The biosynthesis of chlorophyll in greening barley (Hordeum vulgare). Is there a light-independent protochlorophyllide reductase?

Apel, Klaus; Motzkus, Michael; Dehesh, Katayoon

doi:10.1007/bf00407088

Cited by 22 publications

(4 citation statements)

References 19 publications

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“…There is also some evidence for light-independent chlorophyll synthesis in the dicotyledons pea (Adamson and Packer 1984) and tobacco (Ikegami et al 1984). These results have been questioned (Apel et al 1984), but we think that they indicate that chlorophyll synthesis in the dark can take place in angiosperms as well, although this only makes a small comribution to the total chlorophyll synthesis. However, this light-independent chlorophyll synthesis is strictly regulated, and in angiosperm seedlings germinated in absolute darkness, the synthesis of both chlorophyll and the other components of the photosynthetic apparatus are strongly repressed.…”

Section: Discussionmentioning

confidence: 85%

Light-induced changes of photosystem II activity in dark-grown Scots pine seedlings

Jansson¹,

Virgin²,

Gustafsson³

et al. 1992

Physiol Plant

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Virgin, !., Gustafsson. P., Andersson, B. and Oquist, G. 1992. Lightinduced changes of photosystem II activity in dark-grown Scots pine seedlings. -Physio!. Plant. 84: 6-12.Both chlorophyll a and h and polypeptides of the photosynthetic apparatus are found in gymnosperm seedlings germitiated and grown in absolute darkness. The photosystem II (PSII) activity is, however, limited, probably due to an inactive oxygen evolving system. In the present study dark-grown seedlings of Scots pine {Pimis sylveslris L.) were transferred to light and changes in antenna size and the activation process of PSII were investigated using fluorescence nieasurements and quantitative western blotting. It was found that the activation process is rapid, requires very little light and that strong light inhibits the process. It takes place without any changes in the primary reactions of PSII. Furthermore, all polypeptides except the major lightharvesting chlorophyll fl/i>-binding protein complex of PSII (LHCII) were present in dark-grown seedlings in amounts comparable to the light treated control. The darkgrown seedlings had the same LHCII polypeptide composition as light treated seedlings, and the LHCII present seemed to be fully connected to the reaction centre. The results indicate that activation of FSII in dark-grown conifer seedlings resembles the photoactivation process of angiosperms. This implies that the fundamental processes in the assembly of the photosystem II complex is the same in all plants, but that the regulation differs between different taxa.

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Section: Discussionmentioning

confidence: 85%

Light-induced changes of photosystem II activity in dark-grown Scots pine seedlings

Jansson¹,

Virgin²,

Gustafsson³

et al. 1992

Physiol Plant

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“…Our data indicate that the enzyme (or enzymes) responsible for the dark synthesis of chlorophyll in barley is present throughout the leaf but is most active or most abundant in immature chloroplasts. Apel et al (1984) reported that they could find no evidence for the existence of a light-independent Pchlide reductase in isolated mature tissue from etiolated plants which were iltaminated for various periods of time before transfer to darkness. The use of isolated mature leaf pieces instead of intact plants for their incorporation studies probably reduced the possibility of demonstrating the existence of a light-independent enzyme.…”

Section: Discussionmentioning

confidence: 98%

“…It also suggests that the enzyme is likely to be present in barley plants growing normally in diurnal environments. Apel et al,, (1984), by measuring the incorporation of radioactively labelled 5-aminolevulinic acid into^ mature leaf pieces, however, could find no evidence for the presence of such an enzyme.…”

mentioning

confidence: 93%

Light‐independent accumulation of chlorophyll a and b and protochlorophyllide in green barley (Hordeum vulgare)

Adamson

Griffiths

Packer

et al. 1985

Physiologia Plantarum

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Barley (Hordeum vulgare L. cvs Clipper, Procter, Astrix) seedlings were transferred from daylight to darkness and changes in chlorophyll a, chlorophyll b, protochlorophyllide and chlorophyllide (μ leaf−1) in either the first or second leaf determined spectrophotometrically after separating the esterified from unesterified pigments by partitioning between ammoniacal acetone and light petroleum ether. Chlorophyll a and b as well as protochlorophyllide accumulated in the dark. The ratio of chlorophyll to protochlorophyllide formed in the absence of light was 18:1. 5‐aminolevulinic acid (10 mM) promoted the synthesis of chlorophyll a and b and protochlorophyllide. Pigment synthesis and response to 5‐aminolevulinic acid addition was related to tissue age. Mature tissue in the apical third of the leaf accumulated most chlorophyll, but per μg chlorophyll present at the time of transfer to darkness, was less efficient than immature tissue towards the base of the leaf. Immature tissue was also most responsive to added 5‐aminolevulinic acid. Chlorophyll synthesis in the dark was accompanied by chloroplast development. Chloroplasts in immature leaf tissue increased in size and extent of thylakoid development when transferred from daylight to darkness. The results indicate that chlorophyll synthesis and chloroplast membrane development in light‐grown barley continue into the dark phase of the diurnal cycle. A light‐independent protochlorophyllide reductase in light‐grown barley seedlings is postulated.

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“…It has been postulated that the photoreduction of protochlorophyllide to chlorophyllide can occur by means of a protochlorophyllide oxidoreductase that doesn't need light activation (Adamson and Packer 1984). These claims have been disputed as, in the dark, all 14C labeled 5-aminolaevulinic acid in barley was found to be synthesized into protochlorophyllide not chlorophyll (Apel et al 1984). However, Rudoi and Chkanikova (1989) found that 14C labeled 5aminolaevulinic acid is synthesized into chlorophyll in Tradescantia .…”

Section: Dark Experimentsmentioning

confidence: 99%

Chlorophyll Characterization of Three Mistletoes and the Chloroplast Ultrastructure within Aerial and Endophytic Tissues of Phoradendron Juniperinum

Dubbs¹

2000

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The biosynthesis of chlorophyll in greening barley (Hordeum vulgare). Is there a light-independent protochlorophyllide reductase?

Cited by 22 publications

References 19 publications

Light-induced changes of photosystem II activity in dark-grown Scots pine seedlings

Light-induced changes of photosystem II activity in dark-grown Scots pine seedlings

Light‐independent accumulation of chlorophyll a and b and protochlorophyllide in green barley (Hordeum vulgare)

Chlorophyll Characterization of Three Mistletoes and the Chloroplast Ultrastructure within Aerial and Endophytic Tissues of Phoradendron Juniperinum

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