerobic Respiration does

Answer 20

-Initiates biochemical and morphological events that result in the development of a seedling plant.

Question 21

What does Aerobic Respiration trigger the Scutellum to do?

Answer 21

-Triggers scutellum to produce hormones called giberellins.

Question 22

What do the Giberellins do?

Answer 22

They stimulate the aleurone layer to make enzymes.

Enzymes breakdown starch from the endosperm into sugar for food.

Question 23

What is absorbed by the Embryo?

Answer 23

Sugars for food

Question 24

The Plumule grows to become the:

Answer 24

The Shoot

Question 25

The Radicle grows to become the

Answer 25

The first root - (Seminal or Primary Root)

Question 26

What factors lead to succesful seedling development?

Answer 26

* **Available Moisture** * **Temperature - soil temps ctirical ** * **Oxygen** * **Sufficient Light - C3 grasses do not require light, but some C4 grasses do (ex. crabgrass)**

Question 27

How old should the seed be to germinate most effectively?

Answer 27

1 year old

Question 28

What time of year is C3 seed normally harvested?

Answer 28

June and July

Question 29

Define *After Ripening Dormancy*:

Answer 29

* some seeds need to go through a complex series of enzymatic and biological changes – *after-ripening--*before germination will occur. * * • Generally the conditions following seed ripening are unfavorable for seedling establishment due to drought, disease and excessive weed competition. • As a result most grass seed has evolved after-ripening dormancy to delay germination until cooler more favorable conditions prevail

Question 30

The Coleorhiza is what?

Answer 30

The sheath that protects the radicle.

Question 31

What is the origin of a grass seed? How is it formed?

Answer 31

Floret. It gets polinated.

Question 32

Aleurone Layer

Answer 32

Thin protein layer that produces the enzymes that breakdown starch in the endosperm into sugar (food)

Question 33

Endosperm. What is it and what does it do?

Answer 33

FOOD SUPPLY:: Contains starch that is broken down into sugar by enzymes for food supply during germination.

Question 34

What is the Embryo?

Answer 34

Miniature plant.

Question 35

Sexual reproductive propagule of a flowering plant (angiosperm).

Answer 35

What is a Seed?

Question 36

A grass flower.

Answer 36

What is a Floret?

Question 37

A flowering plant.

Answer 37

What is an angiosperm?

Question 38

Lemma and Palea

Answer 38

the Caryopsis is sandwiched between two floral bracts called:

Question 39

a small, dry, one seeded fruit. (the seed)

Answer 39

define Caryopsis:

Question 40

bract

Answer 40

a modified leaf is called a

Question 41

Lemma

Answer 41

The bigger, lowermost (outer) floral bract that encloses the floret is called the:

Question 42

Palea

Answer 42

The smaller, uppermost (inner) of the two bracts enclosing the floret is called the:

Question 43

Seed Coat

Answer 43

(Inside the Caryopsis) The outer, protective layer of the seed is called the:

Question 44

Protective sheath of the Plumule (embryonic shoot)

Answer 44

Coleoptile

Question 45

The meristem where new shoots arise from

Answer 45

define Shoot Apex:

Question 46

The first Seminal (primary) root to emerge from the seed.

Answer 46

What is the Radicle?

Question 47

The sheeth that protects the Radicle

Answer 47

What is the Coleorhiza?

Question 48

They stimulate the aleurone layer to make enzymes. Enzymes breakdown starch from the endosperm into sugar for food.

Answer 48

What do the Giberellins do?

Question 49

The first root - (Seminal or Primary Root)

Answer 49

The Radicle grows to become the

Question 50

FOOD SUPPLY:: Contains starch that is broken down into sugar by enzymes for food supply during germination.

Answer 50

Endosperm. What is it and what does it do?

Question 51

Miniature plant.

Answer 51

What is the Embryo?