| dc.description.abstract | The present study attempted to assess the CO 2 assimilation efficiencies of six tree
species (Terminalia arjuna, Swietenia macrophylla, Pongamia pinnata, Simarouba
glauca, Mimusops elengi, and Syzygium cumini) under controlled growth conditions.
The experiment was carried out in two growth chambers, each with a volume of 6.32
m 3 , constructed with PVC frames and covered with transparent polyvinyl chloride
sheets. The control chamber (CC) was equipped with the facility for the supply of
ambient air, whereas the treatment chamber (TC) with the facility for the supply of
CO 2- air mixture in specific doses using an air compressor and a nebulizer. Both
chambers were fitted with the facility for the analysis of CO 2 (NDIR type Infrared Gas
Analyzer), temperature ( 0 C), and humidity (%) using a Billion Bag digital wireless
electronic hygro-thermometer. Both chambers were also equipped with an exhaust
facility at the top along with a semi-automated facility for the irrigation of plantlets
during experimentation.
For treatment studies, ca. 11⁄2-year-old saplings of T. arjuna, S. macrophylla, P.
Pinnata, S. glauca, M. elengi, and S. cumini were employed separately. For each
study, one set of saplings was retained in the CC and the other in the TC and were
then closed and sealed from the outside. The CC was supplied daily twice (9 am and 6
pm) with ambient air, maintaining a CO 2 concentration of 475±42 ppm, and the TC
with a CO 2 -air mixture, maintaining a resultant CO 2 concentration of 979.83±30.93
ppm. The magnitude of CO 2 concentration (ppm) along with temperature and
humidity within the chambers was monitored twice a day at 9 a.m. and 6 p.m. The
experiment was continued for 15 days. The resultant day and night flux in CO 2 was
estimated from these results of CO 2 . A standardization study was also undertaken in
the same way in empty chambers (without plants) and the results were used for the
estimation of gross and net flux in CO 2 associated with the respective tree species.
During experimentation the growth (plant height, stem diameter, leaf length, leaf
breadth, leaf number, and leaf area and biomass) and biochemical changes (pigments
such as chlorophyll a, b, total chlorophyll, carotenoids; plant metabolites such as
carbohydrates, protein, and phenol; minerals such as calcium, magnesium, sodium and
xviipotassium and carbon and nitrogen) owing to varying levels of CO 2 supply at specific
stages of growth were assessed. The results are statistically validated.
The study revealed that the CO 2 assimilation potentials of Swietenia macrophylla are
higher, followed by Terminalia arjuna, Pongamia pinnata, Simarouba glauca,
Syzygium cumini, and Mimusops elengi. The species Swietenia macrophylla is found
to be more efficient in carbon sequestration, due to its increased CO 2 assimilation,
lower respiratory release, increased biomass content, increased growth characteristics,
metabolites, and nutrients. The species can be considered by policymakers and urban
planners for its inclusion in various carbon offset planting initiatives. However, the
present outcomes are based on a laboratory-based analysis and hence field-level or
site-specific validation of the species is required for further confirmation of their
Carbon sequestration potentials. | en_US |
