bluuebunny/crossref_metadata_2025 huggingface dataset:
The Comparative Boron Nutrition of Several Green and Blue‐Green Algae
Authors: Gerloff G. C.
Published: April 2006

The boron requirements of filamentous and non‐filamentous species of green and blue‐green algae have been investigated. A primary feature of this study was the quantitative analysis of the cells for boron. This permitted expression of the degree of purification of the environment and the boron requirements of the organisms in terms of cell content. Three species of green algae were shown neither to require boron nor to absorb it in appreciable amounts. In contrast, three species of blue‐green algae readily absorbed boron and nitrogen fixing species showed a marked growth response to boron when nitrate was omitted from the culture medium. The response to boron was less with nitrate in the medium, probably due to increased contamination from the nitrate salt rather than an involvement of boron in the fixation process. The boron content of the deficient blue‐green algae was 1–2 μg/g, suggesting a requirement below dicot angiosperms and comparable to monocots. In agreement with other reports, the fungus Penicillium chrysogenum neither required nor absorbed boron.
Occurrence and Metabolism of Indoleacetaldehyde in Certain Higher Plant Tissues Under Aseptic Conditions
Authors: Rajagopal R.
Published: April 2006

Qualitative and quantitative evidence based on thin‐layer chromatography and the Avena curvature test respectively, are presented for the normal and natural occurrence of indoleacetic acid (IAA), indoleacetaldehyde (IAAld) and tryptophol in the etiolated shoots of Pisum sativum, grown, harvested and extracted under aseptic conditions. Non‐aseptic pea shoots contain much more IAA and IAAld than aseptic ones. Extraneous contribution to the indole pool of pea plants grown under non‐sterile atmosphere, other than by the inherent agency of the plant itself, is therefore not excluded.

Indoleacetaldehyde metabolizing activity of the tissues and cell‐free preparations of etiolated Avena seedlings, leading to the production of IAA and tryplophol, is unaffected by the antibiotics actinomycin and streptomycin over a wide range of concentrations. Formation of IAA from IAAld is suppressed by a small degree (10 to 15 %) by chloramphenicol. But this antibiotic does not influence the concurrent production of tryptophol. It is deduced that epiphytic bacteria play little role in the transformation of IAAld to IAA and tryptophol by Avena tissues.
Shoot Formation in Tissue Cultures of Chrysanthemum‘Bronze Pride’
Authors: Hill G. P.
Published: April 2006

Explants of Chrysanthemum stem were cultured on four different media on all of which callus was produced. This callus and explant tissue was then sub‐cultured on to one of two media, making eight different treatments. One of these treatments in which explants were cultured on a medium containing 2 mg/1 1‐naphthaleneacetic acid (NAA) and 0.8 mg/1 kinetin, and then sub‐cultured onto a medium containing 1 mg/1 kinetin and 1 g/1 soya peptone produced numerous shoots. The value of this finding for the propagation of chrysanthemum is discussed.

The technical assistance of Helen Krebs, Sheila Bruce and Maria Bagnall is acknowledged. I also thank Dr. J. L. Bailey for discussions and encouragement.
The “Point of no Return” Concept in Cell Division. The Effects of Some Metabolic Inhibitors on Synchronized Chlorella pyrenoidosa
Authors: Moberg Sidsel , Knutsen Gjert , Gokøyr Jostein
Published: April 2006

The coarse of growth and cell division in synchronized cultures of Chlorella pyrenoidosa was studied after the addition of metabolic inhibitors at differing times during the cell cycle (14 h light ‐ 10 h darkness with nitrate as nitrogen source. 12 h light: 12 h darkness with urea as nitrogen source).

Dinitrophenol (DNP) added to a final concentration of 0.3 mM at any time in the synchronization cycle, the compound remaining in the suspension from the time of addition to the end of the dark period, inhibited spore formation completely. Growth measured as increase in cell volume was less sensitive to the action of the inhibitor. Chloramphenicol (CAP) added dining the 0–5 h interval to a final concentration of 0.1 mM resulted in 80 per cent inhibition of cell division. Similar treatment started at successive times thereafter resulted in a gradual decrease of the inhibition. Treatment at the 14th hour and during the dark period did not affect the sporulation.

Similar experiments with 0.9 mM puromycin added at various times during the illumination period gave almost complete inhibition of cell division, while the growth was reduced by only 25 per cent.

para‐Fluorophenylalanine (p‐FPhe) at 3.3 × 10−2 mM stopped cell division nearly completely irrespective of addition time in the light period. Addition during the dark period also prevented an increase in the number of tree cells. In this case about half of the cells produced spores which were not released.

It is concluded that DNP inhibits all stages of preparation for cell division, as well as the division process itself. With CAP a genuine transition point of preparation for cell division was observed, although its interpretation as related to protein synthesis is somewhat uncertain. With puromycin and p‐FPhe no transitions were observed.
The Adaptation of Plankton Algae
Authors: Nielsen E. Steemann , Jørgensen Erik G.
Published: April 2006

The various aspects of the adaptation of plankton algae lo light and temperature are discussed. The shape of a light intensity‐photosynthesis curve is shown to be an important means of describing the physiological adjustment of an algal population.

If the algae are not exposed to adverse influences such as poisons, pronounced nutrient deficiency or light shocks, the rate of real photosynthesis per mg chlorophyll a at 1 Klux (incandescent light) should be about 0.4–0.6 mg C/hour. Hence this rate presents an excellent means of judging the quality of experiments.

Experiments are presented where Chlorella pyrenoidosa was adapted to light intensities between 0.32 klux and 21 Klux. This alga adapts to different light intensities by varying the amount of pigments per cell. Algae grown at 1 Klux have about 10 times more chlorophyll per cell than those grown at 21 klux. Other species of algae—but by no means all—are shown to behave in the same way.

The problem of algal resistance to photo‐oxidation at high light intensities is discussed. Adaplation is shown to he one of the mechanisms which make the algae resistent. “Chlorophyll inactivation” is another.

Experiments with the diatom Skeletonema costatum concerning adaptation to different temperatures have been performed. The fact that the alga has essentially the same rate of photosynthesis per cell at all light intensities at 20°C and 7°C, may be attributed to an increase of all the enzymes at the low temperature. The amount of protein per cell was twice as high at 7°C as at 20°C.
Water and Sulphate Uptake at Root Reduction in Ricinus communis
Authors: Christersson Lars , Pettersson Sune
Published: April 2006

The aim of the investigation was to study the influence of the rate of water uptake on the uptake of sulphate at supernormal rates of water flow. This was achieved by reducing the size of the root system of 42 days old Ricinus plants. The rate of water flow through the root increased 3 times by reducing the root system to 20 percent. This did not change the retention of sulphate in the roots. The uptake of sulphate was proportional to the size of the root system and thus independent of the rate of water flow while the water uptake (transpiration) was a function of the size of the shoot and the resistance of the root. This was contrary to the conditions at a moderate rate of water flow, when water and sulphate uptake followed each other. The results are discussed in terms of the salt uptake as a series of active and passive processes.
The Adaptation of Plankton Algae
Authors: Jørgensen Erik G.
Published: April 2006

The theory that Skeletonema cells adapt to lower temperatures by increasing their enzyme concentration, is supported by various facts. While the rates of photosynthesis are identical in cells adapted to different temperatures (7–20°C) the growth rate decreases with decreasing temperature and the production of organic matter increases with decreasing temperature. Further, the concentration of protein per cell and the height of the cells increase with decreasing temperature.
Nucleic Acid Metabolism of Vicia faba during Germination and Growth
Authors: Olsson R. , Boulter D.
Published: April 2006

During the growth of Vicia faba seedlings in the absence of an external nitrogen supply, the cotyledons decreased rapidly in dry weight and nucleic acid content. In the developing shoot the dry weight increased rapidly for four weeks and then very slowly over the next two weeks growth; the nucleic acid content of the shoot increased to a maximum after 4 weeks growth and decreased in amount during the next 2 weeks. On the other hand the roots increased in both dry weight and nucleic acid content throughout the growth period, although they only accounted for a small proportion of the total dry weight and nucleic acid content of the plant. These changes during germination and growth are discussed in relation to those occurring during these developmental stages in other plants.
Energy Sources for the Absorption of Rubidium by Chlorella
Authors: Sprimier‐Lederer Helmuth , Rosenfeld David L.
Published: April 2006

Zusammcnfassung

Die aktive (stoffwechselabängige) Aufnahme von Radiorubidium aus 8.10−5 molarer Lösung durch Chlorella pyrenoidosa wurde in Langzeitversuchen (1–2 Tage) untersucht. Die Annahinc ist, daβ die dafür notwendige Energie in Form von ATP bereitgestellt werden muβ. Es wurde gefunden, daβ Gegenwart von Na‐ Oder Cl‐Ionen für die aktive Rb‐Aufnahme nicht notwendig ist; die Rb‐Pumpe ist also nicht an eine Na‐ Oder Cl‐Pumpe gekoppelt. Vorbeladene Chlorella gibt Rb über längere Zeiten langsam an das Medium ab.

Durch Experimente im Licht bzw. Dunkel und in Gegenwart bzw. Abwesenheit von Luft wurde gezeigt, daβ bei 9000 lux die Beleuchtung mehr Energie für die aktive Aufnahme erbringt als die Atmung. Der Ersatz von Luft durch Sauerstoff hat keine Auswirkung. Die Versorgung mit ATP durch Atmung—nicht aber durch (zyklische) Photophosphorylierung—wird durch 5.10−4 M DNP weitgehend unterdrückt. Die aktive Aufnahme ist klein, wenn sie sich nur auf Glykolyse stützt.

Gleichzeitige Einwirkung von Licht, Luft (Sauerstoff) und DNP auf Chlorella führt zu irreversibler Schädigung und Ausbleichung der Algen. Sie hören auf, Rb aufzunehmen und verlieren vorher absorbiertes Rb wieder. Gründe für diesen Effekt werden diskutiert.

Die aktive Aufnahme von Rb wird durch 5.10−2 M Glukose gefördert, u.z.w. im Licht und im Dunkel, in Luft‐ und in Stickstoffatmosphäre. In dieser Beziehung unterscheidet sich die aktive Rb‐ von der aktiven Bromid‐Aufnahme. Die Förderung durth Glukose wird durch DNP gehemmt, ausgenommen im Dunkel in Stickstoffatmosphäre. In Gegenwart von DNP wird die Rb‐Aufnahme durch 1% CO2 sowohl im Licht als auch im Dunkel stark herabgedrückt.
Some Observations on the Sodium and Potassium Interactions in the Blue‐green Alga Anabaena flos‐aquae A‐37
Authors: Bostwick C. D. , Brown L. R. , Tischer R. G.
Published: April 2006

The growth of Anabaena flos‐aquae A‐37 has been shown to be severely limited by the absence of either sodium or potassium from the culture medium. Neither element is capable of replacing the other. The addition of sodium to sodium‐starved cells restores growth while potassium‐starved cells are not affected by the addition of potassium.
Untersuchungen über Beziehungen zwischen Zellteilung und Morphogenese bei Gewebekulturen von Daucus carota
Authors: Linser Von H. , Neumann K. H.
Published: April 2006

Relationship between cell division and morphogenesis of tissue cultures of Daucus carota. I. Observations on rhizogenesis and formation of whole plants.—By using a chemically defined medium the conditions for formation of roots and embryos in callus of various tap root parts of domestic Daucus carota forms were investigated and compared. Whole carrot plants capable of generative reproduction were produced from callus as well as from cell and tissue suspensions.

The influence of various phytohormones on differentiation and cell division activity of explants was studied. A close relationship between cell division activity and differential stains was established and explained as a result of the phytohormone action on the cell division rate.
Interactions between Plants and Epiphytic Bacteria Regarding Their Auxin Metabolism
Authors: Wichner Siegfried , Libbert Eike
Published: April 2006

Homogenates of epicotyls or roots of nonsterile pea plants incubated with tryptophan produce IAA within 1 to 4 hours, which was detected by means of the Avena curvature test and thin layer chromatography.

Three results prove this short‐term IAA production to be mainly caused by epiphytic bacteria: 1) Homogenates of sterile plant parts catalyze a conversion of tryptophan to IAA, a hundredfold lower. 2) Chloramphenicol or streptomycin very actively reduce the IAA gain obtained with nonsterile homogenates. 3) Washing solutions of nonsterile plant parts which do not contain plant enzymes but only epiphytic bacteria, produce IAA from tryptophan, too.

IAA synthesis from tryptophan in vitro by enzymes of the pea plant occurs with lower intensity than hitherto known; possibly it is physiologically unimportant. It is discussed to what extent the hitherto existing research work about the IAA biogenesis in higher plants might be incriminated by disregarding tbe rôle of epiphytic bacteria.
Untersuchungen über Beziehungen zwischen Zellteilung und Morphogenese bei Gewebekulturen von Daucus carota
Authors: Neumann K. H.
Published: April 2006

Relationship between cell division and morphogenesis of tissue cultures of Daucus carota. II. Respiration of tissue cultures in relation to cell division.—The relationship between oxygen consumption and cell division activity has been studied in ex‐plants of the secondary phloem of the tap root of Daucus carota with respect to the influence of various phytohormones. An inverse correlation was found, i.e. explants with a high cell division activity had a low oxygen consumption and explants with a low cell division activity had a high oxygen consumption.
Biochemical Aspects of Parasitism by the Angiosperm Parasites: Starch Accumulation
Authors: Singh M. , Singh D. V. , Misra P. C. , Tewari K. K. , Krishnan P. S.
Published: April 2006

The investigation dealt with starch accumulation in four species of Cuscuta (Cuscuta campestris, C. indecora, C. planiflora and C. reflexa), a leafy mistletoe (Dendrophthoe falcata) and a chlorophyll‐lacking root parasite (Orobanche aegyptiaca). The highest content of starch occurred In O. aegyptiaca, with a maximum of 45 per cent of dry weight Starch in Cuscuta filaments and mistletoe leaves showed a maximum of about 10 per cent of dry weight. The starch content varied along the length of the Cuscuta vine, with a maximum in the apical region. Orobanche had a higher starch content when it was still submerged than it was fully developed. Cuscuta vines did not show any marked diurnal alteration in the starch content. The content of ethanol‐soluble carbohydrate was only a tenth of the starch in Orobanche, but was relatively higher in the other parasites. the neutral sugars in Cuscuta filaments were sucrose and glucose, whereas fructose was also present in mistletoe and Orobanche. Raffinose and stachyose were absent or present only ill traces in parasite tissue. Starch granules from Cuscuta and Orobanche bad ADPG/UDPG‐starch synthetase activity and homogenates starch phosphorylase activity. The former enzyme appeared to be responsible for synthesis of starch and the latter for utilization. The four different species of Cuscnta, growing on alfalfa, had more or less the same activity of starch synthetase and also of phosphorylase activity. Hosts infected by Cuscuta had significantly less starch per plant than the controls. A characteristic feature of invasion by Cuscuta and Orobanche was increased phosphorylase activity in the host tissues. The protein content of the tissues of Cuscuta and Orobanche was of a lower level than that of the host shoot system or foliage, indicating that the parasite differed from the host in having a higher carbon (of starch) to nitrogen (of protein) ratio.
Comparative Physiology of Respiration in Aquatic Fungi II. The Saprolegniales, Especially Aphanomyces astaci
Authors: Unestam Torgny , Gleason Frank H.
Published: April 2006

The endogenous respiration of six members of Saprolegniaceae (Oomycetes), Saprotegnia sp., Thraustotheca sp., Achlya sp., Dichtyuchus sp., Aphanomyces euteiches, and A. astaci were studied in the presence and in the absence of exogenous substrate using conventional manometric techniques. Glucose stimulated the rate of oxygen uptake of unstarved mycelia to some extent in all the fungi. Attempts to increase the weak stimulation of respiration by glucose in A. astaci were not successful. The respiratory quotients of the fungi tested were usually in the range of 0.7 to 0.9 during endogenous respiration, and addition of glucose increased these values more than expected.

L‐leucine and L‐glutamic acid stimulated respiration of A. astaci only when the fugus was starved, and acetic acid and butyric acid were inhibitory. Fructose and acetic acid increased respiration in starved mycelium of A. euteiches while L‐leucine and L‐glutamic acid had little effect. Antimycin A, HOQNO, HCN, and fluoroacetate strongly inhibited endogenous oxygen uptake by A. astaci. Amytal and azide were also markedly inhibitory while rotenone and CO had little effect. DNP and diphenylamine inhibited respiration at a high concentration but at a lower concentration DNP was stimulatory. In contrast the respiration of Saprolegnia sp. was resistant to cyanide, antimycin A, and HOQNO.

Spectrophotometric observations on homogenized mycelia of Saprolegnia sp. and of A. astaci indicated the presence of cytochrome c (551 nm), two b‐type cytochromes (557 and 564 nm) and cytochrome a‐a3 (605 nm) all in approximately equimolar concentrations. In both strains CO combined with cytochrome a3 and an unidentified pigment. A remarkable similarity in the cytochrome system seems to exist between these two strains and some members of the Leptomitales.
Leaf Expansion in the Potato, Solanum tuberosum
Authors: Lovell Peter H.
Published: April 2006

The effects of a number of manipulative treatments together with the application of the growth hormones IAA and GA on leaf expansion in the potato, variety Majestic, were investigated. It was found that removal of the apex and its surrounding non‐expanded leaves resulted in an increase in both the rate and the extent of expansion of Ihe remaining upper leaves on the system. Application of IAA and GA to decapitated shoots showed that the rate of leaf expansion was decreased by IAA both alone and in combination with GA, whereas it was increased by GA treatment. Further investigations indicated that the response of a leaf to GA treatment was determined by the area and position of the leaf al the time of treatment and also by the number of expanding leaves on the system. It is postulated that this is due, at least in part, to competition for some factor or factors, which could be nutrients, within the system.
The Adaptation of Plankton Algae
Authors: Nielsen E. Steemann , Jørgensen Erik G.
Published: April 2006

A survey of the adaptation of plankton algae in Nature to different light intensities and temperatures is given. The adaptation is always important for the plankton populations at all depths. However, the shade adaptation of the algae in the lower part of the photic zone is often of relatively little importance for the integral primary production per unit of surface, except on the by no means rare occasions when the bulk of the algae is found in this lower part. It is shown that the Ik of surface plankton during summer in the Arctic is high despite the low temperatures present. This is due to an increase of the enzyme quantities per cell. Daily fluctuations in Ik are due partly to photooxidation, partly to the fact that the periods for the production of chlorophyll and photosynthetic enzymes are mutually displaced. Despite the daily fluctuations in Ik the difference between “sun” pbytoplankton and “shade” pbytoplankton is distinct.
Blatt‐Atmung der höheren Bodenpflanzen im tropischen Regenurwald
Authors: Löhr Erika , Müller D.
Published: April 2006

Respiratory Activity in Leaves from Herbs in the Tropical Rain Forest.—Plants of the undergrowth flora In the tropical lowland rain forest have typical shade‐leaves distinguished by low dry matter percent, large leaf area per gram fresh weight and very low respiratory intensity per unit area of leaf blade. When the respiratory intensity measured at 26°C is converted to 20°C, the values lie somewhat lower than those for extreme shade‐leaves of the temperate forests of Denmark. The leaf blades of Lomariopsis guineensis have on the whole the lowest respiratory intensity so far measured in leaf blades: 0.06 mg CO2 per 50 cm2 leaf blade (one side only) and hour at 20°C. The semisucculent shade‐leaves of Palisota hirsuta constitute an exception with regard to area per gram fresh weight, in which respect they resemble the semi‐succulent shade‐leaves of the fern Ophioglossum vulgatum in Denmark.

Die Bodenflora von höheren Pflanzen in einem tropischen Regenurwald im Tiefland besteht teils aus Kräutern, teils aus kleinen Bäumen, die eventuell zu grossen heranzuwachsen vermögen; dagegen sind absolut keine Straucher vorhanden. Die Blatter von einigen Kräutern im Urwald bei Adiopodoumé, Elfenbeinsküste, (5°, 20’ nördl. Br, 4°, 10’ west. L) wurden untersucht und zwar folgende: Aframomum sceptrum Schum. (Zingiberaceae), Palisota hirsuta Schum. (Commelinaceae) und Lomariopsis guineensis Kuhn (Farn aus der Familie Polypodiaceae).
Activation of Enzymes during Germination: Amylopectin‐1,6‐glucosidase in Peas
Authors: Shain Y. , Mayer A. M.
Published: April 2006

Development of amylopectin‐1, 6‐glucosidase (amylopectin 6‐ glucanohydrolase) activity in germinating peas occurs under conditions in which protein synthesis is inhibited and α‐ and β‐amylase fail to increase in activity. An increase in activity of amylopectin 6‐glucanohydrolase can be obtained in cell free homogenates of imbibed pea seeds under autolytic conditions. Activation is shown to occur in a particulate fraction and to be due to the action of a proteolytic enzyme in the homogcnates. A system could be constituted consisting of a particulate fraction and trypsin which lead to a rapid activation of the amylopectin 6‐glucanohvdrolase. This is regarded as proof that enzymes in germinating seeds can be formed by liberation or activation of precursor forms. The implications of this are discussed.
Studies of the Growth in Culture of Excised Wheat Roots
Authors: Talbot Beryl , Street H. E.
Published: April 2006

Aeration of root culture medium with air containing 5 % or 10 % CO2 enhances growth, particularly lateral initiation and growth, compared with aeration wilh air or CO2‐free air. This beneficial effect of enhanced CO2 pressure on the growth of cultured roots of Atson Elite 56 wheat ean also be demonstrated in presence of a high (40 %) and inhibiting level of oxygen.

14C labelling from a carbonate–bicarbonate solution of pH 7.0 by cultured wheat roots is enhanced by light and this labelling is not inhibited by the presence of 1 % ethyl urethane.
Movement of Amyloplasts in the Root Cap Cells of Geotropically Sensitive Roots
Authors: Iversen Tor‐Henning , Pedersen Knut , Larsen Poul
Published: April 2006

The root cap of Lepidium sativum under our culture conditions was found to contain 7 (or occasionally 8) storeys of starch‐containing cells. In the youngest one (or two) of these storeys the amyloplasts are small and the cells appear embryonic. In the 6 non‐embryonic storeys the amyloplasts are large. Upon inversion of the root, the amyloplasts in the 3 youngest of the 6 non‐emhryonic storeys start falling toward the opposite end of the cell at about 72 μ per h (at 21 C), hut they maintain this speed for only 6 to 12 min, after which they virtually come to a stop. As a result, it takes 10 to 12 min before any of the amyloplasts get approximately as close to the ceiling as they were to the floor before the inversion; and this is true only of the 2 youngest of the non‐embryonic storeys. When the root is placed horizontal, whether coming from the normal or the inverted position, the amyloplasts reach the lower, longitudinal wall in 15 min or less. The positions of the amyloplasts in the cells of the 3 oldest starch‐containing storeys are erratic and show little, if any, dependency on the preceding time of inversion.
Effect of Kinetin on Ribosomes of Excised Barley Leaves
Authors: Srivastava B. I. Sahai , Arglebe C.
Published: April 2006

The changes in the amount and the composition of ribosomes in excised barley leaves floated on water or on 10 mg/l kinetin solution in the dark were examined.

The rapid loss of polyribosomes and ribosomes in leaves floated on water was greatly retarded by kinetin. The ribosomes‐polyribosomes which originally contained 49 per cent protein showed substantial decline in protein content in leaves floated on water but only slight decline in leaves floated on kinetin solution. It is suggested that kinetin by stimulating RNA synthesis and by suppressing the activities of rihonuclease and peplidase may preserve the ribosomes in excised leaves.
Accumulation and Disintegration of Starch in the Chloroplasts of Stellaria media Grown under Constant Illumination
Authors: Haapala Heikki
Published: April 2006

The persent paper contains a study un the starch content of the chloroplasts of the leaves of Stellaria media, performed by hsitochemical methods. Three leaves were collected at short intervals, fixed and cut in 10 μ sections, and stained according to the PAS‐procedure. The starch content of single chloroplasts was measured by a microscope photometer. The chemical composition of the stainable material was demonstrated by enzyme specific experiments.

At the end of a 12 hours' dark period the chloroplasts contained only traces of starch. Light caused the starch accumulation to begin and after a time chloroplasts seemed to be filled with starch. Subsequently, however, a sudden decrease in the starch content of the chloroplasts took place, in spite of constant illumination. A rather high level of starch content was restored in a few hours.

The author puts forward some ideas about the nature of the factors causing the transitory disintegration of starch in illuminated leaves. The induction or the activation of certain enzymes seems to be the most probable explanalion.
Inducible Formation of Urease in Canavalia ensiformis
Authors: Matsumoto H. , Hasegawa Y. , Kobayashi M. , Takahashi E.
Published: April 2006

Increase in urease activity in leaves of Canavdlia ensifomis has been demonstrated. The activity of excised leaves increased by about 100 percent when 1.5 × 10−1M urea was added externally as inducer. Glycine‐1‐14C was used to investigate whether the increase in activity was dependent on de novo protein synthesis. The Incorporation of labeled amino acid into urease was twofold higher in induced samples than in non‐induced ones. This indicates that the increase in activity is connected with de nova protein synthesis. The once increased activity was always followed by a rapid decrease. The urease activity was lost constantly with time after the external addition of ammonia in vivo. The inhibitory action of ammonia on urease fa vitro was eliminated by dialysis. Accordingly it may be concluded that the loss of activity was dependent on the product repression by ammonia.
Effect of Uracil and 5‐Nitrouracil on Growth and Flowering of Tomato
Authors: Mathur S. N. , Sharma R. A.
Published: April 2006

The effects of uracil and its analogue 5‐nitrouracil on growth and flowering of tomato have been studied. A few drops (0.3 ml) of solutions containing 15, 30, 60, 90 and 150 μg of each prepared from a stock of 500 mg/I in glass redistilled water were applied per plant on 3–4 top leaves and the apex of one month old seedlings with 6–7 leaves. A second application double in volume of the same chemicals was made on the same plants a week later. The controls were given a distilled water treatment.

Treatments with uracil and 5‐nitrouracil significantly increased the plant height and the fresh and dry weights of the shoot. Higher concentrations (500 mg/I) had no promotive effect. Although there had been a significant promotion of the leaf and stem growth, the root growth and the nodes were unaffected.

Flowering was significantly hastened by both bases. Treatments with uracil also resulted in the formation of more flowers. Uracil and 5‐nitrouracil also caused significant increases in the total‐N of the leaf and the stem, and the effect on protein metabolism seems to be localised where they act as RNA metabolites. The presence of the nitro‐group in 5‐nitrouracil does not act as an additional source of nitrogen for protein metabolism as it did not have more promotive effects than uracil.
Effect of Cyclic Variations in Gas Exchange under Constant Environmental Conditions on the Ratio of Transpiration to Net Photosynthesis
Authors: Barrs H. D.
Published: April 2006

Simultaneous cyclic variation in rates of both net photosynthesis and transpiration were induced in attached leaves of cotton and pepper plants under constant environmental conditions. The cyclic variations in photosynthesis and transpiration were found to be in phase, and the ratio net photosynthetic rate/transpiration rate remained constant over a wide range of gas exchange rates. A similar constancy of this ratio was also found as gas exchange rates declined following excision of a sunflower leaf, which was not initially cycling, in air. These results suggested that change in stomatal aperture was the only controlling factor involved and that it was affecting both processes proportionately. Visible loss of leaf turgur and measurable water stress developed in both pepper and cotton at peak exchange rates, but the gas exchange ratio remained constant.

The failure of water stress and increased stomatal aperture to lower the gas exchange ratio suggested an absence of any significant leaf mesophyll resistance (r′m) to inward diffusion of CO2. The possibility that r′m was low is discussed generally, and in relation to the use of chemical antitranspirants to raise the gas exchange ratio. Within the limits of the experiments, water stress apparently had no direct adverse effect on rates of net photosynthesis. The gas exchange ratio did not rise as exchange rates declined. Ultimately, at very low exchange rates, the ratio fell, declining to zero in cotton, but not in pepper. This decline was attributed to the onset of significant gas exchange through the cuticle, which was apparently less permeable to CO2 than to water vapour. Positive net cuticular photosynthesis therefore probably does not occur in cotton. Except at very low exchange rates, the gas exchange ratio was higher in cotton than in pepper; it was similar in sunflower and cotton.
Biochemical Aspects of Parasitism by the Angiosperm Parasites: Phenolics in Parasites and Hosts
Authors: Khanna S. K. , Viswanathan P. N. , Tewari C. P. , Krishnan P. S. , Sanwal G. G.
Published: April 2006

the contents of total phenolics in three parasitic angiosperms, Cuscuta species, Orobanche aegyptiaca and Dendrophthoe falcata and their respective hosts, were colorimetrieally determined. A biochemical comparison was made of the phenolics on the basis of the ability of alcoholic extracts of the tissues to inhibit amylose phosphorylase in vitro.

High concentration of phenolics seemed to be a general feature of parasitic angiosperms. An increase in the concentration of the phenolics occurred in the tissues of infected hosts, in comparison with controls. the phenolics of Orobanche and mistletoe had inhibitory activity against amylose phosphorylase, but those of Cuscuta developed the inhibitory ability only when growing on hosts which themselves possessed inhibitory phenolics. the inhibitory activity of host phenolics was sometimes altered as a result of infection by parasite. Although the hosts often exerted some influence on the concentration and the inhibitory activity of phenolics in the parasites, there was no direct relationship between host and parasite phenolics. the sum of the phenolics in the tissues of parasite and the infected bost generally exceeded the phenolics in the tissues of the control host. The content of phenolics and their inhibitory activity did not appear to be directly related to the resistance of a host or to the extent of its susceptibility to parasite infection.
The Interaction of Coumarin and Temperature in the Germination of Lettuce Seed
Authors: Berrie Alex. M. M.
Published: April 2006

Dormancy was induced in lettuce seed by exposing to coumarin during imbibition. The level of dormancy which is imposed is dependent on the temperature during germination, coumarin being ineffective below 20°C. At 25°C there is marked interaction between coumarin and this temperature, and the response of the seed. It was shown by exposing treated seeds to temperature regimes involving periods at 25°C and 10°C. that the action of coumarin can be explained more readily by concluding that the events which are affected are cell elongation and division. There is also evidence that the coumarin is metabolised more rapidly at 25°C, and that the effectiveness of the coumarin in the experiments cited depends on its presence at the time when embryo growth is initiated. The mode of action of coumarin is unknown.
The Transport of Oleanolic Acid in Calendula officinalis
Authors: Kasprzyk Zofia , Wojciechowski Zdzisław , Czerniakowska Krystyna
Published: April 2006

The transport of oleanolic acid synthesized from 14CO2 in the individual leaves of Calendula officinalis plants was investigated. It was proved that the rate and the direction of the transport depend on the stage of vegetation and the position of the leaf on the plant. The greatest transport rates of oleanolic acid were observed from the upper level leaves towards the inflorescence during the flowering period. The overblowing period was characterized by a slower migration of oleanolic acid from the leaf supplied with radioactive precursor. The migration was directed mainly to the root especially from the low level leaves. Using CH314COONa as precursor, it was established that the root is unable to synthesize oleanolic acid.
Studies of the Growth in Culture of Excised Wheat Roots
Authors: Talbot Beryl , Street H. E.
Published: April 2006

Evidence is presented that the growth of cultured wheat roots is enhanced in closed culture systems not only by carbon dioxide but by a further and apparently very volatile product of root metabolism. The formation of this second growth‐stimulating substance is not considered to depend upon a reduction of oxygen tension in the culture system. Unlike ethanol the activity of the volatile promoter does not depend upon illumination of the cultures. The volatile promoter cannot be effectively absorbed by a number of gas absorbents. Attempts to demonstrate ethylene production by the roots have been unsuccessful.
Uptake of Proteins by Plant Roots
Authors: Seear Joan , Bradfute O. E. , McLaren A. D.
Published: April 2006

The patterns of uptake of fluorescein‐labelled lysozyme (Fl‐lysozyme) by barley, maize, onion, tomato and vetch are similar as revealed by fluorescence microscopy. Penetration of the root cap and through the epidermis into the cortex increases with time of exposure and decreases with higher salt concentrations. In fact, one molar ethylammonium chloride can remove most of the absorbed protein from treated roots and the space observed to be stained by Fl‐lysozyme in this manner can be visualized as “free space”. Results with sterile and non‐sterile barley roots were indistinguishable. At low ionic strength, Fl‐lysozyme can penetrate cells and complex with nucleoli. Such cell protoplasts appear “coagulated”. Uptake results with fluorescein per se were unlike those with protein.

The uptake of a much larger molecule, ferritin, is confined to the epidermis and root cell walls.

Localized, absorbed protein and root growth inhibition by basic proteins have yet to be related.
Ribonucleic Acid and Protein Changes in the Subcellular Components of the Gametophytes of Pteridium aquilinum during Growth in Red and Blue Light
Authors: Raghavan V.
Published: April 2006

The distribution of RNA and protein in the gametophytes of bracken fern, Pteridium aquilinum is affected by the quality of light in which they are grown. Two‐dimensional gametophytes growing in blue light have a greater amount of RNA and protein than one‐dimensional protonema growing in red light. Fractions rich in nuclei, chloroplasts, mitochondria, ribosomes and soluble supernatants obtained from blue‐light grown gametophytes by differential centrifugation contain greater amounts of RNA and protein than corresponding fractions of red‐light grown plants. Differences in RNA and protein content are detected in some of the fractions within 24 hours after start of the treatment.
Effect of Gibberellic Acid and Phosfon on the Critical Dark Period Reqnirement for Flowering of Impatiens balsamina cv. Rose
Authors: Nanda K. K. , Krishnamoorthy H. N. , Lal Krishan
Published: April 2006

The critical dark period requirement for flowering of Impatiens balsamina L. cv. Rose, an obligate short day plant, is about 8.5 hours. While GA3 completely substituted for the dark period requirement, Phosfon prolonged it to 9.5 hours.

GA3 hastened and Phosfon delayed the initiation of floral buds under all photoperiods.

Floral buds opened into flowers only during 8 and 14 hour photoperiods in control and Phosfon‐treated plants but during all photoperiods in GA3‐treated ones.

The delay in floral bud initiation and flowering was correlated with shifting up of the node bearing the first floral bud and flower respectively.

While GA3 increased the numher of floral buds and flowers in all photoperiods except 8‐hour, Phosfon increased their number in the 14‐hour photoperiod only. The number of flowering plants decreased with increasing photoperiod regardless of GA3 and Phosfon application. The effect of Phosfon was completely or partially overcome, depending upon the photoperiod, by simultaneous application of GA3.
The Presence of an Abscisic Acid like Factor in Nonviable Rice Seeds
Authors: Dey Bharati , Sircar S. M.
Published: April 2006

Experiments were carried out with viable and nonviable rice seeds to detect the nature of germination inhibitors.

An abscisic acid like factor is present in nonviable seeds but absent in viable ones. The main source of the factor is the embryo although measurable amounts are also obtained from the husk; it is not found in the endosperm however. Interaction with GA3 and IAA suggests that both the rice seed inhibitor and abscisic acid are antagonistic to GA3 and partially reversed the IAA induced growth. The similarity of the UV absorption spectra of the inhibitor and abscisic acid also proves its presence in nonviable seeds. The inhibitor suppresses the α‐anivlase activity both in intact and excised seeds in the same way as abscisic acid but the suppression is partially overcome with higher concentrations of GA3.
Free Amino Acids in the Leaves of Salvinia natans and Azolla filiculoides Grown in Light and Dark
Authors: Lähdesmäki P.
Published: April 2006

Free amino acids were determined quantitatively by thin‐layer chromatography and identified by various chromatographic methods in the leaves of two floating water ferns. Special interest was paid to the amount of γ‐amino butyric acid.

Water soluble nitrogen compounds increase in the leaves of both plants during the growth of three to four weeks in darkness. Compounds especially accumulating are ammonia and the amides asparagine and glutamine. The amount of most proper amino acids is reduced in the dark, except γ‐amino butyric acid, which, in addition to amides, is the main amino compound increasing in darkness.

0.1 M HCl extracts the greatest amount of nitrogen compounds of low molecular weight from the dried leaves of the experimental plants. If we denote the amount of the dissolved amino compounds as 100 per cent, we can say that water extracts 96 per cent of the amino compounds, and that an 80 per cent ethanol solution extracts 79 per cent of these compounds.
Auxin‐Induced Expansion Growth of Cells and Protoplasts of Yeast
Authors: Yanagishima N. , Shimoda C.
Published: April 2006

Using an auxin‐responsive mutant of Sacchairomyces ellipsodeus, expansion growth of cells caused by auxin was studied especially in comparison with that of protoplasts.

Indole‐3‐acetic acid induced detectable cell expansion growth in 3 hours in a buffered simple solution where no cell division occurred.

The auxin‐induced expansion growth was inhibited by an antiauxin, trans‐cinnamic acid.

Actinomycin D, chloramphenicol and cycloheximide inhibited the auxin‐induced cell expansion growth.

Protoplasts did not expand in response to auxin under the condition where intact cells did.

The stability of protoplasts was not changed by the low auxin concentration (20 mg/1) which induced cell expansion.

High concentrations (100–1000 mg/1) of auxin caused protoplasts to burst even under an osmotically stable condition.
Carbon Dioxide Compensation Points in Maize and Pelargonium
Authors: Manspield T. A.
Published: April 2006

The carbon dioxide compensation paint established by maize leaves in 10,000 lux at 25°C was less Than 2 μl/l. whereas that achieved by Pelargonium under the same conditions was greater than 60 μl/l. Maize and Pelargonium leaves together in the same leaf chamber established a compensation point between 9 and 19 μl/l. It is concluded that it is a difference in the efficiency of absorption of CO2 which leads to the marked difference between maize and Pelargonium, rather than the absence of photorespiration in maize or anatomicad differences between the leaves of the two species.
Strain Dependence of the Cell‐expanding Effect of β‐1,3‐Glucanase in Yeast
Authors: Shimoda Chikashi , Yanagishima Naohiko
Published: April 2006

The effect of β‐1, 3‐glucanase on the cell expansion was studied with diploid strains of Saccharomyces ellipsoideus and S. cerevisiae, and their mutants differing in the response to auxin. The following results were obtained.

Cell expansion was induced by β‐1, 3‐glucanase only in auxin‐responsive or potentially auxin‐responsive strains.

β‐1, 3‐Glucanase induced cell expansion more rapidly than auxin.

The cell wall of the auxin‐responsive strain was more susceptible to digestion by β‐l, 3‐glucanase than that of the auxin‐unresponsive one.

The sensitivity of yeast cells to auxin action is discussed in relation to the nature of cell wall.
Spectral Requirements for Flower Initiation in Two Longday Plants, Rape (Brassica campestris cv. Ceres), and Spring Wheat (Triticum×aestivum)
Authors: Friend D. J. C.
Published: April 2006

Action spectra for the promotion of flowering by long periods of irradiation in the red and far‐red regions of the spectrum have been determined by the use of interference filters. The percentage floral initiation was greatest at 710–720 um for both wheat and rape (about 1 k erg · cm−2· s−1).

Lowering the temperature from 35 to 15°C did not shift the most effective wavelength, suggesting that the effect of high levels of radiation at 710 nm was not related to a balance between photoactivation of phytochrome and its destruction. In both wheat and rape, an increase in temperature promoted the flower‐initiating action of broad‐band far‐red and 710 nm radiation more than the action of broadband red or 660 nm radiation. The flower‐promoting effect of broad‐band red and 600 nm radiation was particularly depressed by temperatures above 25°C.

It is concluded that the promotion of flowering by long periods of high energy at 710 nm is caused by the activity of a high‐energy pigment, rather than through a special effect of phytochrome.
Basipetal and Acropetal Auxin Transport in Relation with Temperature
Authors: Pilet P. E.
Published: April 2006

In stem sections of lentil seedlings, there is a typical polar movement of IAA labelled with 14C. The degree of polarity, expressed as the ratio of basipetal to acropetal transport, was (25°C) 7.6. A decrease (from 25° to 15°C) and an increase (from 25° to 30°C) of temperature cause a reduction of the IAA uptake by the sections and a decrease of both the basipetal and the acropetal translocation of IAA. Results suggest that the basipetal as well as the acropetal movement of auxin, are dependent of a metabolical component which is discussed.
Changes of Sugar Levels in Cucumber Leaves during Ammonium Toxicity
Authors: Matsumoto H. , Wakiuchi N. , Takahashi E.
Published: April 2006

Toxic effects of high concentrations of ammonia were studied in the cucumber plant (Cucumis sativus cv. Suisei No. 2). When the cucumber plant was cultured with 200 mg/l NH3‐N (as NH4Cl), some characteristic symptoms, probably due to ammonium toxicity, appeared in the leaves after about 1 week, while no such symptoms were observed in the plants cultured with 20 mg/1 NH3‐N. The level of free sugars in 20 mg/l NH3‐N treated plants decreased with time and was lower than that in plants treated with 200 mg/l NH3‐N. Specially distinct differences were found as regards the levels of fructose and glucose. After 9 days' culture the content of glucose in 200 mg/l NH3‐N plants was 17 times higher than that of 20 mg/l NH3‐N plants. From the results of an incorporation of photosynthesized 14CO2 for 3 hours into newly synthesized glucose it is evident that this accumulation of glucose can not be the degradative product of a glucose polymer such as starch.

The levels of starch were also studied, and it was found that the starch level decreased due to ammonium toxicity. These results suggest that the translocation of glucose after its synthesis is inhibited by ammonium toxicity, at least up to starch synthesis.
Effect of Defoliation on the Growth and Yield of Wheat
Authors: Lucas Daphne , Asana R. D.
Published: April 2006

The effect of removal of the fifth (L1), fifth and sixth (L2) and fifth, sixth and seventh leaves (L3) from the main shoot and of similar number of leaves from the primary and secondary tillers, on the growth and yield of two varieties of wheat, was investigated. The plants were grown in pots under natural conditions.

Defoliation did not affect tillering, ear number, and number of spikelets per ear. The area of the last 3 leaves was reduced only in L3. Defoliation reduced the growth of stem up to the flag leaf stage but thereafter there was a remarkable recovery in increase in height and dry weight. The grain yield of the main shoot was affected relatively more than that of the primary and secondary tillers by defoliation. The grain yield per plant was reduced by 5 per cent in L1, and L2 and by 11 per cent in L3. The bearing of these observations on productivity per unit area is indicated and it is suggested that a plant with two fewer leaves per shoot may suffer less from mutual shading of leaves and hence prove more efficient in a dense community.