lecture 7_pg.26-36

Question 1

shade plant

Answer 1

N/A

Question 2

sun plant

Answer 2

N/A

Question 3

irradiance

Answer 3

N/A

Question 4

quantum flux density

Answer 4

a measure of the level of irradiance; it is expressed as quanta incident on a (horizontal) plane per unit of time

Question 5

photon flux density (PFD)

Answer 5

a measure of the level of irradiance in the (near) visible spectral region; it is expressed as photons incident on a (horizontal) plane per unit of time; photosynthetic photon flux density (PPFD) refers to the photynthetically active part of the spectrum

Question 6

phytochrome

Answer 6

photoreceptor absorbing red or far-red radiation (depending on its configuration); this pigment is involved in the perception of the presence of light, light quality, and daylength

Question 7

sunflecks

Answer 7

N/A

Question 8

light-compensation point

Answer 8

irradiance level at which the rate of CO2 assimilation in photosynthesis is balanced by the rate of CO2 production in respiration

Question 9

quantum yield

Answer 9

moles of CO2 fixed or O2 evolved in photosynthesis, or electrons transported in the photosynthetic membrane, per mole of quanta absorbed; in the context of gas exchange often restricted to the linear, light-limited part of the photosynthesis-irradiance curve; when measuring chlorophyll fluorescence, it refers to the full range of photosynthetic irradiance

Question 10

apparent quantum yield

Answer 10

N/A

Question 11

path length

Answer 11

N/A

Question 12

ultrastructure

Answer 12

N/A

Question 13

chlorophyll (chl a/chl b)

Answer 13

green pigment in the photosynthetic membrane (thylakoid) involved in light capture as the first step in photosynthesis

Question 14

grana

Answer 14

stacked region of photosynthetic membranes (thylakoids) in chloroplasts that contains PSII with its light-harvesting complex

Question 15

light-harvesting complex (LHC)

Answer 15

complex of molecules of chlorophyll, accessory pigments, and proteins in the thylakoid membrane that absorbs quanta and transfers the excitation energy to the reaction center of one of the photosystems

Question 16

photosynthetic capacity

Answer 16

N/A

Question 17

systemic signals

Answer 17

N/A

Question 18

photodamage/photodestruction

Answer 18

damage to/destruction of components of the photosynthetic apparatus as a result of exposue to high irradiance, frequently in combination with other stress factors; the result is photoinhibition

Question 19

photoinhibition (i.e., dynamic, chronic, sustained)

Answer 19

decline in photosynthetic efficiency upon exposure to high irradiance; the decline can be trasnient (< 24 hrs), which is related to protection of the photosynthetic apparatus, or it can be longer lasting, which implies photodamage