bluuebunny/crossref_metadata_2025_split huggingface dataset:
TOLERANCE OF ANOXIA AND THE METABOLISM OF ETHANOL IN TREE ROOTS
Authors: CRAWFORD R. M. M. , BAINES MARGARET A. 
Published: May 2006

SUMMARYEthanol can always be detected in the trunks and roots of forest trees and in the roots of pot‐grown tree‐seedlings under both flooded and unflooded conditions. The constant presence of this anaerobic product indicates that tree‐roots and trunks exist continually in a state of total or partial anoxia. In forest trees the ethanol content at the base of the tree trunk was correlated significantly with that found in the roots and fluctuated throughout the year, reaching a maximum in winter and early spring. The highest values were noted in trees exposed to the greatest amount of flooding. Pot‐grown trees of Pinus contorta and Picea sitchensis showed an immediate reaction to anoxia with a simultaneous increase in root ethanol content when placed in unaerated water culture. In the flood‐intolerant P. sitchensis anoxia induced a twelve‐fold increase in ethanol and this attained 5 μmoles g−1 fresh weight, while over the same period the ethanol in the roots of the flood‐tolerant Pinus contorta increased only three‐fold to 0.7 μmoles g−1 fresh weight. These species provide another example of flooding tolerance being found in association with the ability to limit ethanol production.
LONG TERM CULTURE METHODS FOR THE PRODUCTION OF ISOTOPICALLY LABELLED PLANT MATERIAL
Authors: KNIGHT A. H. 
Published: May 2006

SUMMARYThe culture of isotopically labelled plant material for subsequent experimental use is described. The isotopes used were 65Zn in ryegrass for chemical composition analysis related to animal nutrition, 22Na and 36Cl in beetroot for plant physiological ionic studies, 59Fe in wheat grain for human metabolic studies, 45Ca in wheat for subsequent germination and the study of calcium distribution in seedling roots, and 14C in plant material for production of labelled humic substances. Consideration is given to the various factors involved, such as methods of incoporation of label into the plant, radiation damage, levels of specific activity and double labelling.
NITRATE REDUCTION BY WHOLE CELLS OF ANKISTRODESMUS BRA UNII AND CHLAMYDOMONAS REINHARDI
Authors: HIPKIN C. R. , SYRETT P. J. 
Published: May 2006

SUMMARYMethods are described for the assay of nitrate reductase in frozen/thawed cells of Ankistrodesmus braunii and Chlamy domonas reinhardi. Because Ankistrodesmus nitrate reductase can use NADPH as an electron‐donor and because the cells of Ankistrodesmus contain a high concentration of glucose‐6‐phosphate, it is suggested that, in frozen‐thawed cells, nitrate reduction is coupled, through NADPH, to the oxidation of glucose‐6‐phosphate. With Chla‐mydomonas cells either exogenous NADH or reduced FMN can act as reductant. The permeability of Chlamy domonas cells can also be increased by glycerol treatment and this makes assay of nitrate reductase possible without freezing and thawing.
THE GROWTH CURVE OF THE CRUSTOSE LICHEN BUELLIA CANESCENS (DICKS.) DE NOT.
Authors: PROCTOR M. C. F. 
Published: May 2006

SUMMARYGrowth curves for Buellia canescens have been constructed using photographic measurements of thalli in situ over yearly intervals. The curves approximate to a simple model based on the assumption that relative growth rate is proportional to the area of thallus in an annulus of constant width within the growing margin.
THE CYTOLOGY OF PLANTLETS DERIVED FROM CULTURED ANTHERS OF NICOTIANA SYLVESTRIS
Authors: McCOMB J. A. , McCOMB A. J. 
Published: May 2006

SUMMARYCultured anthers of Nicotiana sylvestris produced 70% haploid, 14% diploid, 8% triploid, 2% tetraploid and 6% mixaploid plantlets. Immediately pre‐mitotic anthers produced no plantlets; mitotic and immediately post‐mitotic ones did so. Stage of anther development at initiation of culture was not related to production of non‐haploids. Embryoids arose from divisions of the vegetative nucleus. In microspores containing globular embryoids 0, 1 or 2 nuclei derived from the generative nucleus could be recognised; these, however, contributed few if any viable cells to the developing plantlets. Metaphase plates with higher than the haploid number of chromosomes were seen and probably arose through nuclear fusion at an early stage.
A LONG SUB‐FOSSIL OAK TREE‐RING CHRONOLOGY FROM THE NORTH OF IRELAND
Authors: PILCHER J. R. , HILLAM J. , BAILLIE M. G. L. , PEARSON G. W. 
Published: May 2006

SUMMARYA 2990 year floating tree‐ring chronology has been constructed using bog oaks from low altitudes in the north east of Ireland. The basic building blocks of this chronology are site chronologies made from the ring patterns of trees from individual sites. The construction of site chronologies and of the 2990 year master chronology are described. Applications of this chronology and its extensions include radiocarbon calibration which is already under way, stable isotope measurements for palaeotemperature estimation, and climatic interpretations based on the ring widths.
THE DEVELOPMENT OF ENDOMYCORRHIZAL ROOT SYSTEMS: I. SPREAD OF INFECTION AND GROWTH‐PROMOTING EFFECTS WITH FOUR SPECIES OF VESICULAR‐ARBUSCULAR ENDOPHYTE
Authors: SANDERS F. E. , TINKER P. B. , BLACK R. L. B. , PALMERLEY S. M. 
Published: May 2006

SUMMARYFour vesicular‐arbuscular endophytes were inoculated into onions cultured in soil in a growth chamber. Dry weight, root length, infected root length, phosphorus content and quantity of external mycelium were measured at intervals. Three endophytes produced similar hyphal inflows, growth increments and external mycelium. One endophyte produced no growth increase in the host, and had little external mycelium and slow increase in percentage infection.
PLANT GROWTH RESPONSES TO VESICULAR‐ARBUSCULAR MYCORRHIZA
Authors: MOSSE BARBARA 
Published: May 2006

SUMMARYThis paper reports results of inoculation with vesicular‐arbuscular (VA) endophytes in twelve unsterile soils with and without added rock phosphate or Hyperphosphat. Stylosanthes guyanensis, and in two soils also maize, were grown in pots and plant weight, P uptake, nodule weight and nitrogenase activity were measured at harvest.The introduced endophyte established well in all but one of the soils and inoculated plants with added phosphate grew best in eleven soils. Utilization of added rock phosphate was often considerably increased by inoculation but there was no evidence of increased availability. Inoculum density in the soil, rather than its phosphate status seemed to determine responses to VA inoculation, which were greatest in soils containing few indigenous endophytes. VA inoculation often stimulated nodulation by rhizobia but, in contrast to irradiated soils, there was no clear relationship between percentage plant P and nodulation. The results are discussed in relation to the possibility of field inoculation with VA endophytes.
COLORIMETRIC QUANTIFICATION OF VESICULAR‐ARBUSCULAR MYCORRHIZAL INFECTION IN ONION
Authors: BECKER W. N. , GERDEMANN J. W. 
Published: May 2006

SUMMARYA colorimetric method of estimating vesicular‐arbuscular mycorrhizal infection was developed and tested using onions inoculated with Glomus fasciculatus. Absorbances at 400 nanometers of water extracts from a series of mixtures of yellow (mycorrhizal) and white (nonmycorrhizal) roots had significant correlation with the percent yellow roots by weight in the mixtures. The percentage of mycorrhizal infection determined by a chitin assay or by a staining method was significantly correlated with the percentage of yellow roots by weight. The percentage of mycorrhizal infection determined by the colorimetric method was also significantly correlated with root/shoot ratios. The colorimetric method is offered as an alternative to the more time consuming quantitative methods of estimating the extent of vesicular‐arbuscular mycorrhizal infection now in use.
TRANSLOCATION INTO MATURE LEAVES–THE EFFECT OF GROWTH PATTERN
Authors: THROWER STELLA L. 
Published: May 2006

SUMMARYIn rosette plants, import of labelled assimilate by mature leaves is a normal part of the trans‐location pattern. Following elongation and loss of the rosette habit with the onset of flowering, the translocation pattern becomes that typical of elongate plants, characterised by lack of movement into mature leaves.
DIURNAL STOMATAL AND ACIDITY RHYTHMS IN ORCHID LEAVES
Authors: GOH C. J. , AVADHANI P. N. , LOH C. S. , HANEGRAAF C. , ARDITTI J. 
Published: May 2006

SUMMARYThe stomata of Arachnis cv. Maggie Oei, Aranda cv. Deborah, Arundina graminifolia, Bromheadia finlaysoniana, Cattleya bowringiana×C. forbesii and Spathoglottis plicata (Orchidaceae) occur only on the lower epidermis of the leaves and are located within hyperstomatic chambers formed by cuticular ledges extending from the guard cells. Arachnis, Aranda and Cattleya have thick leaves which exhibit Crassulacean acid metabolism, and their stomata open when acidity levels are lowest, or shortly thereafter. Aranda and Arachnis require higher light intensities for sufficient deacidification to permit stomatal opening than Cattleya. Stomata of the thin‐leaved Arundina, Bromheadia and Spathoglottis open during the day. The stomatal rhythms, morphology and distribution, as well as the pathways of carbon fixation and light requirements for deacidification, reflect the natural habitat of each species or the parents of the three hybrids.
HORMONES IN PLANTS BEARING NITROGEN‐FIXING ROOT NODULES:
Authors: HENSON I. E. , WHEELER C. T. 
Published: May 2006

SUMMARYThe content of gibberellin‐like (GA‐like) substances in various parts of young alder (Alnus glutinosa (L.) Gaertn.) plants was estimated by means of the lettuce hypocotyl bioassay. The highest levels of GA‐like activity were found in the root nodules, of dormant plants, plants emerging from dormancy, and plants in full leaf.No major differences were found in the roots and leaves of nodulated as opposed to non‐nodulated plants, although the stems of nodulated plants did contain lower levels of GA‐like activity.The detection of seasonal changes in GA‐like activity in root nodules from mature trees was dependent upon the method of chromatography employed. One major peak of biological activity was detected following paper chromatography and no large changes were detected in the level of this component. In contrast, three zones of GA‐like activity could be detected after thin layer chromatography (TLC) and there were marked seasonal changes in activity in these three zones. This can be attributed either to changes in levels of the GA‐like substances themselves and/or to variations in the amounts of impurities interfering with the response of the bioassay.A number of peaks of GA‐like activity were detected by lettuce and rice bioassays following analysis of a large‐scale extract on a preparative high performance liquid chromatograph (HPLC). However, both the total number and the identity of the substances responsible for this activity, remain to be determined.
CARBOHYDRATE OXIDATION IN DEVELOPING BARLEY ENDOSPERM
Authors: DUFFUS C. M. , ROSIE R. 
Published: May 2006

SUMMARYThe presence of a number of pentose phosphate pathway (PPP) enzymes in developing barley endosperm is reported. The relative importance of the Embden‐Meyerhof‐Parnas pathway (EMPP) and the PPP throughout endosperm development was assessed by following the changes in activity of five EMPP and four PPP enzymes. The patterns of activity of the EMPP enzymes were very similar with pronounced peaks of activity at 35 days after anthesis thereafter falling to low or zero levels at the onset of maturity. The PPP enzymes, on the other hand, rose to maximum levels around 30–35 days falling only slightly thereafter.
VARIATIONS IN THE BASIC PATHWAY OF CHLOROPLAST DEVELOPMENT
Authors: WHATLEY JEAN M. 
Published: May 2006

SUMMARYThe sequence of ultrastructural changes which take place during chloroplast development in leaves of plants of Phaseolus vulgaris grown in the light is compared with that of plants grown in the dark. Further comparisons are made with the developmental sequence found in the hypocotyls of Phaseolus and in the leaves of Zea mays. It is concluded that there is a single basic pathway of chloroplast development. Variations in this pathway are related to blocks in the sequence resulting in the accumulation of storage materials such as phytoferritin and prolamellar bodies, characteristic of the species or tissue concerned. An attempt has been made to assess the ubiquity and duration of an association between plastids and the E.R. in lower plant species compared with the angiosperms. A plastid‐E.R. association is common and persistent in lower plant species whereas in angiosperms it is apparently transitory and confined to immature or specialized cells.
THE EFFECTS OF LIGHT INTENSITY ON ACETYLENE REDUCTION BY BLUE‐GREEN ALGAL MATS IN SUB‐TROPICAL GRASSLAND
Authors: JONES K. 
Published: May 2006

SUMMARYHigh light intensities such as those found during the middle of the day in southern Africa are not responsible for inhibition of acetylene reduction by mats of blue‐green algae in kikuyu lawns. Similar results were obtained with uni‐algal cultures of Nostoc isolated from the algal mats. Short term experiments (3 h) with both cultures and algal mats showed a direct relationship between acetylene reduction and light intensities of up to 323 lux but no significant increase in acetylene reduction for light intensities above this. The amount of acetylene reduction by algae in the dark is determined by the light intensity received prior to darkness.
THE EFFECTS OF TEMPERATURE ON ACETYLENE REDUCTION BY MATS OF BLUE‐GREEN ALGAE IN SUB‐TROPICAL GRASSLAND
Authors: JONES K. 
Published: May 2006

SUMMARYTemperature is the main factor governing the rate of acetylene reduction by mats of blue‐green algae in sub‐tropical kikuyu lawns. High midday temperatures (40°C at soil surface) inhibit acetylene reduction and low temperatures prior to dawn reduce the rate of nocturnal acetylene reduction. Data obtained from laboratory studies on algal mats and on Nostoc isolated from the mats are in agreement with those from in situ measurements confirming an acetylene reduction of 30–35°C with inhibition above 40°C.
A TEST OF BURCK'S HYPOTHESIS RELATING ANTHER DEHISCENCE TO NECTAR SECRETION
Authors: SCHMID RUDOLF , ALPERT PETER H. 
Published: May 2006

SUMMARYWilliam Burck in 1906/07 suggested that anther dehiscence in many flowers results from loss of considerable amounts of water not by transpiration, as commonly believed, but rather by withdrawal of the water internally to other tissues, particularly nectaries. Tests on flowers of eight dicotyledons failed to provide confirmatory evidence for Burck's conclusions. A number of additional, largely theoretical objections to Burck's hypothesis are also presented. Experimental evidence also suggests that anther dehiscence may not be exclusively the simple desiccatory process generally envisioned by botanists.
POLYAMINES AS SOLE NITROGEN SOURCES FOR HELIANTHUS TUBEROSUS EXPLANTS IN VITRO
Authors: BAGNI N. , CALZONI G. L. , SPERANZA A. 
Published: May 2006

SUMMARYPutrescine, spermidine, spermine have been tested for their ability to substitute for inorganic nitrogen for the growth of explants from dormant tubers of Helianthus tuberosus. Explants grew as well on putrescine + indole acetic acid (IAA) as on nitrate + IAA or gluta‐mine + IAA but no growth occurred with spermine + IAA and an intermediate growth effect was observed in explants grown on spermidine + IAA, although this last result was not confirmed in tubers of different years. Growth increments have been related to pH variation in culture medium. Radioactive polyamines were transformed by the tuber explants to arginine and glutamine.The presence of radioactive putrescine after [1,4‐14C] spermidine feeding to explants grown on spermidine + IAA, as well as the presence of large amounts of spermidine in explants grown on spermine + IAA, indicate a reversal of the pathways of spermidine and spermine biosynthesis. We suggest that putrescine arises by such reversal. This hypothesis does not exclude processes of direct transamination from polyamines to α‐ketoacids.
MYCORRHIZAL FUNGI STIMULATE UPTAKE OF SOLUBLE AND INSOLUBLE PHOSPHATE FERTILIZER FROM A PHOSPHATE‐DEFICIENT SOIL
Authors: POWELL C. LL. , DANIEL JEANNETTE 
Published: May 2006

SUMMARYOne crop of clover followed by three crops of ryegrass were infected with several mycorrhizal fungi and grown in sterilized soil which had received soluble phosphate or Nauru rock phosphate. Plant growth responses to mycorrhizal infection were larger in later crops. Glomus tenuis was successfully introduced into soil already infested with the indigenous mycorrhizal fungi, and was the most efficient fungus used at stimulating phosphate uptake. In all four crops, Nauru rock phosphate was available to mycorrhizal plants but unavailable to non‐mycorrhizal plants. Plants infected with G. tenuis and the indigenous mycorrhizal fungi recovered 10‐27% of the phosphate fertilizer applied to the soil while non‐mycorrhizal plants recovered only 0.4‐13%.
EFFECT OF ARBUSCULAR MYCORRHIZA ON PLANT GROWTH
Authors: DAFT M. J. , EL‐GIAHMI A. A. 
Published: May 2006

SUMMARYDefoliation of maize and tomatoes reduced the mycorrhizal growth response and development of the endophyte, estimated as percentage infection, root pigmentation and spore production. More fresh and dry matter was produced in mycorrhizal grasses harvested on three separate occasions than from a single final harvest. The total yields from two harvests and the yield from a single harvest of alfalfa were similar although nodulated and mycorrhizal plants were larger at each harvest. In both grasses and alfalfa, periodic harvesting reduced the mycorrhizal infection by approximately 50%.Reduction in daylength and irradiance depressed the growth more in mycorrhizal than in uninfected maize plants. In Rhizobium‐ and Glomus‐infected alfalfa plants, a daylength of 16 h produced the highest carbon contents and C/N ratios. Plants exposed to short days produced more, smaller nodules and had higher nitrogen contents than plants given long days. Long days favoured the development of the mycorrhizal infection and these dually infected plants produced more dry matter, reduced acetylene faster and contained more nitrogen than nodulated only plants. The supply of photosynthate is probably an important factor controlling the development of the mycorrhiza.
NUMERICAL ANALYSIS OF SURFACE POLLEN SPECTRA FROM BANKHEAD MOSS, FIFE
Authors: CASELDINE C. J. , GORDON A. D. 
Published: May 2006

SUMMARYAn investigation is described which examined the extent to which surface pollen spectra from three transects across a small raised bog reflected the vegetation communities on the bog. Three classification studies of the spectra are described: (i) a principal components analysis; (ii) two hierarchical partitioning methods; (iii) a constrained classification, in which groups of spectra must be formed from neighbouring samples along the transects. Advantages and limitations of these classificatory procedures are discussed, and a synthesis of the results is advocated. The groups of spectra suggested by this approach are found to correspond closely to a grouping of spectra according to the vegetation community from which they were drawn, indicating the existence of characteristic pollen assemblages which are closely related to vegetation communities.
A SUGGESTED CYCLE OF PLASTID DEVELOPMENTAL INTERRELATIONSHIPS
Authors: WHATLEY JEAN M. 
Published: May 2006

SUMMARYIt is suggested that developmental changes in plastid structure follow a cyclic pathway which may involve the dedifferentiation of mature chloroplasts to proplastids and the subsequent redifferentiation of proplastids to mature chloroplasts. The proposal of a cyclic plastid relationship revives the earlier concept of Schimper. This has generally been discarded in favour of a unidirectional concept which discounts dedifferentiation as a normal process. Justification of the cyclic concept depends largely on the verification that plastid dedifferentiation and re differentiation do indeed take place. Evidence for this comes not only from the literature, but also from personal observations.
CELL DIFFERENTIATION IN EMBRYOIDS AND PLANTLETS OF CELERY TISSUE CULTURES
Authors: AL‐ABTA SAHERA , COLLIN H. A. 
Published: May 2006

SUMMARYThe formation of globular, heart‐shaped and torpedo‐shaped embryoids was initiated in a cell suspension culture of differentiating celery callus. Sections of these embryoids were examined for cell differentiation. Sections were also taken from plantlets, seedlings and mature plants. No cell differentiation was seen in the globular and heart‐shaped stages but cell differentiation and tissue organization were present at the torpedo stage. The structure of the plantlet was simpler than that of the seedling but this may have been due to the conditions in the culture flask. Both plantlet and seedling leaf showed comparable levels of organization. It is concluded that biochemical development in the embryoid may be related to the onset of cell differentiation.
RESPONSE TO SOIL MOISTURE SUPPLY IN THREE LEGUMINOUS SPECIES
Authors: FOULDS W. 
Published: May 2006

SUMMARYSoil moisture is an important factor in the distribution of Trifolium repens, Lotus corniculatus and Medicago lupulina. The first proved to be the most successful on moist soil, growing vigorously and forming numerous seeds. However, the plant was unable to avoid desiccation in droughted conditions where physiological processes such as root and shoot growth, and seed production were inhibited.In moist and dry soil, the seed production and vegetative yield of Lotus corniculatus were consistent. However, the slow‐growing seedlings and adult plants were relatively intolerant of severe drought.The annual, Medicago lupulina, displayed the greatest plasticity. On moist soils it formed substantial vegetative parts and prodigious numbers of seeds. In doughted conditions this species was the most tolerant of the three legumes at all stages of the life history, forming many seeds even when the vegetative yield was relatively low.
PHOSPHORUS CONCENTRATIONS IN PLANTS RESPONSIBLE FOR INHIBITION OF MYCORRHIZAL INFECTION
Authors: MENGE J. A. , STEIRLE D. , BAGYARAJ D. J. , JOHNSON E. L. V. , LEONARD R. T. 
Published: May 2006

SUMMARYUsing a ‘split root’ technique, it was found that phosphorus fertilization of half of the root system of sudangrass could significantly reduce the number of chlamydospores of the mycorrhizal fungus Glomus fasciculatus in the unfertilized half of the root system. In a second experiment, vials of soil containing different concentrations of phosphorus were inserted into pots of sudangrass which were fertilized with different amounts of phosphorus and inoculated with G. fasciculatus. The numbers of chlamydospores, vesicles and arbuscles and the amount of hyphae produced by G. fasciculatus on roots within the vials were not influenced by the soil P in the vials but were inversely correlated with the concentration of P in roots outside the vial. All evidence indicates that it is the concentration of P within the plant and not the soil P which leads to a reduction in colonization, infection, and spore production of G. fasciculatus.