摘要:

NADPn–protochlorophyllide oxidoreductase (EC 1.6.99.1; PCR) is the major protein component of the prolamellar body (PLB) membrane of the etioplast. The interaction between the pigment–protein complex of PCR and the membrane lipids is of importance for the induction and maintenance of the regularly branched PLB structure. The isoelectric point of the PLB surface and the impact of salt treatment on the PLB structure, the PCR absorbance properties and the association of PCR to the membrane, have been studied in isolated fractions of PLBs from dark–grown wheat (Triticum aestivumL. cv. Starke 11). We conclude that the PLB membrane has its isoelectric point at pH 4.5. which is similar to that of other plastid membranes. The PLB membrane and the pigment–protein complex of PCR are both affected by salt treatment. Concentrations below 50 mM MgCl2, or 250mM KCI tend to stabilize the regularly branched strueture. while higher concentrations of both mono– and divalent cations lead to disintegration of the membrane and shifts towards shorter wave–lengths of the in vivo absorbance spectra of protoehlorophyllide. PCR. the dominant PLB protein, however, seems to be intimately associated with the membrane lipids and is not washed off the membrane by repeated sal

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1990.tb09042.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Dunalliella salina(Teodoresco) is a unicellular, wall‐less, halotolerant green alga. Previous work has shown that levels of inositol phospholipiils in whole cells ofD. salinafluctuate in response to hyper‐ and hypo‐osmotic shock. In this paper, we report the effects of changes in the light environment on levels of phospholipids, including inositol phospholipids, inD. scilina.Utilizing both short‐term and long‐term labeling of phospholipids with32PO4, we were able to compare both immediate and long‐term changes in lipid metabolism during changes in the light environment. Relative to the other phospholipids. phosphotidic acid and the inositol phospholipids phosphatidylinositol, phosphatidylinositol 4‐phosphate and phosphatidylinositol 4,5‐bisphosphate were rapidly labeled, even in the dark, suggesting that the metabolism of these compounds is more active than that of the bulk cellular phospholipids. There was little change in inositol phospholipid metabolism when cells were illuminated following a 1 h dark adaptation period, Furthermore, the inositol phospholipid signal transduction pathway did not respond to severe photoinhibition treatment. Apparently this plasma‐membrane‐based signal transduction pathway, which responds to changes in the external environment, is relatively insensitive to major changes in chl

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1990.tb09043.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

The regulatory role of abscisic acid (ABA) and kinetin on influx of K+(86RB+) IN tools of 7day old intact winter wheat which plant (Fritieun aestivum I ass starke 1 and 11) Was studied the inhibitory effect of 40,80 μM ABA in the uptake solution on K+(86RB+)influx was transiently stipulated pretreatment of the plants with ABA kinetin content enacted inhibitors effect caused by ABA. At low water potential in the uptake solution (05MPa)K+(86RB+) influx was slights higher in the presence of ABA than in is absence High humidity 123kpa ca 100% relative humidity (RID)around the shoots counteracted the inhibitory effect on k+(86RB+) influx caused by A,B,A IN the uptake solution the present data contain the hypothesis that when plants are subjected to conditions such as low water potential and low temperature. ABA stimulates K influx to facilitate water uptake

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1990.tb09044.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Brauer, D., Schubert C. and Tu, S,‐I. 1990. Characterization of a Ca2+‐translocating ATPase from corn root microsomes. ‐ Physiol. Plant. 78: 335‐344.The existence of a Ca2+‐translocating ATPase in microsomes from maize (Zea maysL. cv, WF9 × Mo17) roots was evaluated using assays to follow Ca2+‐stimulation of ATP hydrolysis and Ca2+transport by changes in the fluorescence of chlorotetracycline, ATP hydrolysis by microsomes was stimulated by the addition of Ca2+and further enhanced by the Ca ionophore A23187 and bovine brain calmodulin only in the presence of Ca2+, Stimulation by these agents was additive and sensitive to vanadate. These results were consistent with the presence of a Ca2+‐translocating ATPase in microsomal membranes. The fluorescence of chlorotetracycline in the presence of microsomes and Ca2+increased upon the addition of ATP, indicating the transport of Ca2+, The initial rate and extent of change in fluorescence were stimulated by calmodulin and quenched by the addition of either A23187 or EGTA, but not by protonophores. Changes in chlorotetracycline fluorescence were prevented by vanadate. Therefore, results using chlorotetracycline also indicated the presence of a Ca2+‐translocating ATPase, Localization experiments indicated that the majority of the Ca2+‐translocating ATPase was on the end

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1990.tb09045.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Corollas ofPetunia hybrida(cv. Hit Parade Rosa) flowers fixed14CO2under both light and dark conditions. Rates of light fixation were much higher in mature pink corollas than in young, green corollas [57 and 9 nmol (ngchl)1min‐1], paralleling the development of chloroplasts in these tissues. Stomatal conductance in corollas was only 12% of that in green leaves, mainly due to the presence of few, and non‐functioning stomata in the corolla. The activity and concentration of ribulose bisphosphate carboxylase (EC 4.1.1.39) in corolla extracts were only about 30% (per unit Chi) of those in extracts from green leaves. These results, together with previous results, might indicate a coordinated reduction in activity of systems participating in photosynthesis in corollas. The fixation products following a 6 s pulse with14CO2, were typical of C, plants in both corollas and green leaves, but a higher level of β‐carboxylation products was found in the corollas. The activity of phosphoenol‐pyruvate carboxylase (EC 4.1.1.31) (per unit protein) was similar in both tissues. Although the total carbon fixed by the corolla constituted only a small part of the metabolites required for flower development, certain photosynthetic metabolites might have a regulatory role in flower dev

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1990.tb09046.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Sodium butyrate at 5mMin aerated White's medium reduced the mitotic index in root meristems of seedlings ofPisum sativumto<1% after 12 h. This effect was lessened as the butyrate concentrations were lowered. The fraction of the root meristem nuclei in G2 increased to ~ 70% after 12 h in butyrate. After 12 h exposure to butyrate, seedlings transferred lo medium without butyrate gradually re‐established their normal root meristem mitotic pattern, with a burst of mitosis at 10 h after the transfer. Even a brief exposure to butyrate inhibited DNA synthesis, and nuclei released from butyrate exposure were still unable to resume normal DNA synthesis even after 12 h. This information suggests that butyrate halts progression through the cell cycle by arresting meristem nuclei in G2 and inhibiting DNA synthesi

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1990.tb09047.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

The ontogenetic course followed by somatic embryos of interior spruce is highly dependent on the media concentration of abscisic acid (ABA). Little or no organized development occurs in the absence of ABA and as the level of ABA is increased, a range of embryo types is produced. “Shooty embryo” structures predominate in many callus lines at low levels of ABA (1‐10 μM), while 10‐20 μM ABA promotes the formation of bipolar embryos that germinate precociously. When ABA is increased to 30‐40 μM, precocious germination is inhibited and opaque cotyledonary embryos characteristic of their zygotic counterparts are formed which enter a period of quiescence. Only “mature” somatic embryos contain significant amounts of storage proteins and the level to which these proteins accumulate is dependent on the concentration of ABA. Indole‐butyric acid (IBA) included with ABA increases the number of mature embryos. Root elongation, which was used as a measure of embryo quality, was never observed from shooty embryo Structures and was 2‐3 fold higher in mature embryos compared to those that ger

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1990.tb09048.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Seasonal fluctuations of carbohydrates and nitrogenous components in the roots of the noxious perennial leafy spurge (Euphorbia esulaL.) are strongly associated with overwintering strategy, Amino acids and distinct soluble proteins accumulate during fall and remain at elevated levels throughout winter. The formation of carbohydrate reserves in roots was not significantly affected by decapitation or selective defoliation; however, maximum amino acid and soluble protein contents were markedly reduced. In particular, the accumulation pattern of a 26 kDa protein was altered. This protein may play a role in plant conditioning and regenerative potential.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1990.tb09049.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

A large–scale purification procedure for mitochondria from spinach (Spinacia oteraceaL, cv Medania) leaves is described. It involves differential centrifugation and density gradient centrifugation on a self–generating gradient of Percoll, From 3 kg of spinach leaves, 150 mg mitochondrial protein are obtained. The thylakoid contamination is lower than 0.2% on a chlorophyll basis. The mitochondria oxidize malate and glycine with state 3 rates of 108 and 140 nmol (mg protein)‐1min‐1, with respiratory control ratios of 2,7 and 3,8 and ADP/O ratios of 2,0 and 2.1, respectively. The present large–scale purification procedure will facilitate further biochemical and molecular biological studies of leaf mitochondrial proteins.A pure and active catalytic moiety of the F1–ATPase (EC 3,6,1,3) was purified from the isolated mitochondria. The yield was 5 mg of F1–ATPase from 150 mg mitochondria. The F1–ATPase contained five polypeptides of apparent molecular mass 54 kDa (α), 52 kDa (β), 33 kDa (γ), 22 kDa (ω) and 11 kDa (ɛ). An additional component at 24 kDa was present in variable amounts in some preparations and was therefore not ascribed to the ATPase complex. The enzyme catalyzed ATP hydrolysis at a rate of 12.5 nmol (mg protein)‐1min‐1. Antibodies against the spinach mitochondrial F1–ATPase cross–reacted only with the a and β subunits of F1–ATPases of spinach chloroplasts, photosynthetic bacteriaRhodospirillum ru

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1990.tb09050.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Solute compartmentation in cells is an important component of metabolic regulation. There is only little information on how stress treatment of cells effects this component. Therefore, the effect of water stress [10% (w/v) PEG 6000] on the vacuolar‐extravacuolar proline compartmentation was studied in a cell suspension culture ofSvlanum tuberosumL, cv, HH258, In non‐stressed cells 34% of the total cellular proline was located in the vacuole. After 20 h of water stress the proline pool of the cells was increased 4‐6 fold and only t6% of it was found in the vacuole. A negative correlation between the total cellular proline content and its percentage in the vacuole was observed, irrespective of the culture method (stress or non‐stress culture). The stress‐induced changes in proline compartmentation are

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1990.tb09051.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY