Ecologia Mediterranea

T. S. KSIKSI, N. O. ALSHAYGI
46
Pigment concentration was measured as an
indicator of the Chlorophyll content (Larsson
et al. 1998) using the following methodology:
5 ml of pure acetone was added to 25 mg of
dry blades sample, where it was kept in 4 ˚C
temperature and darkness for 24 h, grinded
with a tissue grinder and kept overnight. The
samples were exposed to sonication for 2 min
before it was centrifuged in 4 degrees C, span
at 3000 rpm for 15 min. The extract
absorbance was measured using spectrophotometer
at 663.2 nm for Chlorophyll-a,
646.8 nm for Chlorophyll-b, and 470 nm for
Carotenoids (Larsson et al. 1998). The chlorophyll
content (mg.ml -1 ) was calculated using
the formula: Chlorophyll content = A/Ed,
where A is the observed absorbance, E is the
extinction coefficient (=5 mg/ml), and d is the
distance of the light path (=1 cm)
SPSS (Polar Engineering and Consulting
2009) was used to perform ANOVA analysis
to compare the main effects (ambient, alternating
and enriched CO 2 ) for each of variables
under study within each date.
Results
Eco-physiological Growth
Shoots of plants grown under salinity stress
for all three treatments followed an inverted
parabolic shape, with ECO 2 treatment always
higher than the other two treatments (Figure 2).
Figure 2 – Variations in shoot length of C. ciliaris under various levels of atmospheric CO 2 ; ambient (500 ppm); enriched (1000 ppm)
and alternating between ambient and enriched levels: A) subjected to salinity stress, B) under non stressed condition.
Figure 3 – Variations in Inflorescence number of C. ciliaris under various levels of atmospheric CO 2 ; ambient (500 ppm); enriched
(1000 ppm) and alternating between ambient and enriched levels: A) subjected to salinity stress, B) under non stressed
condition.
ecologia mediterranea – Vol. 38 (2) – 2012