bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Fluoride on Nucleic Acids and Growth in Germinating Corn Seedling Roots
Authors: Chang Ghong W. , Thompson C. Ray
Published: April 2006

Corn seeds were treated with 0.01 M sodium fluoride for various time periods. The treated seeds were germinated and grown until the seedling roots reached a standard size of 12±3 mm.

Analyses were made for RNA and DNA contents of 3‐mm seedling root tips. Determinations also were made for growth rate, rate of cell elongation, cell multiplication, and tissue maturity of 12‐mm roots.

RNA contents of 3‐mm root tips were found to be directly proportional to the growth rates of the entire seedling root of corn seeds treated with sodium fluoride for various periods of time. The RNA content was reduced on a cell basis and was independent of the root tip cell number. The amount of DNA was not related to the growth rate of the intact seedling roots. Since fluoride reduced the number of mitotic figures, it was likely that fluoride inhibited DNA synthesis during the interphase of the mitotic cycle.

Growth by cell multiplication was inhibited more than that by cell elongation in the sample treated with fluoride for a shorter period. The two types of growth, however, showed a similar level of growth reduction in the sample treated with fluoride for a longer period. Fluoride seemed to reduce the rates of cellular elongation and multiplication not more than about 40 per cent of the control value in these tissues under present experimental conditions. Fluoride also induced maturity in the seedling roots in proportion to the periods of fluoride treatment.
Boron Deficiency and Translocation Profiles in Sunflower
Authors: Lee Kung‐Woo , Whittle Catherine M. , Dyer Hurert J.
Published: April 2006

The distribution of carbon‐14 down the stems of comparable boron‐deficient and boron‐sufficient sunflower plants after photosynthesis of 14CO2 by a single exposed leaf was investigated. In boron‐deficient plants the advancing front of radioactivity was always found less far down the stem than in boron‐sufficient plants. The general shape of the profile is the same in the two sets of plants. We conclude that the velocity of translocation is reduced in the boron‐deficient plants.
Chlorine Nutrition of Tomato: Observations on Inadvertent Accretion and Loss and Their Implications
Authors: Bkoyer T. C.
Published: April 2006

Development of research on chlorine nutrition of plants is reviewed. Imbalances of supply and recovery of chlorine are discussed. Results elucidate losses to be related to moisture percentages of tissues in preparation for analysis and to ashing techniques. Accretions are related to various advertent contaminations and inadvertent accessions through aerosols in the atmosphere during growth.
The Role of Auxins in Root‐Knot Nematode‐Induced Growth on Excised Tobacco Stem Segments
Authors: Sandstedt Robert , Schuster Max L.
Published: April 2006

Root‐knot nematodes, Meloidogyne incognita, induced lumps of callus tissue on the cambial surfaces of peeled tobacco stem segments cultured in vitro. Except for a layer 1 to 3 cells thick, callus was limited to the basal ends of control segments. Indole‐3‐acetic acid (IAA) applied in agar blocks to the centers of stem segments, when it had any effect on the cambial surface, induced streaks of callus extending from the blocks toward the basal ends of the segments. IAA in agar blocks also increased callus growth at the basal ends of the segments, increased the growth of pith on the undersides of the segments, promoted root initiation, but inhibited bud initiation. Nematodes produced none of these effects, nor did they change the type of organs induced by various concentrations of IAA in the medium. Callus tissue did grow on the cambial surface of stem segments surrounding agar blocks containing 2,3,5‐triiodobenzoic acid, an inhibitor of polar auxin transport.

Paraffin sections showed that the nematodes were confined to the callus tissue on the cambial surfaces of the segments. Except for occasional syncytia and areas of cell division, nematode‐induced callus was composed of thin‐walled, irregularly shaped cells arising from the cambium.

Differences between the responses of tobacco stem segments to root‐knot nematodes and IAA‐agar blocks indicate that auxins were not freed from the plant tissue nor secreted by the nematodes. Instead, it is suggested that nematodes enabled the tissue to retain and use endogenous auxins that otherwise would have been transported to the basal ends of the segments.
Elongation of Stem Internodes in the Japanese Morning Glory (Pharbitis nil) in Relation to Auxin Destruction
Authors: Yoneda Y. , Stonier T.
Published: April 2006

The relationship between auxin destruction and stem internode elongation was investigated in the vines of the Japanese morning glory (Pharbitis nil Choisy). In young plants an age‐dependent gradient was demonstrated in which the decreasing rate of elongation of older internodes correlated with an increasing ability of such tissue to destroy indoleacetic acid. Fragments of tissue from old internodes when incubated with indoleacetic acid (IAA), destroyed the hormone immediately and rapidly; in contrast, young, rapidly elongating internode tissue destroyed IAA only after a lag of several hours. In older plants the gradient was more erratic towards the middle of the plant but old and young tissue behaved as in young plants, i.e., old internodes destroyed IAA rapidly whereas young internodes did not. It appears reasonable to conclude that cessation of elongation in maturing internodes is brought about by developing an internal environment in which auxin is rapidly destroyed.
Relationship of Apical Dominance to the Nutrient Accumulation Pattern in Pisum sativum var. Alaska
Authors: Husain Syed Mushtaq , Linck Albert J.
Published: April 2006

Decapitation of the pea plant resulted in the growth of all the lateral shoots. The initial growth of all lateral buds was somewhat similar. The differential growth rates developed later on. The pattern of growth of lateral shoots varied with the age of the plant when decapitation was performed. The basal shoots dominated when the plants were decapitated at the 2‐leaf stage. At 3‐leaf stage decapitation resulted in the dominance of shoot 5. Decapitation at 4‐or‐more‐leaf stage resulted in the eventual dominance of the suhterminal lateral shoot.

As a rule P‐32 moved to the most actively growing part of the plant, i.e. apex in intact vegetative plant, the growing lateral shoots in a decapitated plant, the elongating subapical parts of the stem and the roots. The various metabolic sinks seemed to compete actively for this nutrient, therefore P‐32 accumulation in any particular growing region of the plant was taken as an indicator of nutrient utilization potential of that part.

The stem apex of an intact plant seemed to loose its dominance with the increasing age of the plant. The loss of apical dominance was almost complete during the reproductive phase of the plant, during which the upper lateral shoots initiated growth. Their growth, however, was inhibited soon because of competition with the other developing sinks, viz., the flower and the fruit.

The amount of soluble carbohydrates in various parts of the pea plant followed essentially the same pattern as did P‐32 accumulation. These distribution patterns were apparently correlated with the growth of the plant.
Germination and Flowering in Arabidopsis thaliana in Sterile Culture
Authors: Anand Renu , Maheshwari S. C.
Published: April 2006

The optimal conditions for the germination, growth, and flowering of an Indian strain of Arabidopsis thaliana were investigated in sterile culture. Seeds require a cold treatment to germinate, and the most effective temperature is 8†C for 48 hours. Germination after vernalization is promoted by red light and inhibited by far‐red. Unvernalized seeds germinated after 31 days and flower buds appeared in 61 days. On verbalization and subsequent transfer to a temperature of 25†C and a light intensity of 4300 lux of fluorescent light, plants flowered in 25 days. Under 7000 lux of light rich in both blue and red region of the spectum, plants flowered in only 12 days. A minimum of five long‐day photocyeles appeared to be necessary for flowering. Kinetin (10−7M) and gibberellic acid (10−7M, 10−6M) accelerated flower formation. Kinetin and 2,4‐D also catised specific types of callussing from different regions of the plant.
Auxin Activity of Glucobrassicin
Authors: Andersen A. Skytt , Muir Robert M.
Published: April 2006

The indole‐glucosinolate, glucobrassicin, which is found in large amounts in members of the genus Brassica, was subjected to tests in the standard Avena curvature bioassay. Both the tetramethylammonium salt of glucobrassicin and the non‐crystallizted material induced curvature at a concentration of 5 × l0−4M. The curvature from the salt was, however, only half of that induced by the acid form.

Bioassays of chromatograms of fresh methanolic extracts of savoy cabbage indicated the presence of indole‐3‐acetic acid as well as indole‐3‐acetonitrile in small amounts along with large amounts of glucobrassicin.

Segments of green hypocotyl tissue of savoy cabbage respond with limited growth to high concentrations of glucobrassicin. Segments of etiolated hypocotyls or green epicotyls give no growth response to glucobrassicin.

Pea stem segments which do not respond to indoleacetonitrile responded with similar growth to glucobrassicin and indoleacetic acid.

Nitrilase activity was found in savoy hypocotyl and epicotyl tissue by chromatography of incubation media.

The growth regulation in savoy cabbage in conjunction with data on the distribution of glucobrassicin in the plant, leads to the conclusion that glucobrassicin is a special, inactive storage and transport form of the active auxin in cabbage.
Metabolic Flux in Yeast Cells with Oscillatory Controlled Glycolysis
Authors: Betz Augustin
Published: April 2006

In yeast cells with oscillating glycolysis the fluctuations in metabolite concentrations are rather small compared with the total glycolytic flux. Glucose is consumed in a pulsatory manner, indicating highly efficient control at one of the first enzymatic steps. Cycling fluctuations in the apparent equilibriums constant of aldolase demonstrate this step being a retarding one and are indicative of different flow rales in the lower and in the upper part of the glycolytic sequence. Alternating phases of inhibition and activation at phosphofructokinase and glyceraldehydphosphatdehydrogenase, two steps interconnected by the retarding aldolase step and further connected by feedback in the ATP/ADP system, are considered as being the source of the observed oscillations.
On Dark‐Germination and Antheridium Formation in Anemia phyllitidis
Authors: Näf Ulrich
Published: April 2006

Schraudolf's finding is confirmed that gibberellic acid induces antheridia in Anemia phyllitidis and Lygodium japonicum. The activity spectra of gibberellic acid and the native antheridiogen of Anemia phyllitidis are similar: Both induce antheridia in the tested species of the family Schizaeaceae but are inactive towards the tested representatives of other fern families. However, the native antheridiogens of two schizaeaceous species are more species‐specific in their action than is gibberellic acid.

Anemia medium cancels the light requirement for spore germination as is the case with gibberellic acid. Chromatographic studies indicate that the dark‐germination‐inducing factor is identical with, or very similar to, the earlier demonstrated antheridiogen. The specificities of the active factors towards dark‐germination in A. phyllitidis and L. japonicum are similar to those encountered with antheridium formation.

Anemia medium induces dark‐germination and induces antheridia on the dark‐grown protonemata to a concentration ca. 30 times lower than it induces antheridia on light‐grown prothalli. The studies indicate that this differential activity results from a differential competence of the prothalli to react to the active substance in light and darkness.
Location of a Protease and its Inhibitor in the Barley Kernel
Authors: Burger W. C. , Siegelman H. W.
Published: April 2006

Tissues of barley caryopsis and seedling were examined for the protease, BAPAase, and an inhibitor. The enzyme was present in extracts of alevn‐one but was absent from aleurone incubation media and extracts of: embryo with scutellum; seedling with scutellum and rootlets, and endosperm that was free of aleurone tissue. The enzyme was present in non‐incubated aleurone and did not increase significantly during incubation under conditions where alpha‐amylase increased in the medium and tissue. Addition of gibberellie acid produced no detectable increase in BAPAase.

Extracts of endosperm had weak BAPAase‐inhibitory activity; embryo or seedling extracts produced strong inhibition. The inhibitor present in these extracts was dialyzable.
Inhibition of Plant Root Growth by Enzymes and Histones
Authors: McLaren A. D. , Bradfute O. E.
Published: April 2006

It has been shown previously that root growth can be inhibited by basic, animal proteins. In an effort to see if a plant histone was more efficacious than the animal protein, roots were grown in the presence of wheat histone. Otber basic polymers were also tested.

Polycations, including salmine, lysozyme, ribonuclease, wheat germ histone, thymus histone and polylysine inhibit root elongation of barley and wheat. Polyglutamate and lysylglycine at comparable weight concentrations are not inhibitory. No difference in the efficacy of tbe plant and the animal histones could be found with either plant, which suggests that the action is non‐specific.

Growth of roots inhibited by histone, trypsin, or lysozyme can resume after removal of the polycation.

The mechanism whereby polycations influence root growth is not known, but it is clear that the polymeric state of ionic functional groups is of paramount importance in the binding of the polycations to cell surfaces.
Studies on the Crayfish Plague Fungus Aphanomyces astaci
Authors: Unestam Torgny
Published: April 2006

A mycelial suspension of the crayfish plague fungus, Aphanomyces astaci, was able to produce large numbers of zoospores, when transferred to redistilled water, at 20°C, even after storage for months at 2°C. Spore production was greater in redistilled water than in tap water and heavier under shake conditions than under stationary ones. In buffered redistilled water sporulation occurred between pH 5 and 8 and the optimal range was about pH 5 to 7.

Of the tested aliphatic alcohols, aldehydes, and carboxylic acids, the long analogues were more toxic to spore formation than the shorter ones. Ethylenediamine‐tetraacetic acid (EDTA) prevented sporulation probably by removing some essential metal (s) with an affinity for EDTA near that of calcium. Calcium protected against the toxic effect of lithium, sodium, and potassium. Magnesium, only tested against lithium, had no such protecting effect.

Cu2+, Ni2+, Zn2+, Co2+, K+ Mn2+, NH4+, Li+, Na+, Ca2+, Mg2+ was the approximate order among tested cations in their ability to stop the swimming stage of the zoospores, the first mentioned being the most effective ones. Nitrate and acetate were more active in the same respect than sulphate, chloride, phosphate, or bicarbonate. The optimal pH range for swimming seemed to be pH 6–7.5, and the maximal range 4.5–9.0.

The zoospores showed no chemotactic response to tested substances. The germination ability was as high in horse blood as in crayfish blood. A spore suspension stored for 2 months at 2°C still contained viable spores.
Chitinolytic, Cellulolytic, and Pectinolytic Activity in vitro of Some Parasitic and Saprophytic Oomycctes
Authors: Unestam Torgny
Published: April 2006

Seven lower phycomycetes, Afhanomyees astaci, A. euteiches, A. cladogamus, A. cochlioides, A. laevis. Pythium sp and Saprolegnia 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 of A. astaci gave 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. cladogamus and A. 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.
Mangan‐Einfluss auf Volumen und osmotischen Wert des Exsudats junger Sonnenblumen
Authors: Höfner W. , Herwig K.
Published: April 2006

In Versuchen mit jungen Sonnenblumen wurde der Einfluβ von mangan auf Volumen und osmotischen Wert des Exsudats innerhalb zweier Tage nach dem Abschneiden untersucht.

Zwischen Volumen und osmotischem Wert des Exsudats konnte keine direkte Korrelation ermittelt weden.

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.

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.

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.

Der fordernde Einfluβ von Manan auf die Exsudatproduktion konnte crnent bestatigt werden.
Carotenoid Synthesis in Leaves of Wheat after Irradiation by Red Light
Authors: Virgin Hemming I.
Published: April 2006

A 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‐irradiation.
Growth Rates of Marine Phytoplankton: Correlation with Light Absorption by Cell Chlorophyll a
Authors: Eppley Richard W. , Sloan Phillip R.
Published: April 2006

To 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 reality.
Chlorophyll Formation in Excised Roots of Cucumber and Pea
Authors: Björn L. O. , Odhelius Ingegerd
Published: April 2006

The 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.
Studies on the Fat Metabolism of Light‐ and Dark‐Germinated Seeds of Scots Pine (Pinus silvestris L.)
Authors: Nyman Bengt
Published: April 2006

The 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 of the germination.
Light‐controlled Cycocel Reversal of Coumarin Inhibition of Lettuce Seed Germination and Root Growth
Authors: Khan A. A. , Tolbert N. E.
Published: April 2006

Lettuce seed germination or lettuce root elongation after germination in water was inhibited by coumarin and these inhibitions were reversed by Cycocel. 2.53 × 103 M Cycocel reversed the inhibition of seed germination by 6.8 × 104 M coumarin. and 6.32 × lO−4 M Cycocel reversed the inhibition of root elongation by 3.4 × 103 M 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 A3 and IAA were unable to reverse these coumarin induced inhibitions. A common mechanism is suggested for Cycocel reversal of coumarin and lAA inhibition of growth.
Inhibition of Lettuce Seed Germination and Root Elongation by Derivatives of Auxin and Reversal by Derivatives of Cycocel
Authors: Khan A. A. , Tolbert N. E.
Published: April 2006

Lettuce seed germination or lettuce root elongation after germination in water was inhibited by 5.7 × 10‐6M indoleacetic acid (IAA) and designated other IAA derivatives. These IAA‐inhibited growth responses were reversed by 10‐5 to 10‐6M Cycocel, (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‐3‐butyric acid.
On the Reversal of the Inhibition of Photosynthesis Induced by Sodium Dimethyldithiocarbamate and Tetramethylthiuram disulphide
Authors: Lindahl P. E. Börn
Published: April 2006

The reversal of 80–100 per cent inhibition of photosynthesis in the green alga Enteromorpha 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 CuSO4 reacted 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 form. (PDF DAMAGE)
Excised Tobacco Pith Bioassays for Root‐knot Nematode‐produced Plant Growth Substances
Authors: Sandstedt Robert , Schuster Max L.
Published: April 2006

Root‐knot nematodes, Meloidogyne incognita, were grown in tobacco pith tissue cultured in vitro on modifired white's medium. The nematodes did not secrete detectable amounts of auxin or cytokinin, but did promote growth in the presence of both types of growth substance. When both IAA and kinetin were supplied, the nematode‐infected tissue was larger, more irregularly shaped than control tissue; nematodes induced syncytia and developed past the second larval stage. When either IAA or kinetin was omitted from the medium, nematodeinfected and control tissue failed to grow and the nematodes failed to induce syncytia or develop.
Temperature Fluctuation in Wintering Trees
Authors: Sakai A.
Published: April 2006

To investigate the mechanism of frost damage in trees, the temperature fluctualions in the stems and leaves of some wintering trees were recorded with copperconstantan thermocouples.

In Sapporo, even the trunk of large elm trees with diameter of 86 cm are frozen during the winter. In a Kalopanax trunk with a diameter of 13.5 cm, the bark temperature on the south side which is exposed to direct sunshine reaches nearly 20°C about midday in midwinter; while, on the north side, the temperature remains nearly the same as the environmental temperature (0 to ‐5°C). The rise in the bark temperature in trees is considerably affected by factors such as the intensity of sunshine, the environmental temperature, the diameter of the trunk, the side of the trunk which the bark is on, the height above the ground, and the colour of the bark surface, etc. This rise is far less in small twigs, slender stems, and small leaves than in large ones. The south side of the bark 10 to 15 cm above the snow surface or above the ground in a slender stem is exposed to a remarkable fluctuation in temperature, especially when the ground is covered with snow.

Even in northern trees, the cortical cells on the south side of trunks and twigs are less resistant to freezing than those on the north.
Light‐Inhibited Leaf Development in a White Mutant: Resemblance to Effeets of 2‐Thiouracil in Normally Pigmented Helianthus annuus
Authors: Habermann Helen M.
Published: April 2006

When the white mutant of Helianthus animus is grown in full sunlight, leaf expansion and differentiation of the mesophyll are inhibited.

More normal development results when incident wavelengths, shorter than 450nm, are removed by appropriate filters.

A short wavelength photoreaction has been proposed which results in cessation of leaf development at a juvenile stage, and is analogous in its mechanism to the effects of 2‐thiouracil on leaf developmient.
Effects of Phenylethyl Alcohol on Chlorella pyrenoidosa
Authors: Knutsen Gjert
Published: April 2006

Asynchronous as well as synchronous cultures were used to study the effect of phenylethyl alcohol on Chlorella pyrenoidosa. The following observations were made:

Autotrophic growth and the synthesis of DNA and chlorophyll were inhibited more than 80% by 8.4 mM phenylethyl alcohol when added to synchronous suspensions containing autospores.

Autospore formation did not occur when fully grown cells capable of division were transferred to 4.2 mM phenylethyl alcohol.

Photosynthetic oxygen evolution of asynchronous cultures was inhibited more than 70 % by 21 mM phenylethyl alcohol.

Endogenous respiration in the dark was stimulated by 8.4 mM, while higher concentrations were inhibitory.

Glucose respiration in the dark was inhibited by all concentrations in the range from 8.4 mM to 21 mM. Assimilation of glucose in darkness was retarded by phenylethyl alcohol at concentrations which gave maximal stimulation of endogenous respiration.

It is concluded that phenylethyl alcohol is not a specific inhibitor of DNA synthesis. The prime effect appears to be on respiration and photosynthesis.
Changes in Growth, Auxin‐ and Ribonucleic Acid Metabolism in Wheat Coleoptile Sections Following Pulse Treatment with Indole‐3‐Acetic Acid
Authors: Truelsen T. A. , Galston A. W.
Published: April 2006

Growth reactions of wbeat coleoptile sections following a brief pretreament in indole‐3‐acetic acid (LAA) were studied. The growth versus concentration curves 24 hours after the treatment showed a minimum value surrounded by bigber values. The minimum was never at concentrations lower than 10‐5M lAA but it could be found at higher concentrations after short pretreatment periods.

The growth versus time curves reveated that the hormone treatment cansed the growth rate initially to increase but later on to decrease. The decrease was followed by a second increase for some treatments.

Analysis of IAA content after the pretreatment showed that the attered growth patterns could be ascribed to declining auxin content with time, but not to thc actual concentration in the sections.

The results indicate that the metabolic activation brought about by IAA leads to its own disappearance. Such a phenomenon was mirroretl in effects of IAA on hte net synthesis of ribonucleic acid.
Sources of Nitrogen for Spruce Tissue Cultures
Authors: White Philip R. , Gilbey Susan N.
Published: April 2006

The major heat‐labile organic ingredient of the nutrient previously developed in this laboratory for spruce cells is glutamine. This cannot be fully replaced by any single stable organic substance or group of substances tested. Its replacement by inorganic ammonium salts results in no significant reduction in growth rate in terms of wet weights but produces qualitative defects which make such sutistitutions undesirable. Of special interest is the production of reticulated xylem cells when cultures are grown in the light on NH4 supplements.
Aging and Mitochondrial Development in Potato Tuber Tissue
Authors: Lee S. G. , Chasson R. M.
Published: April 2006

Respiratory activity of mitochondria isolated from fresh and aged potato tuber tissue has been determined. No significant change in activity of the particles (expressed per unit N) was observed as a result of aging. However, the yield of mitochondrial material increased with aging. It has been suggested that the commonly observed stimulation of respiration that accompanies aging of potato tissue can be attributed largely to an inerease in the mitochondrial population rather than to a stimulation of the particles per se, and that this increase results from a fission of pre‐existing mitochondria.

The respiratory activity of mitochondria isolated from unaged tissue was found to decline following storage of the tubers in the cold for extended periods. This decline was attributed to a loss of cristae structure in the particles, as observed microscopically. The possibility that this reduction in structural organization might be associated with changes in the state of dormancy of the tissue was considered.
Root Nodule Symbiosis II
Authors: Silver W. S. , Bendana F. E. , Powell R. D.
Published: April 2006

Nodule‐roots of Myrica cerifera (Southern Wax Myrtle) and Casuarina cunning hamiana (Australian Pine) have a negative geotropic curvature. Studies of their endogenotts auxin content revealed a pattern of correlation: the absence of detectable auxin when the geotropisni was negative. Non‐nodulated roots of Myrica exhibited a normal positive geotropic curvature and possessed an auxin content within an anticipated range (10 mg/kg). Root nodules of Alnus species, whose roots exhibit a positive geotropic curvature, contained measurable endogenous auxin (20 mg IAA/kg).

The presence of an indoleaectic acid oxidase system in Myrica and Casuarina root nodules has heen described and correlations are drawn between non‐detectable endogenous auxin concentrations and high enzymatic activities.

It is suggested that the negative geotropic curvature of the nodule‐roots of Myrica and Casuarina is due to the presence of a sub‐optimal concentration of auxin which in turn results from the activity of an indoleacetic aeid destroying system.
Photosynthetic and Dark Fixation of 14CO2 in Detached Soybean Cotyledons
Authors: Abrahamsen Mary , Mayer A. M.
Published: April 2006

Detached soybean cotyledons fixed CO2 both in the light and dark. Carbon dioxide fixed by the light and dark reactions replaced only a small portion of CO2 lost by respiration up to the 10th day. In the dark most of the 14C label was found in the acidic fraction, while in the light 65 per cent of the activity was found in the neutral and basic fractions.
Alterations in Amino Acid Content Caused by 3‐amino‐l,2,4‐triazole
Authors: McWhorter C. G. , Hilton J. L.
Published: April 2006

Changes in the amino acid content of Zea mays and Sorghum hnlcpemr by treatments with amitrole (3‐amino‐l,2,4‐triazole) are reported. The evidence suggests that inhibition of histidine biosynthesis is probably not the mechanism of amitrole action in young seedling plants. Reductions in glycine and serine content of treated plants were observed. Results are discussed in relation to current theories on mechanisms of herbicide action.
Primary and Secondary Carotenoids of Spongiochloris typica
Authors: McLean Robert
Published: April 2006

A qualitative and quantitative investigation was made of the pigments of Spongiochloris typica over an 8 week period. The pigments were chromatographed on thin layers of sucrose and measured spectrophotometrically. Pigments present after 1 week of growth were identified as chlorophylls a and b, β‐carotene, lutein, zeaxanthin, violaxanthin, trollein, and neoxanthin. In cultures 2 weeks or more old, secondary carotenoids appeared. These were echinenone, canthaxanthin, astacene, and an unidentified ketocarotenoid. Carotenoids comprised nearly 100 percent of the total pigment composition on the 8th week. About 75 percent of the carotenoid fraction on the 8th week consisted of secondary carotenoids.
The Effect of Chilling of the Physiological and Simulated Apex of 2‐ and 3‐leaf Plants of Pisum sativum L. cv. Alaska on Lateral Shoot Growth, C‐14 IAA Movement and P‐32 Accumulation
Authors: Husain Syed Mushtaq , Linck Albert J.
Published: April 2006

The apex of a 3‐leaf pea plant was chilled in cold chambers maintained at 5–7°C. The lateral shoots 1 through 5 grew, and shoot 5 eventually dominated other lateral shoots. The apex when returned to the ambient temperature did not reimpose apical dominance. The growing lateral shoots competed with the stem apex.

The apices of 2‐ and 3‐leaf plants were chilled and P‐32 distribution in these plants was studied in the entire plant, at various intervals of time. Phosphorus‐32 accumulation followed the growth pattern of the plant. The lateral shoots accumulated P‐32 activity and very little activity was accumulated by the apex. The dominating shoots 2 and 5 accumulated the maximum amount of activity in 2‐ and 3‐leaf plants, respectively.

Labeled‐IAA moved basipetally through the stem when applied to the cut stump simulating the apex. By cold treatment the translocation of IAA was influenced more than its absorption. The plant seems to metabolize this compound in the later periods of application. The plant now becomes “insensitive” to auxin and the lateral shoots grow.
Endogenous Diurnal Rhythm in the Osmotic Surplus of the Guard Cells
Authors: Stålfelt M. G.
Published: April 2006

The osmotic surplus of the guard cells —i.e., the difference between the guard cells’and epidermal cells’omotic value at incipient plasmolysis (Vicia Faba) —exhibits an endogenous diurnal‐periodic variation that is synchronous with the endogenous diurnal periodicity in the movements of the guard cells. The osmotic surplus of the guard cells is found to arise and drop by changes not only in these cells, but also in the epidermal cells.
Effect of Leaf Aging on Water Deficit—Water Potential Relationships of Dogwood Leaves Growing in Two Environments
Authors: Knipling Edward B.
Published: April 2006

Water deficit‐water potential relationships were determined at approximately monthly intervals from May to August on leaves collected from dogwood trees growing in two environments. The relationships were not the same for leaves of different ages or for leaves of the same age, but growing in the different environments. With aging of the leaves, the relationships shifted to progressively lower water potentials for a given water deficit. Increased leaf dry weight, decreased cell wall elasticity, and decreased osmotic potentials accompanied leaf aging. These changes and the shifts in the relationships were greatest for leaves growing under high light intensity and dry environmental conditions. The lack of constancy in the relationships reduces the usefulness of water deficit or relative turgidity as an estimator of water potential. For the purposes of some workers, however, the relationships may be sufficiently constant for mature leaves of a given species growing in a relatively constant environment.
Sulfhydryl and Disulfide Patterns Associated with Vernalization of Wheat
Authors: Ellis R. W. , Trione E. J.
Published: April 2006

Analyses of plumules from seedlings of a winter wheat variety (Elgin) and a spring wheat variety (Red Bobs) indicated that SH and SS contents based on protein levels were similar in the whiter and spring wheat tissues grown at 20 C. Boll) varieties, when grown nt 3 C, contained greater concentrations of SH and SS groups, based on protein levels, than those present in the tissues grown at 20 C. The spring wheat tissues at 3 C maintained relatively constant levels of SH and SS during the growth period.

Sulfhydryl (SH) and SS groups based on fresh weights were present in greater quantities in the tissues of the spring wheat grown at 20 C than in the winter wheat tissues grown at 20 C. The high SH and SS concentrations present in the warm‐grown spring wheat tissues were due to a high concentration of protein extracted from that tissue. The SH and SS contents per unit fresh weight were quite similar in the cold‐grown tissues of both varieties during the growth period. Both varieties at both temperatures showed a similar decrease in SH and SS contents, based on fresh weights, as maturation progressed.

The spring wheats grown at 3 C and 20 C and the winter wheat grown at 3 C all showed similar characteristics and differed considerably from the winter wheat grown at 20 C. These data were positively correlated with the flowering potential of the wheat varieties.
The Effect of Toxic Doses of Copper upon Respiration, Photosynthesis and Growth of Chlorella vulgaris
Authors: McBrien David C. H. , Hassall Kenneth A.
Published: April 2006

When cells of Chlorella vulgaris absorb copper under anaerobic conditions, subsequent respiration, photosynthesis and growth of the cells are all severely inhibited. This does not occur when the metal is absorbed under aerobic conditions. When, after aerobic absorption of copper, the cells are exposed to a period of anaerobiosis, respiratory inhibition is as profound as when the uptake is anaerobic. In this case, however, respiration must eventually recover, for growth is not affected so severely as it is when copper is taken up under anaerobic conditions. It is concluded that the extra copper absorbed under anaerobic conditions is directly or indirectly responsible for the greatly increased toxicity to growth, and that this copper is bound to sites not normally available under aerobic conditions. Some aspects of the apparently unique toxic effect of copper suggest that these extra sites are sulphydryl groups.
Permeability and Respiratory Properties of Germinating Pollen
Authors: Dickinson David B.
Published: April 2006

A study of permeability and respiration of germinating lily pollen (Lilium longi‐florum, variety Ace) was conducted. Calcium was needed in the culture medium to maintain the integrity of the cell membranes. Carbohydrates leaked from pollen when calcium was absent, but little or no leakage occurred when calcium was present. A culture medium containing penlaerythritol was developed for this study. Pentaerythritol allowed normal germination and did not interfere with measurement of carbohydrates. Intact pollen grains possessed a β‐fructofuranosidase external to the cell membrane which hydrolyzed sucrose in the culture medium. External α‐ or β‐glucosidases were absent, although soluble α‐glucosidase was present within the pollen.

Oligomycin, an inhibitor of oxidative phosphorylation, eliminated the 3‐phase patters of respiration associated with normal germination. O2 uptake was inhibited by oligomycin while CO2 output was stimulated. 2,4‐Dinitrophenol, an uncoupler of oxidative phosphorylation, reversed the inhibition of O2 uptake caused by oligomycin.
Action Spectra for Light‐induced Elongation in Fern Protonemata
Authors: Miller John H. , Miller Pauline M.
Published: April 2006

The action spectrum for promotion of elongation of protonemata of Onoclea sensibilis has peaks at 400–420, 580–600 and 640–660 nm. The largest growth increments at saturating light doses are produced by yellow and far‐red light. Elongation induced by yellow and far‐red irradiation persists in old as well as young filaments, while red‐light promotion is found only in young filaments. The growth promotion caused by yellow light is partially reversed by red light down to the level of growth produced by red irradiation alone. Elongation of rhizoids is under reversible red, far‐red control, while yellow light is inactive. A model is proposed and discussed in which the light‐sensitive elongation of filaments is accounted for by the presence of three distinct photoreceptors: phytochrome; a pigment absorbing yellow light. P580; and a pigment absorbing blue light, P420.
The Uptake and Metabolism of Sulphate in Scenedesmus as Influenced by Citrate, Carbon Dioxide, and Metabolic Inhibitors
Authors: Kylin Anders
Published: April 2006

The incorporation of sulphur from external sulphate into different fractions was studied in cells with a P content of 0.6 to 1 mg/g fresh weight as against 3 to 5 mg/g fresh weight in normal cells. — There is a flat and broad optimum for the action of pH in the region between 5.7 and 7. — In most cases, citrate inhibits the uptake of sulphur. — Five per cent CO2 in the air enhances the incorporation of S. It is suggested that the effects of CO2 may well be exerted by way of the carboxylation and decarboxylation mechanisms in the cells. — Selenate inhibits the formation of DNA‐S and protein S more than that of lipid S, but the main effect in both cases seems to be in an early step of the assimilation of sulphate. In the absence of external phosphate, the inhibition is counteracted by CO2, especially in darkness. Phosphate enhances the action of selenate on the organic S fractions, and in its presence CO2 and darkness make the inhibition more pronounced. — Without P in the medium, the effects of selenate on uptake into the inorganic sulphate fraction are smaller than when the organic fractions are concerned. In the presence of CO2 even stimulations due to selenate have been observed. External phosphate brings the inhibition of uptake into cellular SO42‐ to the same level as found in the case of organic S. More than one pathway for the uptake as SO42‐seem possible. — Anaerobiosis and menadione affect the organic S fractions more than the sulphate; 2,4‐dinitrophenol has a more uniform action all over the field.
The Effect of the Plant Growth Retardants Amo 1618 and CCC on Gibberellin Production in Fusarium monili‐forme: Light Stimulated Biosynthesis of Gibberellins
Authors: Mertz D. , Henson W.
Published: April 2006

Through the use of a single gene dwarf mutant of Zea mays L., dwarf‐1, the interaction of growth retardants with gibberellin biosynthesis was studied in Fusarium monitiforme. It was demonstrated that the growth retardants 2‐isopropyl‐4‐dimcthylamine‐5‐methyphenyl‐1‐piperidine‐cai'boxylate methyl chloride (Amo 1618) and (2‐chloroethyl) trimethylammonium chloride (CCC) are more effective inhibitors of gibberellin biosynthesis in cultures maintained under continuous illumination.

Light grown cultures produced significantly more biologically active gibberellin‐like materials than dark grown cultures. Stock cultures exposed to light also promoted the subsequent biosynthesis of gibberellins in the dark. Chromatographical analysis of the soluble gibberellins extracted from the culture medium revealed that large amounts of chromatographically detectable A3 and A7 were produced in light cultures with only A7 produced in the dark. Light also induced a greater incorporation of acelate‐2‐14C into the gibberellins A7, A3 and an unidentified gibberellin.

Growth returdants occasionally caused a complete disappearance of chromatographically detectable gibberellins in the dark; however, in the light at no concentration tested was it possible to detect the complete disappearance of gibberellin‐like material. A3 was always detectable.

Like higher plants, different strains of F. moniliforme exhibit variation which makes them more or less sensitive to the growth retardants. This variation is interpreted to mean that there may be more than one pathway leading to the synthesis of the gibberellins.