Environmental Engineering Reference
In-Depth Information
Table 4.8
Interrelationships between aboveground biomass and carbon with salinity in the western, central and eastern
sector of Indian Sundarbans
Combination
r
Value (AGB)
r
Value (AGC)
Western
sector
Central
sector
Eastern
sector
Western
sector
Central
sector
Eastern
sector
Salinity
×
S. apetala
−
0.8640*
−
0.8307*
−
0.9234*
−
0.8479*
−
0.8477*
−
0.9754*
Salinity
×
A. alba
0.0336
0.2950
0.0401
0.0232
0.2842
0.1375
−
−
−
−
Salinity
×
E. agallocha
0.9183*
0.9714*
0.8811*
0.9340*
0.9654*
0.8246*
Salinity
×
A. ofcinalis
0.0396
0.1679
0.1874
0.0279
0.1657
0.3318
−
−
−
−
Salinity
×
A. marina
−
0.0049
−
0.0647
−
0.2131
0.0038
−
0.0714
−
0.1237
*
p < 0.01
Secondly, the carbon isotope composition of
leaves shows a range of
ranging from 30 to 50 % of full sunlight. Finally,
there is no convincing evidence in mangroves of
environmentally induced from C
3
to either C
4
or
CAM photosynthetic biochemistry. The gas
exchange in mangroves is strongly regulated by
the amount and properties of the enzyme ribulose-
1, 5-biphosphate carboxylase/oxygenase (RuBi-
sCO), which catalyses the combination of carbon
dioxide with the acceptor molecule ribulose-1,
5-biphosphate (Fig.
4.15
).
13
C values from
23.2 to
δ
−
−
/
°°
reported for C
3
plants (Smith and
Epstein
1971
). Thirdly, the carbon dioxide com-
pensation point is at 25
34.3
°
°
C and saturated light
intensity ranges from 45 to 60
ll
−
1
, consistent
with the photorespiratory activity typical of C
3
photosynthesis. Fourthly, the photosynthetic rates
are maximal at leaf temperature less than 35
µ
C
and generally become light saturated at intensities
°
Fig. 4.15
RuBisCo action in mangrove
fl
ora
