EFFECT OF OSMOTIC STRESS ON OSMOLYTE ACCUMULATION AND AMMONIA ASSIMILATING ENZYMES IN CHICKPEA CULTIVARS
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Date
2014
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MPKV, UNIVERSITY LIBRARY RAHURI
Abstract
The present research work entitled “Effect of osmotic
stress on osmolyte accumulation and ammonia assimilating
enzymes in chickpea cultivars” was carried out with a view to
evaluate the effect of PEG-6000 induced osmotic stress on nine
chickpea cultivars. The four drought tolerant viz., ICC-4958, Vijay,
Digvijay, PG-70-52 and five drought susceptible cultivars viz., PG09103,
ICC-11117, ICCGP-11112, JG-216 and PG-1808 were
subjected to mild (-0.4MPa) and severe (-1.2MPa) osmotic stress
induced by PEG-6000. The level of relative leaf water content
(RLWC), chlorophyll stability index (CSI), membrane stability index
(MSI), ammonia assimilation enzymes viz. nitrate reductase (NR),
glutamine synthetase (GS), glutamate synthase (GOGAT), proline,
∆1 pyrroline-5-carboxlate synthetase (P5CS) activity, glycine betaine
and mannitol content were estimated.
The RLWC, CSI, MSI significantly decreased in both
drought tolerant and drought susceptible cultivars of chickpea
under mild and severe osmotic stress conditions.
The levels of osmolytes proline, P5CS, glycine betaine
and mannitol were significantly increased in both drought tolerant
and susceptible chickpea cultivars under mild and severe osmotic
stress condition. The extent of increase was higher in tolerant than
susceptible cultivars. The activity of P5CS, a rate limiting enzyme
in proline biosynthesis also increased under mild and severe stress.
The activity of ammonia assimilating enzymes viz., NR,
GS, GOGAT was significantly decreased in both tolerant and
susceptible cultivars of chickpea under mild and severe osmotic
stress condition as compared to control condition and the rate of
reduction was higher in susceptible than tolerant cultivars.
ICC-4958 recorded higher accumulation of osmolytes
viz., proline, glycine betaine, mannitol and P5CS activity with less
decrease in RLWC, CSI, MSI, NR, GS, GOGAT.
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