Light and nitrate induction of nitrate reductase in kinetin-and gibberellic acid-treated mustard cotyledons

Saroop, Sant; Thaker, Vrinda S.; Chanda, Sumitra; Singh, Y. D.

doi:10.1007/s11738-998-0020-6

Cited by 13 publications

(8 citation statements)

References 11 publications

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“…The positive effect of GAs on NR activity is well known (Khan 1996, Premabatidevi 1998. A marked rise in the protein content (Table 1) of the treated leaves may well be a consequence of this GA 3 intensified NR activity (Saroop et al 1998). This postulation is further complemented by the positive correlation between the content of proteins and that of the enzyme (r = 0.905**).…”

mentioning

confidence: 94%

Responses of Nigella sativa to foliar application of gibberellic acid and kinetin

Shah¹,

Ahmad²,

Samiullah³

2007

Biologia plant.

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Foliar sprays of water or 1, 10 and 100 μM aqueous solutions of gibberellic acid (GA 3 ) or kinetin (KIN) were applied to 40-d-old plants of Nigella sativa (L.) to study their effects on net photosynthetic rate, nitrogen metabolism, and the seed yield. 10 μM solutions of both the hormones, especially GA 3 , appreciably increased the activities of nitrate reductase and carbonic anhydrase, chlorophyll and total protein contents and net photosynthetic rate in the leaves, along with capsule number and seed yield plant -1 , at harvest.Additional key words: black cumin, capsule number, carbonic anhydrase, leaf protein, net photosynthetic rate, nitrate reductase, seed yield.

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mentioning

confidence: 94%

Responses of Nigella sativa to foliar application of gibberellic acid and kinetin

Shah¹,

Ahmad²,

Samiullah³

2007

Biologia plant.

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“…This was confirmed by in vivo and in vitro techniques (Saroop et al 1998(Saroop et al , 1999. It was concluded that two independent NR fractions operate, with apparently identical properties but separate control mechanisms.…”

Section: Resultsmentioning

confidence: 64%

“…Two forms of NR were detected in mustard cotyledons and both the forms were affected by KiN treatment (Saroop et al 1998). In the present work, the differential effects of tungsten on the two forms of NR are reported.…”

Section: Introductionmentioning

confidence: 96%

Effect of phytohormones and tungsten on light-induced and nitrate-induced nitrate reductase activity of mustard cotyledons

2000

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Mustard (Brassica flmcea Coss cv. T-59 'Varuna') seedlings pretreated with gibberellic acid (GA) and kinetin (KIN) were grown in light. In vivo nitrate reductase (NR) activity was estimated and effect of tungsten on light-induced and NO3-induced NR activity was investigated. Different concentrations of GA did not show any effect on induction of light-induced NR; addition of nitrate promoted in vivo NR activity but no concentration effect of GA was evident. Light-induced NR was promoted by KiN and like in GA treatment, addition of nitrate increased NR activity. Addition of Na-tungstate inhibited NO3-induced NR while tight-induced NR was not much affected in both GA and KiN treated seedlings. The two forms of NRs were further characterized by studying the decay kinetics using Na-tungstate. In light-induced NR, tungstate did not affect NR activity up to 11 h, while at later periods, a slight decay was observed. On the other hand, NO3--induced NR activity increased up to 4 h and subsequently a rapid fall was observed. It was therefore apparent that light-induced NR had a very low turnover rate as compared to NO3--induced NR. These results further support the earlier conclusion that in mustard seedlings two distinct types of NR enzyme exist and that nitrate requirement for NR induction is not absolute.List of abbreviations: GA = gibberellic acid; KiN = kinetin; NR = nitrate reductase

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“…In addition, some reports indicate the involvement of cytokinins as possible mediators in the induction of NR expression by nitrate (Parkash 1972, Samuelson et al 1995), whereas others suggest that nitrate and cytokinins stimulate NR gene transcription independently (Kende et al 1971, Rao et al 1984, Schmerder and Borriss 1986, Solomonson and Barber 1990). Synergisms between cytokinins and light in the induction of NRA have also been proposed (Kohler et al 1980, Saroop et al 1998, Suty et al 1993). Therefore, the question is raised whether a link could be established between cytokinins and temperature in the control of NR expression and activity.…”

Section: Introductionmentioning

confidence: 99%

Thermoperiod affects the diurnal cycle of nitrate reductase expression and activity in pineapple plants by modulating the endogenous levels of cytokinins

Freschi

Nievola

Rodrigues

et al. 2009

Physiologia Plantarum

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Nitrate reductase (NR, EC 1.6.6.1) activity in higher plants is regulated by a variety of environmental factors and oscillates with a characteristic diurnal rhythm. In this study, we have demonstrated that the diurnal cycle of NR expression and activity in pineapple (Ananas comosus, cv. Smooth Cayenne) can be strongly modified by changes in the day/night temperature regime. Plants grown under constant temperature (28 degrees C light/dark) showed a marked increase in the shoot NR activity (NRA) during the first half of the light period, whereas under thermoperiodic conditions (28 degrees C light/15 degrees C dark) significant elevations in the NRA were detected only in the root tissues at night. Under both conditions, increases in NR transcript levels occurred synchronically about 4 h prior to the corresponding elevation of the NRA. Diurnal analysis of endogenous cytokinins indicated that transitory increases in the levels of zeatin, zeatin riboside and isopentenyladenine riboside coincided with the accumulation of NR transcripts and preceded the rise of NRA in the shoot during the day and in the root at night, suggesting these hormones as mediators of the temperature-induced modifications of the NR cycle. Moreover, these cytokinins also induced NRA in pineapple when applied exogenously. Altogether, these results provide evidence that thermoperiodism can modify the diurnal cycle of NR expression and activity in pineapple both temporally and spatially, possibly by modulating the day/night changes in the cytokinin levels. A potential relationship between the day/night NR cycle and the photosynthetic pathway performed by the pineapple plants (C(3) or CAM) is also discussed.

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Light and nitrate induction of nitrate reductase in kinetin-and gibberellic acid-treated mustard cotyledons

Cited by 13 publications

References 11 publications

Responses of Nigella sativa to foliar application of gibberellic acid and kinetin

Responses of Nigella sativa to foliar application of gibberellic acid and kinetin

Effect of phytohormones and tungsten on light-induced and nitrate-induced nitrate reductase activity of mustard cotyledons

Thermoperiod affects the diurnal cycle of nitrate reductase expression and activity in pineapple plants by modulating the endogenous levels of cytokinins

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