Modulation of Nitrogen-Utilization Efficiency in Wheat Genotypes Differing in Nitrate Reductase Activity

[], Anjana; Umar, Shahid; Abrol, Y. P.; Iqbal, Muhammad

doi:10.1080/01904167.2011.544529

Cited by 11 publications

(9 citation statements)

References 26 publications

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“…Our results showed that KNO 3 source significantly increased the activities of nitrogen metabolizing enzymes and aminotransferases as also reported by Jain et al (2011);Anjana et al (2011);Asthir and Bhatia (2014);Hawkesford (2014). Whereas, NH 4 Cl elevated activities of GS-GOGAT and aminotransferases (GOT and GPT) along with increase in acid and neutral invertase activities in shoot as well as in root which indicated that unregulated uptake of ammonium supplied as a single nitrogen source is considered to exert a carbon stress on plant roots for its assimilation and subsequent translocation to shoots (Lewis et al 1987;Britto and Kronzucker 2002).…”

Section: Discussionsupporting

confidence: 90%

Hydroponic culturing upregulates sucrose and glutamine metabolism by enhancing their utilization via intermediates of aerobic pathway in wheat

Kaur

Asthir

2016

Cereal Research Communications

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Two wheat genotypes were grown in hydroponic culture, containing 4 mM KNO 3 , NH 4 Cl and NH 4 NO 3 . Activities of N metabolizing enzymes, aminotransferases, carbohydrate and TCA cycle enzymes were analyzed along with protein, amino acid, N, sugar content and growth parameters in shoot and root. After 12 days, the size of shoot and root system decreased significantly when plants were supplied with NH 4 Cl as exclusive N source. Under NH 4 NO 3 growth parameters, N and carbon metabolism were elevated as compared to NH 4 Cl but less than KNO 3 source indicating inhibition of NH 4 + toxicity by NO 3 -uptake. Our results suggested that GDH, aminotransferases and PEPC play an important role in ammonium detoxification by its incorporation into amino acids. Thus, the morphologic differences among plants growing in NH 4 + or NO 3 -nutrition confirm the hypothesis that N source determines the growth habit of plant in wheat by modulating the endogenous levels of protein and sugar content.

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Section: Discussionsupporting

confidence: 90%

Hydroponic culturing upregulates sucrose and glutamine metabolism by enhancing their utilization via intermediates of aerobic pathway in wheat

Kaur

Asthir

2016

Cereal Research Communications

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“…Earlier reports using maize as a model plant, revealed a decreasing trend of N uptake and assimilation at leaf ageing and that the decrease was enhanced when plants were N starved (Hirel et al, 2005). However, reverse trend was observed in crops raised under higher levels of N, which revealed coordinated increase in the activities of all N assimilating enzymes (Anjana et al, 2011). In this study, we elaborated N assimilation in diverse genotypes raised under different N levels to understand biochemical basis of source sink transition of wheat leaves in relation to their variability.…”

Section: Discussionmentioning

confidence: 94%

Nitrogen Nutrition, its Assimilation and Remobilization in Diverse Wheat Genotypes

Kaur¹,

Asthir²,

Bains³

et al. 2015

IJAB

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Nitrogen is an essential element required for plant growth and development. However, over-use of nitrogen fertilizer is not only costly but also environmentally unsafe. Therefore, identification of genotypes possessing higher nitrogen use efficiency (NUE) at sub-optimal dose of nitrogen is the key challenge. In this study, effect of nitrogen on the activities of nitrogen assimilatory enzymes, total soluble proteins and amino acids was studied in wheat genotypes of diverse physiology (viz., GLU 1101, GLU 1356, GLU 2001. Nitrogen was applied at recommended dose (RDN), RDN-50%, RDN-25% and RDN+25% using urea as a source. With increase of nitrogen rate, significant increase in the activities of nitrate reductase, nitrite reductase, glutamine synthetase, glutamate synthase and glutamate dehydrogenase was noted, which caused an increase in protein and amino acid contents in all the genotypes. Activity pattern of studied enzymes revealed an increasing trend from tillering to anthesis stage and thereafter declined in parallel with decrease in protein and amino acid contents. Conversely, nitrogen and chlorophyll content showed a consistent decline with leaf growth. Genotypes GLU 1356 and GLU 2001 maintained higher activities of nitrogen assimilatory enzymes in parallel with higher NUE at RDN-50% and RDN-25%, while genotypes PH132-4836 and PH132-4840 were found to be promising at RDN+25%. A positive correlation of nitrogen assimilatory enzymes (nitrate reductase and glutamine synthetase) with NUE and nitrogen content was also observed indicating that these might be the rate limiting enzymes in nitrogen metabolism. In crux, 25% less than the recommended dose of nitrogen had significant influence on nitrogen metabolism especially in GLU 1356 and GLU 2001 due to high activities of nitrate reductase and glutamine synthetase. These nitrogen efficient genotypes may be exploited in enhancing wheat crop productivity under lower dose of nitrogen to save environment and input cost.

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“…In the recent study Anjana et al (2011) in 15 days old seedlings grown under non limiting N supply, conclusively showed that it was the coordinated increase in the activity of all the enzymes in the N assimilatory pathway in HNR genotype. The present studies were carried out at seedling stage as well as at various growth stages.…”

Section: Discussionmentioning

confidence: 95%

Nitrate assimilation in contrasting wheat genotypes

Jain

Khetarpal

Das

et al. 2011

Physiol Mol Biol Plants

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The plants grown in natural conditions do not express their full potential of nitrogen (N) utilization due to limiting availability of N at later stages of growth. There is a likelihood of manifesting their full potential under non limiting nitrogen supply. In our earlier studies with 15 day old seedlings, it has been shown that high nitrate reductase (HNR) genotype with higher efficiency of the enzymes of the nitrate assimilatory pathway resulted in higher potential of this genotype for N utilization as compared to low nitrate reductase (LNR) genotype. In this study, the two wheat genotypes viz. HNR (HD 2285) and LNR (HD 1981) were grown in pots and were given N in three splits, so as to improve the availability of N at later stages of growth. In another experiment, 15 d old seedlings grown in hydroponics were used for nitrate uptake studies. Examination of the flag leaves at different growth stages revealed that except for nitrate levels which were higher in LNR genotype, the uptake of nitrate from the medium, the activity of the enzymes of the assimilatory pathway including total N were higher in HNR genotypes. In HNR genotype, higher amount of N was mobilized to the grains as compared to the LNR genotype. From our study, it is concluded that that the higher N harvest of HNR genotype is due to the coordinated expression of all the enzymes of the N metabolizing pathway and holistic approach for modifying the plant for better NUE will be beneficial.

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Modulation of Nitrogen-Utilization Efficiency in Wheat Genotypes Differing in Nitrate Reductase Activity

Cited by 11 publications

References 26 publications

Hydroponic culturing upregulates sucrose and glutamine metabolism by enhancing their utilization via intermediates of aerobic pathway in wheat

Hydroponic culturing upregulates sucrose and glutamine metabolism by enhancing their utilization via intermediates of aerobic pathway in wheat

Nitrogen Nutrition, its Assimilation and Remobilization in Diverse Wheat Genotypes

Nitrate assimilation in contrasting wheat genotypes

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