ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1988.tb00045.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1988.tb00046.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractWe report the isolation and characterization of a recombinant cDNA phage from a lambda gt11 expression library made from polyadenylated spinach RNA that encodes the entire precursor polypeptide of ferredoxin I. The deduced sequence predicts a molecular mass of 10.5 kDa (97 amino acid residues) for the mature protein and a transit peptide of 50 residues (5.2 kDa).In vitrosynthesized ferredoxin precursor was used for import experiments with isolated unbroken spinach chloroplasts. The polypeptide was correctly directed to the organelle stroma and processed to the size of the mature protein. Northern analysis indicates a mRNA size of ca. 850 nucleotides which is close to the size of the cDNA insert (ca. 700 bp).

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1988.tb00047.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractChemically inactivated nitrate reductase ofNeurospora crassastrain al‐2, bd can be photoreactivated by blue light. The quantum requirement for this reaction in the presence of exogenous FMN was determined with different light intensities. The results are discussed with the alternate assumptions that free FMN or photoactivated FAD bound to the nitrate reductase molecule is the reactivating specie

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1988.tb00048.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThe xanthophycean algaPleurochloris meiringensiswas homocontinuously cultured under high light (16 W/m2) and low light (2 W/m2) conditions. In low light cells, the chlorophyll a content and the dry weight on per cell basis is increased, the maximal photosynthetic capacity per chlorophyll is decreased. The content of chlorophyll c, vaucheriaxanthin‐ester and heteroxanthin is similar in both cultures, whereas the content of diadinoxanthin and ß‐carotene is twice as high in high light cultures. High light cells contain more photosystem I and cytochrome f per chlorophyll than low light cells, whereas the QBcontent is found to be unchanged. Therefore, the ratio reaction center II/reaction center I is twofold higher in low light cells than in high light ones. The regulation of energy distribution between the photosystems is examined by fluorescence emission spectra at 77 K scanned after different preillumination of the cells. No wavelength dependent state I/state II transition can be detected. However,P. meiringensisregulates the energy distribution in response to light intensity: The higher the irradiance of preillumination, the higher the energy transfer to photosystem I. The sensitivity of the regulation to light intensity is increased in low light c

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1988.tb00049.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractImmunogold labelling on ultrathin sections of Lowicryl K4M embedded lower epidermis of spinach (Spinacia oleraceaL.) with adhering mesophyll cells has been applied to localize five proteins, namely ribulose‐1,5‐bisphosphate carbocylase/oxygenase (EC 4.1.1.39), chloroplast coupling factor (EC 3.6.1.34), NADP‐malate dehydrogenase (EC 1.1.1.82), chloroplast fructose‐1,6‐bisphosphatase (EC 3.1.3.11) and thioredoxinmby electron microscopy in stomata. Comparative data of labelling densities of the localized proteins in chloroplasts of spongy parenchyma, epidermis and guard cells are presented. All five proteins could be detected in guard cell chloroplasts at levels little different from those found in chloroplasts of spongy parenchyma and of epidermis cells. The two light‐activated enzymes NADP‐malate dehydrogenase and fructose‐1,6‐bisphosphatase are reduced in stomata to about one third of the mesophyll concentration. Aldehyde‐sensitivity of the inspected enzymes and suitability of cryosections for immunolocalization studies on plant tissues, in comparison with resin‐embedded specimens, was investigated. Fixation with 2% glutaraldehyde resulted in no detectable decrease of antigenicity. Cryosections were found to be less suitable for immunogold labelling, since labelling densities were lower than on resin. Only labelling of the thylakoid‐bound coupling factor was comparabl

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1988.tb00050.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractIncubation of the green algaChlorella vulgaris(strain K, Tanner and Kandler, 1967) with glucose leads to the induction of a glucose transport system and of two amino acid transport systems. Because it was not clear whether the regulation of 3 different transport systems by glucose is specific to our strain ofChlorellaor whether it is a general property of the genusChlorella, 11 other free living and symbioticChlorellaspecies and strains were tested for glucose‐inducible glucose, arginine and proline transport. It was found that nearly allChlorellaspecies possess glucose and amino acid uptake systems. Often they were constitutive, although in some species they were induced or stimulated by glucose. According to the transport activities of the differentChlorellaspecies and strains, a physiological classification ofChlorellawas constructed, resulting in 3 groups: theC. fusca vacuolata, theC. vulgarisand the symbioticChlorellagroup. OurChlorella(strain K) obviously belongs to theC. vulgarisgroup and forms a link to symbioticChlorellastrains. This suggests that the possession of the glucose‐regulated transport systems is of advantage forChlorellain symbiotic situations, whereas the constitutive systems are useful for free livingChlore

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1988.tb00051.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractMembrane potentials of −;160 to −210 mV were recorded with microelectrodes inserted into meta‐phloem sieve tubes of intact zucchini plants (Cucurbita pepoL. var.medullosaAlef.). The effects of darkness, white light and colored light on membrane potential were studied. Reference electrodes were in contact with the apoplast via fluid‐filled cavities or “drinks”. Electrolyte solutions (100 mM) in the cavities could be quickly replaced by flushing with 100 mM solutions of sucrose, KCl, sorbitol, or EDTA without altering osmolarity. KCl and EDTA caused depolarization of the sieve tube membrane potential, while sucrose caused depolarization or hyperpolarization of the sieve tube membrane potential in mature or growing plant parts respectively. Recovery of the original voltage was recorded when rapid (sucrose) or slow (sorbitol) transients occurred. When two measuring circuits were installed, one in a growing fruit and the other in the petiole of the subtending mature leaf, the alteration of the sieve tube membrane potential at one site was accompanied by an alteration of the potential at the other site after a few seconds. The responses were opposite in the exporting leaf and importing fruit when sucrose was applied. The signal, transmitted via the sieve tubes, reached maximum velocities of 10 cm

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1988.tb00052.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractUptake experiments and efflux compartmental analyses of abscisic acid (ABA) with acid treated epidermal peels ofValerianella locustawere performed to elucidate the mechanisms of transport of ABA across the plasmalemma and tonoplast of guard cells.ABA uptake across the plasmalemma is linearly correlated with external ABA concentration in the incubation medium. Under alkaline conditions ABA‐uptake was not significantly above background, indicating that ABA uptake occurs mainly by diffusion of undissociated ABAH as the most permeable species, which is trapped afterwards in the alkaline cytosol as impermeable ABA−. Efflux analysis of ABA revealed a saturable component of ABA transfer across the tonoplast. A Woolf‐Augustinsson‐Hofstee analysis suggested the existence of two transport systems for ABA at the tonoplast. The high affinity transport system had a KMof 0.21 mol m−3and a Vmax85.8 amol ABA cell−1h−1. Using the data of the uptake and efflux experiments we calculated the permeability coefficients of ABA for the plasmalemma and the tonoplast of guard cells, which are 2.46 10−7m s–1and 1.26 10−8m s−1, respectively. The distribution of the pH‐probe (14C)‐DMO between medium, cytosol and vacuole was investigated and used to calculate cytosolic and vacuolar pH. The vacuolar pH is too low to explain the high vacuolar ABA concentration by trapping of ABA−, whereas the cytosol is sufficiently alkaline to act as an efficient anion trap. Therefore we conclude that ABA transport across the guard cell tonoplast is catalyzed by a

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1988.tb00053.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractCotyledons detached from pumpkin seedlings of different stages of development were either illuminated or treated with 4.10−5M cytokinin (benzyladenine, BA) in darkness. Comparison of the abilities to incorporate14C‐leucine into proteinsin vivoas well as35S‐methioninein vitroby means of an RNA‐programmed cell‐free wheat germ system demonstrates that the patterns of the two‐dimensionally separatedin vivolabelled soluble proteins are very similar in differently developed or treated cotyledons. Although the translatable mRNA patterns were almost identical in qualitative respect, our data do not exclude the appearance of a few minor polypeptides altered by either illumination or BA treatment. The steady‐state levels of the mRNAs in cotyledons from 12 days old seedlings were remarkably similar irrespective of cotyledon treatment (water, BA, light) and resemble those levels obtained with illuminated or BA‐treated cotyledons of earlier seedlings stages. Our results suggest that the amount of abundant (soluble) proteins in pumpkin cotyledons is developmentally regulated mainly at the transcript level. Extrinsic factors such as cytokinins (BA) or light are equally able to accelerate the developmental program of gene expression in early‐detached cotyledons, which are probably deficient in e

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1988.tb00054.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY