bluuebunny/crossref_metadata_2025 huggingface dataset:
Isoenzyme Polymorphism in Flowering Plants III Gel Electrophoretic Methods and Applications
Authors: Brewbaker James L. , Upadhya Mahesh D. , Mäkinen Yrjö , Macdonald Timothy
Published: April 2006

Gel electrophoretic methods and equipment which were devised or modified for rapid and economic application to angiosperm tissues are described. Staining schedules are outlined that proved effective on a wide variety of tissues for elucidation of isoenzymes with the following activities; eslerase, peroxidase, catalase, leucine amino peptidase, phosphatase, amylase, and glutamic‐oxalacetic‐transaminase. Illustrative applications are discussed.
Effect of Photoperiod on Isoenzymic Composition of Citrus and Poncirus
Authors: Warner Robert M. , Upadhya Mahesh D.
Published: April 2006

Long day photoperiod treatments given to Dancy and Clementine tangerines (Citrus reticulata Blanco.), the Mineola tangelo (C. parodisi Macf. × C. reticulata Blanco.) and the Rubideaux trifoliate (Poncirus trifoliata (L.) Raf.) produced 1.5 to 2.5 times the stem area, total linear growth and number of branches compared to short day treatments.

Growing shoot tips were snbjected lo etectrophoretic analyses of tbe isoenzymic composition of esterases, teucine aminopeptidases, peroxidases and amylases. Differences were observed in the number and activity of the isoenzymes between the sbort and the long day treated plants of the three Citrus species aiid Hnbideaux trifoliate orange. The possible significance of tbese differences is discnssed in relation to Ihe growth in response to the photoperiodic treatments.
Photoperiodic Responses of Brassica campestris cv. Ceres
Authors: Friend D. J. C.
Published: April 2006

The photoperiodic responses of Brassica campestris L. cv. Ceres were investigated to determine the suitability of this plant for further studies on the spectral require ments for floral initiation. This is a long‐day plant, sensitive to one inductive photocycle on the fourth day from germination. The flowering response increased with the length and intensity of a single period of supplementary light used to extend an 8‐hour daylength and was greatest at 25°C. Application of nitrates retarded floral initiation by about two days under short day conditions, but did not affect the re sponse to one long day. Gibberellic acid induced earlier floral initiation under short day conditions.

The photoperiodic response was little affected by omitting the main light period immediately before or after the supplementary light, as long as the intensity of supplementary light was greater than 5000 lux. Short interruptions (5–10 minutes) of a single 16‐hour dark period with high energy red or far‐red radiation did not promote flowering. When given continuously during a single 16‐hour dark period, far‐red radiation was more effective in flower promotion than an equal energy of red.
Inhibitors Interacting with Cytokinins
Authors: Kuraishi Susumu , Kasamo Kunihiro , Tezuka Takafumi , Ushijima Tadahiro , Tazaki Tadayoshi
Published: April 2006

Cytokinins and gibberellins stimulate the leaf growth of Raphanus sativus L. var. acanthiformis Makino and the germination of tobacco seeds (Nicotiana tabacum L cv. Bright Yellow) in the dark. An SH bahibitor, p‐chloromercuribenzoate, enhanced physiological effects caused by cytokinins, but not those by gibberellins. The same phenomena were observed with amytal and alloxan. Inhibitors of glycolysis, TCA cycle, evtochrome oxidase and oxidative phosphorylation did not show such an enhancement. These results suggest that certain levels of nicotinamide nucleotides or SH in proteins stimulate the action of cytokinins and that the mode of action of cytokinins has close relation to carbon metabolism.
Fluoride Inhibition of Respiration and Fermentation in Cultured Cells of Acer pseudoplatanus
Authors: Givan Curtis V. , Torrey John G.
Published: April 2006

Low concentrations of sodium fluoride severely inhibit anaerobic CO2 evolution in Acer pseadoplatanus L. cells but have relatively little effect on aerobic respiration. The insensitivity of respiratory O2 uptake to fluoride is due in part to the fact that fluoride reduces the intracellular pyruvate concentration to only a relatively minor extent under aerobic conditions, although it prevents the several fold increase in endogenous private which is normally brought about by anoxia. The respiratory insensitivity is also ascribable to the existence of a respiratory component which is unaffected by the decrease in endogenous private resulting from fluoride treatment. The extremely severe respiratory inhibition brought about by fluoride plus dinitrophenol is not appreciably relieved by exogenous private, indicating that this inhibition is the result of interference with the aerobic oxidation process per se and is not solely a consequence of glycolytic inhibition.
Enzymatic Maceration of Plant Tissue
Authors: Sato Sitiro
Published: April 2006

Tissue cells of Vicia faba were separated from the leaf pieces by the pectinase treatment after which the chlorophyll determination method was employed. The separation proceeded at a constant rate for 3 hours', the maximum rate of separation was at pH 5.3. The optimal pH shifted to 5.5 in the presence of 0.001 M 2Na‐ethylenediaminetetraacetic acid (EDTA), which accelerated the separation at pH levels higher than 5.5. The separation was enhanced by NaCl and MgCL2 and delayed by CaCl2 and hypertonicity produced by sugars. Indoleacetic acid (IAA) and naphthaleneacetic acid (NAA) accelerated the separation at physiological concentrations. The rate of separation differed markedly by the age of the leaf and the species which offered the substrate material.
The Effect of CCC and Amo‐1618 on Growth, Catalase, Peroxidase and Indoleacetic Acid Oxidase Activity of Young Barley Seedlings
Authors: Caspar Thomas , Lacoppe Josiane
Published: April 2006

Barley seedlings were grown in darkness on filter paper saturated with phosphate buffer or CCC and Amo‐1618 buffered solutions. The effects of CCC and Amo‐1618 on growth, catalase, peroxidase and lAA‐oxidase were studied on coleoptile and primary leaves.

Both growth‐retarding chemicals cause an inhibition of growth, Amo‐1618 being more effective than CCC. They have no effect on catalase activity.

Increasing concentrations of CCC and Amo‐1618 progressively stimulate peroxidase and IAA‐oxidase activities (Amo‐1618 more than CCC). The enzymatic activity in short‐treated plants is higher than in the corresponding control plants of the same height.

It is proposed that CCC and Amo‐1618 exert their effect on the growth of barley by acting on auxin catabolism.
The Role of Calcium and Cell Permeability in the Disease Blossom‐end Rot of Tomatoes
Authors: van Goor B. J.
Published: April 2006

Research was carried out concerning the cell‐physiological backgrounds of the disease blossom‐end rot of tomatoes, which, like bitter pit of apple and lipburn of lettuce, is a Ca‐deficiency disease. In our experiments tomatoes with the least amounts of Ca were attacked by the disease. We estimated the ion permeability of tissues with different Ca levels.

Permeability was found to increase with decreasing Ca contents in the tissue. The increase accelerated with the beginning of the disease. The artificial rise in the permeability caused by ether and decenylsuccinic acid resulted in an increased occurrence of the disease.

It is probable that the Ca‐deficiency causes the necrosis of the tissue in blossomend rot and that the shortage of calcium among others affects the disorganization of membranes and organells in the cell.
Photosynthesis, Photorespiration and Respiration of Detached Spruce Twigs as Influenced by Oxygen Concentration and Light Intensity
Authors: Poskuta J.
Published: April 2006

The effects of oxygen concentration and light intensity on the rates of apparent photosynthesis, true photosynthesis, photorespiration and dark respiration of detached spruce twigs were determined by means of an infra‐red carbon dioxide analyzer (IRCA). A closed circuit system IRCA was filled with either 1 per cent of oxygen in nitrogen, air (21 % O2) or pure oxygen (100 % O2). Two light intensities 30 × 103 erg · cm −2· s−1 and 120 × 103 erg · cm−2· s−1 were applied.

It has been found that the inhibitory effect of high concentration of oxygen on the apparent photosynthesis was mainly a result of a stimulation of the rate of CO2 production in light (photorespiration). In the atmosphere of 100 % O2, photorespiration accounts for 66–80 per cent of total CO2 uptake (true photosynthesis). Owing to a strong acceleration of photorespiration by high oxygen concentrations, the rate of true photosynthesis calculated as the sum of apparent photosynthesis and photorespiration was by several times less inhibited by oxygen than the rate of apparent photosynthesis. The rates of dark respiration were essentially unaffected by the oxygen concentrations used in the experiments. An increase in the intensity of light from 30 × 103 erg · cm−3· s−1 to 120 · 103 erg · cm−2· s−1 enhanced the rate of photorespiration in the atmospheres of 21 and 100 % oxygen but not in 1 % O2. The rate of apparent photosynthesis, however, was little affected by light intensity in an atmosphere of 1 % oxygen.
Root Growth Activity of Barban in Relation to Auxin and Other Growth Factors
Authors: Burström H. G.
Published: April 2006

The effect of barban (4‐Cl‐2‐butynyl‐N‐3‐Cl‐phenylcarbamate) on the growth of roots of wheat seedlings has been studied. In concentrations of 10−7 to 5 · 10−7M barban causes rapid inhibitions of cytokineses and cell elongation, the effects of which are spontaneously reversible. The reversion of the meristem inhibition is enhanced by thymidylic acid and indole‐3‐acetic acid (IAA). Initiation of cell elongation is slowed down or ceases during cytostasis; its reversal, on the other hand, is promoted by IAA and kinetin but inhibited by Fe. The final cell elongation attained is strongly reduced by barban and reversed under transient aberrant elongation. This inhibition and the recovery appear both to be additive to cell elongation actions of auxin and antiauxin but reversed by nucleic acid components. The inhibition of elongation is increased by Fe. The following explanation for this phenomenon is suggested: the primary effect of barban is known to be the blocking of metaphases under anaesthesis; this blocking then leads to reduced activation of IAA, kinetin and other metabolites. Auxin is required for cell divisions and initiation of elongation: the apical root growth equals in this respect that of shoot apices and lateral meristems. Initiation of cell elongation is closely dependent upon metabolites produced in dividing meristematic cells, whereas the limitation of cell stretching is independent of the meristem activity. No explanation is offered for the role of Fe.
Stickstoffgehalt in Blättern von Psychotria mit N‐bindenden Endophyten
Authors: Löhr Erika
Published: April 2006

Nitrogen Content in Leaves from Psychotria with Nitrogen‐Fixing Endophytes. — Leaves from Psychotria calva with bacteria along the midrib did not contain more nitrogen than leaves from the surrounding trees. This indicates probably that the nitrogen fixing activity of the endophyte is small or zero.
Resistances to the Diffusion of Gas and Vapor in Leaves
Authors: Gale J. , Poljakoff‐Mayber Alexandra
Published: April 2006

Considerable error may be incurred when the component leaf resistances to gases are calculated from the rates of photosynthesis and transpiration measured for the entire leaf. This is due to the fact that there are two parallel pathways for diffusion — through the upper and the lower leaf surfaces — which in most leaves are asymmetrical. True values for the resistances, and predictions of the results of their modification, have been obtained from separate measurements of the photosynthesis and transpiration via the two leaf surfaces.
On the Delimitation of Chlorophyll Formation after an Irradiation with a Sharply Defined Light Area
Authors: Virgin Hemming I. , Arvidsson Lars G.
Published: April 2006

Leaves of dark grown wheat seedlings have been irradiated for a few minutes with a strictly defined beam of red light. After a stay in darkness for six hours the whole leaves were irradiated for three hours. The pre‐irradiated spot will then stand out greener than the rest of the leaf, due to accelerated formation of protochlorophyll, earlier described (22), and will consequently show a higher concentration of chlorophyll a. By scanning the leaf with a microphotometer it was shown that no spread whatsoever of the effect of the light impulse takes place, i.e. the phytochrome, which is one of the light absorbing systems, exerts its effect strictly locally. This is in contrast to many other red light effects on photomorphogenetic phenomena characterized by a rapid spread of the stimulus. The two kinds of phytochrome actions are discussed.
Effects of Soil Salinity and Growth Regulators on Germination and Seedling Metabolism of Wheat
Authors: Sarin M. N. , Narayanan A.
Published: April 2006

Germination studies were carried out with the wheat varieties NP823, Karchia, Sonora 63, Sonora 64, Mayo 64 and Lerma Rojo in artificially salinized soil maintained at ECe 2, 8, 12 and 16 mmhos/cm at 25°C. Early seedling growth and metabolism of variety NP 823 was studied in salt solutions alone and with addition of the growth regulators GA3 and Cycocel (2‐chloroethyl trimethylammonium chloride). Soil salinity both depressed and delayed the germination. Among the varieties tested NP 823 and Karchia were relatively less susceptible to salt injury while Lerma Rojo exhibited a maximum susceptibility. Salt supply also brought about a reduction in the early seedling growth, the release of reducing sugar and the amylase activity. The adverse effect on amylase activity was not mediated through the synthesis of enzyme protein but by an inhibition of the enzyme activity. Exogenous supply of GA3 counteracted the adverse effect of salt on amylase activity and the release of reducing sugar but not on the early seedling growth.
Palmelloid Formation of Chlamydomonas
Authors: Iwasa Kozo , Murakami Shohachi
Published: April 2006

Organic acids such as citrate, oxalate, succinate, fumarate, malate, glutamate, aspartate, glycolate and phthalate induce palmelloid formation at neutral pH in liquid cultures of Chlamydomonas, while acetate hardly does it. The palmelloids consist of a minimum of four cells and are embedded in a jelly‐like material. The effective organic acids are generally not only unutilizable as respiratory substrates, but affect also slightly the respiration or photosynthesis and tend to inhibit growth. In a synchronous culture, an addition of citrate at an early stage of a light or dark period has little or no effect on cell growth and multiplication but inhibits the dissociation of divided daughter cells strikingly.
Changes in Nucleic Acid Metabolism of Excised Barley Leaves During Senescence and the Effect of Kinetin on these Changes
Authors: Atkin Roger K. , Srivastava B. I. Sahai
Published: April 2006

The changes in the amount, rale of synthesis and the nucleotide composition of different RNA fractions in excised barley leaves floated on water or kinetin (10 mg/l) in the dark were examined. In excised leaves floated on water all nucleic acid components declined and these declines were retarded by kinetin. Barley leaves floated on water showed a stimulation of 32P incorporation into various RNA fractions within 48 hours followed by a decline after 96–144 hours. The leaves floated on kinetin, however, showed an even higher incorporation of 32P into UNA by 48 hours which remained at a comparatively higher level throughout the experiment. In spite of the above changes in RNA synthesis significant differences in the 32P sucrose gradient profiles or in the 32P nucleotide composition of UNA from water and kinetin floated leaves were not noted.

The results of this study show that important changes in nucleic acid metabolism occur during the early stages of leaf senescence and that alterations in nucleic acid metabolism during senescence and during kinetin treatment may involve quantitative and only subtle qualitative changes.
Sweetgum Dormancy Release: Effects of Chilling, Photoperiod, and Genotype
Authors: Farmer Robert E.
Published: April 2006

In Liquidambar styraciflua L., 1200 to 1600 hours of chilling (3°C) resulted in rapid resumption of growth under greenhouse forcing conditions. Long photoperiods were effective substitutes for chilling. Plants from southern Alabama (Lat. 31°) had a lower chilling requirement than those from western Tennessee (Lat. 36°). Growth rate of plants under long photoperiod varied directly with degree of previous chilling.
Transport Gradient of Indoleacetic Acid in Pine Seedlings
Authors: Zaerr J. B.
Published: April 2006

Movement of indoleacetic acid (IAA‐1‐14C) through 5‐min segments from stems and roots of Pinus taeda L., P. jeffreyi Gtrev. and Balf., and P. ponderosa Laws, seedlings was measured. All three species showed the same general pattern of IAA‐1‐14C transport. Predominantly downward movement occurred at all points along the stem and root; least IAA‐1‐14C transport occurred in segments obtained near the shoot apex; and most occurred in segments obtained near or just below the cotyledons. This pattern of transport gradient is different from that reported in other plants. These results could be interpreted in either of two ways: (1) that transport limitations may control movement of the growth‐regulator, or (2) that the transport gradient may be an indication of endogenous growth‐regulator levels.
The Effect of Gibberellin on Tryptophan Conversion and Elongation of the Avena Coleoptile
Authors: Valdovinos Jack G. , Sastry K. S. Suryanarayana
Published: April 2006

Gibberellic acid (GA3) enhanced directly the release of 14CO2 from tryptophan‐1‐l4C by cell free preparations of Avena coleoptile tips. The rate of tryptophan metabolism in the presence of GA3 was increased by approximately 100 per cent. The addition of auxin synthesis inhibitors to incubation flasks nullified the enhancement effect of GA3 on elongation of the coleoptile tips. These studies implicate tryptamine as an intermediate in the formation of auxin from tryptophan. The possibility of GA3‐IAA interaction in the elongation processes was also investigated. Combination treatments of these growth‐promoting substances did not induce a synergistic growth response by the coleoptile tissue.
Cytokinin Reversal of Abscisic Acid Inhibition of Growth and α‐Amylase Synthesis in Barley Seed
Authors: Khan A. A. , Downing R. D.
Published: April 2006

The effect of cytokinin, kinetin, on abscisic acid (dormin) inhibition of α‐amylase synthesis and growth in intact barley seed was investigated. Abscisic acid at 5 × 10−5M nearly completely inhibited growth response and α‐amylase synthesis in barley seed. Kinetin reversed to a large extent abscisic acid inhibition of α‐aniylase synthesis and coleoptile growth. The response curves of α‐amylase synthesis and coleoptile growth in presence of a fixed amount of abscisic acid (6 × l0−6M) and increasing concentrations of kinetin (from 5 × l0−7M to 5 × 10−5 M) showed remarkable similarity. Kinetin and abscisic acid caused synergistic inhibition of root growth. Gibberellic acid was far less effective than kinetin in reversing abscisic acid inhibition of α‐amylase synthesis and coleoptile growth. A combination of kinetin and gibberellic acid caused nearly complete reversal of abscisic acid inhibition of α‐amylase synthesis but not the abscisic acid inhibition of growth. The results suggest that factors controlling α‐amylase synthesis may not have a dominant role in all growth responses of the seed. Kinetin possibly acts by removing the abscisic acid inhibition of enzyme specific sites thereby allowing gibberellic acid to function to produce α‐amylase.
Iris Seed Dormancy
Authors: Stoltz Leonard P.
Published: April 2006

Iris embryos were treated in several ways to study the cause of delayed germination. The results of this work indicate that a chemical inhibitor is present in the endosperm and mechanical inhibition of embryo growth also occurs. The mechanical inhibition reduces excised Iris embryo growth to the same extent as does the chemical inhibitor.
Biochemische Differenzierungen bei Mais unter Mineralstoff mangel
Authors: Horovitz C. T. , Brad I. , Enescu Ioana , Niculescu S. , Jokl Elisabeta
Published: April 2006

Biochemical Differences in Maize as Related to Mineral Deficiencies. I. Changes in the Activity of some Enzymes. — The enzymatic systems in the different organs of corn seedlings are variously affected in the first growing stages by deficiency in nitrogen, phosphorus or potassium, according to the specific physiological functions of the organs. Deficiency in nitrogen causes an increase in peroxidase and catalase activity and inhibition of pyruvic and glutamic decarboxylase. Deficiency in phosphorus causes an activation of peroxidase and catalase in leaves and an inhibition of acid phosphatasc, invertase, pyruvic and glutatnic decarboxylase in roots. Deficiency in potassium, as compared to deficiency in nitrogen and phosphorus, leads to the severest disturbances of the different enzymatic systems. This deficiency causes a strong increase in leaf invertase, catalase and peroxidase activity, a stimulus in respiration intensity in the roots, and an inhibition in pyruvic and glutaniic decarboxylase in leaves and roots. The activation and inhibition changes in the enzymatic processes, appearing as a consequence of nitrogen, phosphorus and potassium deficiency have different significance and intensity.
Effect of Phosphorus Deficiency on Carbohydrate Metabolism of Mentha arvensis
Authors: Singh J. N. , Singh D. P.
Published: April 2006

The effects of phosphorus deficiency on carbohydrate fractions of Mentha arvensis L. var. piperascens were studied. Mint plants were grown in sand cultures under full nutrition and phosphorus deficiency conditions. Component organs, viz., leaf, stem and root, were sampled at four different stages of the growth cycle and analysed for various sugar fractions.

In leaf and root phosphorus deficiency brought about a definite increase in all sugar fractions whereas in stem a reduction was noticed. The stem appeared to be the principal storage organ throughout the growth. Maximum sugar concentration was recorded at the age of 70 days, which represents the full maturity stage, and coincided with maximum essential oil accumulation.
Relationship of IAA‐oxidase Activity to Gibberellinand IAA‐induced Elongation of Light‐grown Cucumber Seedlings
Authors: Katsumi Masayuki , Sano Hiroshi
Published: April 2006

The growth and IAA‐oxidase activity of light‐grown cucumber seedlings (cv. Aonagajibae) were investigated in response to GA3 and IAA.

Both GA3 and IAA induced significant elongation of the hypocotyl. The fresh and dry weights of the hypocotyl increased due to GA3 or IAA treatment, whereas no significant change was observed in the cotyledons of GA3‐treated seedlings as compared with the controls. The fresh and dry weights of IAA‐treated cotyledons were both lower than those of controls.

Treatment with GA3 or IAA resulted in retardation of IAA‐oxidase activity in the hypocotyl and cotyledons. The degree of retardation was less in the cotyledons than in the hypocotyl. An inverse relationship was recognized between GA3‐ or IAA‐induced elongation and IAA‐oxidase activity in the hypocotyl.

The auxin‐mediated mechanism for gibberellin action was discussed.
Interactions between Plants and Epiphytic Bacteria Regarding Their Auxin Metaholism
Authors: Wichner Siegfried
Published: April 2006

During an ether extraction (20 h, 4°C), nonsterilc pea epicotyls deliver at least 5 times more auxin than sterile ones. A great part of the additional auxin originates from a bacterial auxin production during the extraction. Presence of chloramphenicol or streptomycin during the extraction lowers the auxin amount extractable from nonsterile epicotyls. In extraction conditions (i.e. covered with ether, 20 h, 4°C), epiphytic bacteria contained in homogenates of nonsterile plant parts produce IAA from added tryptophan.

Furthermore, first results are presented underlining the fact that epiphytic bacteria already produce auxin at the surface of nonsterile plant parts (before an extraction).
On the Adaptation of Aphanomyces astaci as a Parasite
Authors: Unestam Torgny
Published: April 2006

The crayfish plague parasite Aphanomyces astaci was compared with some other species of Aphanomyces in several physiological respects to detect signs of specialization in the plague fungus which could be connected with its life as a parasite.

Thus, A. astaci showed good growth in crayfish serum in contrast to the other species. Zoospore germination showed a similar hut not so distinct pattern. Chemo‐taxis in zoospores was weak and restricted in its substrate range in A. astaci but was stronger and less restricted in the saprophytic species. Electrotaxis was quite apparent in A. astaci.

Virulence in A. astacin was correlated to linear growth rate of individual hyphae in crayfish serum but neither to spore germination percentage in serum of resistant or susceptible crayfishes nor to motility of the zoospores. The saprophytic Aphanomyces strains did not penetrate the soft cuticle of crayfish in vitro but A. astaci strains did, regardless of virulence.

Zoospore production in A. astaci was restricted to lower concentrations of mineral salts Mum in the other fungi.

No sexual or other resting structures were found in infected crayfish but thick walled as well as gemmae‐like hyphal portions were formed in some media in vitro.

Infection of crayfish can take place between 2 and 25°C and zoospores are able in survive at least a week in an aquarium of redistilled water at 14°C and still infect the animals, but in highly bacterium‐contaminated water they do not cause infection.

The results were discussed with respect to the origin of the “abnormal” parasite. Together with those of earlier experiments they suggest Unit A. astaci is physiologically adapted as a parasite on fresh water arthropods.

This investigation was supported by a grant from the Swedish Natural Science Research Council and by funds paid to the Swedish state by the Swedish water power industry.

The author is deeply indebted to the head of this institute Professor Nils Fries, for his encouragement. advice, and support, let Mr Andrew Watson for help in carrying out the electrotaxis experiment, to Docent Karin Aschan‐Aberg for criticizing the manuscript, to Mrs. Linda Fryktund for revising the English text, and to Mr. Can Wihma for skilful technical assistance.
Retention and Passage of Calcium and Strontium in Stems of Phaseolus vulgaris as Mediated by Xylem Stream Flow Rate and Dinitrophenol
Authors: Emmert Fred H.
Published: April 2006

The influence of the stem on delivery of Ca Sr to the plant top was studied by noting the extent to which the stem interfered with through passage of these elements. Tagged Ca Sr solutions were forced through bean stem sections, and solute which completed passage to the exudate was considered indicative of the nutrition normally available to the plant top. Tests were conducted over two widely different xylem stream flow rates, and with or without the addition of dinitrophenol to the source solution. Approximately identical amounts of cation were introduced into the stem for all test situations.

In all cases, the stem retained the bulk of introduced cation and allowed only a fraction (ca 25 percent) to complete passage to the exudate. Within this pattern, less stem retention and greater through passage occurred at the high (versus the low) stream flow rate, and also where dinitrophenol was present in the source solution.

In all cases, the stem preferentially retained Sr over Ca so that the exudate was relatively dilute in Sr. Such discrimination was less at the high (versus the low) stream flow rate. It was enhanced by the presence of dinitrophenol.
Occurrence of Plant Growth Inhibitors in Tropical and Subtropical Vegetation
Authors: Bovey R. W. , Diaz‐Colon J. D.
Published: April 2006

Acetone, ethanol and water extracts of mature fruits of yaupon (llex vomitoria Ait.) inhibited germination of mesquite (Prosopis juliflora Swartz DC. var. glandulosa (Torr.) Cockerell and sorghum (Sorghum bicolor (L.) Moench). Extracts of guava fruit (Psidium guajava L.) inhibited cucumber (Cucumis sativus L.) seed germination. Water soluble inhibitors were found in fruits, leaves, roots and bark of several tropical species representing 10 different families.

Strong inhibition of cucumber seed germination and growth did not occur in sand when water extracts containing inhibitors were applied. Growth of corn, sorghum, cucumber and bean was reduced in soils collected beneath Malay apple (Eugenia malaccensis L.) trees. Plant growth‐inhibitors occurred in all species studied in various plant parts, and some apparently affect the growth and ecology of other plant species.
Rhizosphere Oxidation in Rice: An Analysis of Intervarietal Differences in Oxygen Flux from the Roots
Authors: ARMSTRONG W.
Published: April 2006

The polarographic technique (Armstrong 1967) has been found suitable for the detection of significant intervarietal differences in oxygen diffusion from rice roots. All the evidence obtained supports the thesis that intervarietal differences in oxygen diffusion rate occur and the varieties tested may be arranged in order of increasing oxygen flux as follows N 36 < N 22 < N 29 < N 32 < Yubae. The lowest oxygen flux rates are found in those varieties (N 22 and N 36) susceptible to Akagare disease of rice while the flux rates of varieties resistant to Akagare (N 29 and N 32) are higher. On the basis of these results one would also expect Yubae to be resistant to Akagare.

The results are discussed with reference to previous work which has shown the oxidising activity and carbohydrate exudation properties of rice roots to be similarly correlated with resistance or susceptibility to Akagare.

Attention is drawn to what it is felt are the shortcomings in existing techniques for measuring the oxidising activity of roots.

It is suggested that with certain provisions the polarographic technique may he found useful in any effort to build up high oxidising power into the new plant type proposed for the tropics.
Wechselwirkung von Riboflavin, Isoriboflavin und 2‐Thiouracil auf die Induktion zweidimensionalen Wachstums von Farnprothallien
Authors: Schraudolf H. , Legler K.
Published: April 2006

Action of riboflavin, isoriboflavin and 2‐thiouracil in the induction of 2‐dimensional growth of fern prothallia.—The inhibition of cell division induced by 2‐thiouracil in prothallia of Dryopteris filix‐mas and Anemia phyllitidis is reversed by riboflavin as well as by its physiological inactive analogue isoriboflavin. This antagonism is not due to an in vivo interaction as stated by Yeoh and Raghavan, but is rather caused by an in vivo sensibilisation of photo destruction of the inhibitor during early phase of spore germination.

Riboflavin as well as isoriboflavin strongly inhibit cell divisions in the prothallia of Anemia phyllitidis.

In spite of a significantly reduced growth rate NO retardation of the onset of the 2‐diniensional differentiation, as related lo a critical cell number, can be slated in the Anemia prothallia.
Comparisons of Phosphate, Carbohydrate, and Kjeldahl Nitrogen Content of Normal and Xantha Mutant Leaves of Helianthus annuus
Authors: Habermann Helen M.
Published: April 2006

Tissues of the xantha mutant of Helianthus annuus have an abnormally high phosphorus content compared to normally pigmented tissues of comparable age and position on the plant. A major portion of the observed differences can be accounted for in the acid‐insoluble “7‐minute” phosphate fraction, a fraction thought to be composed primarily of polyphosphates. Although this suggests that the xantha mutant may possess a mechanism for immobilizing excess phosphates as insoluble polymers, all qualitative tests for polyphosphates in extracts of mutant leaves have been negative.

Carbohydrate levels in the mutant are lower than in wild type leaves due to the absence of photosynthesis in the mutant and its inability to form starch. Differences between mutant and wild type in Kjeldahl nitrogen appear to be a consequence of aging effects resulting from propagation by grafting onto physiologically older stocks.
Studies in Stomatal Behaviour: The Effects of Moving, Normal and Carbon Dioxide‐Free Air on the Stomata of Some Plants
Authors: Hafez M. G. A. , Younis M. E.
Published: April 2006

A series of experiments were conducted to investigate the effects of moving, normal and carbon dioxide‐free air on the stomata within porometer cups attached to the illuminated leaves of Datura stramonium, Pelargonium zonale, Duranta plumieri and Clerodendron inerme.

A marked opening stomatal response was obtained in Datura and Pelargonium on changing to carbon dioxide‐free air. In general no such response was established in Duranta and Clerodendron. Indications of even an opposite closing effect were shown in the case of Duranta.

The present results seem to disprove the reduction of carbon dioxide by photosynthesis as the major factor controlling the wide stomatal opening within a porometer cup. The possibility of a humidity effect is also suggested.
Cellulase Induction and Wall Extension in the Water Mold Achlya ambisexualis
Authors: Thomas D. des S. , Mullins J. T.
Published: April 2006

Branching of the coenocytic hyphae in the water mold Achlya ambisexualis Raper is always accompanied by a rise in cellulase activity. Branching and the cellulase response can be induced either by the sexual hormone atheridiol or by casein hydro‐lysate. Only those strains which branch in response to the inducer show a concomitant rise in cellulase. The peak of induced mycelial cellulase corresponds in time with the appearance of branch primordia.
The Relative Contributions of Sugars from Assimilating Leaves and Stem Storage Cells to the Sieve Tube Sap in Willow Cuttings
Authors: Ho L. C. , Peel A. J.
Published: April 2006

A method is described for the measurement of the relative contributions of sugars from the assimilating leaves and stem storage cells to the sieve tube sap in leafy cuttings of Salix viminalis L. In these experiments sieve tube sap was collected as honeydew from a small colony of aphids, Tuberolachnus salignus (Gmelin).

Using this method it has been shown that in cuttings maintained under continuous illumination prior to experimentation, the leaves contribute about 75 per cent of the total sugars in the sieve tube sap. With cuttings which have been stored by keeping them in darkness, the level of labile carbohydrates in the stem storage cells decreases, in comparison with those growing in light, and the percentage of sugars in the sieve tube sap supplied by the leaves rises to 90 per cent.
Freezing of Conifer Xylem and the Cohesion‐Tension Theory
Authors: Sucoff Edward
Published: April 2006

The research explored the apparent contradiction between the cohesion‐tension theory and the lack of blockage following freezing in conifers.

Five to ten cm lengths of the main stem of actively transpiring Thuja occidentalis, Picea glauca and Pinus sylvestris were frozen. On thaw, there was no evidence of blockage in the formerly frozen xylem. Microscopic examination of frozen wood and hydrodynamic considerations showed that air was present in the xylem water and that bubbles were probably present upon freezing. On freezing about 9 per cent of the water irreversibly migrated into the unfrozen plant parts.

Lack of blockage in the presence of air bubbles was reconciled to the cohesion‐tension theory by a model in which only the largest bubble in a number of interconnected cells expands. As this bubble expands tension is released allowing all bubbles in adjoining tracheids to redissolve. Potential rate of resolution of unexpanded bubbles following release of tension was calculated to be less than 0. 1 second.
Cytokinins and Transfer Ribonucleic Acids. I. Presence of Cytokinins in Various Amino‐acid Specific Transfer Ribonucleic Acids of Baker's Yeast
Authors: Klämbt D. , Kovoor A.
Published: April 2006

Soluble ribonucleic acid of baker's yeast was fractionated by countercurrent distribution and assayed for both cytokinin activity, using tobacco pith callus tissue, and for certain specific amino‐acid acceptor activities.

Two groups of fractions showed cytokinin activity, one of which corresponds to serine and tyrosine transfer ribonucleic acids which are known to contain isopentenyl adenine, while the other corresponds lo undetermined species of ribonucleic acids.
Auxin‐Synergists in the Rooting of Cuttings
Authors: Gorter Christine J.
Published: April 2006

Indole, α‐ and β‐naphtol are synergistic with auxins in enhancing root production of cuttings of Phaseolus vulgaris.

To find an explanation for this synergism the activity was compared with that of phenolic compounds which are known to be:

a. inhibitors of the IAA oxidase system,

b. cofactors of the conversion of tryptophane to IAA.

Both processes appeared to occur in the bean cuttings (as estimated by root production), but none of the phenols bad an activity equally strong as the “synergists”.

It is suggested that indole as well as α‐ and β‐naphtol act as other injurious substances in “just sublethal” dose (Soekarjo 1966).
Interrelationships of Cotyledonary Shoots in Pisum sativum
Authors: Lovell Peter H.
Published: April 2006

Unequal two shoot systems of tall and dwarf varieties of Pisum sativum L. ev, Improved Pilot and Meteor, respectively, were used in experiments where manipulative treatments involving the removal of one or other or both of the shoot apices were carried out. These were combined with GA treatments. Twenty four hours after treatment, 14CO2 was applied to the lowest expanded leaf on the larger shoot, and the distribution of radioactivity was determined after a further 24 hours. Removal ot the apex of the larger shoot reduced the level of translocation from the treated leaf, the effect being enhanced by the additional removal of the other apex. This (Heel was more marked in the tall than in the dwarf variety.

In untreated control plants of both varieties there was very little transfer ot labelled material from the larger (dominant) shoot to the smaller (weaker) shoot. This pattern was not affected by the removal of the apex from the weaker shoot. In Improved Pilot, removal of the apex from the stronger shoot led to considerable transfer of radioactive material to the weaker shoot, GA treatment having little effect. However, in Meteor, transfer of radioactivity from the stronger to the weaker shoot. after removal of the apex from the stronger shoot, only occurred after the application of GA. Removal of both shoot apices again resulted in low levels of transfer of labelled material to the weaker shoot in both varieties.

These results are consistent with the hypothesis that there is competition between the two shoots for photosynthates produced by the leaves and that treatments reducing the competitive ability of one shoot, reduce the level of nutrients received by that shoot and can result in transfer of materials from it to the other shoot. Continuation of such a situation will result in increased inequality and perhaps ultimately in the death of the weaker shoot.
Endogenous Diurnal and Nocturnal Activity of Guard Cells as Indicated by Stomatal Aperture and Protoplasmic Streaming
Authors: Pallas J. E.
Published: April 2006

The hourly stomatal apertures on epidermal strips of Antirrhinum majus, Rheum rhaponticum, Vicia faba, and Zebrina pendula fixed by Lloyd's technique were compared with the number of stomata found to contain streaming at the same time.

With all four species there was an indication of an endogenously controlled rhythm in stomatal opening with both increases and decreases in aperture and streaming during daytime hours in either the light or dark. A similar endogenously activated rhythm was also found at night in Rheum and Vicia.

Some relationships exist between changes in stomatal aperture and streaming. Streaming in guard cells may only be a byproduct of metabolism, but as such, it serves the useful purpose as a mixer of chemical activity.
The Relationship between myo‐Inositol, ATP and Rotational Streaming
Authors: Soran Viorel , Lazăr Georgeta
Published: April 2006

The rotational streaming of cytoplasm in barley root hairs has been stimulated about 1.3–1.8 times through continuous treatment with various solutions of myo‐inositol. The stimulation attained the same level as after ATP administration and was dependent on the external myo‐inositol supply with the employed concentrations. The stimulation was cut off by simultaneous treatment with myo‐inositol and uranyl salts. By using uranyl acetate the rate of streaming was maintained about the value of the control. The uranyl chloride caused an inhibition in the rotational streaming and later made it to cease altogether. The simultaneous treatment with myo‐inositol and 2.4‐DNP (dinitrophenol) induced a quick inhibition in 60% of the root hairs. consecutively stopping rotational streaming.

It is assumed that the stimulation of rotational streaming is not due to the direct effect of myo‐inositol but to ATP formed in the reaction: inositol hexaphosphate ++ ADP ↔ ATP + inositol. According to the results obtained by testing with uranyl salts, the phosphorylation of inositol probably takes place at the cell surface. The effect of 2,4‐nNP points to the presence of two competitive metabolic processes involved in ATP consumption: the upkeep of rotational streaming and the uptake of substances by the plant cell.
Germination of Species of Labiatae in Response to Gibberellins
Authors: Thompson P. A.
Published: April 2006

Gibberellic acid at between 1 and 1000 mg/1 was used to treat fruits of different Labiatae species kept at an unfavourable temperature for normal germination (25°C). Germination requirements were diverse, but all germinated in response to gibberellic acid. Minimum effective concentrations varied widely from 1 mg/1 with Salvia glutinosa up to 1000 mg/1 with Lycopus europaeus and Scutetlaria galericulata.

When species were tested under conditions in which a proportion of the fruits germinated naturally the results suggested that, even under marginal conditions, relatively high concentrations of gibberellic acid were required to promote germination, although hypocotyl extension in each of the species responded to much lower levels (0.1 mg/1).

Treatments applied to fruits of Lycopus europaeus and two Galeopsis species showed that modifications to the physical conditions of the test, such as light and temperature, produced only small changes in response to gibberellic acid. This effect was found even when situations in which a proportion of seeds germinated without gibberellin treatment were compared with conditions extremely unfavourable for germination.

Comparisons of the effects of gibberellic acid (A3) and gibberellin A4 suggested that the latter promoted germination at approximately one hundred times the dilution of the former when tested on Lycopus europaeus and Galeopsis pyrenaica.
Relation Between the Chlorophyll Content and Paleness of Gibberellic Acid‐Treated Leaves
Authors: Szalai I.
Published: April 2006

The rate of chlorophyll synthesis as a function of lime was examined in plants of Hordeum vitlgare L. cultivated in Knop solution containing 1 mg/1 GA3. The action of concentration on the relations of chlorophyll components was investigated in GA3 solutions of five different concentrations.

The relations of total chlorophyll contents, including those of the a and b components, were determined from ethanol and aqueous acetone extract at various periods of treatment, at the same moment but with different concentrations of GA3.

A significant difference is noted between the chlorophyll contents of the GA3 treated plants and those of the control. The chlorophyll contents of treated plants are decreasing. The difference increases with raising GA3 concentration.

The components were separated on thin layer with the partition method, and the spots were eluted. The density was measured with a spectrophotometer.

Among the yellow components in the treated plants, the carotenes (α and β carotenes) increase as compared with the control plants. The total quantity of xanthophylls (lutein, zeaxanthine, lutein‐5, 6‐epoxide, violaxanthine and neoxanthine) almost equals the xanthophyll amount in the control plants; there is no significant difference.

The paleness of leaves treated with GA3 is provoked by the quantitative change of pigment components; the chlorophylls o and b decrease, the xanthophylls remain unchanged and the carotenes increase.
Differenciation cellulaire et composés sulfhydrylés acido‐solubles de la racine de Lens culinaris Med.
Authors: Zryd Jean‐Pierre
Published: April 2006

Cell differentiation and acid‐soluble sulfhydryl compounds in the root of Lens culinaris. Med. — The content of acid‐soluble sulfhydryl compounds (SH + S‐S) is determined amperometrically in tissues of the Lens root. Two distinct zones are analysed: first the meristematic one (0 to 1.6 mm from the tip) and secondly the elongating one (1.6 to 3.7 mm). Measurements concerned the first 80 hours of the root growth. SH/S‐S ratio is minimum in the meristematic ZONE. Connections seem to exist between the growth rate and the amount of SH compounds in the elongating zone. These facts suggest that the increase of cytoplasmic SH is associated with the reduction of protein‐disulfur‐bridges, which account for t he intermicrofibrilar bindings in the cell wall. The effects of auxins (indoleacetic acid and naphtylacetic acid) treatments are also studied. They are strictly localized in the apical zone and their intensity depends upon the auxin concentration. SH‐level is rising: this is due partially to a reduction of acid‐soluble S‐S.
Mannitol Biosynthesis in Pyrenochaeta terrestris I. D‐Maunitol‐1‐Phosphate: NAD Oxidoreductase
Authors: Aitken W. Brent , Wright James R. , Tourneau Duane Le
Published: April 2006

Cell‐free extracts of mycelial mats of Pgrenochaeta terrestris grown in stationary culture on synthetic glucose or sucrose ‐ salts liquid media contained D‐mannitol‐1‐Phosphate:NAD oxidoreductase (EC 1.1.1.17) activity. Greatest activity occurred early in the growth period. The optimum pH for the reduction of NAD+ in the presence of Fru‐6‐P was 7.4–7.5 while the optimum pH for the oxidation of NADH in the presence of Mtl‐1‐P was 8.1–8.2. The enzyme was stabilized to some extent in Tris‐maleate buffer, pH 7.5, and by the addition of 10% (NH4)2SO4, to this buffer. A 10‐ to 16‐fold purification was attained by a combination of (NH4)2SO4 fractionation and gel filtration on Sephadex G‐100. The enzyme was relatively specific in its substrate and coenzyme requirements. The Km values were determined as: Fru‐6‐P ‐ 3 × 10−4 M, Mtl‐1‐P ‐ 1 × 10−4 M, and NAD+ and NADH ‐ 3 × 10−5 M.
Gas Chromatographic Determination of Phytol in Plant Material
Authors: Liljenberg Conny , Odham Göran
Published: April 2006

Phytol can be gas chromatographed without decomposition on an all‐glass column with 2% Hyprose SP‐80 on Chromosorb W; is stationary phase. Utilizing this a technique has been developed by which phytol of plant origin can be quantitatively determined. The practical limit of sensitivity is about 0.02 μg of phytol.