Light-induced Development of Polyribosomes and the Induction of Nitrate Reductase in Corn Leaves

Travis, R. L.; Huffaker, R. C.; Key, Joe L.

doi:10.1104/pp.46.6.800

Cited by 74 publications

(40 citation statements)

References 28 publications

(39 reference statements)

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“…Several workers have reported an increase in the population of polysomes following illumination of etiolated leaves of various species (l1, 32,37). Although an effect of light on the polysome region is apparent from the results in Figures 1 and 2, it was not clear whether this was due to an effect on rRNA Plant Physiol.…”

Section: Methodscontrasting

confidence: 42%

Effect of Light on Ribonucleic Acid Metabolism in Greening Maize Leaves

Harel¹,

Bogorad²

1973

Plant Physiol.

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The effect of illumination on the incorporation of labeled precursors into RNA of dark-grown maize (Zea niays) leaves was studied using either 3P-phosphate or double labeling with "4C-and 3H-uridine. In the dark, label was preferentially incorporated into etioplast ribosomal RNAs. Incorporation into this fraction and into lower molecular weight fractions was strongly and preferentially stimulated by light during the first 2 hours of illumination. The effect persisted after illumination was terminated. The possibility that light-induced alterations in plastid ribosomal RNA metabolism may not be required for chlorophyll accumulation in maize is discussed.Sucrose density gradient analyses of ribosomes and of extracted RNA did not reveal light-induced incorporation of label into messenger-like RNA associated with polyribosomes during brief illumination. However, newly produced RNA which seems to be neither ribosomal RNA nor transfer RNA is detectable after illumination for 2.5 hours or longer.Seedlings of angiosperms growing in complete darkness develop only immature chloroplasts which contain a small amount of protochlorophyllide but lack chlorophyll and many other components of the photosynthetic apparatus. Immediately upon illumination the protochlorophyllide is reduced to chlorophyllide, and the membranous elements of the prolamellar body are rearranged. Soon afterwards additional chlorophyll is produced and a number of plastid enzymes including RNA polymerase increase in activity. These changes are not all controlled by a single mechanism because the production of chlorophyll, for example, ceases soon after illuminated plants are returned to darkness but some other activities increase at accelerated rates even after illumination ceases. The role of light in regulating the various events which occur during greening is not understood although some segments of the processes have been described and studied in detail (3,5,6, 22).Investigations with inhibitors have suggested that continuous protein and DNA-dependent/RNA synthesis are required for at least some of the processes in the development of plastids in higher plants and in Euglena (2,7, 12. 16, 31. 33 MATERIALS AND METHODSMaize (Zea mays) seeds (WF 9 X B 37 -F1 single cross, Illinois Foundation Seeds, Inc.) were soaked for 1 day before planting and grown in vermiculite in the dark for 9 to 10 days at 27 C.Application of Isotopes, Preparation of Subceliular Fractions, and Isolation of Ribosomes. Leaves were harvested under a green safelight, and their cut bases were put into isotope solutions in small tubes. The leaves were placed in front of a fan to accelerate uptake of the isotope. Uptake in the dark usually required 1 to 1.5 hr. Plants were then either transferred to white fluorescent light (400-500 ft-c) or kept in the dark. At the end of treatment, the leaves were frozen in liquid N2 in the dark and were ground in a mortar and pestle with 0.5 ml of 0.5 M sucrose, 0.1 M tris-HCl buffer pH 7.6 containing 25 mM MgCl2 and 2 mm spermidine per gram ...

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Section: Methodscontrasting

confidence: 42%

Effect of Light on Ribonucleic Acid Metabolism in Greening Maize Leaves

Harel¹,

Bogorad²

1973

Plant Physiol.

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“…This is further supported by light measurements taken under the canopy (2000 lux) that were below the light saturation value of 8000 lux. The role of light in inducing the enzyme is a matter of controversy (Beevers et al 1965;Chen and Ries 1969;Travis, Huffaker, and Key 1970). These authors suggest that light affects nitrate absorption and translocation or the maintenance of protein synthesis via the formation of polyribosomes.…”

Section: Discussionmentioning

confidence: 99%

Nitrate Accumulation and Reduction in Papaw Fruits

Menary¹,

Jones²

1972

Aust. Jnl. Of Bio. Sci.

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Nitrate reductase activity was present in roots, stems, leaves, and fruits of the papaw. In fruits, the location and activity of nitrate reductase varied with stage of maturation. Nitrate reductase activity was induced in the exocarp of green and mature green fruits by light and light plus exogenous nitrate. The endogenous nitrate in the exocarp of ripe fruit was not available for reduction and hence no induction occurred in the presence of light only. As fruit tissues comll1enced to show colour changes, there was a marked loss in their nitrate reductase activity. At the mature green stage of maturity, phloem transport appeared to predominate over xylem transport and this reduced the net influx of nitrate to fruit. The levels of nitrate observed in fruits at various stages of maturity may be explained in terms of the following: changes in nitrate reductase activity associated with fruit maturation; the availability of endogenous nitrate for reduction; factors controlling the net influx of nitrate into fruits and distribution of nitrate within fruits.

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“…Light is known to stimulate NR induction through increased protein synthesis (2,18,20,22). The influence of light and dark on NR activity in intact green plants, supplied with sufficient substrate to induce high levels of enzyme activity, has received less attention and may involve different responses than experienced with induction studies.…”

mentioning

confidence: 99%

“…Diurnal fluctuations in NR activity have been reported (7,9), 1 with increased activity upon illumination and decreased activity during a dark period (7,(18)(19)(20). Shading also decreases NR activity (8).…”

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confidence: 99%

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Nitrate Reductase Activity in Soybeans (Glycine max [L.] Merr.)

Nicholas¹,

Harper²,

Hageman³

1976

Plant Physiol.

129

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The optimum In vivo nitrate reductase (NR) asay medium for soybean (Glycine mar [L.] Merr.) leaves was 50 mm KNO3, 1% (v/v) 1-propanol, and 100 mm potasim phosphate buffer (pH 7.5).Loss of in vivo NR activity from leaves of soybean exposed to dark was fastest at 40 C and slowest at 20 C. However, by the end of a 16-hr dark period, even those plants exposed to the lowest (20 C) temperature had lost 95% of the initial activity. Upon re-exposure to lght, following a 16 hr-30 C dark period, in vivo NR activity increased rapidly to maxmum levels after 4 hr lIght. The rate of increase was proportional to gbht intensity (6, 16, and 45 Iklux) and independent of temperature (20, 30, and 40 C).Studies with field-grown soybeaso indicated that nighttime temperature (16-27 C) had no effect on the subsequent in vivo NR activity in sunlight at ambient temperature. There was a marked decrease in in vivo NR activity in late afternoon with the field-grown plants. This decrease continued throughout the night with elevated temperature (27 C) while NR activity increased when a cooler (16 C) night temperature was imposed.The changes in in vivo NR activity in response to lght and dark treatments were quite rapid and thought to be related to energy limittions as well as enzyme level.

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Light-induced Development of Polyribosomes and the Induction of Nitrate Reductase in Corn Leaves

Cited by 74 publications

References 28 publications

Effect of Light on Ribonucleic Acid Metabolism in Greening Maize Leaves

Effect of Light on Ribonucleic Acid Metabolism in Greening Maize Leaves

Nitrate Accumulation and Reduction in Papaw Fruits

Nitrate Reductase Activity in Soybeans (Glycine max [L.] Merr.)

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