Photosynthesis to alter the carbon- fixing process thereby

Photosynthesis
is the key-role to play in the fixation  of inorganic carbon (CO2) from the atmosphere
into the organic carbon (glucose) in the biological system that is in plant.
The rate of this process is determine by many physical and biological factors
like O3, CO2, temperature, humidity, light, soil, moisture and Rubisco,
PEP-carboxylase respectively. Any change in the above mention factors leads to
the alteration in process which affect the overall growth and partitioning of
photosynthates between the source and sink. O3 is one of the potent factor
emerging among others which will discuss in details.O3 has the potential to
alter the carbon- fixing process thereby reducing the carbon storage and plant
performance by many ways which disturb the natural process of carbon-cycling
(Figure). O3 limiting the stomatal pore movement , reduce CO2 uptake and alter
photosynthetic machinery .O3 negatively affect the photosynthetic enzymes and
chlorophyll content caused reduction in photosynthates thereby decreasing
overall plant growth.

O3
caused reduction of total green part of the plant due to leaf injury, early
senescence and abscission (Wittig et al., 2009). Defence system against O3
damages cost more available carbon in the plant system which again interfare in
C-allocation, thereby reduction in both below and above ground plant biomass.

Elevated
O3 causes increases the plant respiration which is again the factor lowering
the carbon fixation. The long term alteration in C- sequestration in soil is
alter by O3 pollution as there is significant decreases in the root to shoot
ratio which depicts that root biomass are more sensitive to O3 than shoot
biomass. On the other hand, O3 cause ethylene formation which directly affect
root formation (Wilkinson and Davis, 2010). Overall affect the C-allocation
towards soil is likely to decreased. O3 affects the litter quality and quantity
which causes changes in soil C-cycle (Chapman et al., 2005). The reduction of
root biomass due to O3 pollution was detected in single growing season (Wagg et
al., 2012) which affects the soil C-pools. This effects leads to long term
affect of O3 on ecosystem. O3 has the capabilities to alter the timing and C-
flux to soil which affect the root stock and root exudates consequent changes
in soil community. Other three important processes are potentially altered by
O3 are changes in rhizodeposition, soil microbial structure and soil
properties. Soil biological community is directly depend on C-stock of soil,
therefore changes in soil C bring bad impact on chemical and physical
properties of the soil such as porosity, water holding capacity and aggregate
structure etc.