Effects of age and variety on nitrate reductase and nitrogen fractions in potato plants

Kapoor, A. C.; Li, Paul H.

doi:10.1002/jsfa.2740330502

Cited by 21 publications

(7 citation statements)

References 15 publications

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“…(2000) studied expression and activity of nitrate reductase in response to nitrate nutrition of potato, but did not detect either expression or activity of this enzyme in the tubers. These results contrast with earlier reports on nitrate reductase activity in tubers (Kapoor & Li 1982). Glutamine synthetase, the enzyme that catalyses ammonium assimilation, has to our knowledge only been studied with respect to its tissue‐specific distribution in tubers (Pereira et al .…”

Section: Introductioncontrasting

confidence: 99%

Effect of NO₃^‐ supply on N metabolism of potato plants (Solanum tuberosum L.) with special focus on the tubers

Mäck¹,

Schjøerring²

2002

Plant Cell & Environment

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The response of the tubers to NO 3 -was studied in comparison to the other organs of Solanum tuberosum var. Sava, with special focus on: (a) whether tubers are capable of primary N assimilation; (b) whether N assimilation is stimulated by NO 3 -; and (c) whether primary N assimilation in tubers is important for tuber growth. NO 3 -reduction via nitrate reductase (NR; EC 1.6.6.1) and NH 4 + assimilation via glutamine synthetase (GS; EC 6.3.1.2) occurred predominantly in the shoots, but up to 20% was contributed by the tubers under low-NO 3 -conditions. NR activation was highest in tubers (up to 90%) and declined in all organs with increasing NO 3 -supply. NR and GS activity responded with a decline in tubers and roots as opposed to an increase in the shoots. This corresponded to relative organ growth: growth of tubers and roots was stimulated relative to that of shoots at a limiting NO 3 -supply. Absolute growth of all organs was stimulated by NO 3 -, whereas tuber number declined. The concentration of N compounds increased with NO 3 -supply in all organs: NO 3 -increased most dramatically in the shoots (81-fold), free amino acids most markedly in the tubers (three-fold). The amount of patatin and of the 22 kDa protein complex in the tuber reached a minimum when the amount of Rubisco in the shoot reached maximum as a response to NO 3 -supply. Tuber sucrose and starch increased by 40%, whereas glucose and fructose declined two-fold as plant N status increased. It is concluded that tubers are potentially N autotroph organs with capacity for de novo synthesis of amino acids. Primary N assimilation in tubers, however, declines with increasing NO 3 -supply and is not of major importance for tuber growth.

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Section: Introductioncontrasting

confidence: 99%

Effect of NO₃^‐ supply on N metabolism of potato plants (Solanum tuberosum L.) with special focus on the tubers

Mäck¹,

Schjøerring²

2002

Plant Cell & Environment

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“…Leaf NR activity was determined in the youngest fully expanded leaf (3rd or 4th leaf from the apex) in vivo according to the method described by Kapoor and Li (1982) at 20, 27, 35, and 50 DAE. Fresh leaf samples were collected in duplicate and cut into small pieces excluding the margin and midrib.…”

Section: Methodsmentioning

confidence: 99%

Effect of salt stress on some chemical components and yield of potato

Ghosh

Asanuma

Kusutani

et al. 2001

Soil Science and Plant Nutrition

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“…For example, the legume C. cajan can, depending on cultivar, sbow characteristics typical of temperate or tropical plants (Andrews, 1986). Tbus, altbougb cultivars of an individual species usually sbow a similar partitioning of nitrate assimilation between root and sboot at a given external nitrate concentration and respond to increases in external nitrate concentration in a similar fashion (Kapoor & Li, 1982;Andrews, 1986), this is not always the case. It may be possible to select genotypes witbin any species tbat sbow major differences in the partitioning of nitrate assimilation between root and sboot when growing under the same conditions.…”

Section: The Site Of Nitrate Assimilalion In Higher Plantsmentioning

confidence: 99%

The partitioning of nitrate assimilation between root and shoot of higher plants

Andrews

1986

Plant Cell & Environment

411

246

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The partitioning of nitrate assimilation between root and sboot of higber plant species is indicated by tbe relative proportions of total plant nitrate reductase activity (NRA) in tbe two plant parts and the relative concentrations of nitrate and reduced N in tbe xylem sap. Tbese have been collated here from tbe literature and temperate and tropical species compared.Both the distribution of NRA and xylem sap nitrate: reduced N indicate tbat tbe following four generalizations can be made. 1. Temperate, perennial species growing in low external nitrate concentralions (about 1 mol m"^) carry out most of tbeir nitrate assimilation in tbe root. As external nitrate concentration increases (in the range found in agricultural soils, 1-20 mol m~~^), shoot nitrate assimilation becomes increasingly important. 2. Temperate, annual legume species growing in low external nitrate concentralions carry out most of their nitrate assimilation in tbe root. Sboot nitrate assimilation increases in imporlance as external nitrate concentration is increased. 3. Temperate, annual non-legume species vary greatly in tbeir partitioning of nitrate assimilation between root and sboot when growing in low external nitrate concentrations. Regardless of the proportion carried out in tbe root at low external nitrate concentrations, nitrate assimilation in tbe shoot becomes increasingly important as external nitrate concentration is increased. 4. Tropical and subtropical species, annual and perennial, carry out a substantial proportion of their nitrate assimilation in tbe shoot wben growing in low external nitrate concentrations. Tbe partitioning of nitrate assimilation between root and shoot remains constant as external nitrate concentration increases.It is proposed that a greater proportion of nitrate assimilation occurs in tbe sboot wben an increase in the rate of nitrate uptake does not induce an increase in NR level in the root. Thus, a greater proportion of the nitrate taken up remains unassimilated and is passed into tbe xylem. A constant partitioning of nitrate assimilation between root and sboot is •Present addie.ss and correspondence: acbieved by balancing NR levels in tbe root witb rates of nitrate uptake.Tbe advantages and disadvantages of assimilating nitrate in either tbe root or shoot are discussed in relation to temperate and tropical babitats.

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Effects of age and variety on nitrate reductase and nitrogen fractions in potato plants

Cited by 21 publications

References 15 publications

Effect of NO₃^‐ supply on N metabolism of potato plants (Solanum tuberosum L.) with special focus on the tubers

Effect of NO₃^‐ supply on N metabolism of potato plants (Solanum tuberosum L.) with special focus on the tubers

Effect of salt stress on some chemical components and yield of potato

The partitioning of nitrate assimilation between root and shoot of higher plants

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Effects of age and variety on nitrate reductase and nitrogen fractions in potato plants

Cited by 21 publications

References 15 publications

Effect of NO3‐ supply on N metabolism of potato plants (Solanum tuberosum L.) with special focus on the tubers

Effect of NO3‐ supply on N metabolism of potato plants (Solanum tuberosum L.) with special focus on the tubers

Effect of salt stress on some chemical components and yield of potato

The partitioning of nitrate assimilation between root and shoot of higher plants

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Resources

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Effect of NO₃^‐ supply on N metabolism of potato plants (Solanum tuberosum L.) with special focus on the tubers

Effect of NO₃^‐ supply on N metabolism of potato plants (Solanum tuberosum L.) with special focus on the tubers