摘要:

AbstractAnacystis nidulansgrown under high and low light, 100 and 10 μE m−2s−1, respectively, was analyzed with respect to chlorophyll/P700, phycobiliproteins/P700, chlorophyll/cell, and oxygen evolution parameters. The photosynthetic unit sizes of this cyanobacterium, measured as the ratio of total chromophores (chlorophyll and bilin) to P700, were shown to be similar to those of higher plants and green algae. High light grown cells possessed a photosynthetic unit consisting of a core of 157 ± 6 chlorophyllamolecules per P700 associated with a light harvesting system of 95 ± 3.5 biliprotein chromophores. Low light grown cells had substantially more biliprotein chromophores per P700 (125 ± 3.1) than high light cells, but showed no significant difference in the numbers of chlorophyllamolecules per P700 (149 ± 4). Analyses of aqueous biliprotein extracts indicate that low light grown cells produce proportionately more phycocyanin relative to allophycocyanin than high light cells. Calculations of the molecular weight of biliproteins per P700 suggest that there is less than one phycobilisome per reaction center I under both growth conditions.Differences in chlorophyll/cell ratios and oxygen evolution characteristics were also observed. High light cells contain 6.3 × 10−12mg chlorophyll cell−1, while low light grown cells contain 12.8 × 10−12mg chlorophyll cell−1. Photosynthetic oxygen evolution rate vs. light intensity curves indicate that high light grown cells reach maximal levels of oxygen evolution at higher light intensity than low light grown cells. Maximal rates of oxygen evolution were 16.6 μmol oxygen min−1(mg chlorophyll)−1for high and 8.4 μmol oxygen min−1(mg chlorophyll)−1for low light cells. Maximal oxygen evolution rates per cell were equivalent for both cell types, although the amount of P700 per cell was lower in high light cells. High light grown cells are therefore capable of producing more oxygen per reaction center

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1980.tb04432.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractTreatment of different plant materials, seeds ofPhaseolus vulgaris, Zea maysandPinus silvestrisand young plants ofPhaseolus, with kinetin increased the level of extractable IAA. For seeds this increase was most pronounced in bean seeds, which contained the lowest amount of endogenous IAA and cytokinins, and lower in maize seeds with high endogenous content of IAA and cytokinins. – For young bean plants the kinetin treatment significantly increased the extractable amounts of IAA from all parts of the plant, hypocotyls, cotyledons, epicotyls and primary leaves, when the cut plants were placed for 24 h in kinetin solution. For plants sprayed with kinetin solution only the primary leaves showed a significantly higher level of extractable IAA, which could be explained by the fact that the plants were growing very close together, so that the primary leaves received most of the kinetin during sprayin

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1980.tb04433.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractKinetin treatment increased the level of an extractable indoleacetyl conjugate, apparently indoleacetylaspartic acid (IAAsp) in germinating seeds and young plants ofPhaseolus vulgarisL. cv. Alabaster. The level of this substance in extracts of treated seeds was always higher than that from water treated seeds irrespective of whether the seeds had been extracted 24, 48 or 72 h after the beginning of the treatment. In all parts of young bean plants treated with kinetin there was more of the substance than in the corresponding parts of water treated plants.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1980.tb04434.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractFour‐day‐old stem segments ofZea maysL. cv. Seneca 60 were treated sequentially with phenolic substances and indole‐3‐acetic [2‐14C] acid ([2‐14C]IAA). Formation of bound IAA was rapid, but a pretreatment withp‐coumaric acid, ferulic acid or 4‐methylumbelliferone decreased the level of bound IAA. The decrease is not likely related to the effect of the phenolics on enzymic oxidation of IAA, since the level of free IAA was not limiting and the activity of ferulic acid in enzymic oxidation of IAA is different from that ofp‐coumaric acid and 4‐methylum‐belliferone. Apparently these compounds inhibited the formation of bound IAA and consequently caused an accumulation of free IAA. In contrast, caffeic acid, protocatechuic acid and 2,3‐dihydro‐2, 2‐dimethyl‐7‐benzofuranol had little effect.After the uptake of IAA there was a slow but steady incorporation of the radioactivity into the 80% ethanol‐insoluble, 1MNaOH‐soluble fraction. Phenolic substances also affected this process. The compounds which are cofactors of IAA‐oxidase increased the incorporation while those which are inhibitors of IAA‐oxidase decreased the incorporation. Results suggest that the phenolics also affected the enzymic oxidation

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1980.tb04435.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractFive‐day‐cultured cells ofVinca roseasuspension culture were labelled with D‐[U‐14C]glucose for 3 h and were then incubated in a medium containing unlabelled glucose for 24 h. Before and after chasing, extra‐cellular polysaccharides (ECP) and the cell walls were isolated from the medium and cells, respectively. ECP and polysaccharides in the hemicellulose fraction of cell walls were fractionated into a fraction precipitated as copper salt and one not precipitated as copper salt, and the latter was further fractionated using cellulose‐powder chromatography. From the results of analyses of the sugar composition and methylation analyses, components of polysaccharides contained in each fraction were deduced. In ECP, the percentage of radioactivity in the arabinogalactan fraction increased during chasing, while in the cell wall radioactivity in the fraction containing arabinogalactan decreased during chasing. These results confirm the view that arabinogalactan in the cell wall is degraded, and secreted into the medium as a

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1980.tb04436.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractSignificant male and female flowering (cone bud production) by girdled branches of 6‐year‐old Douglas fir (Pseudotsuga menziesii(Mirb. Franco) seedlings was promoted by applications (mid‐April to June) of 1.6 or 3.2 mg per branch (in total) of certain non‐polar gibberellins (GA's). Girdling alone was ineffective. When tested alone, a mixture of GA4/7was most effective. GA9less so, while GA5and the more polar GA3were essentially ineffective. For female cone buds GA4/7+ GA9were synergistically effective, but for male cone buds GA4/7alone was best. The auxin naphthaleneacetic acid (NAA) was not tested alone, but at low dosage (0.175 mg/branch in total) NAA enhanced the flowering efficacy of GA's for both sexes; at a high dosage (0.875 mg/branch in total) male cone bud production was further enhanced, but only at the expense of females. For female flowering the best treatment (90% frequency of flowering 6.8 cone buds/branch), was GA4/7+ GA9+ low NAA; for male flowering, it was GA4/7+ high NAA (30% frequency and 4.2 cone buds/branch. Frequency of flowering for controls was 18% and 0%, average number of cone buds/branch was 0.9 and 0, for females and males, respectively. The successful treatments did not affect promordia initiation, rather they caused the differentiation of previously initiated, but undetermined, lateral primordia into cone and latent buds at the expense of vegetative bud differentiation.The lack of success reported by earlier workers in promoting flowering in Pinaceae species by GA's appears to be the unfortunate result of selecting GA3for initial testing. The practical implications of this early and enhanced flowering by non‐polar GA's seedlings of a commercially important conifer are discussed in relation to accelerating the processes of tree im

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1980.tb04437.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractDevelopment of axillary shoots was induced when isolated embryonic axes of chestnut (Castanea sativaMill.) were cultured on a defined medium containing 6‐benzyl‐aminopurine (BAP). The optimal concentrations of BAP were determined for development of axillary shoots from both embryonic axes and subcultured shoots. After shoot multiplication a great number of shoots have been maintained sequentially without significant change in the proliferative rate for one year. Limited rooting has been obtained with excised shoots. Indole‐3‐butyric acid (IBA) at 2 mg/l was used to induce root primordia. After 8 days of treatment the plantlets were transferred to an auxin‐free medium for root de

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1980.tb04438.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractBark banding of morphaction is an effective means of controling stem elongation inPinus radiataD. Don (Monterey pine) but notJuglans regiaL. (English walnut). Diffusion coefficients of14C‐labeled morphactin across excised disks of tree bark, measured in specially designed diffusion chambers, were 11 to 85 fold greater in pine than walnut. In seedlings of comparable age, the suberin layer of walnut bark is much thicker than that of pine; if the layer is removed, diffusion of14C‐morphactin is enhanced 39‐fold in pine and 285‐fold in walnut.Morphactin applied to the bark as an ester is rapidly hydrolyzed to its carboxylic acid derivative in both pine and walnut. This conversion occurs rapidly in the bark of both species and does not appear to limit the rate of morphactin movement across the bark.These results suggest that diffusion across the suberin layer and not metabolism limits morphactin transport across t

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1980.tb04439.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractDuring imbibition and germination of jack pine seeds, the composition of the total extractable chromatin varied. Relative to DNA, the histone levels decreased as the nonhistone chromosomal proteins (NHCP) increased. New chromosomal proteins were synthesized after 2 days of imbibition as judged by recovery of14C‐amino acids from the major protein fractions. Phosphorylation of histones from32P‐phosphoric acid was detected before the incorporation of14C‐amino acids. In the seed the synthesis and relative changes of chromatin coincided with a fall in total soluble protein and free arginine N. By contrast, adenylate energy charge, free glutamine N andin vitrotemplate activity of chromatin increased during chromatin protein synthesis.When seeds had germinated for 4 days after the start of imbibition more radioactivity, derived from free14C‐amino acids, was recovered from the NHCP than from the histones. The percentage amino acid composition of most histone fractions remained stable, whereas the composition of NHCP changed more with time. The phosphorylation of NHCP was 8‐ to 41‐fold greater than that of the histones. Phosphorylation of histone H4 was not detected at any stage of germination. Correlations between recovery of radioactivity (32P and14C) from chromosomal proteins and higher adenylate energy charge we

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1980.tb04440.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Abstract[3H]‐auxin (0.13 to 0.18 nmol) was applied to the apical bud of broadbean plants (Vicia fabaL. cv. Aguadulce). After 24 h, the exportation from the donor organ was ended. After 48 h, i.e. 10–15 h after the passage of the [3H]‐auxin pulse into the root system, the distribution and the nature of labelled molecules located in the basal part of the stem and in the axillary buds were investigated. Chromatographic analyses concerned both intact plants and plants decapitated 12 h, 24 h or 42 h after the [3H]‐auxin application. In intact plants, there was no significant amount of [3H]‐auxin in the axillary buds, whose radioactivity was very low compared to the stem tissues. The labelled molecules with the Rf of auxin represented 50% or more of the whole radioactivity of the stem tissues. The distribution of [3H]‐auxin was not uniform along the stem. In particular, the cotyledonary node zone, bearing the most inhibited buds, which is known to be an important centre of label retention, contained the highest amounts of labelled auxin both in intact and decapitated plants. The decapitation was quickly followed by a decrease of the [3H]‐auxin amount in the stem base more than 15 cm away from the wound, particularly in the scale leaf nodes, whose axillary buds were mainly the ones to grow after relief from apical dominance. The induction of this early decrease was clearly distinct in plants decapitated when auxin exportation from the donor or

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1980.tb04441.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY