Effect of nitric oxide on antioxidant defence system of spring maize (Zea mays L.) under high temperature stress
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Date
2016
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Punjab Agricultural University, Ludhiana
Abstract
The present investigation was undertaken to study the effect of nitric oxide on antioxidant
defence system of spring maize (Zea mays L.) under high temperature stress (40˚C). For this
study, two genotypes of maize viz., LM-11 (relatively susceptible to heat stress) and CML-32
(relatively tolerant to heat stress) were taken into consideration. High temperature stress
reduced lengths and dry biomass of roots and shoots of seedlings of both the genotypes.
However, priming of seeds with 75µM sodium nitroprusside (SNP) improved seedling growth
in terms of their lengths and biomass, under stress conditions. 75µM SNP specifically
enhanced CAT activity in seedlings of both the genotypes under high temperature stress. It
also increased POX activity in the roots of CML-32 seedlings. This showed that SNP
treatment increased the H2O2 scavanging efficiency of CML-32 genotype by enhancing the
cumulative activation of CAT and POX in its roots. An increase in SOD activity was
observed in roots and shoots of SNP treated LM-11 seedlings that might protect the seedlings
against superoxide radicals. SNP decreased the contents of H2O2 and MDA in seedlings of
both the genotypes indicating reduced membrane damage and lipid peroxidation. Proline
content was also improved by SNP treatment in seedlings of both the genotypes. Thus,
exogenous application of nitric oxide (by priming) improved seedling growth and antioxidant
potential of maize seedlings exposed to high temperature stress.
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