Diurnal Acid Metabolism in the Submerged Aquatic Plant, Isoetes tuberculata

3 Pages·1995·1.2 MB·English

by  B D Sharma

American
Fern
Journal 85[2):58-60
(1995)
Diurnal Acid Metabolism Submerged
in the Aquatic
Plant, Isoetes tuberculata
Sharma
and Harsh
B.D.
R.
Dapartment
of Botany, JN Vyas University, Jodlipur, India 342001
metabolism
carry out Crassulacean Acid Metabolism (CAM)
CAM
process, CO^, fixed into malic acid during
is
enzyme PEP
carboxylase enhanced. During
le
is
CO,
decarboxylation
of fixed
enters into the C3
cycle.
ime
the diurnal acid metabolism
Engelm
plant, Isoetes howellii
kn
1985, 1987; Keeley and Bowes, Keeley
1982; genus
et 1983). In India, the
al.,
by
Isoetes is represented several species (Gena and Bhardwaja, 1984; Panigra-
1981; Pant and Sharma
hi, Srivastava, 1962; and they occur
et 1985), as
al.,
amphibious, submerged
terrestrial, or aquatic plants. Diurnal acid metabolism
time submer
in a
sim
method
of monitorin
period.
Methods and
Materials
Well-established, submerged
plants of tuberculata growing an
in
artificial
/.
pond mg
were
selected. 50 leaf samples were washed with water,
distilled
dried by pressing on and pH
blotting paper, crushed The
in distilled water. of
the resulting solution was measured with a Toshniwal pH For each
meter.
was
plant, this procedure repeated at 3 hour intervals up 40 hours, with the
to
arefully
pond was
measured same
artificial also the
at
Results and
Discussion
pH
The
changes
in the of leaf contents during hours two days
different of
and shown pH
nights are The
in Fig. decreases during and
1. the night in-
creases during the This
day. indicates that there an increase in acidification
is
CAM
during the dark, probably due an accumulation
to of malic acid. In
plants, it is malic acid that increases during the night. This malic acid
is uti-
pH
during and
lized the day, the thus increases then.
dH
During the same neriod of time, the of the nnnd watRr alsn c;bnwpd slipht
SHARMA
& HARSH: DIURNAL ACID METABOLISM ISOETES
IN 59
Isoetes tuberculata
10
9
PondwQter
8
7
Leaf
6
5
CL
/;
3
2
1
1 I
1 1 I 1
10
7 10 16 19 22 7 13
13
1 I,
1 I,
HOURS
pH day and During the
Fig. Changes of in the leaves of Isoetes tuberculata during the night.
1.
same period, water from the surrounding pond habitat shows negligible changes.
changes during the day and night. However, this variation is negligible
(Fig.
1).
amounts
show of
tuberculata significant
Preliminary investigations that in
/.
CAM
diurnal acid metabolism occur, and suggest that this species is a plant.
pH method
However, simple measurement of not a conclusive for deter-
is
CAM pH may
An
changes
absence of
mining the operation of in a species.
CAM.
than the absence of Titration (Kee-
well-buffered cytosol, rather
reflect a
CAM.
more method elucidating Further investiga-
1983) a accurate for
ley,
is
tions in this regard are being undertaken in this laboratory.
Literature Cited
HARDW
B
AJ
Bombay 81:165-168.
Nat. Hist. Soc.
420-424
Keeley, 1981
E.
J.
submerged aquatic Isoetes hovveUii
1983. Crassulacean acid metabolism in the seasonally
.
Oecologia 28:57-62.
CAM
economy submerged aquatic Isoetes howellii
The carbon of the
1985. role of in the
.
Angew. Limnol. 22:2909-2911.
Vereinigung Theor.
Verb.
Int.
1987. The adaptive radiation of photosynthetic modes in the genus Isoetes (Isoetaceae)
.
and amphibious Black
aquatic habitats.
113-128 M. M. Crawford, Plant in
Pp. in R. ed., life
England.
Oxford,
well Scientific Publications,
submerged aquatic eras
and Bowes. 1982. Gas exchange characteristics of the
Keeley, G.
E.,
J.
70:1455-1458.
Physiol.
sulacean acid metabolism plant Isoetes howellii. Pi.
AMERICAN
60 FERN JOURNAL
Keeley, Mathews, and M. Walker.
E., R. P. C. 1983. Diurnal acid metabolism in Isoetes howellii
J.
from a temporary pool and a permanent Amer. 70:854-857.
lake. Bot.
J.
Kluge, and
M., P. Ting. 1978. Crassulacean acid metabolism (CAM): Analysis an
I. of ecological
adaptation. Springer-
Verlag, Berlin.
PANIGRAHI. G. 1981. Svstematirs of the Peniis TfinRfR<; fTcnpfarP^ip) in TnHia TnrliaTi n\n] \Aam
T.
6:129-138.
Pant, and
D. D., G. K. Srivastava. 1962. The genus
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Sharma,
B. D., R. Singh, and M. S. Vyas. 1985. Isoetes in Rajasthan—a systematic study. Bull.
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