Effect of spermidine on antioxidant defense system in wheat (Triticum aestivum L.) under high temperature stress
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Date
2021
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Punjab Agricultural University, Ludhiana
Abstract
In the present study, the effect of spermidine (Spd) was studied on the antioxidant defense
system of three wheat (Triticum aestivum L.) genotypes (Unnat PBW 343, HD 2967 and HD
3086) under high temperature (HT) stress. The analysis was carried out on the seedling raised
in laboratory (25oC or 32oC) in the pots filled with field soil for six days and yield parameters
in field crop. The crop was sown under three planting conditions i.e. normal (11th November),
late (11th December) and very late (11th January). High temperature significantly reduced
root/shoot lengths, fresh weight and dry weight of all the three genotypes, whereas Spd
mitigated this effect by increasing these attributes. High temperature significantly increased
the activities of superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (GPX) and
ascorbate peroxidase (APX) in shoots of all genotypes. Higher activities of CAT, GPX and
APX in Unnat PBW 343 demonstrate their important role in scavenging H2O2. Conversely,
high temperature stress led to a significant decline in SOD, CAT, APX and GPX activities in
roots with a subsequent increase in diamine oxidase (DAO) and polyamine oxidase (PAO)
activities especially in HD 3086 and HD 2967. Spermidine responded to high temperature
stress by increasing Spd and spermine levels and decreasing putrescine levels. An increase in
MDA and H2O2 content was observed under high temperature stress. However, pretreatment of
Spd under HT further elevated activities of DAO, PAO, SOD, CAT, APX and GPX whereas
contents of MDA and H2O2 were reduced. In fact, Spd treated seedlings performed better in
terms of antioxidant response under HT than seedlings in its absence. Various yield and yield
related parameters like plant height, spikelets per spike, tiller count, 1000-grain weight,
number of grains per ear head, grain yield and biological yield were decreased in late and very
late sown crop. However, Spd application under HT stress increased these parameters. Overall,
the wheat seedlings respond to HT mediated increase in antioxidant defense system by altering
polyamine catabolism though differentially in three wheat genotypes. Among three genotypes
studied, Unnat PBW 343 seems to be better protected against HT stress. Thus, the results
suggested that shoots were more resistant against the destructive effects of H2O2 as also
indicated by low levels of MDA content under HT stress.
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Citation
Jagmeet Singh (2021). Effect of spermidine on antioxidant defense system in wheat (Triticum aestivum L.) under high temperature stress (Unpublished M.Sc. thesis). Punjab Agricultural University, Ludhiana, Punjab, India.