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  • Fisheries  (64)
  • Phytochrome  (31)
  • 1
    Electronic Resource
    Electronic Resource
    Regulation of enzyme levels by phytochrome in mustard cotyledons: Multiple mechanisms? (1977)
    Springer
    Planta 136 (1977), S. 181-186 
    Details
    ISSN: 1432-2048
    Keywords: Enzyme Regulation ; Sinapis alba ; Phytochrome ; Phenylalanine ammonia-lyase ; Ribulosebisphosphate carboxylase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Phytochrome controls the appearance of many enzymes in the mustard (Sinapis alba L.) cotyledons. The problem has been whether the effect of phytochrome on the appearance of enzymes in this organ is due to a common initial action of Pfr, e.g. due to the liberation of a “second messenger”. We have compared the modulation by light (phytochrome) of the appearance of phenylalanine ammonia lyase (PAL)+ and ribulosebisphosphate carboxylase (Carboxylase)+. PAL becomes detectable in the mustard cotyledons at 27 h after sowing while Carboxylase starts to appear only at 42 h after sowing (starting points, 25° C). The starting points cannot be shifted by light. As a major result, in the case of PAL the inductive effect of continuous red light (given from the time of sowing) remains fully reversible by 756 nm-light up to the starting point (27 h after sowing) while with Carboxylase full reversibility in continuous red light is lost at approximately 15 h after sowing. While the induction of Carboxylase is already saturated at a very low level of Pfr (e.g. continuous 756 nm-light saturates the response) and does not depend on irradiance (e.g. continuous 675 mW m-2 red light and 67.5 mW m-2 red light lead to the same time course), PAL induction is a graded response over a wide range of Pfr doses and depends strongly on the fluence rate (high irradiance response, HIR). It is concluded that PAL induction and Carboxylase induction are not only separated in time but differ in every regard except that both responses are mediated by phytochrome. The present data support the previous conclusion that the specification of the temporal and spatial pattern of development is independent of phytochrome even though the realization of the pattern of development can only occur in the presence of phytochrome (Pfr). It seems that there is no feedback from pattern realization to pattern specification.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00396196
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  • 2
    Electronic Resource
    Electronic Resource
    Investigations on the role of ethylene in phytochrome-mediated photomorphogenesis (1978)
    Springer
    Planta 142 (1978), S. 109-117 
    Details
    ISSN: 1432-2048
    Keywords: Anthocyanin synthesis ; Ethylene ; Phytochrome ; Sinapis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The etiolating, intact mustard (Sinapis alba L.) seedling exhibits a distinct temporal pattern of ethylene production. Light, operating through phytochrome, increases the rate of ethylene production without changing the pattern. Ethylene production of the isolated plant parts (segments), added together, exceed the production of the intact system even if the wound effect is taken into account. There is no significant light effect on ethylene production of the segments. Phytochrome-mediated anthocyanin synthesis in the cotyledons is inhibited by ethylene. The responsiveness towards ethylene of the anthocyanin producing metabolic chain is decreased by phytochrome. As anthocyanin synthesis is only partly inhibited under saturating ethylene concentrations in the atmosphere around the seedlings (100 μl l−1), a twofactor analysis becomes feasible. This analysis leads to the result that phytochrome and ethylene show multiplicative behavior, meaning that phytochrome and ethylene act on the same metabolic sequence (leading to anthocyanin) but independently of each other, and at different sites. Therefore, the hypothesis that ethylene mediates the action of phytochrome in anthocyanin synthesis and photomorphogenesis in general appears to be inapplicable.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00385128
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  • 3
    Electronic Resource
    Electronic Resource
    Control by light of hypocotyl growth in de-etiolated mustard seedlings (1978)
    Springer
    Planta 141 (1978), S. 211-216 
    Details
    ISSN: 1432-2048
    Keywords: Hypocotyl growth ; Photomorphogenesis ; Phytochrome ; Sinapis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract After sowing, mustard (Sinapis alba L.) seedlings were grown for 48 h in white light (25°C). These fully de-etiolated, green seedlings were used as experimental material between 48 and 72 (84) h after sowing. The question researched was to what extent control by light of hypocotyl elongation is due to phytochrome in these seedlings. It was found that the light effect on hypocotyl growth is very probably exerted through phytochrome only. In particular, we found no indication for the involvement of a specific blue light photoreceptor pigment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00387891
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  • 4
    Electronic Resource
    Electronic Resource
    Investigations on the role of ethylene in phytochrome-mediated photomorphogenesis (1978)
    Springer
    Planta 142 (1978), S. 119-122 
    Details
    ISSN: 1432-2048
    Keywords: Chlorophyll ; Ethylene ; Phenylalanine ammonia-lyase ; Phytochrome ; Sinapis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The concept (Burg, 1973) that ethylene mediates the action of phytochrome in seedling photomorphogenesis was tested in the intact mustard (Sinapis alba L.) seedling. The effect of exogenous ethylene (100 μl l−1) on five distinct, phytochrome-mediated photoresponses of the cotyledons was investigated. It was found that anthocyanin contents (see Bühler et al., 1978) and phenylalanine ammonia-lyase levels (EC 4.3.1.5) are strongly reduced by ethylene while the capacity of chlorophyll synthesis is considerably enhanced. Levels of glutathione reductase (EC 1.6.4.2) and pools of photoconvertible protochlorophyll(ide) are unaffected by ethylene. It is concluded that these findings are incompatible with the idea that ethylene plays the role of a mediator in phytochrome-induced photomorphogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00385129
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  • 5
    Electronic Resource
    Electronic Resource
    Inhibition of carotenoid biosynthesis by the herbicide SAN 9789 and its consequences for the action of phytochrome on plastogenesis (1979)
    Springer
    Planta 145 (1979), S. 497-505 
    Details
    ISSN: 1432-2048
    Keywords: Carotenoids ; Chlorophylls ; Herbicides ; Phytochrome ; Plastid development ; Ribulosebisphosphate carboxylase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Treatment of the mustard (Sinapis alba L.) seedling with the herbicide SAN 9789 inhibits synthesis of colored carotenoids and interferes with the formation of plastid membrane lipids without affecting growth and morphogenesis significantly. In farred light, which is hardly absorbed by chlorophyll, development of plastid ultrastructure, synthesis of ribulosebisphosphate carboxylase and synthesis of chlorophyll are not affected by SAN 9789. It is concluded that normal phytochrome actions on plastid structural development, protein and chlorophyll syntheses are not affected by the absence of carotenoids provided that there is no significant light absorption in chlorophyll. The findings show that the inhibition of synthesis of one set of plastid membrane components (the carotenoids) does not stop synthesis of other components such as chlorophyll and does not halt membrane assembly. Supplementary experiments with the closely related compound SAN 9785, which affects the amount and composition of plastid lipids but not carotenoid and chlorophyll syntheses, suggest that the effect of the herbicide SAN 9789 is due exclusively to its inhibition of synthesis of colored carotenoids. In the presence of SAN 9789 white or red light at high fluence rate causes photodestruction of chlorophyll and ribulosebisphosphate carboxylase and photodecomposition of thylakoids. These effects are interpreted as resulting exclusively from the self-photooxidation and photosensitizing action of chlorophyll once the protection by carotenoids of chlorophyll against self- and sensitized photooxidation is lost.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00380105
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  • 6
    Electronic Resource
    Electronic Resource
    Analysis of light-controlled accumulation of carotenoids in mustard (Sinapis alba L.) seedlings (1980)
    Springer
    Planta 148 (1980), S. 279-286 
    Details
    ISSN: 1432-2048
    Keywords: Carotenoids ; Chlorophylls ; Light control ; Phytochrome ; Plastid development ; Sinapis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Carotenoid accumulation in the cotyledons of the mustard seedling (Sinapis alba L.) is controlled by light. Besides the stimulatory function of phytochrome in carotenogenesis the experiments reveal the significance of chlorophyll accumulation for the accumulation of larger amounts of acrotenoids. A specific blue light effect was not found. The data suggest that light exerts its control over carotenoid biogenesis through two separate mechanisms: A phytochrome regulation of enzyme levels before a postulated pool of free carotenoids, and a regulation by chlorophyll draining the pool by complex-formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00380039
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  • 7
    Electronic Resource
    Electronic Resource
    Appearance of nitrite reductase in cotyledons of the mustard (Sinapis alba L.) seedling as affected by nitrate, phytochrome and photooxidative damage of plastids (1986)
    Springer
    Planta 168 (1986), S. 369-376 
    Details
    ISSN: 1432-2048
    Keywords: Nitrate assimilation ; Nitrate reductase ; Nitrite reductase ; Phytochrome ; Plastidic signal ; Sinapis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nitrite reductase (NIR; EC 1.7.7.1) is a central enzyme in nitrate assimilation and is localized in plastids. The present study concerns the regulation of the appearance of NIR in cotyledons of the mustard (Sinapis alba L.) seedling. It was shown that light exerts its positive control over the nitrate-mediated induction of NIR via the farred-absorbing form of phytochrome. Without nitrate the light effect cannot express itself; even though the light signal is accumulated in the cotyledons it remains totally cryptic in the absence of nitrate. Moreover, it was recognised that ‘intact plastids’ are important in the control of the appearance of NIR. If the plastids are damaged by photooxidation the action of nitrate and phytochrome on NIR appearance is abolished. The appearance of nitrate reductase (NR; EC 1.6.6.1) responds similarly to photooxidative damage even though this enzyme is cytosolic. While the data strongly indicate that some ‘plastidic signal’ is a prerequisite for the nitrate-induced and phytochrome-modulated appearance of NIR and NR, the possibility could not be ruled out that photooxidative damage affects the accumulation of NIR in the organelle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00392362
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  • 8
    Electronic Resource
    Electronic Resource
    Expression of nuclear genes as affected by treatments acting on the plastids (1986)
    Springer
    Planta 168 (1986), S. 482-492 
    Details
    ISSN: 1432-2048
    Keywords: Nuclear gene expression ; Photooxidation of chloroplast ; Phytochrome ; Sinapis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In a preceding paper (Oelmüller and Mohr 1986, Planta 167, 106–113) it was shown that in the cotyledons of the mustard (Sinapis alba L.) seedling the integrity of the plastid is a necessary prerequisite for phytochrome-controlled appearance of translatable mRNA for the nuclear-encoded small subunit (SSU) of ribulose-1,5-bisphosphate carboxylase and the light-harvesting chlorophyll a/b-binding protein of photosystem II (LHCP). It was concluded that a signal from the plastid is essential for the expression of nuclear genes involved in plastidogenesis. The present study was undertaken to characterize this postulated signal. Chloramphenicol, an inhibitor of intraplastidic protein synthesis and Norflurazon, an inhibitor of carotenoid synthesis (to bring about photooxidative sensitivity of the plastids) were applied. We obtained the following major results. (i) After a brief period of photooxidative damage a rapid decrease of the above translatable mRNAs was observed. Conclusion: the signal is short-lived and thus required continually. (ii) Once the plastids became damaged by photooxidation, no recovery with regard to nuclear gene expression was observed after a transfer to non-damaging light conditions. Conclusion: even a brief period of damage suffices to prevent production of the signal. (iii) Chloramphenicol inhibited nuclear gene expression (SSU, LHCP) and plastidic development when applied during the early stages of plastidogenesis. Once a certain stage had been reached (between 36–48 h after sowing at 25° C) nuclear gene expression became remarkably insensitive toward inhibition of intraplastidic translation. Conclusion: a certain developmental stage of the plastid must be reached before the signal is released by the plastid. (iv) Under the growth conditions we adopted in our experiments the plastids in the mesophyll cells of mustard cotyledons developed essentially between 36 and 120 (-144) h after sowing. Only during this period could translatable mRNAs for SSU and LHCP be detected. Conclusion: the signal is released by the plastids only during this time span.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00392267
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  • 9
    Electronic Resource
    Electronic Resource
    Regulatory factors involved in gene expression (subunits of ribulose-1,5-bisphosphate carboxylase) in mustard (Sinapis alba L.) cotyledons (1986)
    Springer
    Planta 169 (1986), S. 260-266 
    Details
    ISSN: 1432-2048
    Keywords: Gene expression ; Phytochrome ; Plastidic factor ; Ribulose-1,5-bisphosphate carboxylase ; Sinapis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Phytochrome-controlled appearance of ribulose-1,5-bisphosphate carboxylase (RuBP-Case) and its subunits (large subunit LSU, small subunit SSU) was studied in the cotyledons of the mustard (Sinapis alba L.) seedling. The main results were as follows: (i) Control of RuBPCase appearance by phytochrome is a modulation of a process which is turned on by an endogenous factor between 30 and 33 h after sowing (25° C). Only 12 h later the process begins to respond to phytochrome. (ii) The rise in the level of RuBP-Case is the consequence of a strictly coordinated synthesis de novo of the subunits. (iii) While the levels of translatable mRNA for SSU are compatible with the rate of SSU synthesis the relatively high LSU mRNA levels are not reflected in the rates of in-vivo LSU or RuBPCase syntheses. (iv) Gene expression is also abolished in the case of nuclear-encoded SSU if intraplastidic translation and concomitant plastidogenesis is inhibited by chloramphenicol, pointing to a “plastidic factor” as an indispensable prerequisite for expression of the SSU gene(s). (v) Regarding the control mechanism for SSU gene expression, three factors seem to be involved: an endogenous factor which turns on gene expression, phytochrome which modulates gene expression, and the plastidic factor which is an indispensable prerequisite for the appearance of translatable SSU mRNA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00392323
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  • 10
    Electronic Resource
    Electronic Resource
    Coaction of blue/ultraviolet-A light and light absorbed by phytochrome in controlling growth of pine (Pinus sylestris L.) seedlings (1990)
    Springer
    Planta 180 (1990), S. 212-216 
    Details
    ISSN: 1432-2048
    Keywords: Coaction of photoreceptors ; Cryptochrome ; Phytochrome ; Pinus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Photomorphogenesis is a conspicuous feature in conifers. In the case of the shade-intolerant Scots pine (Pinus sylvestris L.), control of stem growth by light is well expressed at the seedling stage and can readily be studied. The present data show that hypocotyl growth is controlled by the far-red-absorbing form of phytochrome (Pfr). However, the Scots pine seedling requires blue or ultraviolet (UV-A) light to become fully responsive to Pfr. Blue/UV-A light has no direct effect on hypocotyl growth and its action appears to be limited to establishing the responsiveness of the seedling to Pfr. This type of coaction between phytochrome and blue/UV-A light has been observed previously in a number of angiosperm seedlings. With regard to the ‘high irradiance reaction’ of phytochrome in long-term far-red light the pine seedling deviates totally from what has been observed in etiolated angiosperms since continuous far-red light has no effect on stem growth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00193998
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