ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1966.tb09069.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

SummarySeven lower phycomycetes,Afhanomyees astaci, A. euteiches, A. cladogamus, A. cochlioides, A. laevis. Pythiumsp andSaprolegnia sp., have been investigated in respect of chitinolytic and cellulolytic activity. The five Aphanomyces species were also tested for pectinolytic activity. Different ages of stationary and shaken cultures, 2 or 3 different substrates, and 2 test pH were used for each enzyme to be tested. Chitinase and cellulase were assayed with 2 different methods.All the fungi showed chitinase activity, although in varying degree. In liquid cultures the strains ofA. astacigave the by far highest ac tivity. Differenl results were obtained with different growth media aud lest methods.Chitinase of some of the fungi was readily adsorbed on chilin. Adsorbed chitinase seemed to withstand heating more than unadsorbed enzyme.Only the three plant parasites,A. euteiches, A. cladogamusandA. codilioides, showed appreciable cellulase and pectinase activities which in some cases were stimulated by the presence in the medium of the enzyme substrate.Different assay methods and growth conditions showed difterent pattern regarding the difference in activity between the tested fungi and between used media.The conceivable roles in vivo of found activities were discussed.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1966.tb09070.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

Zusammenfassung1.) In Versuchen mit jungen Sonnenblumen wurde der Einfluβ von mangan auf Volumen und osmotischen Wert des Exsudats innerhalb zweier Tage nach dem Abschneiden untersucht.2.) Zwischen Volumen und osmotischem Wert des Exsudats konnte keine direkte Korrelation ermittelt weden.3.) Die osmotischen Werte des Exsudats lagen zwischen 0.18 und .12 alm and verringerten sich im laufe des 1. Tages kontinuierlich. Am 2. Tag blieben sie annachernd konstant. Eine Ausnahme bildete nur die Versuchsreihe mit der hochsten Mn‐Steigerun, die den zu Angang gemessenen hohen Wer nach geringfugiger Abnahme wahrend des 1. Tages bis zur zweiten Abanahme des 2. Tages fast wider erreichte, dann aber wegen des Absterbens der Pflanzen nicht weiter verfolgt werden konnte.4.) Die Volumina des Exsudats verringerten sich zwar ebenfalls int Laufe des 1. Tages doch erfolgte am 2. Tag mittags ein vermutlich durch die Tagesrhy thmik der Pflanzen bedingler Anstie der Exsudatproduktion, ohne dass die osmotischen Werte starkere Zunahmen erfubren.5.) Von der letzten Abnahme des 1. Tages an fuhrte die Mn‐Steigerung zu einem gesicherten Anstieg des osmotischen Wertes, ohne jedoch einen Einfluss aut die Exsudatproduktion nach sich zu zichcn.6.) Der fordernde Einfluβ von Manan auf die Exsudatproduktion konnte crnent

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1966.tb09071.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractA short inipulse of red light induces a Carotenoid synthesis in dark‐grown wheat leaves. This effect is particularly evident if the leaves, having received a short light impulse, are kept in darkness for six hours prior to a period of continuous irradiation for six hours. During this second period of irradiation much more carotenoids are formed than during an irradiation period of the same length, but not preceded by a pre‐irradiation. The main increase in pigment contents can be brought back to β‐carotene. For this pigment the short light impulse nearly doubles the pigment synthesis during a subsequent dark and light period of six + six hours as compared to the amount formed during six hours of light without pre‐irr

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1966.tb09072.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractTo better predict plant production in the sea, it would be desirable to be able to calculate, from easily obtainable measurements at one sampling, the growth rate of the prevailing stock of phytoplankton. To this end growth rates, pigment composition, cell volume and cell surface area data were collected for several species of marine phytoplankton in logarithmic growth at 20–21°C and 0.07 cal/cm2. min light intensity. Similar data for one species,Dunaliella tertiolecta, are given for several combinations of light intensity and temperature, and for another species,Ditylum brightwellii, grown in nitrogen deficiency.The problem of estimating growth rates of phytoplankton was divided into three parts: 1) variation of growth rate among diverse species and its relationship to light absorption by cell chlorophyll a: 2) variation in growth rate with light intensity; 3) variation in growth rate with temperature. An equation has been formulated for calculating growth rate which provides a more precise fit of the data than do equations for growth rate based upon cell surface/volume ratios or cell volume. The formulation is based upon light absorption by chlorophyll a. It allows for variations in the efficiency of utilization of light absorbed by chlorophyll a and the changes in chlorophyll a content resulting from light intensity and temperature differences. We do not attempt to predict variations in growth rate with photoperiod or spectral distribution, nor do we allow for light effects upon growth rate not mediated by photosynthesis, so the model is, at best, a rough approximation of reali

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1966.tb09073.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractThe effects of red and blue light on the formation of chlorophyll in excised roots of cucumber and pea was investigated and compared with previously reported experiments on wheat roots. All three kinds of roots are similar in that in continuous red light no or very little chlorophyll is formed. and in blue light a considerable amount of chlorophyll is produced. Roots of cucumber and pea differ from those of wheat, in that red light is ineffective (or nearly so) even when combined with blue.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1966.tb09074.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractThe aim of the present investigation has been to study whether the light factor influences the fat metabolism in the scots pine seeds in any way which could be correlated with its effect on the germination. The studies have been made on petroleum ether extracts. Gravimetric determinations showed small increases of extractable material during the first 24 hours of the germination process. After a longer time there was a small but insignificant consumption (72 hours). No effects of the light factor could be found. Investigations with gas‐liquid chromatography on the corresponding extracts did not reveal any influence on the fatty acid composition, either of the light factor or of the germination period. The main identified fatty acids were linoleic, oleic, palmitic and stearic acid. One of the unidentified components (“c”) was also present in a large amount. Principally the same acids were found as free fatty acids but in different proportions: oleic, palmitic, linoleic and stearic acid. After the onset of the imbibition the linoleic acid appeared in the largest proportion. The total content of free fatty acids increased with increasing germination period. This was found both in titration experiments and in gas‐liquid chromatography with an internal standard. The latter method permitted studies on the content of the individual acids. During the period 0–21 hours there were no evident differences between the content in light‐ and dark‐germinated seeds, during the period up till 48 hours there was lower content in the light‐germinated seeds concomitant with the onset of the mitotic activity in these seeds and after 48 hours there was a rapid increase in the same ones corresponding to the opening of the seed coats and the incipient protrusion of the rootlets. Thus changes of free fatty acid content were found only after the start of the light‐induced growth but not under the preliminary phase, which earlier has been shown to be the determinative one in the light control o

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1966.tb09075.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractLettuce seed germination or lettuce root elongation after germination in water was inhibited by coumarin and these inhibitions were reversed by Cycocel. 2.53 × 103M Cycocel reversed the inhibition of seed germination by 6.8 × 104M coumarin. and 6.32 × lO−4M Cycocel reversed the inhibition of root elongation by 3.4 × 103M coumarin. No other analogs of Cycocel reversed these coumarin induced inhibitions of growth. Cycocel reversal of coumarin inhibition of lettuce seed germination occurred in red light but not in far‐red light or darkness. The red‐far‐red system was photoreversible. Cycocel and kinetin appear to act similarly in reversing coumarin inhibition of germination. Gibberellin A3and IAA were unable to reverse these coumarin induced inhibitions. A common mechanism is suggested for Cycocel reversal of coumarin and lAA inhibitio

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1966.tb09076.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractLettuce seed germination or lettuce root elongation after germination in water was inhibited by 5.7 × 10‐6Mindoleacetic acid (IAA) and designated other IAA derivatives. These IAA‐inhibited growth responses were reversed by 10‐5to 10‐6MCycocel, (2‐chloroethyl) trimethylammonium chloride, which alone was without effect. Only those Cycocel analogs, which have previously been shown to be active as plant growth retardants, were effective in reversing IAA inhibition of germination or root elongation. These results are consistent with the concept that Cycocel at low concentrations acts as an auxin antagonist. However. Cycocel did not reverse the inhibitory effects from indole‐3‐propionic acid or indole

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1966.tb09077.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

AbstractThe reversal of 80–100 per cent inhibition of photosynthesis in the green algaEnteromorpha linza(L.) J. Ag., obtained with tetramethylthiuram disulphide (TMTD) and the corresponding sodium dithiocarhamate (Na‐DMDT), was investigated. The inhibition obtained by the two compounds proves to be almost completely reversible by simply washing away the inhibitors. Copper(II) sulphate partially reversed the inhibition obtained with Na‐DMDT while reduced glutathione (GSH) partially reversed inhibition obtained with both Na‐DMDT and TMTD. The time to complete the reversal varied between 12 and 33 min. Almost no reversal of the TMTD induced inhibition was achieved with CuSO4.Na‐DMDT and CuSO4reacted instantaneously with each other. GSH most probably reduced TMTD stoichiometrically to DMDT. This reaction was complete‐ within 6 seconds. No reaction took place between GSH and Na‐DMDT.The interpretation of The results eliminates the most conventional explanation of the mechanism of the inhibition of photosynthesis in E. linza with Na‐DMDT,viz.complex formation with functional metals. The reaction between TMTD and functional thiol groups in the alga is the most plausible inhibition mechanism. It is inferred from the results that Na‐DMDT is most probably oxidized by E. linza to TMTD and effects inhibition in this

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1966.tb09078.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY