bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE DORSIVENTRALITY OF LEAF PRIMORDIA
Authors: SNOW MARY , SNOW R. 
Published: May 2006

summaryWhen in shoot apices of potatoes the presumptive area of I1, the next leaf due to arise, or of 12, was isolated from the growing‐point by a vertical cut, the isolated pieces regularly formed dorsiventral leaves, even when slips of mica were left in the cuts.These results differ from those of Sussex, who reported that he obtained radial leaves from nearly similar operations on potatoes, and interpreted them as due to interruption of an induction of dorsiventrality by the apex.The difference in the results cannot be explained by supposing that our isolated pieces were larger than his, since the evidence indicates that they were smaller. It may have been due to differences in the conditions of culture.In apices of Epilobium hirsutum on the other hand, I1 areas when isolated by vertical cuts developed often into radial leaves, though sometimes into dorsiventral leaves. So also did P, primordia if isolated on small pieces at early plastochron.These and other experiments on E. hirsutum make it probable that in that species the dorsiventrality of the leaves is induced by the apex. But this cannot be concluded with certainty, since the experiments show also that reduction of size contributes towards making an isolated I1 or P1 develop as a radial leaf, and it remains possible that this factor may have been effective alone.In earlier experiments on E. hirsutum P1, I, or I2 was narrowly confined between two vertical radial cuts, without being isolated from the apex, and several of these confined primordia or presumptive areas formed radial leaves, which are illustrated. But in more numerous later experiments this result was not obtained again.The determination of the dorsiventrality of leaves in these and other species is briefly discussed.
THE MODE OF ORIGIN OF VEIN‐ENDINGS IN THE LEAF OF LIRIODENDRON TULIPIFERA L.
Authors: SLADE BRENDA F. 
Published: May 2006

SummaryIn a study of the development of the reticulate venation of the leaf of Liriodendron tulipifera L. the mode of origin of the vein‐endings receives particular attention.At an early stage in development the veins form a network with very few free ends. Increase in area of the lamina by cell enlargement is accompanied by expansion of the vein system. Its weaker components which are not capable of extending at the same rate as the lamina become broken or disconnected and produce the abundant blindly ending veinlets characteristic of the mature leaf. The pattern of development thus agrees with that already described for Cercis and Primus and probably occurs generally in dicotyledon leaves with reticulate venation.
CYTOGHROME OXIDASE IN MYCORRHIZAL AND UNINFEGTED ROOTS OF FAGUS SYLVATICA
Authors: HARLEY J. L. , PREES T. A. 
Published: May 2006

SummaryThe effect of azide, cyanide, carbon monoxide and DNP upon the respiration of mycor‐rhizal roots of beech is stimulatory. The stimulations are shown to be the result of the reaction of the fungal sheath. Host tissue of mycorrhizas and of uninfected roots react in a more expected fashion and are inhibited by azide, cyanide and carbon monoxide. In spite of this the fungal sheath is shown to possess a succinic dehydrogenase‐cytochrome oxidase system inhibited by malonate, cyanide and azide. Host tissue, whether from infected or uninfected roots, gives extracts containing a heat‐stable reductant of cytochrome C which interferes with spectrophotometric assay of the oxidase system. It is concluded that a significant part of electron transport of intact mycorrhizas may pass through the cytochrome oxidase system and, on inhibitor evidence alone, that the respiration of the host tissues is catalysed also by such a system. An explanation of stimulatory effects of inhibitors of cytochrome oxidase is suggested and discussed.
PHYSIOLOGICAL AND ECOLOGICAL FACTORS INFLUENCING THE EFFECTS OF MYCORRHIZAL INOCULATION
Authors: LEVISOHN I. 
Published: May 2006

SummaryInoculations of mycelia known to be mycorrhiza‐formers of certain tree species have frequently been recorded to produce indifferent effects on the development of these species. In a particular heathland soil, the introduction of Boletus scaber was even observed to depress the vigour of birch, a tree which is generally regarded as the mycor‐rhizal host parexcellence of this fungus. Pot‐culture experiments revealed that the harmful influence of the inoculum on the higher plant was due to certain fungal interactions. From an analysis of the fungal components concerned in these interactions, it appeared that the interplay of two factors was mainly responsible for bringing about the adverse effect on the young trees: (a) the physiological character of the particular form of B. scaber used as inoculum, i.e. its pronounced rhizosphere activity; (b) the presence of a deleterious pseudomycorrhiza‐former, Mycelium radicis atrovirensβ, in the experimental soil. Introduction of Boletus scaber into cultures of Pinus sylvestris demonstrated that, although this tree species is, generally, not a congenial mycorrhizal partner of the fungus, the formation of mycorrhizal infection and simultaneous growth stimulation of the host plant was achieved under certain ecological conditions.
THE MORPHOLOGY AND CYTOLOGY OF SPOROGENESIS OF TRICHOMANES PROLIFERUM BL.
Authors: BELL P. R. 
Published: May 2006

SummaryThe morphology of Trichomanes proliferum is described and the anatomy of the petiole and rhizome is discussed in relation to the habitat of the plant and its growth.It is suggested that after the initial phases each frond may be regarded as a more or less independent colony of cells, the complexity ultimately attained by the frond depending upon the supply of primary metabolites reaching it directly from without.It is reported that in the plant collected from Gunong Poe the chromosomes failed to pair at meiosis and 108 univalents were present.A means is suggested by which polyploidy could have arisen frequently in the Hymenophyllaceae.
THE CYTOLOGY OF THE DESMIDS: THE CHROMOSOMES*
Authors: KING G. C. 
Published: May 2006

SummaryNew cytological techniques for handling desmid chromosomes are described. Twenty new chromosome counts are recorded.Parallel disjunction of chromatids at anaphase has been observed for the first time in the desmids, and from this and other criteria it has been inferred that a non‐localized type of centromeric organization of the chromosomes is present.
AMINO ACID CONTENTS OF SOME MARINE ALGAE FROM BOMBAY
Authors: LEWIS E. J. , GONZALVES ELLA A. 
Published: May 2006

SummaryTwelve species of algae from Bombay were analysed by quantitative paper chromatographic technique. The methods of preparation of protein‐hydrolysates, the resolving solvent system, Colour reagents and a modified colorimetric elution reagent have been described. In all, twenty amino acids were identified and estimated. From these ornithine is a rare record for marine algae, while hydroxyproline is a new record. The results obtained here compare favourably with those of other workers.
THE COMPARATIVE BIOLOGY OF CLOSELY RELATED SPECIES LIVING IN THE SAME AREA
Authors: MCNAUGHTON I. H. , HARPER JOHN L. 
Published: May 2006

SummaryThe morphology of Papaver dubium and P. lecoqii are contrasted. The colour of latex, leaf dissection, petal shape and height of stamens are considered good characters for distinguishing between them. The shape of the capsule and stigmatic disc are considered unreliable taxonomic characters.Experimental cross‐pollinations show that the species can produce hybrids readily, that the hybrid seed germinates with little or no dormancy, to give plants showing some degree of hybrid vigour but morphological characters intermediate between the parents. The F1 hybrids show very severely reduced fertility, but this is rapidly restored in many of the F2 and backcross progeny.Naturally occurring hybrids have not been found, and there are problems in the way of recognizing them and proving their hybrid nature if they do occur.The continued coexistence of these two species without merging of their specific characters is made possible by barriers to gene flow occurring at three levels of organization: (a) ability of the parents to set seed by selfing, (b) ill‐adapted hybrids and (c) infertility of the F1 generation.
SHORT‐TERM FLUCTUATIONS IN LEAF AND INTER‐NODE GROWTH IN THE APPLE ROOTSTOGK CRAB C
Authors: HANCOCK C. R. , BARLOW H. W. B. 
Published: May 2006

SummaryA method of handling data on leaf and internode growth on Crab C stoolbed shoots is described whereby average values for leaf length, leaf width and internode length were obtained from twenty‐seven shoots, with certainty that all leaves contributing to the average were passing through the same stage of development at the same time.The effect of temperature (defined as accumulated day degrees above 42° F between noon and noon) on growth rate at five stages of growth of the leaf in length and width, and of the internode in length, is shown by means of linear regressions.Attempts are made to relate final leaf length with the temperature regime through which the leaf had passed; partial correlations and a multiple regression gave results which are difficult to interpret.Similar treatment of the internode data yielded a more logical relationship.‘Normal curves of growth’ were constructed for leaf length, leaf width and internode length. By plotting these on a common time scale certain relationships between growth of one organ and another are clarified.The effect of temperature at stages earlier than those observed in these studies is discussed.
CARROT TISSUE AND ETHANOL
Authors: LOWE CELIA , JAMES W. O. 
Published: May 2006

SummaryThe presence of alcohol in an aerated external medium increases the respiration rate of carrot discs. If the alcohol is labelled no labelling appears in the CO2 emitted or the acids formed in the tissue. Alcohol dehydrogenase is shown to be located almost wholly among the soluble proteins of the cytoplasm. The failure to oxidize alcohol is attributed to its spatial separation from the terminal oxidase system located in the mitochondria.
ROOT FORKING OF PINE SEEDLINGS GROWING UNDER NON‐STERILE CONDITIONS
Authors: LEVISOHN IDA 
Published: May 2006

SummaryIt has been demonstrated under particular pot‐culture conditions that, without establishing an association, the mycorrhiza‐formers Boletus bovinus, B. granulatus, Mycelium radicis nigrostrigosum, and Rhizopogon luteolus are capable of inducing short‐root forking in actively growing pine seedlings, while haustorial (pseudomycorrhizal) mycelium causes forking accompanied by infection. A number of soil fungi which are not common root associates failed to bring about dichotomous root branching, but there is evidence that certain other mycelia, whose identity is not known yet, can do so.In water‐cultures of pines tryptophan induced root forking, the kind and degree of branching depending on the concentration of tryptophan.From a morphological study of the root systems developing in pot‐ and in water‐cultures, it would appear that two types of forking may occur in both infected and uninfected pine roots, and that one type is connected with the activity of mycorrhiza‐formers, while the other seems to develop under the influence of non‐mycorrhizal fungi and can also be induced by certain growth‐substances and other media so far not defined.
POLLEN SPECTRA FROM RECENT HELIANTHEMUM COMMUNITIES
Authors: PROCTOR M. C. F. , LAMBERT CAMILLA A. 
Published: May 2006

SummaryPollen spectra are given from eight present‐day habitats of Helianthemum species. From a consideration of the recent and Late‐glacial spectra it is concluded that Helianthemum‐rich communities contributed only a part of the Late‐glacial pollen rain, and that they were probably mostly grass‐dominated. Some implications of the occurrence of Helianthemum for Late‐glacial conditions are discussed.
DIFFERENTIAL RESPONSE TO CALCIUM WITHIN THE SPECIES FESTUCA OVINA L.
Authors: SNAYDON R. W. , BRADSHAW A. D. 
Published: May 2006

SummaryAn investigation of population differentiation within the species Fcstuca ovina in relation to soil factors has shown that populations within this species differ greatly in their response to calcium in culture solution. Populations from acid, low calcium soils showed a weak response to calcium, whilst those from calcareous soils showed a strong response. All populations responded linearly to the logarithm of the calcium concentration at the low levels, but there was a decrease in yield of the acidic populations at higher calcium levels. The difference in response to calcium between the acidic and calcareous types of populations was as great as that previously shown to exist between extreme calcicole and calcifuges species. Such differences were found even between populations taken from areas only about I mile apart.Smaller scale variation was also shown to exist between individuals within single populations.Chemical analysis of the plants indicated that the differences in response between populations were due to differences in ability to absorb calcium from low solution concentrations, rather than to differences in ability to metabolize at low internal concentrations of calcium. The populations were also found to differ in ability to absorb other cations and in ability to root at low levels of calcium.The evolutionary significance of the results is discussed, and the importance of recognizing such variability, within apparently homogeneous species, in ecological and physiological studies is stressed.
STUDIES IN BRITISH PRIMULAS
Authors: WOODELL S. R. J. , VALENTINE D. H. 
Published: May 2006

Summary

Artificial autotetraploids of three species of Primula have been made and crossed reciprocally with their diploid parents.
Data on the character of the seeds produced, derived from dissection and embryo‐logical examination, are presented. It is shown that the seeds from reciprocal diploid‐autotetraploid crosses fall into two classes, type A and type B, which resemble in general features and pattern of development those from reciprocal crosses between the diploid species. They are normally practically empty at maturity, and no triploid offspring have been obtained.
Diploid‐autotetraploid crosses in general are discussed, and it is pointed out that the nature and goodness of their seeds varies greatly from genus to genus. The crosses can be arranged in four groups on a basis of triploid productivity.
The embryological data on these crosses are also briefly reviewed. While some general similarities can be recognized, there is so much diversity that no generalizations about the pattern of breakdown can be made.
COMPARATIVE CYTOLOGICAL STUDIES OF THE POLLEN AND POLLEN‐TUBES IN DIPLOID AND TETRAPLOID SPECIES OF SESBANIA
Authors: DANA S. K. , DATTA R. M. 
Published: May 2006

Summary

Both Sesbania aculeata and S. speciosa have binucleate, prolate, tricolpate pollen grains.
The rate of pollen‐tube growth in vitro is higher in S. speciosa than in S. aculeata. The maximum pollen‐tube length for the former is 2151.5 μ and for the latter 1062.0 μ. The tubes continue to grow in culture for 8 hours.
The tube‐nucleus generally precedes the generative cell, but sometimes follows it.
The generative nucleus divides normally with regular equational division of its chromosomes.
Spindle formation is clear, and the spindle can develop in any position in relation to the longitudinal axis of the pollen‐tube.
Cytokinesis takes place by cell‐plate formation.
Two sperms are formed.
S. aculeata has twenty‐four chromosomes in somatic cells, and only one pair has secondary constrictions. Meiosis is regular, with rare multivalent formation. Although a polyploid race its behaviour is that of a diploid.
S. speciosa has twelve chromosomes in somatic cells, and only one pair has secondary constrictions.
FLOWERING BEHAVIOUR, COMPATIBILITY AND MAJOR GENE DIFFERENCES IN HOLCUS LANATUS L.
Authors: BEDDOWS A. R. 
Published: May 2006

Summary Holcus lanatus is wind‐pollinated. Anthesis occurs twice a day if weather conditions are favourable, the first time between 5 and 9 a.m. and the second between noon and 4 p.m. G.M.T. The two florets composing the spikelet each produce anthers but the upper may sometimes be hermaphrodite and can then develop a caryopsis.Self‐compatibility varies from low to very low, and plants of high self‐fertility, not uncommon in other species, have not been found. The I1 progenies frequently contain mutant seedlings, and of these a lethal yellow and a lethal pale green are described. Neither type developed anthocyanin even when genes for its production were present. The possible reasons for this are discussed.The great majority of uncultivated (wild) plants are anthocyanin‐positive. The purple colour is especially prominent along the veins of the sheaths and forms a diagnostic character. Failure to produce anthocyanin is a result of homozygosity for recessive allelomorphs at either of two loci. The non‐anthocyanin plants occasionally found fall, therefore, into two groups which can be genetically designated CCrr and ccRR.A number of other qualitative differences were studied, including a new mutant dark green dwarf. This has very short broad leaves and crowded tillers, resulting in a rosette‐like plant about 6 cm in diameter. In all instances the differences were controlled by a single gene.Although H. lanatus shows much variability in the degree of hairiness, a truly glabrous plant has not yet been found.
DAY‐LENGTH AS RELATED TO VEGETATIVE DEVELOPMENT IN ULEXEUROPAEUS I.
Authors: MILLENER L. H. 
Published: May 2006

SummarySeedling development, especially in respect of the ‘juvenile‐adult’transition, is shown to be far‐reachingly affected by day‐length. Extension of high‐intensity, short‐day illumination with sub‐compensation‐point light affects leaf and branch ontogeny both qualitatively and quantitatively. It is suggested that the changes affecting vegetative growth that go on during the low‐intensity light phase are of a formative nature, and that they may be more fundamental, in a general metabolic sense, than photoperiodic reactions (flower‐inducing) sensu stricto.
THE FINE STRUCTURE OF THE POLLEN WALL OF TILIA PLATYPHTLLOS
Authors: CHAMBERS T. C. , GODWIN H. 
Published: May 2006

SummaryThin sections of the pollen wall of Tilia platyphyllos and T. europaea have been studied by electron microscopy and it has proved possible to obtain both serial transverse sections and surface sections. An attempt has been made to relate the electron micrographs to the structures seen under the light microscope. It appears that an inner and an outer layer of the exine are joined by a system of hollow funnels and pillars crossing a cavity or void occupied by cytoplasm. In terms of density to an electron beam no support can be found for the idea that the exine is made up of layers of inherently different properties, nor for the present complex nomenclature applied to light microscope interpretations of pollen‐wall structure. Tapetal cytoplasm has been found to be continuous with cytoplasm in the wall of the pollen grain, and spheroids comparable with those described by Rowley et al. (1959) have been found associated with the tapetal strands surrounding the developing microspores.
RATES OF MITOSIS IN A PARTIALLY SYNCHRONOUS MERISTEM
Authors: CLOWES F. A. L. 
Published: May 2006

SummaryIn root apices of Sinapis alba mitosis is partially synchronous under certain cultural conditions, with two maxima and two minima of mitotic index each day. But the phase of the partial synchrony is different in the stele and cortex from that in the cap initials and that in the quiescent centre. The average rates of mitosis vary from once in 35 hours in the cap initials to once in 500 hours in the quiescent centre. Cells of the cortex and stele divide more slowly near the quiescent centre than at 150 microns from it. In this respect Sinapis differs from Zea and the dissimilarity in organization may be due to the possession of partial synchrony and the opportunity it gives for phasic differences in synthesis.
DAY‐LENGTH AS RELATED TO VEGETATIVE DEVELOPMENT IN ULEX EUROPAEUS L.
Authors: MILLENER L. H. 
Published: May 2006

SummaryThe extent of the juvenile phase in gorse seedlings grown under uniform conditions from seed collected from various stations throughout Britain, has been shown to vary significantly with the latitude of the parent plants. Regular seasonal variation in the juvenile‐adult balance of seedlings has also been demonstrated. Day‐length seems to be the only environmental factor which can be postulated to explain such variations—for it alone changes consistently with latitude and from season to season.
THE EFFECTS OF INJECTING 2,3,5,‐TRIIODOBENZOIC ACID INTO KALAMCHOE DAIGREMONTIANA*
Authors: BOHLEN JOSEPH , APPLEGATE HOWARD G. 
Published: May 2006

SummaryLow concentrations of 2,3,5‐triiodobenzoic acid (TIBA) injected into Kalanchoe daigremontiana induced hyponasty while high concentrations induced epinasty. Changes in oxygen uptake preceded any visible morphological changes. Both hyponasty and oxygen uptake varied directly with the concentration of TIBA. Following injection very little lateral movement of TIBA occurred. Virtually all the TIBA initially moved directly up or down from the point of injection. This movement could be correlated with the vascular anatomy of K. daigremontiana. Explanations are advanced to account for the hyponasty, epinasty and oxygen uptake induced by TIBA.
THE UPTAKE AND ASSIMILATION OF AMMONIA BY NEOCOSMOSPORA VASINFECTA
Authors: BUDD K. , HARLEY J. L. 
Published: May 2006

SummaryA low‐nitrogen mycelium prepared by suspending freshly grown mycelium in a nitrogen‐free medium for 22 to 24 hours was transferred to buffered media containing NH4Cl as sole nitrogen source for estimation of ammonia absorption. In one experiment a 'sugar‐starved’mycelium, obtained by suspending the fresh mycelium for a similar period in a medium lacking both nitrogen and glucose, was employed.During the absorption of ammonia by low‐nitrogen mycelium, there is an increase in the ammonia content of the cells, and also in the total organic nitrogen, showing that assimilation of ammonia takes place. The rate of increase of both forms of nitrogen is greatest during the first 10 minutes of uptake and the maximum level of ammonia in the cells is reached within this initial period. External glucose is required for maximal uptake only after the second hour and it increases only the rate of assimilation. In the sugar‐starved mycelium, uptake of ammonia is considerably smaller: ammonia increases within the cells but ammonia assimilation is very slow in the absence of external glucose.The chief soluble product of ammonia assimilation is glutamine. Ethanol‐insoluble nitrogen compounds are also formed, suggesting that proteins may be synthesized.Assimilation of ammonia is only slightly affected by external ammonia concentration above 5 mM, but is markedly sensitive to temperature, external pH, anaerobic conditions and low concentrations of sodium azide or 2,4–dinitrophenol. The effects of the last three factors indicate that ammonia assimilation depends upon aerobic respiration, including the transfer of high‐energy phosphate. The level of ammonia in the mycelium depends on the external concentration and pH; it is reduced by anaerobic conditions and by sodium azide and 2,4–dinitrophenol although sensitivity to these factors is apparently much smaller than is that of ammonia assimilation. The participation of respiration is therefore implicated both in the assimilation of ammonia and also in some process leading to the increase of ammonia in the mycelium.