摘要:

AbstractSymptoms of sugarcane mosaic virus disease caused by strains B and D were accompanied by a reduction in the rate of photosynthesis per unit area; the severe symptoms of strain A and the mild symptoms of strain I produced rates no different from those of healthy plants of variety C.P. 31‐588. All four strains decreased chlorophyll content and increased the amount of light transmitted by the leaf. Photosynthetic rates were reduced less than the reduction of chlorophyll would indicate. Symptoms moderated on older leaves, but rates of photosynthesis per dm2were less in older leaves of both healthy and diseased plants. Sugarcane varieties differed in their rates of photosynthesis in both healthy and in virus‐infected plants; a significant reduction in photosynthetic rate by sugarcane mosaic occurred in three of the four variet

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1971.tb06714.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractThe cyanophyte,Oscillatoria princeps, and the enigmatic hot‐spring alga,Cyanidium caldarium, contain two branching isoenzymes which can act on amylose and amylopectin, converting these polyglucans into highly branched phytoglycogens. The red alga,Rhodymenia pertusacontains three branching isoenzymes, only one of which is capable of the dual activity of the other algal branching isoenzymes. The other two red algal branching isoenzymes are Q enzymes and can only act on amylose, forming moderately branched amylopectìns. However, when the isoenzymes of all three algae are separated on different concentrations of polyacrylamide gel via electrophoresis, the mobilities of the isoenzymes show that the Q enzymes and the branching enzymes are related and true isoenzymic molecules. They differ only in electrical charges, probably caused by the substitution of amino acid residues in their active peptides. It is possible that if these charge isomers are due merely to amino acid substitutions, the enzymes may have been originally derived from a common catalytic molecule. The study indicates the identity of the branching isoenzymes ofOscillatoriaandCyanidium, and lends further supporting evidence to the cyanophyte origin of the enigmatic al

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1971.tb06715.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractThe uptake and assimilation of nitrate and ammonia have been studied inZea mays.Nitrogen‐starved maize roots are capable of accumulating a potential capacity for nitrogen uptake and assimilation. Reestablishment of nitrogen supply leads to intense uptake, reaching 154 % of the reference variant level after 24 hours when nitrate is supplied, and 121 % when ammonia is supplied. After 24 hours the insoluble nitrogen fraction accounts for 80, 54 and 55 % of the total taken up in the PK + NO3‐, PK + NH4+and NPK variants respectiv

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1971.tb06716.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractPea seeds were soaked in distilled water or in saturated D‐mannitol solution either under normal or under high external pressures (10‐30 atms.) for approximately 24 hours. Imbibition in distilled water was independent of the hydrostatic pressure. However, imbibition in D‐mannitol solution was enhanced by the pressure. It was concluded that hydrostatic pressure caused by turgor could enhance imbibition of the protoplast. Under high turgor, the protoplast may swell even at a high osmotic potential. Turgor seems to be of importance for the physiological activity of the plant

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1971.tb06717.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractThe development of lateral buds in isolated stems ofColeus blumeiis inhibited by low concentrations of indoleacetic acid or other auxins, just as in other plants. The inhibition can be fully reversed by kinetin, about 3 times as much kinetin as IAA being needed. However, the outgrowth of the same lateral buds on intact Coleus plants is sensitive to environmental conditions, well‐nourished plants in full daylight often showing little inhibition by applied auxin. It is shown that (a) the solvent used for IAA, (b) the light intensity and (c) the nitrogen and phosphorus nutrition, all control the sensitivity of the buds to auxin inhibition. Using water instead of lanolin, lowering the light intensity or decreasing the supply of either nitrogen or phosphorus all increase the degree of apical dominanc

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1971.tb06718.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractSeeds ofSalicornia bigeloviiwere germinated at 4.4°C, 15.5°C, and 26.6°C in saline solution containing from 0% to 8.08% sea salt. At 4.4°C, germination was delayed until the 26th day, but the final germination per cent was high in all salinities. At 15.5°C, germination was delayed until the 19th day, and the germination per cent was higher in the higher salinities. At 26.6°C, the germination began within one day and the germination per cent was higher at the lower salinities. With the exception of 26.6°C data, the maximum germination occurred at a sea salt concentration at 4.04 % which is very close to the salinity of t

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1971.tb06719.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractThe interrelation between the effects of abscisic acid (ABA) and the effects of cytokinins and gibberellic acid in retarding leaf senescence was investigated. Leaf discs from plants ofTaraxacum megallorrhizon, Rumex pulcberandTropaeolum majuswere floated on solutions of cytokinin or GA to which given amounts of ABA were added. After five days, chlorophyll was extracted and the amount estimated spectrophoto‐metrically. The interrelation between the effects of abscisic acid and cytokinins differed from that between the effects of ABA and gibberellic acid. Abscisic acid reduced the senescence retarding effect of GA more than that of cytokinins. A high concentration of cytokinins nullified the senescence enhancing effect of low concentrations of ABA. GA did not reverse the effects of AB

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1971.tb06720.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractGerminating pollen was supplied D‐glucose‐3H and myo‐inositol‐3H. Pollen tube growth was terminated at varying intervals and the cytoplasmic contents removed or left intact. Empty pollen tubes were treated with β‐1,4‐glucanase, β‐1,3‐glucanasc or pectinase and the residual radioactivity was determined. Analysis of autoradiograms showed the pollen tip contained primarily pectin, the subtending cell wall of the tube was primarily cellulose, or possibly hemi‐cellulose, and callose accumulated most heavily toward the rear, older segments of the tube. Callose was also heavily formed in the tip region of non‐growing tubes. Pectin formed from myoinositol appeared to be solubilized, or removed, from the wall to the cytoplasm with agi

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1971.tb06721.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractBy means of experimentation with the barley endosperm system and with peroxidase isoenzyme production during culture of tobacco pith the mode of action of abscisic acid (ABA) was investigated. Gibberellic acid (GA3) promoted reducing sugar production was significantly inhibited by ABA and bovine pancreas ribonuclease (RNase), while the specific RNA polymerase inhibitor rifamycin was without effect. In tobacco pith culture, ABA promoted appearance of induced isoenzymes, the effect being completely checked by rifamycin. Furthermore ABA significantly inhibited, and GA3 promoted production of RNA in treated tobacco plants. It is suggested that the mode of ABA action in these systems may be an inductive one on the degradative enzyme, RNase, and not necessarily a negative one on the promotive RNA polymerase. This conclusion implies effect on some preexisting RNA, the breakdown of which is mediated by ABA‐activated RNas

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1971.tb06722.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractThe Effect of Pre‐irradiation on the Content of Growth Substances in Xi‐Plants of Brassica oleraceavar.acephala.The auxin content of growth stimulated young plants (Brassica oleraceav ar.acephala) of the X2‐generation, originating from X‐ray irradiated seeds (75 kR) was determined. Methanolic extracts were separated on thin‐layer‐chromatograms, which were analyzed by ultra‐violet light and various chemical reactions. Quantitative determinations of growth substances were made using the Avena‐coleoptile‐cylinder‐test. The following results were obtained: 1. X2‐plants had a higher content of IAN compared with unirradiated control samples; 2. IAAm was detectable in only two out of 40 experiments; 3. Two fluorescent substances were detected: a hydroxycinnarmc acid derivative and a long chained unsatu‐rated ketone or aldehyde,

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1971.tb06723.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY