Phytochrome and Photomorphogenesis Flashcards Preview

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Flashcards in Phytochrome and Photomorphogenesis Deck (58)
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1

is as protein pigment that absorbs red and far-red light most strongly, and also blue light

phytochrome

2

each subunit of phytochrome consists of a light absorbing pigment molecule called

chromophore

3

each subunit of phytochrome consists of a polypeptide chain

apoprotein

4

T/F: Phytochrome is a soluble, light-regulated protein kinase, which first auto phosphorylates and then activates other proteins

true

5

In dark-grown or -- plants, phytochrome is present in a red light-absorbing form Pr

etiolated

6

Pr is converted by -- to a far-red light absorbing form, Pfr

red light

7

switching of forms between Pr and Pfr

photoreversibility

8

Pr = red light

650-680 nm

9

Pfr = far red light

710-740 nm

10

Which form is physiologically active?

Pfr

11

-- red:far red ratio → germination. Lets wild seeds respond when they arrive in a forest gap or clearing

high

12

Low red:far red ratio → -- in sun plants

elongation

13

“Etiolation” response involves allocating strongly to --, to escape the shade

long, thin stems

14

-- plants show etiolation response more strongly

Sun-adapted

15

phytochrome regulates - leaf movements (open day, close night)

nyctinastic

16

in legumes nyctinastic movements are caused by rhythmic -- changes in flexor and extensor motor cells int eh pulvinus at the base of the petiole

turgor

17

because red:far red ratio is low under canopies, plants can sense --

green shade

18

domestic plants lose etiolation response so they can be grown in -- without etiolating

high densities

19

floral meristems distinguished from vegetative meristems by their

larger size

20

transition from vegetative to reproductive dev is marked by an increase in -- in central zone of shoot apical meristem

frequency of cell divisions

21

when reproductive dev is initiated, vegetative meristem is transformed into the -- which bears cauline leaves and flowers

primary inflorescence meristem

22

axillary buds of cauline leaves dev into --

secondary inflorescence meristem

23

inflorescence meristem has -- growth

indeterminate

24

flowers have -- growth

determinate

25

floral meristems initiate four organ types in concentric rings called

whorls

26

initiation of -- consumes all of the meristematic cells in the apical dome

carpels

27

specifies sepals

A

28

specifies petals

A + B

29

specifies stamens

B + C

30

specifies carpels

C