Nitrate reduction in cotyledons of Cicer arietinum L.: regulatory role of cytokinins

Bueno, Maria Soledad; Alonso, Ángel Cabo; Villalobos, Nieves

doi:10.1016/0168-9452(94)90085-x

Cited by 12 publications

(8 citation statements)

References 15 publications

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“…Very low activity was recorded in dark minus NO 3 grown seedlings, whereas, the addition of NO 3 in dark, induced sig- An increase in NR activity by cytokinins in nitrate fed plants was reported (Gaudinova 1990) and it was shown that cytokinins modulate NR protein as well as NR mRNA synthesis (Banowetz 1992). However, it has been proposed that cytokinin and NO 3 regulate NR activity independently, since in many cases the induction of this activity by cytokinin was not related to the accumulation of NO 3 (Bueno et al 1994). BA induces NR activity in cucumber cotyledons in the absence of NO 3, even in dark (Knypl 1973) while, in the present study the requirement of light was absolute (Fig.…”

Section: Resultsmentioning

confidence: 89%

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

et al. 1998

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Nitrate reductase activity in gibberellic acid and kinetin treated mustard (Brassicajuncea Coss. cv. T-59 'Varuna') seedlings, grown in the presence or absence of light and/or NO3 was investigated. While both light and NO3, alone could induce NR activity, their combination showed additive effects. Kinetin treatment significantly promoted both light-and NO3-induced NR activities, assayed by either in vivo or in vitro techniques, whereas, gibberellic acid was almost ineffective. In the absence of both light and NO3, however, phytohormones alone could not induce NR activity. Both light-induced and NO3 induced NR fractions had a pH optima of 7.5, preferred NADH as an electron donor (NADH : NADPH ratio 2.5) and Km values for NO3 was 0.2 mM. Actinomycin D, cycloheximide and tungstate were equally effective in suppressing the development of NR activity after exposure to light or NO3. These results indicate that two independent NR fractions operate, with apparently identical properties but separate control mechanisms.List of abbreviations: GA = gibberellic acid; KN = kinetin; NR = nitrate reductase

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Section: Resultsmentioning

confidence: 89%

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

et al. 1998

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“…a) Extraction of nitrate and nitrite. The extraction of nitrate and nitrite was accomplished following the method of Chartarotwong et al (1976), as modified by Bueno et al (1994). Dry material obtained from calluses was incubated with deionised water (at a proportion of 10 ml/g of sample) in flasks placed in a shaking bath at 80°C for 4 h. After this time, the flasks were boiled for 10 min to complete the extraction.…”

Section: Methodsmentioning

confidence: 99%

“…The method employed to determine nitrate consisted of spectrophotometric measurement at 410 nm of the oxidation product of brucine in sulphuric medium (Marczenko 1976), modified by Bueno et al (1994). The nitrate concentration was deduced from the equation using the experimental value of absorbance at 410 nm.…”

Section: Methodsmentioning

confidence: 99%

“…These can be coupled to another aromatic amine or to phenols to produce an azo dye. The determination method of Marczenko (1976) and modified by Bueno et al (1994) consisted of the reaction between nitrite and sulphanilic acid in HCl medium and later coupling with phenol to form an azo dye that presents the absorbance maximum at 425 nm. The results obtained were expressed as milligrammes per gramme of callus dry weight.…”

Section: Methodsmentioning

confidence: 99%

“…The method of Avalos and Vicente (1986), as modified by Bueno et al (1994) was followed. Fresh M. arborea callus (1 g) was washed with 60 mM PEG and with distilled water, after which they were homogenised with 0.1 M Tris-HCl, pH 7.5 in a mortar with sea sand.…”

Section: Methodsmentioning

confidence: 99%

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Nitrogen compounds in embryogenic and non-embryogenic calluses of Medicago arborea L.

Gutiérrez

Gallego

Alonso

et al. 2010

In Vitro Cell.Dev.Biol.-Plant

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Nitrogen (N) metabolism during embryogenesis may be fundamental in the embryogenic response. We used different explants of Medicago arborea L. subsp. arborea seedlings: cotyledons, petioles and leaves, which form calluses with different embryogenic responses. The endogenous contents of total nitrogen, nitrate, nitrite and ammonia and nitrate reductase activity were determined in embryogenic and non-embryogenic calluses induced from the different explants. The endogenous total N content decreased in the calluses as the culture time progressed, this decrease being more pronounced in the more embryogenic calluses obtained from petioles with the H8 and F0 media. Inorganic N decreased during embryogenesis, coinciding with an increase in organic N. Thus, N metabolism somehow seems to be essential in embryogenesis. The N detected in calluses, at the start of culture, was mainly metabolised to nitrite. This metabolism was very pronounced; especially in embryogenic calluses obtained from cotyledons and petioles. That is, the metabolism of N seemed to be more marked in the calluses in which embryogenesis was greater. The nitrite content decreased in all the calluses, the contents being lower, especially in the last months of culture, in the more embryogenic calluses obtained from petioles. In many calluses, ammonia levels did not follow any general pattern. Neither was it possible to detect changes in ammonia levels between the embryogenic and non-embryogenic calluses. Regarding nitrate reductase activity, no clear differences between embryogenic and non-embryogenic calluses were found.

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Interaction of nitrogen and phosphorus nutrition in determining growth

Groot¹,

Marcelis²,

Boogaard³

et al. 2003

Structure and Functioning of Cluster Roots and Plant Responses to Phosphate Deficiency

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Nitrate reduction in cotyledons of Cicer arietinum L.: regulatory role of cytokinins

Cited by 12 publications

References 15 publications

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

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

Nitrogen compounds in embryogenic and non-embryogenic calluses of Medicago arborea L.

Interaction of nitrogen and phosphorus nutrition in determining growth

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