bluuebunny/crossref_metadata_2025_split huggingface dataset:
CLASSICAL DATA ON THE GROWTH OF MAIZE: CURVE FITTING WITH STATISTICAL ANALYSIS
Authors: HUNT RODERICK , EVANS G. CLIFFORD 
Published: May 2006

SUMMARYA new method of fitting curves to long sequences of data from successive harvests from populations of growing plants is applied to the classical data of Kreusler and his co‐workers on the growth of maize, carried out near Bonn in 1875 to 1878. The method effectively divides the data into phases, which are fitted by splined cubic polynomials meeting in‘knots’where adjacent curves agree in position, slope and rate of change of slope, thus ensuring smooth transitions and minimizing loss of degrees of freedom. The phases can be chosen on some physiological or morphological criteria, or (as here) best positions for knots can be determined statistically by a method which minimizes sums of squares of deviates.The curves are fitted to the natural logarithms of the primary data on dry wt and leaf area, and relative growth rates, leaf area ratios and unit leaf rates are derived by manipulating the equations of the original fitted curves. All these curves are presented for five varieties grown in 1875 and one variety grown from 1875 to 1878. A full statistical apparatus gives confidence limits for all the interpolated points along all these curves. The variances are homogeneous along any one of the sixteen original fitted curves, and taken as a whole the data show remarkable statistical uniformity, reflecting great credit on the experimental planning and execution a century ago.The fitted curves and their derivates show a large measure of agreement on common developmental progressions, with differences from variety to variety and year to year. Detailed examination shows that a number of these differences, particularly cases involving only a short sequence of harvests, were almost certainly due to deficiencies in the original data, the fitted curves and their associated statistics being valuable in detecting these. At the same time no serious example was detected of the fitting program injecting features not present in the primary data; but one minor example, not affecting specific conclusions, shows how necessary it is always to be on guard.
EFFECT OF CHLORAMPHENICOL ON GROWTH, CHEMICAL COMPOSITION AND CHLOROPHYLL CONTENT OF INTACT PLANTS
Authors: SMITH G. S. , EDMONDS A. S. , MIDDLETON K. R. 
Published: May 2006

SUMMARYThe growth of perennial ryegrass and lucerne was inhibited by d‐threo‐chloramphenicol at concentrations generally considered safe for preventing bacterial contamination. Inhibition of growth was the result more of a reduction in photosynthetic activity than of a specific effect on ion absorption. Young plants were more susceptible to chloramphenicol than older plants and the cumulative effect of repeated applications of the bactericide at low concentrations depressed growth and chlorophyll content to the same extent as a single concentrated application. The present results have been related to known effects of chloramphenicol on protein synthesis, leading to the conclusion that its use to prevent bacterial contamination in studies on the growth of green plants is inadvisable. Recognition of this fact makes suspect much published work where chloramphenicol has been used for this purpose.
THE SERIAL OBSERVATION OF EMBRYOGENESIS IN A CARROT CELL SUSPENSION CULTURE
Authors: FUJIMURA TATSUHITO , KOMAMINE ATSUSHI 
Published: May 2006

SUMMARYSerial observations were made of the early stages of somatic embryogenesis in a cell suspension culture of carrot (Daucus carota L. cv. ‘Kurodagosun’) using a series of cell clusters which divided synchronously. Three phases were recognized in each of which the rate of cell division was different: the first phase (0 to 3 days) during which cells divided slowly, the second phase (3 to 4 days) during which cells divided very rapidly in the determined locus of the cell cluster, leading to the formation of globular embryos, and the third phase (4 to 6 days) during which cell division occurred at a slower rate than the second phase. Three regions were distinguishable in the cell clusters at the end of the second phase: a transparent region destined to develop into the shoot, an opaque region destined to develop into the root and another opaque region which had ceased to grow, suggesting that the determination of differentiation had already occurred by the end of the second phase. The rapid cell division which occurred in the second phase is considered to be a characteristic event in embryogenesis.
BRANCHING PATTERNS IN FOREST SHRUBS AND UNDERSTORY TREES IN RELATION TO HABITAT
Authors: PICKETT S. T. A. , KEMPF J. S. 
Published: May 2006

SUMMARYWe investigated the branching and leaf display of dominant forest shrubs and understory trees in central New Jersey to determine (1) whether branching differentiation occurs in shrubs which reach optimum development in different successional environments, (2) the contrast in branching of small trees between field and forest and (3) the nature of within‐crown branching plasticity in a mature canopy tree. We discovered that shrubs do not differ in gross branching structure (ratio of terminal to supporting branches) and propose that branch angle, length and alteration of leaf orientation may be significant display characters. Small trees exhibit markedly variable response to open ν. closed habitats, confirming the expected increase in branching ratio in open environments. Within, but not outside, the forest, earlier successional species were more variable in branching. A single canopy tree crown also demonstrated alteration of leaf display components, including increased length and wider angle of branches, but not branch ratio in the shaded, lower crown. We suggest some of the fine‐scale morphological traits of shrub branching which may be important in determining their leaf display. Finally, we discuss differences in shrub and tree habit, such as cloning and the presumably reduced costs of support in shrubs, which may explain the failure of shrubs to exploit the same component of branching strategy as trees.
THE EFFECT OF FESTUCA RUBRA ON SIZE, LEAF DEMOGRAPHY AND REPRODUCTIVE CAPACITY OF VULPIA FASCICULATA
Authors: ROGERS R. W. 
Published: May 2006

SUMMARYThe effect of a perennating population of Festuca rubra on a population of Vulpia fasciculate, in which a second generation was grown using seeds produced by the first, was observed over 2 years. After one season, there was no apparent effect of F. rubra on performance of V. fasciculata as measured by leaf number, total length of leaf produced, number of seeds produced, dry wt of individuals, and dry wt of propagules. Within V. fasciculata populations, it was possible to follow life histories of individual plants and their leaves. Plants which germinated later remained smaller than early germinants, additional nutrients exaggerating this effect. Sixty seven per cent of the variance in total length of leaf produced by a plant in its life could be accounted for in terms of leaf number. It appears that counting leaf number, or measuring length of leaf produced, is a suitable method for studying interactions between grasses and the manner in which these change with time without the need for destructive harvesting. After a second year of growth and interaction, F. rubra severely reduced the dry wt and percentage of V. fasciculata plants able to flower. This was probably due to root interaction and not to exhaustion of nutrient reserves in the seed.
BORON, LIGNIFICATION AND THE ORIGIN OF VASCULAR PLANTS‐A UNIFIED HYPOTHESIS
Authors: LEWIS D. H. 
Published: May 2006

SUMMARYIt is proposed that the development of an essential role for boron was a prerequisite for the evolution of vascular from prevascular plants since there is a prima jade case that a primary role of boron concerns the biosynthesis of lignin and, in conjunction with auxin, differentiation of xylem. In particular, a potential role for borate in regulating the hydroxylase and oxidase activities of the phenolases involved in the biosynthesis of caffeic and hydroxyferulic acids is suggested. The origin of this role for boron depended on the selection of sucrose in the Chlorophyta as a mobile and storage carbohydrate since, compared with the acyclic sugar alcohols accumulated in other algal groups, sucrose forms only a very weak complex with borate. It is argued that only when borate was not sequestered by complexing with other carbohydrates did the way become clear for it to acquire an essential role. This acquisition catalysed the evolutionary dichotomy between non‐lignified and lignified photosynthetic land‐plants, the bryophytes and tracheophytes. Boron subsequently became involved in two other requirements for success on land ‐ the exploitation of soil for anchorage, water and minerals, and the emancipation of fertilization from external water‐since this element is required for development of adventitious roots (again in conjunction with plant hormones) and, in angiosperms, for germination of pollen.
THE ROLE OF LEAVES IN AUXIN AND BORON‐DEPENDENT ROOTING OF STEM CUTTINGS OF PHASEOLUS AUREUS ROXB.
Authors: MIDDLETON W. , JARVIS B. C. , BOOTH A. 
Published: May 2006

SUMMARYThe promotion of rooting of cuttings of Phaseolus aureus by indolebutyric acid (IBA) occurs only when leaves are present. IBA may have some direct action on root initiation in the hypocotyl but its main action is in the leaves where it leads to an early increase in free sugars. A later increase in sugars in the hypocotyl is largely dependent on exogenous boron which is essential for root development in cuttings of light‐grown material. IBA also stimulates and boron promotes the accumulation of l4C in hypocotyls when [l4C]sucrose is applied to the leaves. These events occur before roots develop on the hypocotyl. Illumination of the leaves of cuttings during the rooting treatment (IBA for 1 day, followed by boron for 6 days) is beneficial for root development. A progressive loss of response to IBA and boron by cuttings aged in water prior to the rooting treatment is greater in cuttings with leaves in the light during the period of ageing than with leaves in darkness. Possible roles of leaves, auxin and boron in rooting are discussed.
DISTRIBUTION OF ATPASE IN CELLS OF SALICORNIA PACIFIC A VAR. UTAHENSIS AS DETERMINED BY LEAD PHOSPHATE PRECIPITATION AND X‐RAY MICROANALYSIS
Authors: WEBER D.J. , HESS W. M. , KIM CHONG KYUN 
Published: May 2006

SUMMARY Salicornia pacifica stem tissues were treated with ATP, Ca(NO3)2 and Pb(NO3)2 to localize ATPase. ATPase activity was present along the plasma membranes and in the cytoplasm of the cortical palisade, inner cortex and vascular cells of young shoots. ATPase was also present in the plasma membranes of tracheids which are present in the palisade region. Ouabain did not inhibit ATPase, but NaF‐, crown ethers, and N.N′‐dicyclohexyl carbodiimide (DCCD) did so in vitro. Only DCCD significantly inhibited (82 %) ATPase in tissues processed for electron microscopy. Energy dispersive microanalysis was used to verify that the precipitates were Pb phosphate.
THE KINETICS OF REHYDRATION OF DETACHED SUNFLOWER LEAVES FOLLOWING SUBSTANTIAL WATER LOSS
Authors: CRUIZIAT P. , TYREE M. T. , BODET C. , LoGULLO M. A. 
Published: May 2006

SUMMARYThe rate of rehydration of sunflower (Helianthus annuus L.) leaves was measured after dehydration (in air or in a pressure bomb) down to a relative water content of about 89 %. The results, when plotted as the log of the rate of rehydration (mg min‐1) against time, displayed an unusual shoulder in which a phase with a long half time was succeeded by a phase with a short half time. The rehydration kinetics can be explained by two cellular compartments in series in which the bulk elastic modulus increases substantially during rehydration. The first compartment might be associated with the phloem and bundle sheath cells. Water rehydrating the second compartment, consisting of the remainder of the leaf cells, must pass through the first compartment by a transcellular pathway.
VISUALIZATION OF PHOSPHATE ACCUMULATION IN BEECH MYCORRHIZAS
Authors: Chilvers G. A. , Harley J. L. 
Published: May 2006

SUMMARYHistochemically monitored uptake experiments, using strips of fungal sheath dissected from beech (Fagus sylvatica) mycorrhizas and incubated in phosphate solutions under a range of conditions, show that accumulation of phosphate is closely paralleled by increases in the number and size of polyphosphate‐containing metachromatic granules, suggesting that these granules represent a major pool of storage phosphate.
SEASONAL CHANGE IN THE PATTERN OF NET CO2 EXCHANGE IN UMBILICARIA LICHENS
Authors: LARSON D.W. 
Published: May 2006

SUMMARYThe response of net photosynthesis and respiration in five species of Umbilicaria to thallus moisture content at three temperatures (0, 14, 28 °C) and four light intensities (0, 100, 330, 700 μmol m‐2 s‐1) was studied in collections made in summer and winter.The pattern of response to these variables suggests that each species is uniquely adapted to the cliff environments in which they grow. A simple model suggests further that each species can maintain a positive energy balance provided that its distribution does not extend to sites with temperatures in excess of certain values.None of the species show photosynthetic acclimation to temperature, yet they all exhibit large seasonal changes in their response structures. The significance of such patterns is discussed.
THE PLASMALEMMA STRUCTURE IN THE PHYCOBIONT TREBOUXIA AT DIFFERENT STAGES OF HUMIDITY OF A LICHEN THALLUS
Authors: Peveling E. , Robenek H. 
Published: May 2006

SUMMARYUsing the freeze‐fracture technique, the plasmalemma structure of the phycobiont Trebouxia was observed to depend on the hydration of the thallus. The EF and PF fracture faces showed characteristic ridges and corresponding grooves as well as intramembranous particles found in plasmalemma membranes. After prolonged drying of the thallus, the particles were reduced in both number and size and they became reorganized after moistening for a few hours. The ridges appear most distinct and close in dry stages while they are almost completely overlayed by particles in moist thalli. The possible significance of the findings is discussed.
THE EFFECTS OF STARVATION ON THE SYMBIOTIC CHLOROPLASTS IN ELYSI A VIRIDIS: A FINE STRUCTURAL STUDY
Authors: Hawes C. R. , Cobb A. H. 
Published: May 2006

SUMMARYAn ultrastructural approach was used to study the effects of light and dark starvation on chloroplasts symbiotic in the mollusc Elysia viridis.Starvation for 27 days in a 16 h light/8 h dark photoperiod resulted in loss of starch grains and a gradual disintegration of the chloroplasts by a progressive increase in the inter‐thylakoid spaces, resulting in the separation and degeneration of the photosynthetic membranes. To account for these observations a process of photodestruction is suggested.Chloroplasts in animals starved in total darkness for a corresponding period remained relatively intact, and showed a marked increase in the number of plastoglobuli per chloroplast. This increase in plastoglobuli may be a result of the normal ageing process of chloroplasts with a redundant photosynthetic apparatus.
EVOLUTIONARY IMPLICATIONS OF THE DISTRIBUTION AND ECOLOGY OF THE TROPICAL CONIFER AGATHIS
Authors: WHITMORE T. C. , PAGE C. N. 
Published: May 2006

SUMMARY Agathis is one of two genera of a taxonomically isolated southern hemisphere conifer family, Araucariaceae. The geographical range and ecological niches of the thirteen species are briefly described. On the Gondwanic fragments of north Queensland and New Caledonia there are respectively three and five sympatric species mostly with a different habitat. Elsewhere, from New Zealand and Fiji west throughout the Malay archipelago to Sumatra, the species are (with one minor exception) allopatric and all show ecotypic differentiation. In Malesia Agathis only dominates and regenerates in situ in forests on poor sites but in Melanesia it is not restricted in this way. The hypothesis is put forward that Agathis has expanded its range from these two Gondwanic centres and is most successful in competition with angiosperms in relatively species‐poor forests.
THE RELATIONSHIP OF MYCORRHIZAL INFECTION TO PHOSPHORUS‐INDUCED COPPER DEFICIENCY IN SOUR ORANGE SEEDLINGS*
Authors: TIMMER L. W. , LEYDEN R. F. 
Published: May 2006

SUMMARYIn an initial experiment, inoculation of sour orange (Citrus aurantium L.) seedlings in sand with Glomus fasciculatus greatly increased growth with or without fertilization with P or Cu. Application of P or Cu to non‐mycorrhizal seedlings in sand did not stimulate growth. Application of P to non‐mycorrhizal seedlings in a sandy loam soil increased growth, but induced Cu deficiency symptoms and reduced foliar Cu concentrations. Application of P to mycorrhizal seedlings did not induce Cu deficiency symptoms, but reduced foliar Cu concentrations slightly. In a complete factorial experiment, sour orange seedlings in the sandy loam soil, were inoculated with G. fasciculatus or not inoculated, fertilized with 5 levels of P from 0 to 800 mg P 1‐1 of soil and 3 levels of Cu from 0 to 8.6 mg 1‐1. Non‐mycorrhizal seedlings, which received no Cu, developed copper deficiency symptoms which were most severe at 200 mg P 1‐1. Copper deficiency symptoms did not appear on the seedlings receiving no P because seedlings failed to grow. Deficiency symptoms disappeared and foliar Cu concentrations increased when seedlings were fertilized with P at 800 mg 1‐1 probably because the high rates of P decreased the pH making Cu more soluble. On seedlings inoculated with G. fasciculatus and not fertilized with Cu, increasing rates of P decreased percentage mycorrhizal infection, the number of chlamydospores per g of soil, and the foliar Cu concentrations. Copper deficiency symptoms occurred only at 800 mg P 1‐1 and were mild. No Cu deficiency symptoms occurred and foliar Cu concentrations were in the optimum range where Cu was applied. Apparently, P induces Cu deficiency by stimulating growth of non‐mycorrhizal seedlings until Cu becomes the limiting nutrient, whereas, P‐induced Cu deficiency appears to be due to P inhibition of mycorrhizal development on seedlings inoculated with G. fasciculatus.
EFFECT OF VESICULAR‐ARBUSCULAR MYCORRHIZA ON CITRUS JAMBHIRI WATER RELATIONS
Authors: LEVY YOSEPH , KRIKUN JAMES 
Published: May 2006

SUMMARYRecovery from water stress was studied on similarly sized VA mycorrhizal and non‐mycorrhizal rough lemon seedlings (Citrus jambhiri Lush). VA mycorrhiza affected stomatal conductance, photosynthesis and proline accumulation, but not leaf water potential, suggesting that most of the effect of the mycorrhizal association is on stomatal regulation rather than on root resistance.
EFFECTS OF AMMONIUM AND NITRATE IONS ON MYCORRHIZAL INFECTION, NODULATION AND GROWTH OFTRIFOLIUM SUBTERRANEUM
Authors: CHAMBERS C. A. , SMITH S. E. , SMITH F. A. 
Published: May 2006

SUMMARYAddition of combined nitrogen decreases vesicular‐arbuscular mycorrhizal development in youngT. subterraneumplants. Ammonium ions, added as (NH4)2SO4, are more effective than nitrate ions, added as NaNO3. Addition of Na2SO4as a control treatment also decreases infection, suggesting a less specific ‘salt effect’ underlying the responses to combined nitrogen. Inhibition of nodulation and nitrogenase activity occurs (as is normal) in the presence of combined nitrogen.These effects have been studied as a function of time (10 to 30 days), using a range of external concentrations. Different methods of application (surface addition versus mixing throughout the soil) have been tested. Effects on the levels of N, K+and Na+in the plants have also been determined.The results are discussed in relation to the effects of ammonium nitrogen and nitrate nitrogen on the mineral nutrition of plants, especially within the context of the influence of vesicular‐arbuscular mycorrhizas on plant growth.
THE EFFECT OF COPPER ON NITROGEN FIXATION IN SUBTERRANEAN CLOVER (TRIFOLIUM SUBTERRANEUM)
Authors: SNOWBALL K. , ROBSON A. D. , LONERAGAN J. F. 
Published: May 2006

SUMMARYCopper deficiency decreased nitrogen fixation in subterranean clover. Three lines of evidence support this conclusion. Firstly, while both copper and nitrogen application increased the growth of the legume the interaction between copper and nitrogen on growth was negative. Secondly, the application of copper increased the concentrations of both total and protein nitrogen in the plant. Lastly, nitrogen fixation as measured by the acetylene reduction assay increased with copper application to the soil.
HEAVY METAL CO‐TOLERANCE IN A COPPER‐TOLERANT POPULATION OF THE MARINE FOULING ALGA, ECTOCARPUS SILICULOSUS (DILLW.) LYNGBYE
Authors: HALL A. 
Published: May 2006

SUMMARYThe growth of individuals from a copper‐tolerant and a non‐tolerant population of Ectocarpus siliculosus (Dillw.) Lyngbye, in media containing copper (0.10 mg 1‐1), cobalt (0.10 mg 1‐1), zinc (0.25 mg 1‐1) or cadmium (1.50 mg 1‐1) was measured using a wet wt method. The copper‐tolerant population was found to have an increased tolerance to cobalt and zinc, in addition to a high tolerance to copper. It is believed that the copper tolerance mechanisms, or other physiological processes, typical of the fouling population, are the basis of this co‐tolerance. The importance of a general tolerance to heavy metals in a major fouling alga is noted.
A GENECOLOGICAL STUDY OF PUCCINELLIA MARITIMA HUDS. (PARL.) I. VARIATION ESTIMATED FROM SINGLE‐PLANT SAMPLES FROM BRITISH POPULATIONS
Authors: GRAY A. J. , SCOTT R. 
Published: May 2006

SUMMARYBy means of a replicated clone trial of 56 plants taken at random from six geographical regions a preliminary assessment was made of variation in Puccinellia maritima (Huds.) Parl., the predominant grass species on British salt marshes. We found significant differences between genotypes in the mean values for 19 morphological and flowering characters. The variation between genotypes was further examined using a correlation matrix of these values (plus seed weight). The first three principal components extracted from the matrix defined variation trends in vegetative biotype, yield, and reproductive strategy respectively. Graphic representations revealed that variation on the vegetative biotype component, a measure of tillering rate, overall plant leaf size, and the tendency to produce either a few large or many small tillers, was associated with variation in growth habit (erectness) and that genotypes originally collected from grazed salt marshes tended to be fast‐tillering, small, short‐leaved, and prostrate. Variation in yield (dry‐matter production) appeared to be related to the soil nutrient status of the site of collection, the relatively high yielding genotypes generally coming from mature marshes at higher elevations. There is no evidence of an effect of grazing on the reproductive strategy component, which measured the relative allocation of resources to flowering or vegetative tillers, but, probably through its association with date of ear emergence, variation on this component had an apparently regional basis.Estimates of genetic coefficients of variation and heritability suggested that much of the variation was genetically controlled and indicated, for example, that date of ear emergence was genetically more variable and had a higher heritability than date of anthesis. These results indicated that, in future trials, measurement on only three occasions of only eight characters would provide a reasonable estimate of the variation within and between populations of the species.