Isozyme Variation in Wild and Cultivated Species of the Genus Trifolium L. (Leguminosae)

Isozyme patterns for PGI (phosphoglucoisomerase), MDH (malatedehydrogenase), EST (esterase) and SOD (superoxide dismutase)were evaluated in 36 accessions of eight Trifolium species,namely T. incarnatum, T. polymorphum, T. pratense, T. repens,T. resupinatum, T. riograndense, T. subterraneum and T. vesiculosum.Similarity between species and accessions was estimated by Jaccard’ssimilarity index based on presence or absence of bands. TheUPGMA method was utilized for the groupings and dendrogram constructionwith the aid of the NTSYS-PC program. Interspecific similaritywas low (J 0.351). The dendrogram presented eight groups, eachone corresponding to a taxonomic species. Most of the accessionsof the same species grouped together at J > 0.50, exceptT. riograndense, T. repens and T. pratense. These three speciesshowed the lowest similarity between their accessions, reflectinghigher intraspecific variation. Some accession-specific bandswere identified. The species groupings are consistent with traditionaltaxonomic species delimitation. Therefore isozyme patterns,especially when several systems are employed, are useful andreliable biochemical markers for the taxonomic delimitationand characterization of Trifolium germplasm. Copyright 2000Annals of Botany Company Genetic diversity, germplasm characterization, isoenzymatic variability, biochemical markers, isozymes,Trifolium     

Biochemical Studies on Ipomoea Pollen to Understand Species Homology

Studies on pollen phenolic compounds and isozyme profiles of twelve species of Ipomoea to trace the linkage and homology between the species, through UPGMA method, revealed two broad clusters or groups. The trend of clustering and species composition of each group for both the parameters were close to each other and almost in accordance with phylogenetic interpretation with minor variations. The variations are probably due to the fact that phenolics and isozymes are different biomolecules.     

Genetic Diversity inBrassica oleraceaL. (Cruciferae) and Wild Relatives (2n=18) using Isozymes

Genetic diversity in 36 populations of wild taxa of theBrassicaoleraceaL. group (2n=18) and two cultivated forms was studiedusing isozyme variation at 11 loci for five enzyme systems (IDH,6-PGD, PGM, PGI, MDH). Mean values for the percentage of polymorphicloci and expected heterozygosity were 54% and 0.224, respectively.Statistically significant differences among allele frequencieswere found with the 6-PGD isozyme system. Intrapopulationalgenetic diversity was 67% while interpopulational genetic diversitywas only 33%. The dendrogram obtained, using genetic distancesamong taxa, showed three different groups. With the exceptionofB. incana,they agree to the already accepted relationshipsamong the 14 taxa studied: the West Mediterranean group, withB.oleracea, B. alboglabra, B. bourgeauiandB. incana; another groupof species growing in the central Mediterranean area, whichincludesB. villosa, B. villosasubsp.drepanensis, B. rupestris,B. macrocarpa(the four taxa together withB. incanaare consideredtheB. rupestrisgroup) andB. montana; and finally the Aegeangroup, which includes the three subspecies ofB. cretica.Clearlyseparated wereB. insularisandB. hilarionis, showing the maximumgenetic distance. Separate dendrograms were also obtained forB.oleracea, B. montana, B. creticaandB. rupestrisgroup, and geneticdiversity parameters were estimated. Genetic distances amongB.oleraceapopulations are in the same range as populations oftheB. creticasubspecies. Highest genetic distances were foundamong populations of theB. rupestrisgroup.Copyright 1998 Annalsof Botany Company. Brassica oleraceaL., wild relatives, genetic diversity, genetic resources, isozymes.     

Allometric Root/Shoot Relationships and Predicted Water Uptake for Desert Succulents

Root morphology, shoot morphology, and water uptake for Agavedeserti and Ferocactus acanthodes of various sizes were studiedusing allometric relationships (y = ax^b) and a previously developedwater uptake model. Shoot surface area increased with shootvolume with an exponent b of 0.75 for both species. Root lengthand the ground area explored by the roots increased with shootsurface area with b's of 0.72 for A. deserti and 0.92 for F.acanthodes. Various sized individuals had about the same ratioof root length to explored ground area, with higher values occurringfor A. deserti. Predicted water uptake averaged over the exploredground area was approximately constant over a 10⁴-fold rangein shoot surface area, suggesting that shoot size confers nointraspecific competitive advantage for water uptake. For theroot lengths per explored ground area observed in the field,water uptake was predicted to be 85 per cent of maximal; wateruptake could be increased by the production of more rain roots.When differences in shoot volume were accounted for by allometry,small plants had relatively less shoot surface area and relativelymore root length per shoot volume than did large plants, whichmay be important for the water relations of seedling establishment. Agave deserti, Ferocactus acanthodes, allometry, desert succulents, root distribution, root length, seedling growth, seedling establishment, shoot surface area, shoot volume, water uptake     

Nutrient Supply, Dry-matter Production and Nutrient Uptake of Forest Tree Seedlings

The dry-matter production and nutrient uptake of forest-treeseedlings grown under controlled levels of nutrition in sub-irrigatedsand culture were investigated. Hardwood seedlings attainedgreater dry weight than conifer seedlings, and Pinus radiataa greater dry weight than P. contorta and P. nigra, but thesegreater dry weights were not related to greater leaf/weightratios, although seed size may have been an important influenceon final seedling dry weight. P. radiata was found to have alower requirement for P than P. contorta and P. nigra in oneexperiment. The demand (total nutrient uptake per unit of time) made bythree species for nutrients upon a site was shown to dependmore upon growth-rate per annum than on efficiency (quantityof nutrients required to produce a unit of dry matter). It isconcluded that the ability of tree species to grow satisfactorilyon soils of low nutrient status depends largely on their abilityfor relatively slow growth. On the other hand, species showinggood response to favourable sites may also make satisfactorygrowth on poor sites.     

Cladistic Approaches in the Study of Soil and Plant Parasitic Nematodes

Cladistic analysis of free-living soil nematodes of the Leptonchoidea(Nematoda: Dorylaimida) resulted in groupings different fromthose obtained by traditional methods. We can interpret distributionsof species groups obtained by phyletic analysis in relationto plate tectonic events. Similar techniques are applicableto plant parasitic nematodes. Grouping on the basis of synapomorphiesproduced a cladogram of genera of the family Heteroderidae (Nematoda:Tylenchida) in which Meloidodera and Cryphodera appear to bethe most ancestral genera and the cyst forming genera the mostderived. A cladogram of groups of species in Heterodera sensulato showed a major division, with the round cyst nematodesand the Cacli group in one grouping and the rest of the Heteroderaspecies in the second. I interpret present-day distributionsby a strict vicariance view and suggest potential falsifiers;and also discuss ancient dispersal routes as alternative waysof thinking about nematode distribution.     

Isozyme and RAPD Analysis of the Genetic Diversity Within and BetweenVigna luteolaandV. marina

Nineteen accessions ofVigna luteola,five ofV. marinassp.oblonga,and two ofV. marinassp.marinawere analysed using variation ofisozymes and RAPD markers to obtain better insight into geneticrelationships within and between these taxonomic entities. Thirteenputative isozyme loci were scored, seven of which were polymorphic.Both species showed very low genetic diversity indices and mostof the variation was detected among populations. Pairwise Nei'sgenetic distances based on allozyme frequencies were also verylow and the accessions ofV. marinassp.marinawere the least relatedto the others. RAPD analysis was more discriminating and 66bands out of a total of 85 were polymorphic. Based on the presenceor absence of bands, Jaccard's similarity index was calculated.Similarity ranged from 0.476 to 0.98. Matrices derived fromboth isozyme and RAPD data were used to construct UPGMA dendrograms.In the tree obtained from Nei's genetic distance, based on allozymefrequencies, accessions belonging toV. marinassp.oblongaweremixed withV. luteolaaccessions; on the other hand, the twoV.marinassp.marinaclustered separately, with oneV. luteola.Thedendrogram derived from RAPD data showed three main groups correspondingto the three taxa analysed. Moreover, according to these data,V.marinassp.oblongais more closely related toV. luteolathan toV.marinassp.marina.Copyright 1997 Annals of Botany Company Vigna luteola(Jacq.) Benth.; Vigna marina(Burm.) Merrill; isozymes; RAPDs; genetic relationships; genetic variation     

Isozyme variation in Silene pratensis: a response to different environments

The isozymes of nine enzyme systems were screened and the frequencies of the flavone glycosylating genes were determined in an outdoor experiment with 70 populations of European S. pratensis and an indoor experiment with 30 populations of the same species. Cluster analysis (using Ward's cluster criterion) were performed on all data sets. In the outdoor experiment, cluster analysis of the flavonoid data gave the same pattern that we obtained in an ealier survey of a larger set of populations and showed clearly that there are eight chemical races in European S. pratensis. No comparable geographic distributiion could be found in the isozyme data set, although the dendrogram showed two very clearly separated groups. The two groups represented the two years in which the populations were grown. This result indicates that isozyme variation in European S. pratensis is largely determined by environmental factors. Observations on changes in isozyme patterns during ontogeny and on differences between indoor and outdoor grown plants of the same F2 crosses confirm this. Differences in isozyme patterns can be caused by very small differencs in environment as is shown by the results of the indoor experiment, in which a slight gradient in environmental conditions was present in the greenhouses. The cluster analysis of the isozyme data from the indoor experiment revealed three distinct groups of populations that could be related to location within the greenhouses. As in the outdoor experiment, the dendrogram for the flavonoids gave the same geographic pattern as found with the earlier survey.     

Responses of young trees to wind and shading: effects on root architecture

Two wind tunnels were designed to detect influences of windon the development of the root systems of young trees: Piceasitchensis and Larix decidua were grown in the first and L.decidua only in the second. In the second experiment, the taproot of each L. decidua seedling was removed in order to mimicthe formation of a shallow root-plate. Responses of shoot growthto wind stress were small, although uneven irradiance levelsresulted in asymmetric growth of both shoots and roots; thedistribution of root biomass around the tree was related spatiallyto that of shoot growth In both experiments there was an increase in the number of largewindward and leeward roots in both species. In the first experiment,the sum of the crosssectional area (     

Effect of Plant Growth Promoting Bacillus Strains on Pine and Spruce Seedling Growth and Mycorrhizal Infection

Rifamycin-resistant derivatives of plant growth promotingBacilluspolymyxa strains L6, Pw-2, and S20 were used to evaluate theinteraction of bacterial–mycorrhizal co-inoculation onpine and spruce seedling growth. We were particularly interestedin determining if the mechanism by which bacteria stimulatedseedling growth depended on the presence of ectomycorrhizae.Mycorrhizal inoculum was introduced by adding 2ml of one ofsix forest floor soil types originating from different spruceand pine stands to seedling containers. Mycorrhizal roots developedin 34% of pine and 27% of spruce seedlings treated with forestsoil, but no differences between forest soils were detected.Most mycorrhizae were formed byWilcoxinasp. (E-strain) (98%for spruce and 67% for pine); small numbers ofAmphinema-like,Myceliumradicis atrovirens, Suillus-like,Thelephora-like, andTuber-likemycorrhizae were also found on pine (27% in total).Thelephora-likefungi comprised 2% of spruce mycorrhize. In the absence of bacterialinoculum, spruce seedling biomass was positively correlatedwith the number of mycorrhizal root tips, but this trend wasnot detected in spruce inoculated with bacteria or in pine.Bacterial inoculation did not influence the mycorrhizal statusof seedlings, but all threeBacillusstrains stimulated growthof both conifer species. Root biomass, in particular, was significantlyenhanced by up to 18% compared with uninoculated controls. Mycorrhizalfungi improved the growth of spruce seedlings, but plant growthpromotion byBacilluswas similar for mycorrizal and non-mycorrhizalseedlings of both species. Our results suggest thatBacillusstrainsL6-16R, Pw-2R, and S20-R enhance conifer seedling growth througha mechanism unrelated to mycorrhizal fungi. Hybrid spruce; Picea glaucaxengelmannii ; lodgepole pine; Pinus contortavar.latifoliaEngelm.; inoculation; Bacillus polymyxa; seedling growth promotion; mycorrhizae     

Genes from Nine Genomes Are Separated into Their Organisms in the Dinucleotide Composition Space

A set of 16 kinds of dinucleotide compositions was used to analyzethe protein-encoding nucleotide sequences in nine complete genomes:Escherichia coli, Haemophilus influenzae, Helicobacter pylori,Mycoplasma genitalium, Mycoplasma pneumoniae, Synechocystissp., Methanococcus jannaschii, Archaeoglobus fulgidus, and Saccharomycescerevisiae. The dinucleotide composition was significantly differentbetween the organisms. The distribution of genes from an organismwas clustered around its center in the dinucleotide compositionspace. The genes from closely related organisms such as Gram-negativebacteria, mycoplasma species and eukaryotes showed some overlapin the space. The genes from nine complete genomes togetherwith those from human were discriminated into respective clusterswith 80% accuracy using the dinucleotide composition alone.The composition data estimated from a whole genome was closeto that obtained from genes, indicating that the characteristicfeature of dinucleotides holds not only for protein coding regionsbut also noncoding regions. When a dendrogram was constructedfrom the disposition of the clusters in the dinucleotide space,it resembled the real phylogenetic tree. Thus, the distinctfeature observed in the dinucleotide composition may reflectthe phylogenetic relationship of organisms.     

Phylogenetic relationships in the family Resedaceae L.

A study was made on the phylogenetic relationships of species of the family Resedaceae, based on morphological features, chromosome meiotic behaviour, karyotype features, size and fertility of pollen grains, nucleotypic parameters, seed protein profiles and esterase isozyme patterns.For the comparison of the seed protein profiles among species a method was developed based on the presence or absence of the bands by means of a computer program. The dendrogram obtained by such a method is in line, to a great extent, with the clusters (sections) obtained within the family based on morphological features.Data on meiotic behaviour and on morphology, such as the type of fruit, carpel numbers and others, suggest that x=5 is the primitive basic chromosome number of this family. x₁=6 and x₂=7 are considered as secondary basic numbers derived from x=5 through aneuploid changes.The results support a proposed phylogenetic tree of the genera and sections of the genus Reseda represented in the European Flora.The principal phenomena that have operated in the evolution of the Resedaceae seem to be aneuploid changes, polyploidy and structural rearrangements. A trend towards DNA increase in the evolution of this group is also apparent.     

Phylogenetic relationships among five species of starfish of the genus,Asterina: an electrophoretic study

• 1.1. Variations and similarities of seven different enzyme systems were analysed electrophoretically in and among five species of starfish belonging to the genus Asterina, and the dendrogram showing their phylogenetic relationships was constructed.
• 2.2. Electrophoretic data thus obtained agrees well with the phyletic relationships inferred from the immunological, morphological and embryological evidence.

     

Genetics of adaptive radiation in Hawaiian and Cook Islands species of Tetramolopium (Asteraceae; Astereae). I. Nuclear RFLP marker diversity

Thirty-three nuclear RFLP (restriction fragment length polymorphism) probes were used to study genetic diversity in Hawaiian and Cook Islands species of Tetramolopium for comparison with previous morphological and isozyme studies and to provide greater resolution of the events associated with adaptive radiation in the genus. Levels of RFLP diversity are greater than those reported for isozymes, yet are still low in comparison to continental species. Genetic differentiation is greatest among species in sections rather than among sections and is concordant with the hypothesis of phyletic sorting of initial variability as suggested for morphological traits. Hypothesized introgression between T. lepidotum and T. filiforme is supported, but the evidence suggests bidirectional gene flow. Systematic relationships derived from the data agree with hypotheses based on morphology in the placement of populations within their respective species and the recognition of three main lineages within Hawaii. Inclusion of the Cook Islands species, however, renders section Tetramolopium paraphyletic, contradicting morphological, ecological, and crossing evidence. Interpreting these results in light of evidence from previous studies, the genetic diversity and relationships seen among species and sections of Hawaiian and Cook Islands Tetramolopium reflect the recent and rapid evolution of this group, limited addition of new variability, and phyletic sorting.     

Comparative Growth Behaviour and Leaf Nutrient Status of Native Trees Planted on Mine Spoil With and Without Nutrient Amendment

The effect of nutrient amendment on growth of nine indigenoustree species planted on coal mine spoil was studied. Greatergrowth in fertilized plots was accompanied by greater foliarN and P concentrations in all species. The response to fertilizationvaried among species and was greater in non-leguminous thanin leguminous species. Furthermore, leguminous species exhibitedhigher growth rates compared to non-leguminous species. Thelog-transformed height-diameter relationships were significantfor all tree species and treatments. Acacia catechu, Dalbergiasissoo, Gmelina arborea and Azadirachta indica fitted the elasticsimilarity model of tree growth; whereas Pongamia pinnata andPhyllanthus emblica followed the constant stress model. Tectonagrandis was the only species which fitted the geometric similaritymodel. In Albizia lebbeck and Terminalia bellirica, the b -values(the gradients of the log-transformed height to diameter relationships)were considerably lower (<0.5), and these two species didnot fit any model of tree growth. In several cases, the b -valueswere considerably influenced by nutrient amendment. The log-transformedcrown mass and trunk mass relationships were significant forall treatments and species. The slope of the crown mass:trunkmass relationship was near unity in A. indica, D. sissoo, G.arborea, P. emblica, P. pinnata, T. grandis, and T. bellirica.However, in A. catechu and A. lebbeck, this slope was well belowunity suggesting a greater allocation to non-photosynthetictissue. Fertilizer amendment resulted in a heavier crown relativeto trunk in A. indica, T. grandis and T. bellirica. Copyright2001 Annals of Botany Company Diameter increment, fertilizer application, foliar N, foliar P, height increment, tree growth, volume increment     

Biodiversity of Convolvulaceous species that contain ergot alkaloids,indole diterpene alkaloids,and swainsonine

Convolvulaceous species have been reported to contain several bioactive principles thought to be toxic to livestock including the calystegines, swainsonine, ergot alkaloids, and indole diterpene alkaloids. Swainsonine, ergot alkaloids, and indole diterpene alkaloids are produced by seed transmitted fungal symbionts associated with their respective plant host, while the calystegines are produced by the plant. To date, Ipomoea asarifolia and Ipomoea muelleri represent the only Ipomoea species and members of the Convolvulaceae known to contain indole diterpene alkaloids, however several other Convolvulaceous species are reported to contain ergot alkaloids. To further explore the biodiversity of species that may contain indole diterpenes, we analyzed several Convolvulaceous species (n = 30) for indole diterpene alkaloids, representing four genera, Argyreia, Ipomoea, Stictocardia, and Turbina, that had been previously reported to contain ergot alkaloids. These species were also verified to contain ergot alkaloids and subsequently analyzed for swainsonine. Ergot alkaloids were detected in 18 species representing all four genera screened, indole diterpenes were detected in two Argyreia species and eight Ipomoea species of the 18 that contained ergot alkaloids, and swainsonine was detected in two Ipomoea species. The data suggest a strong association exists between the relationship of the Periglandula species associated with each host and the occurrence of the ergot alkaloids and/or the indole diterpenes reported here. Likewise there appears to be an association between the occurrence of the respective bioactive principle and the genetic relatedness of the respective host plant species.     

Isoforms of NADP-dependent Malic Enzyme in Tissues of the Greening Maize Leaf

Scagliarini, S., Pupillo, P. and Valenti, V. 1988. Isoformsof NADP-dependent malic enzyme in tissues of the greening maizeleaf.—J. exp. Bot. 39: 1109–1119. The compartmentation of the isoforms of NADP-dependent malicenzyme (E.C. 1.1.1.40 [EC] ) has been studied in cell-free extractsand in enzymatically-isolated protoplasts of mesophyll tissue(MT) and bundle sheath (BS) strands of greening maize leaves.The etiolated leaf of 10-d-old seedlings contains a cytosolicisozyme with a pl of 5.4 ?0.1 at low specific activity (s.a,45 ? 3 nmol min^–1 mg^–1 protein), found both in MTand BS. The green leaf on the other hand contains the dominantBS chloroplast isozyme with pl 4.6 ? 0.2 at a s.a, of 370 ?40 nmol min^–1 mg^–1 protein (3.2 ? 0.5 µmolmin^–1 mg^–1 chl) and a minor, previously undescribedisoform with pl 6.5 ? 0.1 also localized in the BS at a s.a.of 38 ? 6 nmol min^–1 mg^–1 protein. Green MT protoplastshave only traces of pl 4.6 isozyme. After illumination of dark-grown seedlings, the total leaf activityshows a rapid increase (1.5-fold within 2 h), attributed mainlyto the pl 5.4 isozyme of MT protoplasts and BS strands. Thisis followed by a large increase of enzyme activity due to thecontinued rise of pl 5.4 isozyme for about 24 h and, after aninitial lag of a few hours, to the accumulation of pl 4.6 isozyme.After 18 h illumination, pl 4.6 and 5.4 isozyme activities tendto decline in the MT whereas they are still increasing in theBS, particularly the former. This pl 4.6 species has becomethe major one by 48 h illumination. The final pattern of greenleaves is established around 96 h light, when the chloroplastisozyme has attained its maximum level, the pl 5.4 isozyme ofBS strands has been superceded by the pl 6.5 species (also supposedto be cytosolic) and MT protoplasts retain little residual activity.Some metabolic implications of the changing pattern of NADP-dependentmalic isozymes during maize leaf greening are discussed. Key words: C₄, isozymes, malic enzyme, photodifferentiation, Zea mays