bluuebunny/crossref_metadata_2025_split huggingface dataset:
Herbicidal Effects on Water Uptake of Seeds of Selected Weed Species
Authors: Biswas P. K. , Haynes R. L. 
Published: April 2006

AbstractSeeds of yellow foxtail, johnsongrass, pigweed and quackgrass were investigated to determine the effects of certain herbicides on water uptake by these species. Seeds of johnsongrass showed slight increase in water uptake over the 20‐h period when treated with 1, 5, 10, and 500 mg/1 of 2,4‐D. Tordon caused a most pronounced increase in water uptake at 0.1 and 1 mg/l as compared with the controls. Johnsongrass gave indications of either increases or decreases in water uptake when treated with herbicides during the 20‐h period, but showed no effects during the 10‐h period. Dormant seeds of yellow foxtail indicated an enhancement in water uptake at all 2,4‐D concentrations during the 20 h period. The effects which the different herbicides had upon the uptake of water in yellow foxtail seeds seemed to be directly proportional to increase in imbibition time. In all cases, more water was imbibed after 20 h over that observed at 10 h. During the 10‐h imbibition period, pigweed seeds treated with 2,4‐D was noted to have a slight stimulating effect on water uptake at all concentrations employed except 5 mg/l, which indicated a depressing effect. It was also observed that 2,4‐D caused a significant stimulating effect on water uptake of pigweed seeds over the 20‐h period as compared with the controls. A stimulation in the total quantity of water imbibed after 20 h was noted at dacthal concentrations below 100 mg/l whereas at the 500 mg/l, a slight depression in water imbibition was observed. At dalapon concentrations of 1 to 100 mg/l, a marked stimulation in total water imbibed by quackgrass seeds was shown during the 10‐h period.
Effect of Morphactin, Gibberellic Acid and Auxin and on Growth and Development of Bryophyllum tubiflorum
Authors: Nanda K. K. , Purohit A. N. , Kaura Neena 
Published: April 2006

Abstractsix month old LD‐ and SD‐ grown plants of Bryophyllum tubiflorum were treated with morphactin (n‐buty1‐9‐hydroxy‐fluorene‐(9)‐carboxylate), singly and in combination with GA3 and IAA.Morphactin and IAA decreased stem elongation and number of leaves, the effect increasing with concentration concentation. Morphactin also caused lateral buds to develop into branches and the fusion of upper leaves to form structures of different shapes. GA3 enhanced stem elongation, increased leaf number and induced floral buds under SD conditions. It reversed the inhibitory effect of morphactin on stem elongation, leaf number and leaf fusion and also restored apical dominance when applied simultaneously with morphactin. The stimulaneous application of IAA also reversed the morphactin effects on leaf fusion and on apical dominance.The results have been discussed in the light of literature available on the subject.
Rhizosphere Oxidation in Rice and other Species: A Mathematical Model Based on the Oxygen Flux Component
Authors: Armstrong W. 
Published: April 2006

AbstractA mathematical model is presented from which one can predict the likely dimensions of oxidised rhizospheres due to oxygen diffusing from roots into anaerobic media such as wet soil. The analysis applies Fick's law of diffusion to the diffusion of oxygen from a cylindrical object (the root) into a sink (the soil) which is absorbing oxygen at a constant rate M. Solution of the final equation gives the dimensions of the oxygenated rhizosphere, i.e. the distance from the root at which the oxygen concentration becomes zero.The results obtained supoprt the view that oxygen diffusing from roots will produce a rhizosphere ‘sheath’ charged with oxygen. Furthermore, some of the predicted limits for this oxygen sheath correspond with those of ferric iron sheaths around roots in waterlogged soils. Calculations also show that oxygenated rhizospheres around the roots of plants very tolerant of reducing conditions. e.g. Menyanthes trifoliata, Oryza sativa and Eriophorum angustifolium, should be from two to three times as broad as for Molinia coerulea which is a species intolerant of strong reducing conditions.Consequently if oxidation reactions are not instantaneous but occur only gradually as quantities of reduced products enter the oxygenated zone, then the plants with the larger rhizospheres will be significantly better protected from absorbing large amounts of reduced products than will those plants with smaller oxygenated zones. This may in part explain the reason for intervarietal defferences in physiological disease resistance in rice.Finally the observation is made that small lateral roots can be expected to oxygenate a zone nearly as large as, or probably larger, than the primary root from which they have arisen.
The Water Relations of Pinus sylvestris
Authors: Hellkvist Jerk 
Published: April 2006

AbstractComparative field studies of transpiration rate and drying‐transpiration in Scots pine were carried out in the autumns of 1964 and 1965 and in the early summer of 1966. The experimentl material was nineteen to twinty year old grafts, of the same clone but growing on different types of ground, or of different clones but growing in close proximity and under the same environmental conditions. Transpiration rates were measured on detached shoots. The results indicated that the type of ground did not very much modify the responses of the shoots to illumination‐darkness treatment.Drying‐transpiration is here defined as the transpiration occurring when detached shoots are prevented from water uptake. Measurements were made of the rate of loss of weight and the amount of water given off from illuminated shoots. Defferences were found both in the rate of weight loss, and in the amount of water given off, between pine trees of the same clone but growing on different types of ground, and between pine trees of different clones but growing on the same type of ground.
Further Evidence for the Relative Immobility of Water in Sieve Tubes of Willow
Authors: Peel A. J. 
Published: April 2006

AbstractGradients of tritiated water, 35S‐sulphate and 32P‐phosphate, were established in isolated segments of willow stems. Sieve tube exudate was collected as honeydew from the high activity end of the segment. After girdling the stem a few centimetres from the site of sieve tube puncture, the specific activity of 35S and 32P in the honeydew rose, whilst the specific activity of tritium remained constant.These findings indicate that prior to girdling, unlabelled sulphates and phosphates were contributing to the honeydew, whilst there had been no detectable contribution by unlabelled water from the low activity end of the segment.The data support the conclusions drawn from previous experiments by Peel et al. (1969), that water is relatively immobile in sieve tubes of willow when compared to solutes.
Light and Nitrate Requirements for Induction of Nitrate Reductase Activity in Hordeum vulgare
Authors: Travis R. L. , Jordan W. R. , Huffaker R. C. 
Published: April 2006

AbstractThe importance of light to the induction of nitrate reductase activity in barley (Hordeum vulgare L.) was studied. Activity in etiolated leaves in darkness stayed at a low endogenous level even while large amounts of nitrate were actively accumulated. Light was required for any increase in activity, though the requirement may be satisfied to a limited extent before nitrate is available. Nitrate reductase activity was induced in the dark in green leaves which had not previously had nitrate but were supplied nitrate at the beginning of the dark period. If the nitrate then made available was sufficient, nitrate reductase activity increased until the effect of the previous light treatment was exhausted. Activity then decreased even though nitrate uptake continued. Upon returning the leaves to light, enzymatic activity increased again, as expected.Nitrate uptake was eliminated as an experimental variable by giving dark‐grown plants nitrate, then detaching the leaves for induction studies. Under these conditions light saturation occurred between 3600 and 7700 lux at exemplary periods of illumination. At intensities of 3600 lux and above, activity increased sharply after a 6‐hour lag period. As light intensity was decreased below 3600 lux the lag period became longer. Thus, when sufficient nitrate was available, the extent of induction of nitrate reductase activity was regulated by light.
Uptake, Distribution and Translocation of 32P Absorbed through Roots of Cotton Seedlings as Affected with CCC Treatment
Authors: El‐Fouly Mohamed M. , Ismail A. A. , Abdalla F. E. 
Published: April 2006

AbstractThe effects of CCC on the 32 P amounts absorbed by cotton seedlings were studied. CCC was applied to the seedlings either as spray or as addition to the nutrient solution in concentrations of 0, 25, 50, 100 and 200 mg/1. 32P was added to the medium as KH232P O4 in the concentration of 40 μCi/50 ml.During the experimental period, no morphological changes were observed. The total 32P uptake was inhibited in CCC treated seedlings. The application of CCC, both as spray and as addition to the medium, led to an accumulation of 32P in stem, but to a decrease in root. The leaves showed different responses to different methods of application; spraying increased, while an addition of CCC to the medium decerases the 32P content in the leaves. It is concluded that CCC inhibits 32P uptake, whereas it ac accelerates the 32P translocation from root to the aerial parts.
Induction and Repression of β‐Galactosidase Synthesis by Verticillum albo‐atrum
Authors: Keen N. T. , Long Margaret , Malca Isaac 
Published: April 2006

Abstract Verticillium albo‐atrum grew on lactose‐containing culture media only after a prolonged lag phase. The intracellular specific activity of β‐galactosidase [EC 3.2.1.23] increased 40–200 times during he lag phase. The β‐galactosidase was induced by lactose and to a lesser degree by galactose. The appearance of the enzyme in lactose cultures was decreased by cycloheximide. Glucose and other readily metabolized carbon sources were effective repressors of β‐galactosidase production. The production of β‐galactosidase therefore appeared under control by lactose induction and catabolite repression.
The Effect of Colored Light on Pigment Synthesis in Cultured Fern Leaf Primordia
Authors: Haight Thomas H. , Kuehnert Charles Carroll 
Published: April 2006

AbstractThe effect of white, blue, yellow, red and far‐red light on the quantitative synthesis of the primary and auxilliary photosynthetic pigments in cultured leaf primordia of Osmunda cinnamomea L. is reported. The P660 form of the now classical photoreceptor pigment system, phytochrome, has been demonstrated to be active in chlorophyll synthesis in cultured cinnamon fern leaf primordia as shown by red/far‐red reversibility of chlorophyll synthesis. Also, it is apparent from the data presented that a blue absorbing pigment (P420) is responsible for the extensive accumulation of chlorophylls and carotenoids in these cultured leaves.
Fatty Acid Induced Leaking of Organic Compounds from Boletus variegatus
Authors: Lode Aaslaug , Pedersen T. A. 
Published: April 2006

AbstractAddition of octanoic acid (2· 10‐3M) to the suspending medium (final pH 4.85) of Boletus variegatus mycelium induced a marked leaking of UV absorbing substances from the cells. The material had an absorption maximum at 260 nm, a minimum at 240 nm, and the absorption ratios 250: 260 and 280:260 were 0.81 and 0.49.The material released immediately after addition of the acid consisted mainly of low molecular weight substances. These substances, listed according to decreasing rates of leaking, were identified as pentoses, pentosephosphates, nucleosides, and mono‐ and di‐nucleotides. Also, purine and pyrimidine bases were released at this early stage of treatment.After 90 minutes' treatment, an outflux of oligoribonucleotides was observed. The oligoribonucleotides did not occur as single substances, but were forming complexes with peptides. Minor amounts of ribonucleic acid were also leaking out from the cells. Deoxyribose containing substances were never observed in the filtrates.The compounds were subjected to enzymatic degradation after they had left the cells. This was shown by a marked increase with time of inorganic phosphorus, pentose/pentosephosphates, and nucleosides in the filtrate.The leaking of low molecular weight substances immediately after acid addition is correlated to seriously reduced growth. However, the growth was wholly restored after a three days' lag period. On the other hand, when considerable amounts of oligoribonucleotide peptides had been released from the cells, growth could not be re‐established.
Changes in Germination Responses of Silene secundiflora in Relation to the Climate of its Habitat
Authors: Thompson P. A. 
Published: April 2006

Abstract Silene secundiflora is a Mediterranean species restricted in range to the southern coasts of Spain and the Balearic Islands. Germination tests were made in incubators and on thermo‐gradient bars to evaluate changes in temperature‐responses at intervals after seed harvest. Results were compared to average temperatures occurring in the region and interpreted in relation to the climatic characteristics of the area.Germination of freshly harvested seed was restricted to a narrow temperature band between ca. 7 and 16°C. After‐ripening during the first four months resulted in a progressive widening of the temperature band favouring germination, but this remained below average summer temperatures. Exposure of imbibed seed to high temperatures (31°C) reduced the subsequent temperature maximum for germination by about 4°C, but did not induce a fully effective secondary dormancy. The results appeared to be well correlated with a situation in which germination normally occurs in September at the start of the winter growing season.
Interactions between Peroxidases, Polyphenoloxidases and Auxin‐Oxidases
Authors: Pilet P. E. , Lavanchy P. , Sevhonkian S. 
Published: April 2006

AbstractRoot extracts, prepared from young Lens culinaris seedlings, are analysed after a gel chromatography on Sephadex G‐25 and G‐100.IAA‐oxidase, peroxidase and polyphenoloxidase activities were found in the same fractions.
Penetration, Retention and Transport of Foliar Applied Single Salts of Na, K, Rb and Cs
Authors: Levi E. 
Published: April 2006

AbstractThe penetration, retention and transport of foliar applied chloride salts of Na‐22, K‐43, Rb‐86, and Cs‐134 were studied under controlled environmental conditions. Penetration although occurring at different rates was found to be non‐selective and appears to be a passive free diffusion process. Retention in the treated area is similar for Na, K and Rb and greater for Cs. Transport of these elements away from that area and in the plant was greatest and fastest for Na and Rb and slower for Cs and K. Distribution in the plants following leaf treatment was similar for K, Rb and Cs but no significant upward transport was noted for Na. Losses from roots were greatest for Na. No significant K could be detected in the culture medium 4 days after treatment of the leaves.
Influence of Deleterious Concentrations of Copper on the Growth of Chlorella pyrenoidosa
Authors: Nielsen E. Steemann , Kamp‐Nielsen Lars 
Published: April 2006

AbstractThe effect of deleterious concentrations of ionic Cu on the growth of Chlorella pyrenoidosa has been studied. An earlier paper showed a distinct effect of the same concentrations on the photosynthesis of the alga. Several substances, e.g. Fe and citric acid counteract the effect of Cu. In media ordinarily used for growing unicellular algae the influence of Cu is relatively slight due to the extraordinarily large concentrations. of Fe. At a concentration of 6 μg/I Fe – near to that in nature –even one μg/I Cu significantly decreases the growth during the first 24 hours. Cu is adsorbed to the negative charges on micelles of Fe(OH)3 created in the alkaline medium. Citric acid is readily assimilated by Chlorella and thus counteracts the influence of Cu for only relatively short period.Cell concentration is of decisive importance for the deleterious influence of Cu on growth. The effect of a certain Cu concentration stops at a certain concentration of of the algae regardless of whether the experiment is started at this cell concentration or this concentration is attained during the experiment. This is due to the binding of Cu by the organic matter of cell walls and slime envelopes.H+ ions compete with Cu both when combining with the organic matter in the cell walls and when occupying the active sites of the cell membranes. The latter explains the fact that the influence of Cu is only slight at pH 5 compared with that at pH 8.At a Cu‐concentration where no growth of algae can take place, the algae are by no means killed. After being transferred to an ordinary medium the algae start to grow again.The influence of Cu depends on the division stage of the algae. If the initial steps of cell division have taken place, the cell continues to divide.
Mechanism of Zinc Uptake in Bean (Phaseolus vulgaris) Tissues
Authors: Rathore V. S. , Wittwer S. H. , Jyung W. H. , Bajaj Y. P. S. , Adams M. W. 
Published: April 2006

AbstractUptake of micronutrient zinc by intact leaves, enzymically isolated leaf cells, leaf disks, excised roots, and stem‐callus tissue of two field bean cultivars 'Saginaw’ and ‘Sanilac’) was studied using radio‐isotope tracer technique. Radio‐phosphorus absorption by these tissues was also followed under comparable experimental conditions. A rapid absorption of the micronutrient and strong dependency on external zinc concentration and pH were revealed. Absorption of zinc was not inhibited by respiratory inhibitors (dinitrophenol, azide, cyanide, and amytal), and was not light or temperature dependent. Q10 values for zinc uptake ranged between 1 and 1.2. Uptake of phosphate, on the other hand, was temperature and light dependent and drastically reduced by the presence of metabolic inhibitors.Differences in responses to respiratory inhibitors, temperature, pH, light and darkness, and kinetic data, strongly suggest that zinc uptake in bean tissues occurs primarily by a passive mechanism, involving possibly a physical or physiochemical binding of the micronutrient ions to the cell wall and free space components, and a passive diffusion into the interior of the cell.
Effects of Pyrocatechol on Some Metabolic Processes of Mature Sugar Beet (Beta vulgaris) Plants
Authors: Singh B. , Wort D. J. 
Published: April 2006

AbstractPyrocatechol (PC), 10‐2M, was applied to the foliage of mature plants of sugar beet (Beta vulgaris L.). Its effect on the activity of nitrate reductase, transaminase, invertase, phosphatases, sucrose synthetase, sucrose phosphate synthetase, and UDPG‐pyrophosphorylase were determined 7, 14, and 21 days after treatment. Significant reductions in the activity of nitrate reductase, transaminase, invertase, and phosphatases (including phenyl phosphatase, glucose‐1‐, glucose‐6‐, fructose‐6‐phosphatase, and adenosine triphosphatase) in the treated plants occurred. On the other hand, activities of the enzymes of sucrose biosynthesis, uridine, diphosphate glucose pyrophosphorylase (UDPG‐pyrophosphorylase), sucrose synthetase, and sucrose phosphate synthetase were significantly stimulated by the application of pyrocatechol. The results suggest that the growth inhibition following the application of PC to sugar beet plants may stem in part from an amino acid stress resulting from a PC‐induced decrement in nitrate reductase and transaminase activity. Its application also creates an enzymatic condition favorable for sucrose biosynthesis and storage.
Germination et culture aseptique de Thlaspi sylvestre Jord. subsp. calaminare (Lej.) Maly
Authors: Méalotte R. , Ramaut J. L. 
Published: April 2006

AbstractWe have studied the action of different zinc concentrations (10, 50 and 100 mg/l) on the germination of Thlaspi seeds and on the seedlings obtained from them when grown on water containing the same zinc concentrations.It appears that the 10 mg/l zinc concentration enhances slightly the percentage germination and that the 50 mg/l concentration is the optimum one for the growth of the seedlings. Therefore it seems that the normal growth of a plant growing on a “calamine soil” demands a given quantity of zinc, the optimum being in the neighbourhood of 50 mg/l.
Selectivity and Ion Transport in Excised Bean Hypocotyls
Authors: Waisel Y. , Neumann Ruth , Kuller Z. 
Published: April 2006

AbstractIon transport and ion selectivity in bean hypocotyl slices were investigated. The transport mechanism is practically independent of temperature and in short term experiments appears to be non‐metabolic.Selectivity may be attributed either to specific adsorption sites or to the properties of the diffusion barrier. The fact that with a physical transport mechanism selectivity is observed only under physiological temperature conditions hints that a flexible barrier (plasmalemma?) rather than fixed adsorption sites should be regarded as governing the process.
Root Growth Inhibition by Siduron and Its Relief by Kinetin
Authors: Splittstoesser Walter E. , Hopen Herbert J. 
Published: April 2006

AbstractThe growth of crabgrass (Digitaria ssp.) and barley (Hordeum vulgare) seedlings was susceptible to injury by siduron (1‐2(methylcyclohexyl)‐3‐phenylurea). In both species, root growth was inhibited more than shoot growth and if a functional root system was developed before coming into contact with siduron the plant survived.Kinetin partially overcame the effect of siduron on root growth and increased root length and the number of cells undergoing mitosis per root tip. The effect of siduron seems specific to cell division.
Conversion of Various Substrates to Ethylene by Flowers
Authors: Phan Chon‐Tǒcn 
Published: April 2006

AbstractThe emanation of Petunia (Petunia hybrida) flowers fed with various substrates has been found to be a mixture of at least four gaseous components, one of which being ethylene. The relative proportions of these gases change with the substrate, which therefore means that the compounds generally accepted as ethylene precursors are not all converted primarily into ethylene.
Colony Size of Tuberolachnus salignus (Gmelin) in Relation to Mass Transport of 14C‐labelled Assimilates from the Leaves in Willow
Authors: Peel A. J. , Ho L. C. 
Published: April 2006

AbstractWillow cuttings were used in which u narrow, longitudinal strip of bark was removed commencing from the base of the leafy shoot. Aphid colonies of different sizes were then sited on the stem either side of the strip, 10 cm below the base of the shoot. The leaves were allowed to assimilate 14CO2, and the dry weight and total activity of the honeydew from each colony was measured over a given period of time.It was found that not only did the total activity from the large colony exceed that of the small colony, but that the specific activity of the honeydew from the large colony was higher than that from the small colony. This has been taken as evidence that neighbouring pierced sieve tubes do not act independently of each other; mutual interference occurs. Increasing the distance between pierced sieve elements by dispersing the members of the large colony over a greater area of stem, did not apparently reduce interference effects.The results are explained in relation to the magnitude of the contributory length (Peel and Wealherley 1962), of individual sieve tubes pierced by the large, as opposed to the small colony.