Photosynthesis light limitation

Littler, M. M., Littler, D. S., and Lapointe, B. E. (1988). A comparison of nutrient and light-limited photosynthesis in psammophytic versus epilithic forms of Halimeda caulerpales Halimedaceae from the Bahamas. Coral Reefs 6, 219—226. 

Under conditions of low photorespiration, about 90% of photochemical product is allocated to COj fixation. The progression from light limitation to light saturation in photosynthesis is illustrated in Pig. 3 A which shows a typical light saturation curve for photosynthesis illustrated in the shmb Juanulloa aurantiaca. The quantum requirement per mole COj fixed (on an incident irradiance basis) increases as the irradiance and rate of CO2 assimilation increase. The higher the flux the lower the efficiency of COj assimilation (Fig. 3B). As the ATP and NADPH requirements for COj fixation are independent of... 

During light-limited photosynthesis in leaves, the apparent quantum yield for electron transport, where Jg = e -... 

At high irradiance photosynthesis is limited by CO2 assimilation and more light is absorbed than can be effectively used to drive photosynthesis. Dissipation of surplus excitation energy is essential because excessive excitation leads to the light-induced loss of thylakoid efficiency called photoinhibition. When the rate of carbon assimilation limits the overall rate of photosynthesis the capacity of ATP and NADPH production exceeds that of demand by the Benson-Calvin cycle and photosynthetic control of electron transport would be expected (1, 2). Photosynthetic control... 

In an attempt to reveal the relative rates of recovery of partial steps of photosynthesis, the time course of recovery of light limited and light saturated 02-evolution were determined. After 48 h, the apparent quantum yield had increased from less than 0.008 to 0.057 (fig 2). No further recovery of the apparent quantum yield occurred under conditions used for recovery. The recovery of the light saturated rate... 

Figure 2 illustrates the recovery of photosynthesis of rye cells measured at 25 C under light limiting conditions. The recovery rates were significantly slower at 5 C than at 20 C, but RH and RNH cells show similar rates of recovery. 

FIGURE 3. Comparison of estimates of light limitation obtained from the three approaches a) fluorescence peak, b) burst of photosynthesis, c) light sensitivity. 

Krah N.M. Logan, B.A. (2010). Loss of PSBS Expression Reduces Vegetative Growth, Reproductive Output, and Light-Limited but not Light-Saturated Photosynthesis in Arabidopsis thaliana (Brassicaceae) Grown in Temperate Light Environments. American Journal of Botany, Vol.97, No.4, (April 2010), pp. 644-649. 

The chemical reactions through which chlorophyll converts the energy of solar light to energy in organic compounds is one of nature s best-kept secrets. Man has not been able to unlock it, as he has so many of life s other processes. Moreover, photosynthesis is limited to plants animals store energy in their products—meat, milk, and eggs—but they must depend upon plants to manufacture it. 

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