摘要:

A particulate form of the lectin, trifoliin A, has been isolated from the root exudate of axenically grown seedlings of white clover (Trifolium repensL. cv. Louisiana Nolin). The majority of trifoliin A active in binding toR. trifolii0403 was sedimented from root exudate by centrifugation at 15 000 g for 30 min, indicating that it was particulate. Immunofluorescence, electron and immunoelectron microscopy using antibody prepared against trifoliin A from seeds, suggested that trifoliin A was associated with the particles in root exudate that bound specifically to the acidic capsular polysaccharides ofRhizobium trifolii0403. Electron microscopic examination also showed that trifoliin A‐colloidal gold conjugates bound to these same particles, indicating that they also have affinity for the lectin. The particles could be dislodged from intact seedlings by vigorous shaking in isotonic plant growth medium. Isolated particles fractionated by ultracentrifugation through a metrizamide gradient had a mean density of 1.12 g cm‐3. These isolated particles retained the ability to bind toR. trifolii0403 as shown by immunofluorescence using anti‐trifoliin A antibody. Sodium dodecyl sulfate polyacrylamide gel electrophoresis showed that the isolated particles are a mixture of proteins including one with an approximate molecular weight of trifoliin A. The protein which electrophoretically comigrated with trifoliin A also reacted with anti‐trifoliin A antibody by western blot analysis, confirming that it was trifoliin A. The protein composition of the isolated particles did not reflect the total protein composition of the root exudate, which was far more complex. These studies indicate that the majority of trifoliin A which can bind toR. trifoliiin root exudate of white clover seedlings is associated with electron‐dense particles, and that a major early interaction betweenR. trifoliiand clover roots involves the binding of these particles containing trifoliin A to acidic polymers on the bacterial cel

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1986.tb05582.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

The effects of switches between high and low nutrient supplies on growth and mineral nutrition of winter wheat (Triticum aestivumL. cv. Martonvásári‐8) were followed in four main developmental phases: tillering, shooting, heading and grain filling. Growth of the shoots was significantly affected by switches. Under low nutrient supply the life cycle was shortened. Root growth was only slightly affected by switches, but an early high nutrient supply followed by low nutrient supply gave an impetus for root development. In general, the growth data indicate that the nutrient status of the plants is determined by the nutrient level supplied during shooting. A high level of nutrients during shooting leads also to high vegetative growth, whereas the best grain yield was obtained by a high dose of nutrients during tillering followed by low nutrient conditions during the shooting stage and later. K+(86Rb) influx in the roots decreased with age. The potential for K+(86Rb) influx was low in plants of high‐salt status, but it became high in response to switching to low supply at shooting, whereas later switches had no influence on this function in high‐salt plants. The highest K+(86Rb) influx was found in plants starting with high nutrient supply followed by low‐salt conditions; this plant group was outstanding also with respect to its high gr

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1986.tb05583.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Lipids and pigments of the chlorophyllb‐deficient mutant pg‐113 and the parent strain (ps) ofChlamydomonaswere analysed and compared. Monogalactosyldiglyceride, digalactosyldiglyceride, diacylglyceryl(N, N, N‐trimethyl)homoserine, sulfoquinovosyldiglyceride, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol were found as major lipid components. While the lipid patterns were qualitatively and quantitatively almost the same in the two strains, the C16/C18fatty acid ratios were different, 0.85 in the mutant and 1.11 in the parent strain. Furthermore, the relative amounts of C16‐ and C18‐monoene fatty acids were slightly enhanced and the C18‐trienes slightly reduced in the mutant. In the parent strain, chlorophyllsaandb, α‐ and β‐carotene, lutein, violaxanthin, neoxanthin and loroxanthin were detected by HPLC. In the mutant, similar pigments were found, except that only traces of chlorophyllband a reduced amount of neoxanthin were present. Since no chlorophyll‐protein complex CP II could be detected in the mutant by electrophoresis, the possible interrelationships between pigment deficiency and alteration of chlorophyllprotein comp

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1986.tb05584.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

The effect of heat shock on the thermotolerance of etiolated mung bean seedlings (Vigna radiataL. cv. Wilczek) and the effects of gibberellic acid (GA) were studied. The potentially lethal temperature of etiolated mung bean seedlings was 45°C. But, when seedlings were pretreated with a heat‐shock period at 40°C for 1 h before incubation at 45°C, they become thermotolerant and survived the 45°C treatment. The addition of actinomycin D or cycloheximide during the heat‐shock period decreased the subsequent thermotolerance of the seedlings. Depending upon the time of its application, GA appeared to have multiple effects: (1) when applied during the 40°C heat‐shock period, GA enhanced the heat‐shock effect; (2) when applied during the 45°C potentially lethal temperature period, GA enhanced the subsequent growth of hypocotyls. This suggests that GA makes the seedlings tolerant to the potentially lethal temperature; (3) when GA was applied during a following 25°C growth period to seedlings which had been exposed first to 40°C and then 45°C, it promoted growth, suggesting that GA enhanced the restoration of the seedlings from high temperature damage. The role of GA and heat shock in the acquisition of thermotolerance in etiolated mung bean seedlin

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1986.tb05585.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Activated charcoal (AC, 0.25–1%) added to Murashige and Skoog medium supplemented with coconut milk (CM, 15%), inhibited the androgenic response ofDatura metelanthers excised from fresh as well as cold pretreated buds (3 days at 3±2 °C). The inhibitory effect of AC was directly proportional to its concentration for fresh as well as cold pretreated explants. This indicated that either AC itself is toxic or reduces the response by adsorbing some substance(s) from explants and/or from the medium. It was thought that AC is probably reducing the response by adsorbing some active component(s) of CM. This possibility was tested by studying the effect of different concentrations of CM in the presence (1%) and absence of AC. It was found that AC reduced the response only in the presence of CM, which was below the level recorded for anthers incubated on basal medium alone. Individually, both CM and AC enhanced the plantlet yi

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1986.tb05586.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Paraquat (1,1′‐dimethyl‐4,4′‐bipyridinium) resistant biotypes ofErigeron philadelphicusandE. canadensis, from fields where paraquat had been used for weed control, showed more than 100 times higher resistance than the susceptible biotype of both plants. Excised leaves of the susceptible biotypes wilted when supplied with more than 5 μMparaquatat at the cut ends, but those from the resistant biotypes did not wilt even at 500 μM.Autoradiographs indicated that (14CH3)‐paraquat taken up through the cut ends was rapidly distributed through the vascular system in leaves of the susceptible biotype, but was barely translocated in leaves of the resistant biotype. The amount of paraquat taken up during 48 h in the resistant biotype was 0.5% of that in the susceptible biotype in light. This difference in paraquat movement may be correlated with paraquat resistan

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1986.tb05587.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

The response of pericarp disks from ripening tomato (Lycopersicon esculentumMill. cv. Traveler‘76) to CaCl2, additions was studied to determine the effect of Ca2+on ethylene and CO2production. Application of 5 mMCaCl2resulted in a 2, 20, 33, 39, and 50% increase in ethylene production in disks obtained from preclimacteric minimum, climacteric rise, climacteric peak, one, and two days postclimacteric fruit, respectively. CaCl2concentrations of 10 and 50 mMgave no additional stimulation of ethylene production; CO2production at 5 mMCaCl2was not different from controls, but is increased at 10 and 50mMCaCl2. CaCl2also increased ethylene production in disks treated with 1‐aminocyclopropane‐1‐carboxylic acid (ACC) or aminoethoxy‐vinylglycine. Chloride salts of K+, Na+, Mg2+, Sr2+and La3+did not stimulate ethylene production. SrCl2stimulated ethylene production to a lesser degree than CaCl2. Disks from potato (Solanum tuberosumL. cv. Katahdin) tubers produced greater quantities of ethylene and ACC when 5 mMCaCl2was included in the incubation medium (K. B. Evensen, 1983. Physiol. Plant. 60:125–128). Ca2+‐treated disks had more than three times as much ACC synthase activity as control disks after 18 to 24 h incubation, when ethylene and ACC were maximal. The apparent Kmfor S‐adenosylmethionine was 13 μMat 29°C, pH 8.0 in extracts from both Ca2+‐treated and control disks. Inclusion of 1 to 50 mMCaCl2in the assay medium did not significantly affect enzyme activity. ACC synthase extracted from control and Ca2+‐treated disks had a pH optimum of 8.5 and an apparent molecular weight of 72 kdalton, estimated by gel filtration. It is likely that the presence of Ca2+in the buffer allows greater synthesis of ACC synthase as part of the wound‐healing response in potato, while in tomato the predominant effect is on

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1986.tb05588.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

The localization of NADPH‐protochlorophyllide oxidoreductase (PChlide reductase, EC 1.6.99.–) in dark‐grown and in irradiated dark‐grown leaves of wheat (Triticum aestivumL. cv. Walde) was investigated by subjecting thin sections of Lowicryl K4M‐embedded leaf pieces to a monospecific antiserum raised against PChlide reductase followed by protein A‐gold. A well‐preserved antigenicity of the tissue was achieved by polymerizing the resin under UV‐light at low temperature. In dark‐grown leaves PChlide reductase was found in prolamellar bodies only. In leaves irradiated for 30 min with white light PChlide reductase was found not only in the transformed prolamellar bodies but also to a large extent in connection with the prothylakoids. The localization of PChlide reductase is discussed in relation to fluorescence emission spectra of the dark‐grown and greening leaves. We conclude that the light‐dependent transformation of protochlorophyllide to chlorophyllide initiates a translocation of PChlide reductase from the prolamellar bodies

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1986.tb05589.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

The generation of ethylene from 1‐aminocyclopropane‐1‐carboxylic acid (ACC) added to a cell‐free preparation from etiolated pea (Pisum sativumL. cv. Alaska) epicotyls was found not to be due to a specific ACC oxidase or to oxygen radicals. Rather, endogenously produced H2O and manganese ions are coupled in a reaction sequence which produces ethylene from ACC. In a model system, H2O and Mn2+converted ACC to ethylene under conditions similar to those in the pea preparation. Ultrafiltration of the pea preparation inhibited ethylene production, but it could be reconstituted either by adding an H2O2‐generating system to the ultrafiltrate or Mn2+to the retentate. H2O2‐generating systems could reconstitute ethylene formation in a heat‐inactivated cell‐free sample while the loss of ability to produce ethylene upon dialysis of the pea preparation correlated with the loss of Mn2+from the sample. Studies using cell‐free preparations to investigate ethylene synthesis should take care to exclude the possible involvemen

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1986.tb05590.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Legumes of the Phaseoleae (Glycine maxL. Merr.,Phaseolus coccineusL.,P. vulgarisL.,Vigna radiataL. Wilczek andV. unguiculataL. Walp.), when grown on 10 mMnitrate, had a low in vitro nitrate reductase (NR) activity in the root compared to the shoot (<15%). In legumes of the Vicieae (Cicer aerietinumL.,Pisum sativumL. andVicia fabaL.), Genisteae (Lupinus albusL.) and Trifolieae (Medicago sativaL. andM. truncatulaGaertn.), 30–60% of their total NR activity was in the root. The Phaseoleae had a higher nitrate content in the shoot. Decreasing the nitrate supply increased the relative proportion of NR activity in the root of garden pea (Pisum sativum) and wheat but did not alter the predominantly leaf‐based assimilation of nitrate inPhaseolus vulgaris.When in vitro NR activity of the pea shoot was compared with the in vivo NR activity and the rate of accumulation of reduced N by this tissue, similar values were obtained. In vitro NR activity of the wheat shoot was 5 times its in vivo NR activity and 12 times its rate of accumulation of reduce

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1986.tb05591.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY