摘要:

Cruciferin (12S globulin) is a large, neutral, oligomeric protein synthesized in rapeseed (Brassica napus) during the seed development. It is composed of six subunit pairs. Each pair consists of one heavy α chain (30 kDa) and one light β chain (20 kDa). Four different subunit pairs exist. In contrast to earlier studies, our investigations using two‐dimensional electrophoresis showed, that the majority of α and β chains of each subunit are disulfide‐linked. Analysis of subunit composition of cruciferin hexamers by ion‐exchange chromatography suggested that a large array of hexamers exist, composed of mixed combinations of the four

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1990.tb02097.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Effects of photoperiod and temperature on vegetative growth of seedling populations and clones of white clover (Trifolium repensL.) originating from various latitudes (58°48′–69°54′N) and altitudes (up to 1100 m above sea level) were studied in a phytotron. Dry matter production, stolon elongation, petiole elongation and leaf lamina size were enhanced by long photoperiod. The requirement for long photoperiod increased with decreasing temperature. At 6°C the maximum growth was recorded under 24‐h daylength. At 18°C already an increase in photoperiod from 12 to 15 h significantly enhanced growth, and maximum growth was obtained at 21‐h photoperiod. The studied populations responded similarly to daylength, and the results did not indicate photoperiodic ecotypes in the material. The southernmost clones and populations generally had the highest dry matter production at all temperature treatments (6–18°C). Variation between clones within one location was, however, significant, and rapidly growing clones were found also in high‐latitude locations. Dry matter production was poorly correlated with the morphological characters observed, but in some cases significant correlation with leaf lam

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1990.tb02098.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Effects of photoperiod and temperature on frost resistance of seedling populations and clones of white clover(Trifolium repensL.) originating from various latitudes (58°48′–69°54′N) and altitudes (up to 1100 m above sea level) were studied in a phytotron. Low‐temperature‐induced cold acclimation in all populations was significantly stimulated by short photoperiod and low temperature. The highest levels of frost resistance were found in the northernmost seedling populations and in clones from northern coasta

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1990.tb02099.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

The effects of the lysine‐reactive chemical modification reagents, uridine 5’ diphospho (UDP)‐pyridoxal and formaldehyde (HCHO), on the activity of membrane‐bound and solubilized UDP‐Glc: (1,3)‐β‐D‐glucan synthase (callose synthase) from red beet (Beta vulgarisL.) storage tissue were compared. Exposure to micromolar levels of UDP‐pyridoxal, or millimolar levels of HCHO in the presence of NaCNBH3, resulted in complete enzyme inactivation. Conditions for inhibition of membrane‐bound enzyme activity by the two reagents were markedly similar; divalent cations were required for inactivation, and complete protection of activity was obtained with EDTA or EGTA. The substrate, UDP‐Glc, protected membrane‐bound callose synthase against inactivation by UDP‐pyridoxal or HCHO, but protected the solubilized enzyme only against inhibition by UDP‐pyridoxal, suggesting that the lysine residue modified by both these reagents is at the enzyme active site, and that the site is more open or has a certain conformational flexibility in the solubilized enzyme.Potential UDP‐Glc‐binding polypeptides of callose synthase were identified by a two‐step labeling procedure. First, nonessential lysine residues were blocked by irreversible modification reaction with HCHO or UDP‐pyridoxal in the presence of UDP‐Glc to protect lysines at UDP‐Glc‐binding sites. In the second step, proteins were recovered, reacted with [14C]‐HCHO in the absence of UDP‐Glc, and polypeptide labeling patterns analyzed by SDS‐polyacrylamide gel electrophoresis and fluorography. This procedure reduced incorporation of label by 5‐ to 8‐fold compared to a procedure omitting the preblocking step, and with enzyme partially purified by solubilization in CHAPS followed by product entrapment, labeling was limited to a small set of polypeptides. Taken together with the results of other studies, the data suggest that one or more polypeptides migrating in the 54–57 kDa region are good candidates

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1990.tb02100.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Evidence was obtained by gas chromatography‐mass spectrometry and gas chromatography‐selected ion monitoring for the presence of gibberellin A20), GA1, GA29, GA8and 2‐epiGA29in vegetative shoots of tall sweet pea,Lathyrus odoratusL. Both tall (genotypeL–) and dwarf (genotypeII) sweet peas elongated markedly in response to exogenous GA1attaining similar internode lengths at the highest dose levels. Likewise internode length in both genotypes was reduced by application of the GA biosynthesis inhibitor, PP333. The ratio of leaflet length to width was reduced by application of PP333 to tall plants and this effect was reversed by GA1. When applied to plants previously treated with PP333, GA20promoted internode elongation ofL– plants as effectively as GA1, but GA29was not as effective as GA1when applied toIIplants. In contrast, GA20and GA1were equally effective when applied to the semidwarflbmutant but GA‐treatedlblbplants did not attain the same internode length as comparable GA‐treatedLb– plants. The difference in stature between the tall and dwarf types persisted in dark‐grown plants. It is concluded that GA1may be important for internode elongation and leaf growth in sweet pea. Mutantlmay influence GA1synthesis by reducing 3β‐hydroxylation of GA20whereas mutantlbappears to a

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1990.tb02101.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

After the application of [13C3H]‐gibberellin A20to wild‐type (tall) sweet peas (Lathyrus odoratusL.) labelled gibberellin A1(GA1), GA8, GA29and 2‐epiGA29were identified as major metabolities by gas chromatography‐mass spectrometry after high performance liquid chromatography. By contrast in genetically comparable dwarf (II) plants only labelled GA29and 2‐epiGA29were produced in significant amounts, although evidence was obtained for trace amounts of labelled GA1and GA8. The apical portions of dwarf plants contained 8–10 times less GA1than those of tall plants but at least as much GA20(measured using di‐deuterated internal standards). In conjunction with previous data these results strongly indicate that in genotypellinternode length is reduced and leaf growth altered by a reduction in GA1 levels attributable to a partial block in the 3β‐hydroxylation of GA20to GA1.In contrast to dwarf plants, semidwarf plants (genotypelblb) contained more GA1in the apical portion than wild‐type counterparts. This is consistent with the suggestion thatlbalters some aspect

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1990.tb02102.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Copper deficiency in wheat (Triticum aestivumL. cv. Nazareno Stramppeli) markedly affects photosynthetic activity. Flag leaves of copper‐deficient plants showed a 50% reduction of the photosynthetic rate expressed as mg CO2dm−2h−1. The activities of PSI and PSII, determined for isolated chloroplasts, as well as fluorescence measurements on intact leaves of copper‐deficient plants, indicated a low activity of photosynthetic electron transport. Ribulose bisphosphate carboxylase/oxygenase (Rubisco) activity was not affected by copper deficiency but copper deficiency affected the chloroplast ultrastructure, especially at the level of grana, where a disorganization of thylakoids is

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1990.tb02103.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Seedling ofEuphorbia lambiiSvent. were grown in the dark, and the levels of organic acids in the endosperm were monitored during the 6–7 day period in which all the reserves were depleted. Glycolate, glyoxylate, succinate, fumarate and 2‐oxoglutarate occurred in traces only, the citrate concentration remained rather constant (0.4 μmol endosperm−1), malate varied from 0.2 to 0.4 μmol endosperm−1, but malonate appeared to be the major organic acid in the endosperm ranging from 0.75 to 1.25 μmol endosperm−1. Radioactive malonate was easily taken up by the cotyledons of growing seedlings, and up to 11.2% of the label proceeded to the sterols, the triterpenes and triterpene esters in a 48 h incorporation period. No label from [14C]‐malonate was built into the triacylglycerols in the seedling. Maximum uptake values of 0.6 μmol malonate seedling−1day−1were measured, and this value was not altered by a simultaneous uptake of sucrose. Conversely, the uptake of labeled sucrose and its subsequent conversion into sterols and (latex) triterpenes was not altered by a simultaneous uptake of low concentrations of malonate. Increased amounts (from 0.25 μmol malonate seedling−1and up) caused a 75–90% reduction of both uptake and conversion of sucrose into neutral lipids. To maintain a daily uptake of 4 μmol of sucrose by the cotyledons (required to maintain seedling growth) the simultaneous in vivo uptake of malonate from the endosperm was supposed not to exceed 0.2 μmol seedling−1day−1.Thin sections of the endosperm revealed the morphology of the process of reserve depletion. The occurrence of vacuoles 2 days after germination, coincided with the increase in the malonate level. The protein bodies first disappeared completely from the outer layers, whereas the triacylglycerols gradually disappeared from the entire endosperm. About 80% of the endosperm cells contained a large vacuole until the stage of complete depletion, probably serving as the

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1990.tb02104.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Specific polypeptides and antigenic determinants in abscission zone cells of the leaf rachis ofSambucus nigraL. (elderberry) were identified. Extracts from abscission zone tissue (OZ) and from ethylene‐treated abscission zone tissue after separation (Zone) were probed, using sodium dodecyl sulphate‐polyacrylamide gel electrophoresis (SDS‐PAGE) and immunological techniques, for unique peptide components absent from neighbouring non‐zone mid‐rachis tissue (MR). Ouchterlony immuno‐diffusion revealed differences in the spectrum of antigenic determinants possessed by each tissue type when challenged with antiserum raised against OZ. Immuno‐electrophoresis showed a basic polypeptide which is expressed preferentially in the abscission zone.Immune‐competition of OZ, MR and Zone extracts using immuno‐affinity column chromatography has identified polypeptides of ca 34, ca 32, and ca 28 kDa which are (up to the limits of detection) abscission‐cell specific. An antibody raised against the ca 34 kDa polypeptide recognises a peptide of ca 34 kDa present in OZ and Zone. This peptide is absent from MR.These results suggest that the specific positional differentiation of ethylene‐responsive target cells which constitute the leaf rachis abscission zone inS. nigrais accompanied by the expression of zone‐cell‐specific antigenic determinants which are not expressed by non

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1990.tb02105.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Salt (NaCl) tolerance of 3 eucalypt species (Eucalyptus albaReinw. ex Bl.,E. camaldulensisDehnh andE. microthecaf.v. Muell.) was studied: three‐month‐old seedlings grown in a greenhouse were watered by a saline solution (up to 700 mM) for 1 month. Mineral, water and sugar contents were highly affected by the saline stress. Sodium, K and Ca were accumulated in the leaves. No significant differences were found betweenE. camaldulensisandE. microtheca, the tolerant species, in water and mineral contents. Sugar contents were greater inE. microtheca. InE. microthecaNa was highly accumulated in roots [up to 910 μmol (g fresh weight)−1], less in stems [up to 580 μmol (g fresh weight)‐1]and leaves [up to 410 μmol (g fresh weight)−r]. Chloride was also accumulated, its content was greater than the total content of Na and K, especially in the salt‐tolerant provenance. Potassium and Ca contents were variously affected by the saline stress whereas soluble protein, amino acid and sugar contents were increased. Just after the saline stress, plants showed a large increase in the Na content of the leaf while the decrease in the K content of the stem and leaf continued. Plants were killed by the stress, probably because of too high accumulation of Na in leaves or roots according to the provenance. Osmoregulation and especially the participation of Na

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1990.tb02106.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY