bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Protein Synthesis Inhibitors, Auxin, and Gibberellic Acid on Abscission
Authors: Valdovinos Jack G. , Ernest Leland C.
Published: April 2006

Chloramphenicol, actinomycin D, and other inhibitors of protein synthesis promote abscission in several plant genera. Abscission is accelerated in species where an abscission layer is present, as well as in tissue where no abscission layer develops prior to abscission. The inhibitors promote abscission in species where cell division is reported to precede the separation processes as well as in tissues where no cell division is associated with the initiation of abscission. Indoleacetic acid (IAA) or auxin precursors, when applied with chloramphenicol and aclinomycin D, overcome the promotive effects of the inhibitors on abscission. These inhibitors apparently do not promote abscission through their effects on auxin precursor conversion, IAA transport, and IAA destruction in the petiole. IAA increases the incorporation of leucine‐1‐14C into a trichloroacetic acid precipitable fraction of the abscission zone under conditions where abscission is retarded. A low concentration of IAA which accelerates abscission, decreases incorporation of leucine into protein. Other promoters of abscission — chloramphenicol, d‐aspartic acid, and gibberellic acid —also decrease the incorporation of leucine into the protein of the abscission zone. The data indicate that enzymes required for the degradative processes associated with abscission are already present in the abscission zone whereas a continuous synthesis of protein is required for the retention of the leaf.
Respiratory Patterns in Fruit of Pineapple, Ananas comosus, Detached at Different Stages of Development
Authors: Dull Gerald G. , Young Roy E. , Biale Jacob B.
Published: April 2006

The postharvest respiratory drifts for six stages of development of pineapple fruit (Ananas comosus cv. Cayenne) ranging from dry flower to senescence are presented. Based upon these data, pineapple is a non‐climacteric fruit. Pineapple does produce ethylene gas hut when levels ranging from 0.01 to 1000 μl/l were applied to stage 4 fruits (fruit just at the start of ripening) no respiration or chemical changes were induced which could he interpreted as affecting the ripening processes. A decrease in the oxygen concentration (to 2.5 per cent) resulted in a decrease in the respiration rate. An increased carbon dioxide concentration (up to 10 per cent) had not detectable effect on the respiration rate.
Methods for Measuring Phototaxis of Cell Populations and Individual Cells
Authors: Feinleib Mary Ella Harman , Curry George M.
Published: April 2006

Two quantitative methods have been devised for studying the phototactic response of Chlamydomonas. In the first procedure, the movement of a cell population is continuously monitored photometrically, yielding a permanent record of the time course of the response. The monitoring system consists of a pair of photovoltaic cells connected in a comparison circuit, and a dim red light which passes through the swimming chamber and strikes the photocells. A stimulus beam enters the chamber at right angles to the monitoring light. The movement of algae towards the stimulus light produces a difference in output between the photocells. With a continuous stimulus, this difference increases in a nearly linear fashion for several ninutes. The slope of the linear portion depends on such factors as stimulus ntensity and wavelength and is used as the index of the response.

In the second procedure, a photomicrographic method is used to resolve the population response into its components; i.e., the number of cells responding, the directness of the swimming path, and the rate of swimming. The photographs are taken with a fixed exposure time, during which each cell in the field describes a swimming track on the film. Swimming rate is determined by measuring the length of the photographed track, while directness of path is indicated by the angle between the track and the stimulus light beam. The number of cells going towards the light is calculated from counts made while observing the culture through the microscope.

These methods have been used to investigate the dependence of phototaxis on stimulus intensity and wavelength, age of culture, and pre‐illumination.

This work formed a portion of a doctoral thesis submitted by one of the authors (M. E. Feinleib) to Harvard University, Cambridge, Mass. The work was supported in part by a U.S. Public Health Fellowship, No. FI‐GM‐17, 305–04, and by a National Science Foundation research grant, No. G14266.
14C‐Studies on Apple Trees III. The Influence of Season on Storage and Mobilization of Labelled Compounds
Authors: Hansen Poul
Published: April 2006

The present paper reports an attempt to elucidate the storage and mobilization processes in 1‐year‐old apple rootstocks by studying the 14C content of different parts of the tree following application of 14CO2. The translocation of the 14C taken up from the leaves to other parts proceeds at the highest rate during the first few days after the application of 14C. The distribution in shoots, trunk and roots after application of 14C during May, July, August, and in part of September depends in particular upon the intensity of growth in the various parts. From the lime of the application of 14C until leaf‐fall, 40–50 per cent of the 14C initially absorbed disappears from the tree.

After exposure to 14C during October, and in part of September, a relatively large part of the 14C applied goes to the root. In this case there is a considerable reduction in the 14C‐conlent from leaf‐fall to the following spring after leafing, especially in the root, although relatively speaking reduction is also considerable in the bark of the parts above ground, and it is most pronounced in the methanol (80 %) soluble fraction. The reduction takes place primarily during spring, and comprises, after application during October, for the whole tree 20–25 per cent of the 14C initially absorbed. Only 13–17 per cent of this amount was recovered in the newly developed shoots and leaves in the following June.
The Minimum Growth Temperature of Obligately Thermophilic Bacteria as Influenced by Inhibitors in Complex Growth Media
Authors: Ljunger Claes
Published: April 2006

The inability of several obligately thermophilic bacteria to grow at or below 37°C in common laboratory media was shown to be caused by inhibitors present in these media. The inhibitors could be removed by extraction with chloroform and by adsorption on ion exchange resins or starch. It was concluded that they were of organic nature, probably bile acids. Four laboratory strains of Bacillus stearothcrtno‐philus grew readily at 37°C in detoxified media. With one of them (NCA 1503) growth was obtained at 34–35°C. A fresh soil isolate having a minimum growth temperature of 40°C in glucose nutrient broth grew at 30°C in this medium after the inhibitors had been removed.
Hydrolysis of Inorganic Pyrophosphate in Dictyostelium discoideum
Authors: Gezelius Kerstin
Published: April 2006

The hydrolysis of inorganic pyrophosphate has been studied in cell‐free extracts prepared at different stages of development of Dictyostelium discoideum. Two enzyme reactions, pH optima 7.25 and 9.0, appear specific for inorganic pyrophosphate and have an absolute requirement for a divalent cation, preferably Mg2+. The enzyme specific activities do not change significantly during differentiation. Neither enzyme reaction is inhibited by orthophosphate and the presence of exogenous potassium phosphate does not affect the levels of pyrophosphalase at any stage. Exogenous glucose raises the pyrophosphatase levels in the sorocarps.
Effects of Various Concentrations of Carbon Dioxide on Respiration and Potassium Uptake in Barley Roots
Authors: Jacobson L. , Schaedle M. , Cooper B. , Young L. C. T.
Published: April 2006

Barley roots contain a CO2 sensitive respiratory fraction which is inhibited in 50 per cent CO2 and is partially restored upon subsequent exposure to air. The residual O2 consumption occurring at CO2 concentrations between 50 per cent and 95 per cent amounts to about 40 per cent of the O2 uptake in air and can support K+ uptake for a limited time at a rate equal to or higher than occurs in air. Above 95 per cent CO2 both O2 and K+ uptakes decrease rapidly. 2,4‐dinitrophenol (DNP), in the range of 10−6 to 10−5M, stimulates O2 uptake by the roots in air. The stimulation is absent when roots are treated with DNP in 80 per cent CO2, presumably because of the reduced demand for inorganic phosphate and phosphate acceptor at the lower respiratory level in high CO2. In either air or CO2, K+ uptake is strongly inhibited by DNP. A comparison of the respiratory and K+ uptake data indicates that O2 consumption is a necessary requirement for the uptake process in high CO2.

Protoplasmic streaming in the root cells is rapidly stopped by high CO2 although K+ uptake and O2 consumption continue. The cation uptake mechanism in high CO2 appears to be limited to the stationary cytoplasm. It is also possible that a similar mechanism may be involved in cation uptake in air.
Multiple Forms of Polyglucoside‐Branching Enzyme in the Algae
Authors: Fredrick Jerome F.
Published: April 2006

Three isozymes specifically concerned with the “branching” of linear polyglucosides have been delected in algae. These enzymes were detected using two‐dimensional polyacrylamide gel electrophoresis, and were found to be present in blue‐green, red and in green algae. Two isozynies were found in Oscillatoria princeps; three enzymes were present in Spirogyra setiformis, and two and three such enzymes were detected in red algae of the Rhodymenia type. The significance of the multiple forms of this branching enzyme was assessed in light of the type of storage poly‐glucosides formed by these plants. The “degree of branching” of the storage sugar appeared to be related to the evolutionary status of these algae.
Isocitric Lyase and Isocitric Dehydrogenase in Germinating Lettuce
Authors: Mayer A. M. , Krishmaro N. , Poljakoff‐Mayber A.
Published: April 2006

A soluble isocitric lyase is shown to occur in lettuce seeds. Its activity increases during germination till 72 hours and then falls again. No particulate lyase could be detected. In addition both a soluble and a particulate isocitric dehydrogenase is present in the seeds. Both enzymes react with NAD as well as with NADP. The soluble enzyme drops sharply in activity during germination, while the particulate enzyme remains at a more or less constant level of activity. By gel electrophoresis the isocitric lyase and the isocitric dehydrogenase were shown to consist of what appear to be several isozymes. The interrelation between the enzymes and their relation to fat metabolism during germination is discussed. Evidence is brought for an enzymic reaction by which isocitric acid is converted to pyruvic acid. The nature of this reaction is not clear.
Reversal of (±) ‐Abscisin II Induced Inhibition of Lettuce Seed Germination and Seedling Growth by Kinetin
Authors: Sankhla N. , Sankhla D.
Published: April 2006

Observations have been made on the effect of synthetic, (±)‐abscisin II (dormin), alone and in combination with gibberellin, kinetin and indoleacetic acid, on seed germination and seedling growth of two strains of lettuce, cv. Attraktion and cv. Hohlblättriger Butter. (±)‐Abscisin II inhibited seed germination and seedling growth in both strains. The inhibitory effect of abscisin II on seed germination as well as seedling growth was completely overcome by kinetin in both dark and light. Gibberellic acid, on the other hand, proved ineffective in exerting its influence on seed germination in presence of abscisin II but affected subsequent seedling growth as usual. Indoleacetic acid was found to be least potent in reversing abscisin II caused inhibition of seed germination and seedling growtb. It is concluded, that like its effect on certain other naturally occurring inhibitors of seed germination, kinetin can effectively undo the inhibitory effects of abscisin II in these growth processes.
The Distribution of Mineral Elements Following Leaf and Root Uptake
Authors: Levi E.
Published: April 2006

The initial and subsequent distribution of 22Na, 43K, 86Rb, 134Cs, 32P, 35S, 45Ca, 65Zn and 85Sr in bean plants, following leaf and root uptake was studied under controlled environmental conditions. Autoradiographic and counting methods reveal vascular connections between leaves and roots and two patterns of distribution in the leaves following root uptake are reported. Distribution following treatment of specific parts of the leaves or roots points to a morphological unity in the bean plant. A possible circulation pattern for some ions is discussed.
Interactions between Plants and Epiphytic Bacteria Regarding Their Auxin Metabolism
Authors: Wichner Siegfried , Libbert Eire
Published: April 2006

Proofs of different kind are presented of the existence of highly active bacteria producing IAA from tryptophan on plant surfaces and in plant homogenates.

Both homogenates and washing solutions of nonsterile pea plant parts are active in producing IAA from tryptophan. Activity is much enhanced by the addition of glucose or by preincubating the preparations; it is abolished by sterile filtration, by some bactericidic and bacteriostatic substances, by chloramphenicol, streptomycin, and albucid (penicillin being only partly effective). Preparations of sterile plants do not produce IAA from tryptophan within the detection limit of the Salkowski test. The bacteria are even present on seed surfaces, in the air, and in aceton or ammonium sulfate precipitations of homogenates.

Main products of the bacterial tryptophan conversion, as demonstrated by paper chromatography, are indolepyruvic acid, indoleacetic acid, indolecarboxaldehyde, and indolecarboxylic acid. In presence of glucose indolepyruvic acid is by far dominating.

Many hitherto known results about tryptophan conversion to IAA by higher plants are likely to be falsified by epiphytic bacteria.
How Mangroves Desalinate Seawater
Authors: Scholander P. F.
Published: April 2006

Water relations of a number of mangroves and other halophytes were studied. All mangroves had high negative pressure in the xylem (30 to 60 atm) which more than balances the osmotic pressure of the seawater (25 atm). Freezing a short stem section of an attached twig always resulted in wilting caused by eavitation of the tensile sap. Semipemeable membranes in the leaves remained functioning in spite of being iced or healed (50°C), or being poisoned by dinitrophenol and carbon monoxide (13 atm). Chloroform and ether ruptured the membranes.

When some 40 atm pressure was applied to the root system of a decapitated seedling potted in seawater, a flow of nearly fresh water ensued. This separation kept on for hours in spile of chilling and poisoning with dinitrophenol or 20 atm carbon monoxide. A reversal of the gradient made roots lose water to the seawater. One may conclude, therefore, that mangroves separate fresh water from the sea by a simple non‐metabolic ultrafiltration process, in a system where high tension obtains in the xylem and where turgor of the living cells is produced by an active maintenance of high solute pressure.
Growth Inhibition and Recovery in Roots Following Temporary Treatment with Auxin
Authors: Hejnowicz Z. , Erickson R. O.
Published: April 2006

Continuous recording (streak photography) of elongation of roots treated with IAA (10–6–10–7M) showed that removal of IAA from the nutrient solution resulted in a rapid resumption of elongation, unless the IAA treatment was shorter than 60 min. If it was shorter, the recovery was delayed, so that it occurred about 1 hour after the beginning of the treatment, independently of the duration of the treatment, down to 4 min. This behavior of roots was observed in all the species investigated (corn, pea, sunflower, onion), also in response to NAA and 2,4‐D. This time lag in recovery of elongation after brief auxin treatment is discussed in connection with the radial concentration gradient of auxin in the root imposed by external auxin. The possible role of a radial gradient of auxin (concentration decreasing with distance from the center) in the control of root elongation is suggested.
Effects of Extended Periods of Osmotic Stress on Water Relationships of Pepper
Authors: Janes Byron E.
Published: April 2006

Pepper plants grown to uniform size in a controlled environment were subjected to an osmotic stress for periods of 1 to 10 days. Polyethylene glycol 400 was used as the osmotic agent.

Leaf area of the plants, grown under uniform conditions, was proportional to the weight of the plants. This relationship was not altered by reduction in rate of growth due to a decrease in osmotic potential of the nutrient solution.

The rate of transpiration of the pepper plants decreased as the osmotic potential of the nutrient solution was decreased. The reduction in rate of transpiration was most rapid when the osmotic potential was reduced from −0.5 to −7.5 bars. There was continued reduction in the rate of transpiration with change in potential to −12.5 bar but this change was less than that at the higher potentials. The rate of transpiration remained at a reduced rate for as long as the plants were growing in the solution with low osmotic potential. Alternating the osmotic potential of the nutrient solution between −0.5 and −5.0 bar did not change the response to the −5.0 tension. The reduction in rate of transpiration resulting from the lowering of the osmotic potential by addition of NaCl was similar to that produced by addition of polyethylene glycol.

Water potential, osmotic potential, relative water content and stomatal movement were all in dynamic equilibrium with the water content of the leaves. The water content of the leaves was regulated by the supply and demand. In these investigations the demand remained constant. The supply was altered by decreasing the difference in water potential between leaf and substrate and by an increase in resistance to flow of water in the roots as a result of the decrease in osmotic potential of the nutrient solution.
Changes in Nicotinic Acid Content and Its Nucleotide Derivatives of Rice and Wheat Seeds during Germination
Authors: Mukherji Subhendu , Dey Bharati , Sircar S. M.
Published: April 2006

Relative distribution of bound and free forms of nicotinic acid in rice and wheat seeds and their metabolism during germination were the subject of the present investigation. Measurement of the levels of NAD (nicotinamide adenine dinucleotide) and NADP (nicotinamide adenine dinucleotide phosphate) formed another part of the work.

Total nicotinic acid in both rice and wheat increased with germination and was maximum at 72 hours. From this time onwards, it began to decline rapidly and at the end of experiment, i.e., after 120 hours, it was lower than that for ungerminated seeds on per seedling basis, although it was slightly higher on per g dry weight basis.

Ungerminated seeds of wheat and rice contained about 89 per cent and 80 per cent respectively of their total nicotinic acid in bound form which became partially free in course of germination.

Total nucleotides (oxidised plus reduced forms) increased progressively up to 96 hours followed by a slight fall at 120 hours. NAD reached a maximum at 24 hours and fell gradually thereafter. The depletion of NAD was associated with a progressive accumulation of NADH. NADP decreased from the peak value at 72 hours. Formation of NADP and its maintenance at high level depend on NAD in the oxidised form and the content slowed down in tissues with higher NADU/NAD ratio. A relatively large amount of NADPH was present throughout the experiment.
Integrity and Respiration of Red Beet Mitochondria Isolated and Examined in Different Sucrose Concentrations
Authors: Christiansen K.
Published: April 2006

Respiration experiments with succinate as substrate were made with red beet mitochondria isolated in soluitions containing 0.25 to 1.25 M sucrose. The respiration was measured in reaction media adjusted to be 0.25, 0.50, 0.75 or 1.0 osmolar.

With mitochondria isolated in 0.25 or 0.50 M sucrose the rate of succinate oxidation was completely dependent on the osmotic pressure of the reaction medium (decreasing with increasing osmotic pressures). Isolation in 0.75 M sucrose caused a slight after‐effect of the osmotic pressure of the isolation medium, and by isolation in 1.0 M or 1.25, M sucrose the after‐effect was complete. The rate of oxidation was low and independent of the osmotic pressure of the reaction medium.

An electron microscopic examination of the state of the mitochondria before and after the respiration period showed that with the conditions used in the present experiments the structure of the mitochondria remained well preserved regardless of the osmotic pressures used.
Oxygen Diffusion from the Roots of Woody Species
Authors: Armstrong W.
Published: April 2006

Application of the‘polarographic’ technique for studying oxygen diffusion from roots has provided preliminary results which establish that oxygen passes through the woody species Salix atrocinerea Brot., Salix fragilis L., Salix repens L., and Myrica gale L., in the gaseous phase as it does in other wetland species. Entry into the shoots occurs through the bark directly above the water table and in the willow cuttings the effective length of shoot for gas intake was the basal three centimetres above the water table. The length of shoot involved was longer in Myrica gale and the roots were of the normal (un‐nodulated) type.

Trials on Alnus glutinosa (L.) Gaertn. provided no conclusive results and it is thought that this was perhaps because measurements were on nodulated roots only.
Seasonal Rhythm of Rooting of Salix atrocinerea cuttings
Authors: Vieitez E. , Peñta J.
Published: April 2006

The response of rooting and the content of growth substances in Salix atrocinerea cuttings were studied every month throughout the whole year. To study the rooting response 100 cuttings were put into a rooting mist‐propagator frame and the results were observed 30 days later. The hormone content was studied with the same type of cuttings by means of methanol extraction, fractionating into acid, basic and neutral substances and chromatographic analysis on paper and bioassays.

Salix atrocinerea cuttings have three rooting phases: one very active in January, February, March and April with plentiful roots, not ramified, originating at the base of the cutting; a second lesser phase from May to August with numerous small and very ramified roots formed at a more ample area on the stalk. Both peaks are separated by a sharp fall in June. From September to December the third phase of rooting takes place. Response is practically nil and the few small roots formed are originated at the base of the stalk, again, as in the first phase.

In the histograms a remarkable activity in the acid fraction at Rf = 0.30–0.50 was found and IAA was identified. The rooting capacity of these cuttings and the IAA content show some correlation but not exact enough to assert that the root response is governed by an optimum hormonal content.

In Salix atrocinerea cuttings inhibitors are absent during the whole year which support the hypothesis that root formation might in some cases be influenced also by the presence or absence of inhibitory growth substances.
Growth Curves and pH‐Optima for Cyanide Producing Bacteria
Authors: Wissing Feode
Published: April 2006

Hydrogen cyanide producing bacteria of the genus Pseudomonas were isolated and cultured so that activity could bo maintained under laboratory conditions. Formation of cyanide is influenced by the type of Carbon source and the amino acids contained in the media. The bacteria produced most cyanide when grown on succinate plus glycine methyl ester and on glucose plus glycine and D, L‐methionine. pH‐Optima for the production of cyanide by lyophilized bacteria were found to be 8.3 with Tris/HCI buffer.
The Correlation of Physiological Differences and Varions Leaf Forms of an Aqnatic Plant
Authors: Gaudet John J.
Published: April 2006

An analysis of the celluar constituents of the leaves of an aquatic fern, Marsilea vestita, was done after and during the formation of different leaf forms.

Land leaves of Marsilea produced almost twice as much dry material, soluble carbohydrate, insoluble protein and soluble peptides compared to submerged leaves on a fresh weight basis, but on a dry weight basis there is tittle difference between the two types of leaves. the submerged leaf soluble nitrogen fraction consisted mostly of ammonia and free amino acids, while that of the land leaf probably con tained mostly peptides. Free arginine was present in large quantities in megaspores and as the plant matured, at the expense of the megaspore, the amount of arginine left in the pool diminished. A correlation was found between soluble sugar increase and leaf elongation, Just prior to the production of submerged leaves the developing leaves contained low levels of protein and soluble sugar, but high levels of soluble nitrogen and an increased amount of starch. A theory which involves metabolism was proposed to account for the leaf form changes in Marsilea.
Action Spectra for the Transient and the Normal Photosynthetic Oxygen Evolution in Wheat Leaves
Authors: Egnéus Hans
Published: April 2006

An action spectrum within the wavelength region 430–700 nm has been determined for an oxygen Iransient isolated from the main photosynthetic oxygen evolution in wheat leaves. the spectrum follows the absorption spectrum of chlorophyll b.

In order to compare this oxygen evolving process with the normal photosynthetic oxygen evolution, an action spectrum for this later process was also determined but only in the wavelength region 600–700 nm. This action spectrum closely corresponds to other action spectra for the photosynthetic oxygen evolution found in the literature.

The behaviour of the oxygen transient after various treatments was also studied. It was found that the transient oxygen evolution was influenced by the dark period between irradiations, and by a previous irradiation with a wavelength longer than 695 nm, both conditions having a promoting effect on the oxygen evolution.

The action spectra and the other findings are discussed on the basis of the two‐pigment hypothesis.
Lipids in Cruciferae
Authors: Appelqvist Lars‐Åarke
Published: April 2006

Diploid and tetraploid types of white mustard (Sinapis alba) and turnip rape (Brassica campestris), annual and biennial forms, were grown in Turkey and in Sweden. Seed weight and oil content were measured and fatty acid composition determined by gas chromatography.

Polyploidization of all cultivars effected an increase in seed size but did not markedly change the oil percentage or fatty acid composition.

Growing conditions in Turkey caused an over‐all decrease in seed size although the oil content was reduced only in the spring Turkish plantings. Fatty acid composition was influenced by the environment to a small but probably significant extent in all cultivars. For Swedish and Turkish winter turnip rape the mean content of oleic acid was 13.7 per cent and 15.8 per cent, of linolenic acid 9.5 per cent and 8.6 per cent, of erucic acid 45.7 per cent and 42.4 per cent, respectively; no consistent differences were observed for linoieic acid. Similar differences were observed for summer turnip rape and white mustard. Thus the warmer and drier Turkish climate favoured a higher oleic acid, lower linolenic and erucic acid content, i.e. a reduction in the per centage of the major end products of fatty acid biosynthesis.
Biosynthesis of Thiazole in Exobasidium
Authors: Sundström Karl‐Ragnar
Published: April 2006

In some Exohmidium strains, which grow on a synthetic medium containing glucose citralc, and thiamine as the only organic compounds, growth usually does not start until after more than 800 honrs if thiamine is replaced by pyrimidine.

Homocysteine and methionine are able to shorten this lag phase of E. vaccinil“myrt.” Methionine is growth‐promoting only at about pH 4. At low concentrations the yield is proportional to the concentration of methionine. Growth ceases when the methionine is consumed and the fungus then enters a lag phase as long as that in methionine‐free medium. Methionine does not indnce the thiazole‐synthesizing enzymes, but is probably consumed as a precursor of thiazole.

The utilization of this precursor is delayed by some growth factors and amino acids, i.e. cholin, betaine, glutamic acid or glutamine. The delayed adaptation of the methionine‐ and thiazole‐synthesizing enzymes seems to be regulated by changes in the nutritional state of the ageing cultures. The mechanism of this regulation has not been settled.
The Effect of Prevention of Flowering on the Vegetative Growth of Inoculated Pea Plants
Authors: Roponen Ilma E. , Virtanen Artturi I.
Published: April 2006

The removal of the apical buds from the top of inoculated pea ptants before flowering caused the axillary buds of the stem leaves to develop and thus further to branch. The vegetative growth of the test plants continued to be luxuriant when blooming was delayed. While the control ptants formed seeds and ripined. the vegetative growth of the stem of the test ptants increased at most eight‐fold during the same time. A new, additional red part grew at the same time in the root nodules, which had already partly become green. The new red part branched later so that the imusuatty large nodules appeared quite odd. The weight of the branched, large nodules had at the same time increased on the average six‐fold and the vegetatively grown test plants synthesized even eight times more nitrogen than did the control plants. The concentration of teghaemoglobin in the nodules formed by the bacterial strain used in the experiment was not inereased, but the absolute amount of the pigment was raised six‐fold as a result of the increased nodule mass. While the vegetative growth was going on, oxidation of the leghaemoglobin was delayed.

Analyses of nitrogen and amino acids were made for both test and control plants.

The total length of the branches in the largest test plant was 32 m compared with the unbranched control plant which was 1.30 m.
Trehalose, Respiration und Photosynthese in dem Farn Ophioglossum, Ein neuer Schattenblattypus
Authors: Löhr Erika
Published: April 2006

Trehalose, Resipration and Photosynthesis in the Fern Ophioglossum. A new Type of Shade‐Leaves.—Trehalose has been identified in the leaf‐blades, sporehouses, stems and rhizomes of the fern Ophioglossum vulgatum by paper chromatography. The leaf‐blades represent a hitherto undescribed type of shade‐leaf. Just like normal shade‐leaves, they have a low respiratory activity ∼0.2–0.3 mg CO2 per 50 cm2 leaf‐blade (one side only) and hour at 20°C and low maximal photosynthesis: 2–2.7 mg CO2 per 50 cm2 leaf‐blade (one side only) and hour at 20°C and a CO2‐pressure of 0.25 mm Hg and a light intensity of 20,000 lux. But in contrast to the hitherto described type of shade‐leaves, the area per 1 g fresh weight is that of typical sun‐leaves which is 35–50 cm2 (one side only) per 1 g fresh weight. The large area weight is connected with particularly low dry matter content ∼10–11 per cent in the leaf‐blades; this indicates that the material is a kind of semisucculent shade‐leaf.
Leaf Factors Affecting Light‐Saturated Photosynthesis in Ecotypes of Solidago virgaurea from Exposed and Shaded Habitats
Authors: Holmgren Paul
Published: April 2006

Plants of Solidago virgaurea L. from exposed and shaded habitats differ with respect to the response of the photosynthetic apparatus to the level of irradiance during growth. An analysis was carried out on leaf characteristies which might be responsible for the differences established in the rates of Hght‐saturated CO2 uptake. The clones were grown in controlled environment chambers at high and low levels of irradiance. Light‐saturated rates of photosynthesis and transpiration were measured at natural and lower ambient CO2 concentrations.

A low temperature dependence of light‐saturated CO2 uptake at natural CO2 concentrations, and a strong response to changes in stomatal width, suggested that the rate of CO2 transfer from ambient air towards reaetion sites in chloroplasts was mainly limiting the pholosynthetic rate. Resistances to transfer of CO2 for different parts of the pathway were calculated. There was a weak but significant correlation between stomatal conductance and the product stomatal frequency ± pore length. Mesopbyll conductance and dry weight per unit area were highly correlated in leaves not damaged by high irradiance. This suggests that mesophyll conductance increases with increasing cross sectional area (per unit leaf area) of the pathways of CO2 transfer in the mesophyll from cell surfaces to reaction sites.

The higher light‐saturated photosynthesis in clones from exposed habitats when grown at high irradiance than when grown at low irradiance was attributable mainly to a lower mesophyll resistance. In shade clones the effect upon CO2 uptake of the increase in leaf thickness when grown at high irradiance was counteracted by the associated inactivation of the photosynthetic apparatus. The difference in CO2 uptake present between clones from exposed and shaded habitats when preconditioned to high irradiance resulted from differences in both mesophyll and stomatal resistances. A few hybrid clones of an F1‐population from a cross between a clone from an exposed habitat and a clone from a shaded habitat reacted, on the whole, in the same way as the exposed habitat parent. When grown at high irradiance, the hybrid clones showed higher photosynthetic rates than either parent; this was largely attributable to the unusually low stomatal resistance of the hybrid leaves.
An Evaluation of Specific and Non‐Specific Inhibition of 2‐Dimensional Growth in Fern Gametophytes
Authors: Miller John H.
Published: April 2006

Gametophytes of Onoclea sensibilis were grown under continuous white light of 90 lux. Filaments were produced having 4–6 cells before the initiation of 2‐dimensional growth. There was a close correlation between the average cell number of a population of plants and the proportion of 2‐dimensional forms. 8‐Azaguanine produced a general inhibition of growth, and it was shown that the reduced proportion of 2‐dimensional plants caused by 8‐azaguanine was a secondary consequence of the general growth inhibition. IAA however gave a true specific inhibition of 2‐dimensional growth.

Based on these experiments the proper criteria for establishing a specific inhibition of 2‐dimcnsional growth arc discussed. These criteria are applied in a critical review of previous papers on the inhibition of 2‐dimensional growth. It is concluded that no firm evidence is available that inhibition of protein synthesis specifically blocks 2‐dimensional growth.
Extraction, Assay and Partial Purification of a Factor from Tumorous Leaves that Promotes Crown‐gall Tumor Growth
Authors: El Khalifa M. D. , Lippincott James A.
Published: April 2006

A tumor growth factor was extracted from primary pinto bean leaves {Phaseolus vulgaris L. cv. “Pinto”) having crown‐gall tumors. Application of these extracts to primary pinto bean leaves at day 3 after inoculation with Agrobacterium tumefaciens (Smith and Town.) Conn resulted in an increase in the diameter of tumors on these leaves after 24 hours that was 25–60 percent greater than that of the controls. No growth promoting activity was detected in comparable extracts from control leaves or from cultures of the bacterium. The tumor growth factor did not affect tumor number when applied in this fashion. The active extracts were fractionated on Sephadex (1–15 columns and an active component obtained which eluted in a volume suggesting a molecular weight in the range of 100–200. A spectrum of the material in this fraction is shown and some of the characteristics of this material are described. Reasons are presented for considering this growth factor to be identical with at least one of the growth factors previously hypothesized to account for the greater tumor growth observed as tumor number is increased in this system.
The Effect of Limitation in Light During the Rest Period On Leaf Bud Break of the Peach (Prunus persica)
Authors: Erez A. , Lavee S. , Samish R. M.
Published: April 2006

Reduction in the amount of light supphed during the mid‐rest period caused a hetter leaf bud opening in the peach as compared with natural winter daylight; this includes darkness, short photoperiod and reduced light intensity. The quantitative nature of this light effect was shown. The role of light as a factor regulating dormancy is discussed.
The Relationship of Carbohydrates to Cold Acclimation of Hedera helix L. cv. Thorndale
Authors: Steponkus Peter L. , Lanphear F. O.
Published: April 2006

While both the total sugar content and cold hardiness greatly increased during artificial cold acclimation, no direct parallelism was demonstrated. In fact, plants hardened in the dark exhibited an increase in hardiness during the period when the total sugar content declined, furthermore, while there was evidence for an accumulation of sugars (especially sucrose) incorporation of 14C indicated that all of the isolated fractions were in a dynamic state.

Dehardening, paralleled by a large increase in the starch content, was more rapid in the light than in the dark. Furthermore, in stems the sugar content increased after 3 days of dehardening but declined after 7 days. This increase may represent the release of sugars from a previously unextractable form such as a glycoprotein complex.

Starvation experiments indicate that photosynthates produced during the cold acclimation period are preferentially used during cold acclimation rather than reserve carbohydrates. This was also indicated by the smaller amount of starch hydrolysis in plants hardened in the light. Thus, while there appears to be a role for carbohydrates in the cold acclimation process, the lack of parallelism between sugar content and hardiness may be interpreted as indicating 1) cold acclimation is not merely an accumulation of sugars or an osmotic effect per se, and 2) under normal conditions, the level of carbohydrates is not limiting the rate or degree of cold acclimation.
Action comparée de la 6‐furfurylaminopurine et de la 6‐(γ, γ‐dimethylallylainino)purine sur la croissance, l'activité peroxydasique, la teneur en chlorophylles et en caroténoïdes
Authors: Caspar Th. , Xhaufflaire A.
Published: April 2006

Comparative Effects of 6‐Furfurylaminopurine and 6‐(γ, γ‐Dimethylallylamino) purine on Growth, Peroxidase, Chlorophyll and Carotenoid Content. — 6‐Furfurylaminopurine (FAP) and 6‐(γ, γ‐dimethylallylamino) purine (IPA) both inhibit root growth and cause an increase in peroxidase activity. When used at 10−8 and 10−8M, IPA stimulates elongation of the coleoptile test, at 10−4M both FAP and IPA provoke an inhibition. FAP and IPA maintain a high level in chlorophylls and carotenoids in floating leaves discs. In all these experiments, IPA has thus a higher effect than FAP.
Dependence of Root Growth on Photosynthesis in Populus tremula
Authors: Eliasson Lennart
Published: April 2006

Hoot elongation of rooted cuttings of aspen, Populus tremula L., was followed on moist filter paper. The time course of root growth during treatments which decrease or interrupt the supply of carbohydrates to the roots was studied.

At light intensities below 4000 lux the rate of root elongation was found to berelated to the light intensity over the leaves. In the dark, root growth decreased within 24 hours and the roots stopped growing completely during the second or third day. Excision of the leaves or steam‐killing of the tissue in a stem section below the leaves was followed by root growth stoppage within 24 hours.

These results imply that the rate of root growth under certain conditions is determined by the supply of carbohydrates from the leaves.
Effect of Auxin on Cell Wall Degrading Enzymes
Authors: Tanimoto Eiichi , Masuda Yoshio
Published: April 2006

The effect of auxin on the activities of amylase, cellulase, β‐1, 3‐ and/or β‐l, 6‐glucanase and hemieellulase were observed using etiolated barley coleoptile and pea epicotyl internode segments. The activities of β‐1, 3‐ and/or β‐l, 6‐glueanase and hemicellulase of barley were increased by indole‐3‐acetic acid in a 3 hours' treatment. Amylase activity was not influenced by the auxin. Cellulase activity was not detected under the experimental conditions. 2, 4‐Dichlorophenoxyacetic acid increased hemicellulase activity, but not cellulase and amylase activities, in pea epicotyl segments in 3 hours.

Fungal β‐1, 3‐glucanase exogenously applied induced the elongation of barley coleoptile segments. The elongation induced by the enzyme was as high as that induced by indole‐3‐acetic acid at least for the first 1 to 3 hours.
The Effect of Temperature Treatments on Growth and the Metabolism of Ribonucleic Acid in Relation to Cell Division and Cell Elongation of Pisum sativum Roots
Authors: Kung Huei‐Kuen , West S. H.
Published: April 2006

We observed the effects of a range of temperatures on root elongation, cell production, total RNA in the root tip, and changes in various nucleic acid fractions in dividing and elongating areas of pea roots. High temperatures affected elongation of roots more adversely than cell production. In the tip section of the root, growth was positively associated with a decrease in the first soluble RNA peak that eluted from a MAK column, and with an increase in ribosomal RNA. There was no similar change in these RNA fractions in the elongating area of the pea root.

In pulse type tests sRNA‐1 labeled first and the isotype was depleted upon subsequent growth. The specific activity of sRNA‐1 and the depletion of the radioactivity was not nearly so great in the elongating as in the dividing portion of the pea root.
Isoenzyme Polymorphism in Flowering Plants
Authors: Mäkinen Yrjö
Published: April 2006

A total of 21 esterase, 3 acid phosphatase and 2 leucinc aminopeptidase isoenzymes, in addition to peroxidases and catalases, were demonstrated in onion seedlings by starch‐gel electrophoresis. In seedlings two weeks old, the root tip and the differentiated zone show very little enzymatic activity, whereas the secondary roots, hypo‐cotyl and cotyledon are enzymatically very active. These differences are correlated with the intensity of cell division. Some esterase isoenzymes are apparently restricted to root, others to shoot tissues. At pH 8.1, anodically moving peroxidases are totally absent from shoot tissues.

A developmental study of esterase isoenzyme patterns indicated that no great differences exist between primary root tips from roots 6–18 mm long and seeds germinated for three days, whereas a sudden decrease in enzymatic activity occurs in root tips after seven days' germination when the roots are about 25 mm long. This coincides with the decrease in mitotic Frequency.

Actinomycin D and gamma irradiation decreased mitotic frequency almost to zero but did not significantly affect the esterase isoenzyme pattern in root tips. This shows that the activity of these isoenzymes, at least, is not necessarily dependent on cell division but may well be a prerequisite for it.
On the Physiological Effects of Phloridzin, Phloretin and some Related Substances upon Higher Plants
Authors: Stenlid Göran
Published: April 2006

Some dihydrochalcones and related flavonoids were tested Cor their effects upon indoleacetic acid oxidase (mainly from pea roots) and upon oxidative phosphorylation in mitochondria from cucumber hypocotyls. Also their influence upon the growth of wheat roots and upon the absorption of 14C‐labelled sugars and 2, 4‐dichloro‐phenoxyacetic acid in wlieat roots was studied.

The dihydrochalcone glucoside phloridzin known for its strong inhibitory effects upon sugar transport in some animal tissues gives no corresponding specific effects in higher plants. Phloridzin and some related dihvdrochalcone glycosides as well as the structurally similar compounds naringenin and 2′, 4, 4′‐trihydroxychalcone are potent stimulators of indoleacetic acid oxidase. Sieboldin, which compared to phloridzin has an additional hydroxyl group (giving an ortho‐diphenolic substitution in the B‐ring) is a strong inhibitor of indoleacetic acid oxidase (10−6M gives about 50 per cent Inhibition). Phloridzin and sieboldin replace each other in different groups of species in the genus Malus.

The aglycones phloretin, naringenin and 2′, 4, 4′‐trihydroxychalcone stimulate wheat root growth (especially in the presence of auxins or growth‐inhibilory sugars) and inhibit the absorption of sugars and of 2, 4‐dichlorophenoxyacetic acid. They also inhibit oxidative phosphorylalion and give a distinct uncoupling effect. The glycosides are as a rule less active in all these respects and sieboldin is almost inactive.

There is a rather good correlation between uncoupling of oxidative phosphorylation and effects upon root growth, whereas there is no agreement in the details between the effects upon root growth and upon IAA oxidase.
Red Light Effects on Uptake of 14C and 32P into Etiolated Corn Leaf Tissue During Photomorphogenic Leaf Opening
Authors: Steiner A. , Price L. , Mitrakos K. , Klein W. H.
Published: April 2006

Red light effects on the uptake of 14C and of 32P was studied by observing leaf sections from 8‐day‐old etiolated corn leaves that were placed on various substrates following a brief exposure to red radiant energy. There was a general increase of 14C uptake over dark levels into all metabolite fractions that were prepared. This is in contrast with results obtained previously in which leaf samples were first floated on substrate and then irradiated (Mitrakos et al. 1967, Price et al. 1965). The latter tests resulted in a general decrease in sugar and starch as well as 14C content of all fractions. However, under both types of experimental conditions the red light effect manifested itself as an increase in hexosemonophosphate turn‐over rate and accumulation of radioactivity in the cell wall polysaccharide fraction. The present data further substantiate the previous work in that they demonstrate the regulatory influence of the hexose pool size on the intermediary metabolism and the manifestation of the phytochrome responses. From the data thus far obtained it cannot be determined as to whether or not phytochrome mediates by controlling phosphorylating activity or through control of specific enzymatic processes that lead to observable cell wall polysaccharide synthesis and leaf unrolling.
A Re‐examination of the Penetration of Nitella Cells by Non‐electrolytes
Authors: Milborrow B. V. , Williams D. A.
Published: April 2006

The increase, followed by culmination and decrease, of biological activity often observed within a homologous series of toxic compounds has previously been explained by assuming that their rate of movement between the lipid cell membrane and the aqueous protoplasm passes through an optimum as the partition coefficients increase progressively. In contrast to this, it has been claimed that direct measurements of the penetration rate of compounds through individual Nitella cells show tbat penetration rates are proportional to partition coefficients.

In this attempt to investigate these two opposed hypotheses an analysis of published penetration rate data, obtained with Nitella, showed that the direct penetration measurements were best described by an equation which included a quadratic function of partition coefficient. There is, therefore, no inconsistency between the measurements of penetration by biological activity and by direct measurement. The compounds used in the latter procedure were all relatively hydrophilic and although a maximum rate of penetration was observed tbere was no indication of a subsequent decrease as there were no compounds with high partition coefficients. The correlation of penetration with other physical properties of the compounds is discussed.