a) discuss light efficiency, light saturation point, lap and respiratory rate b)

Question

a) discuss light efficiency, light saturation point, lap and respiratory rate
b)list relevant acclimation mechanism specific to light usage this should include mechanism specific to protein concentration and light depended on reaction
c) include discussion about measuring efficiency of light reaction, pigment concentration

uestion 5: Data from a field study were collected to test whether forest thinning (a treatment to allow more light exposure) has an impact the photosynthetic capacity in 2-year-old mrianchevu setd bel oer ollowing questions (25 ps - Control Thinned 2 0 .2 0 500 1000 1500 PPFD (umol-m-2s-1) Figure. Mean light-response curves for American chestnut seedlings grown in control and thinned treatments. Net CO2 assimilation was measured over a range of light levels (PPFD also called PAR)

Explanation / Answer

The question is about forest thinning and its impact on photosynthesis in American chestnut seedlings. Net Carbon dioxide assimilation was measured over a range of light levels (Photosynthetically Active Radiation, PAR)

a. From the graph, it is evident that as light (PAR) is more, more the Carbon dioxide assimilation in thinned compared to control. At light saturation point, Carbon dioxide assimilation was found to be more in thinned seedlings (light saturation point is a particular light intensitiy, after which any increase in amount of light does not increase the rate of photosynthesis. During photosynthesis, respiration rate in comparison to photosynthesis will be less as photosynthesis is considered to be more advantageous to plant as it helps in conserving energy more the rate of respiration, less the rate of photosynthesis so compared to control, thinned seedlings show less respiratory rate which is evident in more net carbon dioxide assimilation.

b.As fixation of Carbon dioxide is more in thinned seedlings compared to control shows that this is acclimation to high light during which photosystem II comes into role. It undergoes rearrangement resulting in reduction of PSII semi-crystalline arrays and reduction in concentration of PsbS protein due to which rate of photosynthesis in high light is more.

c.As light is necessary for photosynthesis and till light saturation point, rate of photosynthesis (which is advantageous to plant ) increases for which chlorophyll pigment is responsible which contains PSI (photosystem I) and Photosystem II (which contains Light harvesting complexes) and depending upon the intensity of light, Photosystems will take the major lead (either I or II) and accordingly increases the efficiency of photosynthesis by utilizing light available.

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