The Identification of the Seeds and Achenes of the British Plantaginaceae

The morphology of seeds and achenes of the British members ofthe Plantaginaceae has been examined. Keys to the identificationof seeds in the genera Plantago and Littorella are presented.Quantitative data on size and weight, as well as informationabout shape, colour and surface features of the seeds are givenfor: Plantago major L., P. media L., P. lanceolata L., P. martimaL., P. coronopus L., P. indica L., P. sempervirens Crantz, andLittorella uniflora (L.) Aschers. A representative sample ofeach seed is illustrated.     

Environmental Factors Affecting Airborne Pollen Concentration in Anemophilous Species of Plantago

Pollination of Plantago species in the Extremadura Region (SWof the Iberian Peninsula) was studied using three volumetrictraps located in the cities of Badajoz, Mérida and Cáceresbetween 1994 and 1999. Variations in atmospheric concentrationof Plantago pollen were analysed between locations, and annual,daily, and hourly variations recorded for each location. Thehighest concentrations of pollen were recorded at Cáceres,while the Mérida and Badajoz values were similar. Thisis explained by the nature of the surroundings of each city.Interannual variations in pollination levels were significantlycorrelated with autumn rains, which determine the extent ofdevelopment of the populations. The hourly patterns of pollencapture were well-defined and similar for all three study sites.Maximum levels were reached between 1000 and 1200 h. Nocturnalconcentrations were very low. Furthermore, this pattern wasmaintained throughout the flowering period, impling a very closelink with the patterns of anthesis of the species. The threestations showed similar patterns of daily variation, which weresignificantly correlated with certain meteorological parameters.Pollen concentrations were affected positively by temperature,but negatively by relative humidity. The influence of wind directionalso seemed to be explicable in these terms since the easterlywinds, which are dry and hot in this region, had a positiveinfluence, and the westerly winds which are moist and cool hada negative effect. The most relevant factor influencing levelsofPlantago pollen in the atmosphere was wind speed, which wasnegatively correlated with pollen levels. Copyright 2001 Annalsof Botany Company Plantago, aerobiology, reproduction, anemophily, pollen     

Characterization and physical mapping of ribosomal RNA gene families in Plantago

• Background and Aims The organization of rRNA genes incultivated Plantago ovata Forsk. and several of its wild allieswas analysed to gain insight into the phylogenetic relationshipsof these species in the genus which includes some 200 species. • Methods Specific primers were designed to amplify theinternal transcribed spacer (ITS1 and ITS2) regions from sevenPlantago species and the resulting fragments were cloned andsequenced. Similarly, using specific primers, the 5S rRNA genesfrom these species were amplified and subsequently cloned. Fluorescencein-situ hybridization (FISH) was used for physical mapping of5S and 45S ribosomal RNA genes. • Results The ITS1 region is 19–29 bp longer thanthe ITS2 in different Plantago species. The 5S rRNA gene-repeatingunit varies in length from 289 to 581 bp. Coding regions arehighly conserved across species, but the non-transcribed spacers(NTS) do not match any database sequences. The clone from thecultivated species P. ovata was used for physical mapping ofthese genes by FISH. Four species have one FISH site while threehave two FISH sites. In P. lanceolata and P. rhodosperma, the5S and 45S (18S-5·8S-25S) sites are coupled. • Conclusions Characterization of 5S and 45S rRNA geneshas indicated a possible origin of P. ovata, the only cultivatedspecies of the genus and also the only species with x = 4, froma species belonging to subgenus Psyllium. Based on the studiesreported here, P. ovata is closest to P. arenaria, althoughon the basis of other data the two species have been placedin different subgenera. FISH mapping can be used as an efficienttool to help determine phylogenetic relationships in the genusPlantago and show the interrelationship between P. lanceolataand P. lagopus.     

Karyotype, DNA Content and Meiotic Behaviour in Five South American Species ofVicia(Fabaceae)

This paper presents the karyotype, DNA content and meiotic behaviourof five species ofViciafrom Argentina (V. macrogramineaBurk.,V.gramineaSM.,V. epetiolarisBurk.,V. pampicolaBurk. andV. nanaVog.).All the species have the same chromosome number and karyotypeformula (2n=14; 6m+4st+4t). Each species, however, displaysa characteristic number and position of the nucleolar organizerregion (NOR) and different sizes of the respective satellites,confirmed by Ag-NOR banding. Moreover, significant differenceswere found in the total chromosome volume (TCV) and DNA contentof the species. Positive correlations between DNA content andTCV, and between DNA content and type of life cycle were alsofound. TCV and DNA content are lower inV. nana(annual) and higherinV. macrograminea(biennial–perennial). The material displayedmarked karyotypic orthoselection, with similar karyotypes inall studied species, even when the overall chromosome size varied.Evolutionary changes in DNA amount are proportional to the relativelength of each chromosome arm, maintaining karyotypic uniformity.Significant differences were found between the meiotic behaviourofV. gramineaand that of the other species.V. gramineahas alower frequency of ring bivalents and chiasmata per cell, andalso has a lower interstitial chiasma frequency. In general,the results are congruent with the morphological data reportedfor these species.Copyright 1998 Annals of Botany Company. Viciaspecies, karyotype, orthoselection, nuclear DNA content, NOR banding, meiotic behaviour.     

Comparison of the Respiratory Metabolism of Plantago lanceolata L. and Plantago major L.

Bryce, J. H. and ap Rees, T. 1985. Comparison of the respiratorymetabolism of Plantago lanceolata L. and Plantago major L.—J.exp. Bot. 36 1559–1565. The aim of this work was to discover if the respiratory metabolismof the roots of Plantago lanceolata L. differed from that ofthe roots of Plantago major L. Measurements of oxygen uptakeand dry weight of excised root systems during growth of seedlingsprovided evidence that the two species differed in the amountof respiration needed to support a given increase in dry weight.Excised root systems were given a 6-h pulse in [U-¹⁴C]sucrosefollowed by a 16.5-h chase in sucrose. The detailed distributionof ¹⁴C amongst the major components of the roots at the endof the pulse and the chase revealed no significant differencebetween the two species. Patterns of ¹⁴CO₂ production from [1-¹⁴C],[2-¹⁴C], [3,4-¹⁴C], and [6-¹⁴C]glucose of excised root systemsfrom plants of three ages were similar for the two species.It is suggested that there is no conclusive evidence for anysignificant inherent difference in the respiratory metabolismof the roots of the two species. Key words: ¹⁴C sugar metabolism, respiration, roots, Plantago     

Morphology of Leaf Surfaces of Tomato Cultivars in Relation to Possible Invasion into the Leaf by Pseudomonas syringae pv. tomato

The role of morphological characteristics of tomato leaves inthe infection process of the pathogen Pseudomonas syringae pv.tomato was studied in 15 cultivars of varying susceptibility.Natural openings such as stomata, broken trichomes and cuticularcracks were counted. It was found that susceptibility increasedin proportion to the number of these potential penetration sites.However, their role is probably limited because even in thehighly resistant cultivars there are enough natural openingsto enable successful bacterial penetration. Bacterial speck of tomato, Lycopersicon esculentum, phytopathogenic bacteria, plant morphology, Pseudomonas syringae pv. tomato, tomato     

Development of Floral Apex After Floral Induction in Stylo (Stylosanthes guianensis (Aubl.) Sw. var. guianensis)

The apex morphology of stylo (Stylosanthes guianensis var. guianensis)is described in four developmental phases (vegetative, transitional,initiated and floral) further subdivided into a total of tenstages. The apical dome broadens and flattens as induction proceedsuntil the initiation phase when apical diameter within 0.05mm of the dome apex is 55 per cent greater than in the vegetativeapex. Changes in vegetative morphology during induction aredescribed. Stylosanthes guianensis var. guianensis, stylo, flowering, reproductive anatomy, developmental stages     

Effects on Phytochrome Controlled Germination Produced by Far-Red Irradiation of Seeds Before and During Rehydration

Seeds irradiated with red light and then re-dried will respondto this light treatment on subsequent rehydration in the dark.If such high-Pfr seeds are irradiated in the dry state withfar-red light immediately before rehydration the percentagegermination is significantly reduced in the case of Plantagomajor and Sinapis arvensis but increased in Bromus steriliswhere Pfr inhibits germination. This effect of far-red lightcan be reversed by red light despite the fact that red lightalone has no effect on dry seed. This is due to the interconversionof Pfr and the red light absorbing phytochrome intermediatecomplex meta-Fa. If there is a delay between far-red irradiationand rehydration of Sinapis seeds, the inhibitory effect of thefar-red irradiation becomes progressively less the longer thedelay. This reduction in effectiveness of far-red is interpretedin terms of a dark reversal of meta-Fa to Pfr with a half-lifeof about 4–6 h. The reappearance of Pfr is either veryslow or docs not occur in dehydrated Plantago seeds, as far-redtight given 96 h prior to hydration is just as inhibitory asfar-red light given immediately before hydration. Meta-Fa doesappear to revert to Pfr in darkness in Bromus seeds, but onlyvery slowly. The rapid increase in effectiveness of red irradiationduring rehydration of high-Pfr Plantago seeds suggests that,in this species, the pre-treatment used in preparation of high-Pfrseeds may increase the receptivity or amount of the Pfr reactionpartner. Key words: Phytochrome intermediates, Seeds, Germination     

Nucleolar organizing region in theApiaceae (Umbelliferae)

Data available for the nucleolus organizing region in the familyApiaceae are reviewed. An attempt has been made to establish the exact number of this region in various subfamilies and tribes through studies on the karyotype and nucleolus. Most of the taxa have a single nucleolar chromosome per haploid complement. The location of the nucleolar organizing region (NOR) on the chromosome varies. Members ofHydrocotyloideae differ drastically from those of subfam.Saniculoideae andApioideae, with respect to the location of NOR. Despite wide geographical distribution, varied ecological preferences and differences in morphology, anatomy and cytology, Umbellifers have attained stability in the number and location of NORs. Characters of NOR offer scope for utilization in understanding phylogenetic relationships at higher levels of taxonomic hierarchy.Studies on the Nucleolus and Nucleolar Chromosomes in Angiosperms XII.     

Nucleolar organiser region (NOR) location in karyotypes of Australian ground frogs (family Myobatrachidae)

Nucleolar organiser regions (NORs) were examined in over 90% of the species of Australian ground frogs (familiy Myobatrachidae), including representatives from all twenty currently recognised genera and the three subfamilies. Throughout the family, location of the NOR within the karyotype showed considerable variation yet karyotype morphology showed uniformity. The precise mechanism(s) whereby variation in NOR location evolved while karyotype morphology was unchanged remains uncertain. Comparison of the two major subfamilies showed that the Limnodynastinae had a greater diversity of NOR location than the Myobatrachinae. The limnodynastine genus,Heleioporus, was the only one to show multiple NOR sites in several species. NOR location was particularly stable within most polytypic genera. Differences in NOR location within the remaining polytypic genera (Heleioporus, Limnodynastes, Neobatrachus, Philoria andRanidella) pointed to taxonomic discriminations that were generally consistent with recent proposals based on other criteria.     

Morphogenesis of Schizophyllum commune III.Activity of inhibitors of energy metabolism

The effect of azide, 2,4-dinitrophenol, malonate and 2-deoxyglucoseon the physiology and morphology of normal and mutant strainsof Schizophyllum commune was studied. Normal, thin and puffstrains showed a decrease in dry weight and an increase in glucoseutilization in response to azide, dinitrophenol and 2-deoxyglucose.Streak was less sensitive to azide and dinitrophenol and almostcompletely resistant to 2-deoxyglucose. Numerous morphogeneticeffects were caused by the inhibitors. These included the inductionof certain aspects of the morphology of the common-A sexualreaction in normal and thin homokaryons by 2-deoxyglucose, areversion to normal morphology by thin strains in response toazide and dinitrophenol, and a morphogenetic insensitivity tothe inhibitors by the streak mutants. A discussion of the relationshipof these effects to the control of morphology in S. communeis given. ¹This investigation was supported in part by Research GrantAI-06570 from the National Institute of Allergy and InfectiousDiseases of the U. S. Public Health Service and by Grant No.GB-3613 from the National Science Foundation (U.S.A.). ²Present Address: Department of Biology, State College at Bridgewater,Bridgewater, Massachusetts 02324, U. S. A.     

Seed-protein Electrophoretic Pattern in Brachypodium P. Beauv. Species

The seed-protein band patterns of seven species, four variantsand plants of intermediate morphology between different pairspecies of Brachypodium have been analysed The data provideuseful information for the identification of the taxa, theirrelationship, and the delimitation of their taxonomic status Brachypodium P Beauv, seed-protein, electrophoretic pattern     

Membrane State and Pollen Viability

The relationship between germinability and fluorochromasia (FCR)has been studied in pollen of eight genera, Secale, Iris, Carex,Eleocharis, Cytisus, Digitalis, Plantago and Lonicera. The FCRtests two properties of the pollen, (a) the integrity of theplasmalemma of the vegetative cell and (b) the presence of anesterase capable of cleaving the fluorogenic ester, fluoresceindiacetate. In general, the correlations between FCR and germinabilitywere found to be very highly significant. This is interpretedas meaning that the primary determinant of pollen viabilityin short-term storage is the state of the vegetative cell membranes.It is suggested that in the partly dehydrated grain at the timeof dispersal the membranes are largely dissociated and do notform an osmotic barrier, but that normal properties are recoveredduring controlled hydration which would normally take placeon the stigma. According to this view, the decay of apparentviability is related to the progressive loss of the capacityof the vegetative cell membranes to regain a normal structureon rehydration. The genera investigated varied in their longevityin storage in low and high humidity conditions. After low-humiditystorage, most showed some enhancement of germination with 1h exposure to a humid atmosphere before transfer to the germinationmedium. During this ‘conditioning’ period the membranesrecover their fluorescein retentivity in step with the increasein germinability. pollen testing, pollen membranes, pollen fluorochromasia, Secale cereale L., Iris pseudacorus L., Carex ovalis Good., Carex nigra (L.) Reichard, Eleocharis palustris (L.) R.Br., Cytisus battandieri Maire, Plantago lanceolata L., Digitalis purpurea L., Lonicera periclymenum L.     

Genetic and Structural Analysis of Five Arabidopsis Mutants with Abnormal Root Morphology Generated by the Seed Transformation Method

A number of Arabidopsis thaliana mutants with abnormal rootmorphology have been isolated from a population of Agrobacterium-mediated seed transformants. Five of these mutants identifiedby their abnormal root morphology have been genetically andmorphologically characterised. Two mutants, 5905 and 1767 havedefective cellular elongation, mutant 7203 lacks an endodermalcell layer and mutants 4792 and 7133 exhibit abnormal radialcellular expansion. It is apparent from detailed analysis thatabnormal root morphology is accompanied by abnormal hypocotylphenotype. Genetic analysis has revealed that only one of thesemutants is tagged with a T-DNA insert.Copyright 1994, 1999 AcademicPress Arabidopsis thaliana, root, development, T-DNA insertion mutagenesis, endodermis, elongation     

Epacris crassifolia R. Br. (Epacridaceae) - A Reappraisal

Epacris crassifolia R. Br.s. lat.,as represented in collectionsat G, BM, HO, NSW, MEL, CBG and CAN, has been redefined as threeseparate species. The common lax, prostrate form includes twosubspecies,E. crassifoliassp.crassifoliaR. Br.stat. nov. andE.crassifoliassp.macrofloraCrowden et Menaduessp. nov.separatedon floral morphology.E. pinoideaCrowden et Menaduesp. nov.andE.lithophilaCrowden et Menaduesp. nov.are erect and woody, beingdistinguished on leaf and floral characters. Epacridaceae; Epacris crassifolia ; Epacris lithophila; Epacris pinoidea; new species     

The Production of Plantlets from Tissue Cultures of Brussels Sprout (Brassica oleracea L. var gemmifera D.C.)

Shoots were induced on callus derived from sprout sections andpetiole slices of an inbred parent line of Brussels sprout (Brassicaoleracea L. var gemmifera D.C.). The shoots, when excised andtransferred to fresh medium, enlarged and formed roots. Theseplantlets could be transferred to soil or their number increasedby a multiplication process involving the production of newshoots from the dormant lateral buds. Some of the plantletsderived from sprout callus were grown to maturity in the fieldand their morphology and chromosome number compared to seedgrown plants. There were no significant differences in sproutsize and stem diameter but there were significant differencesin plant shape. None of the plants in the field experiment showedpolyploidy. Plants derived from callus possessed an enhanced ability toform callus and redifferentiate when sections from these plantswere placed back on to nutrient medium.     

Scanning electron microscopy of Heterocapsa pygmaea sp. nov., and evidence for polyploidy as a speciation mechanism in dinoflagellates

The thecal morphology of three isolates of the marine dinoflagellateHeterocapsa pygmaea sp. nov. are here examined by manning electronand light microscopy. The thecal tabulation of these isolatesis p.p., c.p., 5', 3a, 7', 6c, a.s., r.s., l.a.s., l.p.s.,[?a.a.s. and p.a.s.], 5' ' and 2' ' and is identical to thatof H. niei and H. illdefina. The assignment of thecal platesto various series is based on interpretation of plate homologiesamong peridinioid genera. The above formula represents the basicpattern for Heterocapsa. The cell dimensions of four Heterocapsaspecies are determined; Heterocapsa pygmaea is the smallestspecies. Heterocapsa pygmaea differs from the next largest species,H. niei, in having approximately half the number of chromosomesand as such can be interpreted as a case of polyploidy. If so,this is the first evidence of polyploidy as a speciation mechanismin the Pyrrhophyta. ¹Present address: Department of Botany, Duke University, DurhamNorth Carolina 27706 ²Present address: The Biological Laboratories, Harvard University,Cambridge, Massachusetts 02138     

Sensing Iron--A Whole Plant Approach

Regulatory mechanisms leading to cellular Fe homeostasis wereinvestigated inPlantago (Plantago lanceolata L.) plants grownhydroponically at different temperature regimes either in thepresence or absence of iron. During the experimental periodof 6 d, growth was not affected by Fe availability, but wasdecreased by lowering the root zone temperature (RZT) from 24to 12°C. Cultivating plants at low RZT decreased the reductionactivity for ferric chelates in Fe-deficient plants. In thepresence of iron, the temperature regime did not affect Fe accumulationby root cells, but decreased translocation of Fe to the shoot,and chlorosis of young leaves was observed at suboptimal RZT.Under these conditions root-mediated reduction of ferric chelateswas increased. In cold-treated plants this effect was specificto Fe and could not be evoked by Mn²⁺and Zn ^{+ 2}additions. Supplementingthe medium with the ferrous scavenger ferrozine caused a furtherenhancement in reduction rates, probably due to mobilizationof apoplastic Fe. These results can be explained plausibly ifdifferent sites of Fe sensing are postulated and if it is assumedthat both the absence and presence of iron could be a signalincreasing root reduction activity. Copyright 2000 Annals ofBotany Company Adaptation, iron uptake regulation, ferric reduction, Plantago lanceolata, root zone temperature, whole plant signalling