摘要:

Prolamellar bodies and prothylakoids from etioplasts of wheat (Triticum aestivumL. cv. Starke II, Weibull) were separated by sucrose density gradient centrifugation. Top‐loaded and bottom‐loaded sucrose gradients were compared. As a consequence of avoiding long time exposure of the membranes to low sucrose concentrations, separation in bottom‐loaded gradients, as compared to separation in top‐loaded gradients, resulted in a sharper and more narrow band of prothylakoids, and in better preservation of phototransformable protochlorophyllide, especially in the prothylakoids. In bottom‐loaded gradients, the prothylakoids were found concentrated in a band at a density of 1.20 g'ml−1. The prolamellar bodies were found at a density of 1.17 g'ml−1. In top‐loaded gradients the prothylakoids were found at a lower density than the prolamellar bodies. The prothylakoid fraction contained about 60% of the recovered protochlorophyllide and about 85% of the recovered protein. Absorption and fluorescence emission spectra revealed a higher amount of phototransformable protochlorophyllide, in relation to non‐phototransformable, in the prolamellar body fraction than in the prothylakoid fraction. Polyacrylamide gel electrophoresis indicated a high proportion of protochlorophyllide reductase in the prolamellar bodies. Chloroplast ATPase (CF1) was found predominantly in the prothylakoid fraction. Thus, our results strongly indicate the presence of phototransformable protochlorophyllide in the prolamellar bodies proper, while the main bulk of proteins are located in

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1982.tb00313.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The relation between the different protochlorophyllide (PChlide) forms in isolated etioplast inner membranes was dependent on the concentration of sucrose and NADPH in the isolation media. Etioplasts were prepared from wheat (Triticum aestivumL. cv. Starke II, Weibull) by differential centrifugation. The etioplasts were freed of envelope and stroma and the etioplast inner membranes were exposed to a concentration series of sucrose. Fluorescence emission spectra revealed a positive correlation between the emission ratio 657/633 nm and the sucrose concentration in which the membranes were suspended. Addition of NADPH prevented the degradation of 657 nm emission caused by low sucrose concentrations. PChlide already altered to PChide628–632could not re‐form PChlide650–657after the addition of NADPH in darkness. Prolamellar bodies and prothylakoids were separated in a bottom‐loaded sucrose density gradient in the presence of NADPH. The dominating PChlide‐protein complex in the prolamellar bodies was PClide650–657. Only minor amounts of PChlide628–632were found in these membranes. The prothylakoids had a higher content of PChlide628–632, relative to PChlide650–657, than the prolamellar bodies, as judged from absorption and fluorescence spectra. After phototransformation the fluorescence emission at 633 nm increased relative to the emission from phototransformed PChlide indicating an efficient energy transfer between PChlide628–632and PChlide650–

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1982.tb00314.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The accumulation of polyols byAspergillus niger(van Tiegh) strain S 1 andPenicillium chrysogenum(Thom) strain S 30 was followed during growth in media of different concentrations of NaCl. The major polyols found were glycerol, erythritol and mannitol. The total polyol pool increased in both organisms in response to raised salinity, and the proportion of glycerol and erythritol was markedly enhanced at high salinity.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1982.tb00315.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Contact of adjacent root hairs of seedlings of white clover (Trifolium repensL. cv. Ladino and Louisiana Nolin) led to cell‐cell adhesion of root hair tips. The involvement of the root lectin, trifoliin A, in this phenomen was examined in slide cultures of axenically grown seedlings. Trifoliin A was detected by indirect immunofluorescence on root hair tips, which had adhered to one another. Seedlings grown under conditions which specifically reduce the levels of this lectin on the root surface (e.g., in the presence of 15 mMNO3– or 5 mM2‐deoxy‐d‐glucose) had significantly fewer adhesions of root hair tips. In addition, flushing the slide cultures with 20 mM2‐deoxy‐d‐glucose resulted in an immediate 4‐fold reduction in frequency of tip adhesions. These results are consistent with the lectin cross‐bridging model, which predicts that cell‐cell adhesions would occur when trifoliin A on root hair tips contacts complementary glycosylated receptors on n

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1982.tb00316.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Protein kinase activity was associated with chromatin in wheat (Triticum aestivumL. cv. Mukakomugi) embryos. The kinase activity did not change significantly during germination, whereas the activity of poly (ADP‐ribose) synthetase decreased significantly. The protein kinase activity in chromatin was inhibited by NAD, NADH, and ADP‐ribose, and was enhanced by treatment of the chromatin with snake venom phosphodiesterase or soybean trypsin inhibitor. The activity in chromatin was not stimulated by cyclic AMP. Different subfractions of the histones, H1 and H2, were mainly phosphorylated in germ and 3 day‐germinated seedling chromatins. The histones, H3 and H4, seemed unable to accept phosphate from ATP in thein vitroreaction system. Different acidic non‐histone chromosomal proteins were phosphorylated in germ and 3‐day‐germinated seedling chromations, and germ‐specific and seedling‐specific acidic non‐histone chromosomal proteins seemed unable to accept p

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1982.tb00317.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The effects of changes in source‐sink relation and of cytokinin applications were examined with regard to the development of flag leaves and grain growth in two contrasting spring wheats,Triticum aestivumL., cv. Kolibri and Solo, grown in hydroculture at mean day/night temperatures of 21/19°C.Lowering temperatures during the phase of ear differentiation decreased the ratio of source and sink size (flag leaf area/grains per ear) but hardly affected maximum chlorophyll content of the flag leaf (source activity), maximum rates of grain growth (sink activity), or final grain weight. Nevertheless, considerable differences were produced with regard to the duration of grain filling, the development and coordination of source and sink activities after maxima had been attained.Changing the ratio of source and sink size during grain filling by spikelet removal affected final grain weight the less, the later the treatments began. Comparing, plants with identical source activities demonstrated that differences in grain weight were mainly due to different growth rates between day 16 and 40. Source activities were raised only temporarily (day 23) by spikelet removal done at day 2 or 14.From this it may be concluded that changing the ratio of source and sink size influenced grain weight by creating different intrinsic growth potentials in the grains. These potentials might be estimated 3 weeks after ear emergence by DNA and RNA content per grain.The effects of exogenous cytokinins were consistent with those due to spikelet removal suggesting that this hormone participates in a joint regulation of source and sink activity during grain filli

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1982.tb00318.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Auxin‐binding proteins, have been identified in the soluble cytoplasrnic protein fraction of etiolated pea epicotyls,Pisum sativumL., cv. “Dippes Gelbe Victoria”. The binding is specific for the auxins NAA, IAA and 2,4‐D with a KDin the range of 0.1–0.4 μM. Moreover, the binding is competitive, sensitive to digestion by proteinase and shows linearity with the protein content of the assay mixture. The binding proteins appear to be very labile, since repeated freezing and thawing destroys specific binding. No clear pH‐optimum could be detected in the physiological pH‐range 5.5–8.0, but the binding was doubled at pH 8.0 compar

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1982.tb00319.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The role of uronic acid oxidase in abscission was studied in explants of citrus (Citrus sinensisL. Osbeck; var. Shamouti) leaves and fruits. In leaf explants, activity of uronic acid oxidase prior to onset of abscission and the rate of abscission were markedly accelerated by ethylene and delayed by 2,4‐dichlorophenoxyacetie acid. Similar results were obtained for uronic acid oxidase activity in the exocellular fraction of young fruit explants. In mature fruit explants, treated with ethylene, an immediate increase in activity was evidenty in the non‐active shoot/peduncle abscission zone, whereas in the calyx abscission zone the rise in activity occurred after a prolonged exposure to ethylene, when most of the fruits had already abscised. Whenever ethylene enhanced uronic acid oxidase activity, 2,4‐dichlorophenoxyacetic acid delayed it. A gradient of decreasing activity or uronic acid oxidase was recorded from both sides of the abscission zone in leaves and fruits toward the separation line, where activity was the lowest as compared with the activity found in adjacent tissues. It is suggested that uronic acid oxidase is involved in senescence and cell wall degradation. However, it is yet questionable whether this enzyme is directly related to the control mechanism of absci

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1982.tb00320.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Hoflacher, H. and Bauer, H. 1982. Light acclimation in leaves of the juvenile and adult life phases of ivy (Hedera helix). – Physiol. Plant. 56: 177–182.Light acclimation was investigated during the juvenile and adult life phases of the whole‐plant‐development inHedera helixL. For this purpose, cuttings of the juvenile and adult parts of one single parent plant were grown under low‐light (PAR 30–50 μmol photons m−2s−1) and high‐light (PAR 300–500 μmol m−2s−1) conditions: CO2exchange, chloroplast functions, and specific anatomy of fully developed leaves differentiated under these conditions were determined.In juvenile plants the leaves formed under low and high light had light‐saturated rates of net photosynthesis of 6.5 and 11.1 mg CO2(dm leaf area)−2h−1, respectively. In adult plants the rates were 9.4 and 22.2 mg dm−2h−1, indicating a more pronounced capacity for acclimation to strong light in the adult life phase. Higher photosynthetic capacities were accompanied by higher conductances for the CO2transfer through the stomata, leading to almost the same CO2concentration in the intercellular spaces. Thus, stomatal conductances were not primarily responsible for the different photo‐synthetic capacities. The higher rates in adult and high‐light grown leaves were mainly the result of formation of thicker leaves with more chloroplasts per unit leaf area. Expressed per chloroplast, the photosynthetic capacity, the Hill reaction, and the activity of ribulose bisphosphate carboxylase were almost identical in plants grown in low‐light and high‐light.Measurements of photosynthetic capacity and thickness of leaves ofHederasampled from field habitats with contrasting light regimes confirm the results of growth chamber studies. It is, therefore, concluded that both life phases ofHederaare capable of acclimating to strong light, but that during the juvenile

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1982.tb00321.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The level of 7 chlorophyll‐carotenoid‐proteins was determined in chloroplasts from radish seedlings (Raphanus sativusL. var. Saxa Treib) grown in high‐light (HL; 90 W m−2and low‐light (LL; 10 W m−2) growth conditions with and without application of the photosystem 2 herbicide bentazon (10−4M) and compared with the degree of thylakoid stacking.1The photosynthetic apparatus of HL‐chloroplasts contains higher proportions of the photosystem 1 chlorophylla‐proteins CPI and CPIa than LL‐chloroplasts or chloroplasts from bentazon‐treated plants.2In LL‐chloroplasts and in chloroplasts from bentazon‐treated plants a higher proportion of light‐harvesting chlorophylla/b‐proteins (LHCP1, LHCP2, LHCP3, LHCPy) is found. Bentazon treatment changes the proportion of LHCPs to about the same levels under both HL and LL‐growth conditions. The amounts of free chlorophyll found in bentazon chloroplasts (27–29%) is higher than in the HL or LL‐controls (16–18%).3The increase in degree of thylakoid stacking (% proportion of appressed membranes per total chloroplasts membranes) of LL‐chloroplasts as compared to HL‐chloroplasts of 7 to 9% (3rd to 5th day of illumination) is paralleled by a similar increase in the LHCPs of 5% and 8% (3rd and 5th day). The importance of light harvesting chlorophylla/b‐proteins as a prere

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1982.tb00322.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY