Sulfur and Calcium Simultaneously Regulate Photosynthetic Performance and Nitrogen Metabolism Status in As-Challenged Brassica juncea L. Seedlings

In the present study, the role of sulfur (K2SO4: S; 60 mg S kg-1 sand) and/or calcium (CaCl2: Ca; 250 mg Ca kg-1 sand) applied alone as well as in combination on growth, photosynthetic performance, indices of chlorophyll a fluorescence, nitrogen metabolism, and protein and carbohydrate contents of I...

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Main Authors: Rachana Singh, Parul Parihar, Sheo M. Prasad
Format: Article
Language:English
Published: Frontiers Media S.A. 2018-06-01
Series:Frontiers in Plant Science
Subjects:
Online Access:https://www.frontiersin.org/article/10.3389/fpls.2018.00772/full
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spelling doaj-dad60bfea5464ea2a934690cd3baf3412020-11-25T02:41:14ZengFrontiers Media S.A.Frontiers in Plant Science1664-462X2018-06-01910.3389/fpls.2018.00772374618Sulfur and Calcium Simultaneously Regulate Photosynthetic Performance and Nitrogen Metabolism Status in As-Challenged Brassica juncea L. SeedlingsRachana SinghParul PariharSheo M. PrasadIn the present study, the role of sulfur (K2SO4: S; 60 mg S kg-1 sand) and/or calcium (CaCl2: Ca; 250 mg Ca kg-1 sand) applied alone as well as in combination on growth, photosynthetic performance, indices of chlorophyll a fluorescence, nitrogen metabolism, and protein and carbohydrate contents of Indian mustard (Brassica juncea L.) seedlings in the absence and presence of arsenic (Na2HAsO4.7H2O: As1; 15 mg As kg-1 sand and As2; 30 mg As kg-1 sand) stress was analyzed. Arsenic with its rising concentration negatively affected the fresh weight, root/shoot ratio, leaf area, photosynthetic pigments content, photosynthetic oxygen yield, and chlorophyll a fluorescence parameters: the O–J, J–I and I–P rise, QA- kinetic parameters, i.e., ΦP0, Ψ0, ΦE0, and PIABS, along with Fv/F0 and Area while increased the energy flux parameters, i.e., ABS/RC, TR0/RC, ET0/RC, and DI0/RC along with F0/Fv and Sm due to higher As/S and As/Ca ratio in test seedlings; however, exogenous application of S and Ca and their combined effect notably counteracted on As induced toxicity on growth and other important growth regulating processes. Moreover, inorganic nitrogen contents, i.e., nitrate (NO3-) and nitrite (NO2-) and the activities of nitrate assimilating enzymes, viz., nitrate reductase (NR) and nitrite reductase (NiR) and ammonia assimilating enzymes, viz., glutamine synthetase (GS) and glutamate synthase (GOGAT) along with protein and carbohydrate contents were severely affected with As toxicity; while under similar condition, ammonium (NH4+) content and glutamate dehydrogenase (GDH) activity in both root and leaves showed reverse trend. Furthermore, S and Ca supplementation alone and also in combination to As stressed seedlings ameliorated these parameters except NH4+ content and GDH activity, which showed an obvious reduction under similar conditions. These findings point out that exogenous application of S and/or Ca particularly S+Ca more favorably regulated the photosynthesis, contents of protein, carbohydrate and inorganic nitrogen, and the activities of nitrate and ammonia assimilating enzymes, which might be linked with the mitigation of As stress. Our results suggest that exogenous application of S+Ca more efficiently defends Brassica seedlings by declining As accumulation in root and shoot tissues and by maintaining the photosynthesis and nitrogen metabolism as well.https://www.frontiersin.org/article/10.3389/fpls.2018.00772/fullchlorophyll a fluorescenceglutamate dehydrogenaseglutamate synthaseglutamine synthetasenitrate reductasenitrite reductase
collection DOAJ
language English
format Article
sources DOAJ
author Rachana Singh
Parul Parihar
Sheo M. Prasad
spellingShingle Rachana Singh
Parul Parihar
Sheo M. Prasad
Sulfur and Calcium Simultaneously Regulate Photosynthetic Performance and Nitrogen Metabolism Status in As-Challenged Brassica juncea L. Seedlings
Frontiers in Plant Science
chlorophyll a fluorescence
glutamate dehydrogenase
glutamate synthase
glutamine synthetase
nitrate reductase
nitrite reductase
author_facet Rachana Singh
Parul Parihar
Sheo M. Prasad
author_sort Rachana Singh
title Sulfur and Calcium Simultaneously Regulate Photosynthetic Performance and Nitrogen Metabolism Status in As-Challenged Brassica juncea L. Seedlings
title_short Sulfur and Calcium Simultaneously Regulate Photosynthetic Performance and Nitrogen Metabolism Status in As-Challenged Brassica juncea L. Seedlings
title_full Sulfur and Calcium Simultaneously Regulate Photosynthetic Performance and Nitrogen Metabolism Status in As-Challenged Brassica juncea L. Seedlings
title_fullStr Sulfur and Calcium Simultaneously Regulate Photosynthetic Performance and Nitrogen Metabolism Status in As-Challenged Brassica juncea L. Seedlings
title_full_unstemmed Sulfur and Calcium Simultaneously Regulate Photosynthetic Performance and Nitrogen Metabolism Status in As-Challenged Brassica juncea L. Seedlings
title_sort sulfur and calcium simultaneously regulate photosynthetic performance and nitrogen metabolism status in as-challenged brassica juncea l. seedlings
publisher Frontiers Media S.A.
series Frontiers in Plant Science
issn 1664-462X
publishDate 2018-06-01
description In the present study, the role of sulfur (K2SO4: S; 60 mg S kg-1 sand) and/or calcium (CaCl2: Ca; 250 mg Ca kg-1 sand) applied alone as well as in combination on growth, photosynthetic performance, indices of chlorophyll a fluorescence, nitrogen metabolism, and protein and carbohydrate contents of Indian mustard (Brassica juncea L.) seedlings in the absence and presence of arsenic (Na2HAsO4.7H2O: As1; 15 mg As kg-1 sand and As2; 30 mg As kg-1 sand) stress was analyzed. Arsenic with its rising concentration negatively affected the fresh weight, root/shoot ratio, leaf area, photosynthetic pigments content, photosynthetic oxygen yield, and chlorophyll a fluorescence parameters: the O–J, J–I and I–P rise, QA- kinetic parameters, i.e., ΦP0, Ψ0, ΦE0, and PIABS, along with Fv/F0 and Area while increased the energy flux parameters, i.e., ABS/RC, TR0/RC, ET0/RC, and DI0/RC along with F0/Fv and Sm due to higher As/S and As/Ca ratio in test seedlings; however, exogenous application of S and Ca and their combined effect notably counteracted on As induced toxicity on growth and other important growth regulating processes. Moreover, inorganic nitrogen contents, i.e., nitrate (NO3-) and nitrite (NO2-) and the activities of nitrate assimilating enzymes, viz., nitrate reductase (NR) and nitrite reductase (NiR) and ammonia assimilating enzymes, viz., glutamine synthetase (GS) and glutamate synthase (GOGAT) along with protein and carbohydrate contents were severely affected with As toxicity; while under similar condition, ammonium (NH4+) content and glutamate dehydrogenase (GDH) activity in both root and leaves showed reverse trend. Furthermore, S and Ca supplementation alone and also in combination to As stressed seedlings ameliorated these parameters except NH4+ content and GDH activity, which showed an obvious reduction under similar conditions. These findings point out that exogenous application of S and/or Ca particularly S+Ca more favorably regulated the photosynthesis, contents of protein, carbohydrate and inorganic nitrogen, and the activities of nitrate and ammonia assimilating enzymes, which might be linked with the mitigation of As stress. Our results suggest that exogenous application of S+Ca more efficiently defends Brassica seedlings by declining As accumulation in root and shoot tissues and by maintaining the photosynthesis and nitrogen metabolism as well.
topic chlorophyll a fluorescence
glutamate dehydrogenase
glutamate synthase
glutamine synthetase
nitrate reductase
nitrite reductase
url https://www.frontiersin.org/article/10.3389/fpls.2018.00772/full
work_keys_str_mv AT rachanasingh sulfurandcalciumsimultaneouslyregulatephotosyntheticperformanceandnitrogenmetabolismstatusinaschallengedbrassicajuncealseedlings
AT parulparihar sulfurandcalciumsimultaneouslyregulatephotosyntheticperformanceandnitrogenmetabolismstatusinaschallengedbrassicajuncealseedlings
AT sheomprasad sulfurandcalciumsimultaneouslyregulatephotosyntheticperformanceandnitrogenmetabolismstatusinaschallengedbrassicajuncealseedlings
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