bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractSimultaneous 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

Abstractthe 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

AbstractDormancy 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

AbstractThe 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

AbstractEvidence 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

AbstractThe 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

AbstractThe 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

AbstractThe 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

AbstractExperiments 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

AbstractFree 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

AbstractUsing 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

AbstractThe 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

AbstractThe 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

AbstractAction 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

AbstractIn 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

AbstractToxic 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

AbstractThe 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.
Mechanism of Antifungal Action of 2,4,5,6‐Tetrachloroisophthalonitrile
Authors: Vincent Phillip G. , Sisler H. D. 
Published: April 2006

AbstractStudies of the toxicity of 2,4,5,6‐tetrachloroisophthalonitrile (TCIN) to cells of Saccharomyces pastorianus and Neurospora crassa showed that 2 to 4 μg/ml of the toxicant were required to inhibit growth. Several thiol compounds reversed toxicity to growth.Glucose oxidation was severely impaired in treated cells of both test organisms. The toxicant at 2 or 4 μg/ml markedly reduced soluble thiol content of these cells. Bound thiol content was less affected in S. pastorianus cells than soluble thiol content.Uptake of toxicant by yeast cells was accompanied by formation of derivatives, some of which resembled those formed by reaction of glutathione with TCIN in vitro. Coenzyme A, glutathione, and 2‐mercaptoethanol readily formed derivatives with TCIN in vitro. The nature of these derivatives was studied using 2‐mercaptoethanol products as model substituents. Four derivatives were formed with 2‐mercaptoethanol each with similar functional groups but showing dissimilar degrees of mobility during silica gel chromatography. Evidence indicated that these are derivatives of TCIN in which 1 to 4 of the halogens has been substituted by 2‐mercaptoethanol.The mechanism of fungicidal action of TCIN is attributed to thiol inactivation.
Effect of Ethylene on Peroxidase Activity
Authors: Gahagan H. E. , Holm R. E. , Abeles F. B. 
Published: April 2006

AbstractEthylene increased the peroxidase activity of nine out of ten varieties of sweet potato (Ipomoea batatas (L.) Lam.) root disks tested. The increase which was observed four hours after ethylene treatment was partially overcome by carbon dioxide. The increase was inhibited by actinomycin D and cycloheximide, indicating de novo protein synthesis. Electrophoretic separation on polyacrylamide gels indicated the appearance of two new peroxidase bands. Peroxidase activity in bean petiole explants was localized around the separation layer. Ethylene caused a small increase in peroxidase activity in the petiolar portion of the explant. Phenolic substances had no effect on abscission consistent with their proposed roles as cofactors for auxinoxidase, indicating that auxin‐oxidase does not play a role in abscission of Coleus blumei Benth. abscission zone explants.
Dynamic Modifications in Alfalfa Leaves Growing in Subtropical Conditions
Authors: Gindel I. 
Published: April 2006

AbstractIn upper Galilee a field of alfalfa was sown in April 1965 in order to study the influence of the quantity of irrigation on leaf structure and on yield. Three treatments were given, each on five experimental plots: 1) Irrigation, with 5000 m3 per ha; 2) Irrigation with 10,000 m3 per ha; and 3) non‐irrigated. Leaves were picked four times during 1965/66, each time after the field had been cut and after the regrowth had developed. The following conclusion can be drawn from the results. Each regrowth shows changes in the number of stomata and epidermis cells, in the length of stomata, and in leaf area as a result of the three treatments and of the changing environmental factors during the period of development of the four regrowth leafages.The greatest modification was noted in the non‐irrigated experimental plots of highest stomata density; the least modification in plots with 1000 m3 per ha irrigation.The results show that there is a relationship between modification of stomata and changes in edaphic and climatic factors.
Changes in Individual Nucleotides of Developing Soybean Seeds
Authors: Galitz Donald S. , Howell Robert W. 
Published: April 2006

AbstractPerchloric acid extracts of soybean seeds were separated by column chromatography into 17 peaks. Thirteen nucleotides were identified in 11 of these peaks (NAD, CMP, CDP, CTP, AMP, ADP, ATP, GMP, GDP, GTP, UMP, UDP, and UTP). Two of the peaks were identified as ascorbic acid and dehydroascorhic acid. Four peaks remain unidentified although one of these appears to be protein.Monophosphates decreased and triphosphates increased as development proceeded. Diphosphates were initially low and showed no statistically significant difference with maturity.The accumulation of triphosphates in late stages of development is discussed in relation to synthetic activities of the developing seeds.
Dark‐Germination of Reciprocal Hybrid Seed from Light‐Requiring and ‐Indifferent Nicotiana tabacum
Authors: Kasperbauer M. J. 
Published: April 2006

AbstractSeed resulting from self‐fertilization of Nicotiana tabacum plants was tested for germination in uninterrupted darkness at monthly intervals beginning at time of harvest. All seed lots were light‐requiring immediately after harvest. Some lots continued to be light‐requiring, but others gradually became light‐indifferent during storage under laboratory conditions. One light‐requiring and one light‐indifferent selection were self‐pollinated, and reciprocally crossed. The seed resulting from self‐fertilization was light‐requiring or light‐indifferent, respectively, according to the parentage. Seed resulting from the reciprocal crosses differed in dark‐germinability. Further, dark‐germination of seed from each of the reciprocal crosses differed from that of either parent. Both parents contributed toward light sensitivity of the seed; however, contribution of the maternal parent was greater than that of the pollen parent.