Showing papers in "International Journal of Plant Sciences in 2015"
TL;DR: A suite of N fixers, methanotrophs, cobalamin producers, and early-diverging fungi was consistently associated with modern streptophyte algae and bryophytes studied, suggesting features of early land plants that have played significant, previously unrecognized roles in global nitrogen and carbon cycling for hundreds of millions of years.
Abstract: Premise of research. The origin of land plants catalyzed key changes in Earth’s atmosphere and biota. Microbial associations likely nurtured earliest plants and influenced their biogeochemical roles. Because angiosperm and animal microbiomes—bacteria, archaea, microbial eukaryotes, and genes that promote host survival—are known to display lineage effects, we hypothesized that microbiomes of early-diverging modern bryophytes and phylogenetically closely related green algae might likewise reveal commonalities reflecting ancestral traits.Methodology. New metagenomic sequence data were obtained for the late-diverging streptophyte algae Chaetosphaeridium globosum and Coleochaete pulvinata and the liverwort Conocephalum conicum, representing early-diverging land plants. New 16S rDNA amplicon sequences were acquired for the charalean Nitella tenuissima. Sequence data were used to infer bacterial genera and fungi for comparisons among streptophyte microbiota and with our published microbiome data for the outgroup...
75 citations
TL;DR: These data demonstrate that botanic garden collections can better conserve the genetic diversity of in situ cycad populations if four recommendations are followed.
Abstract: Premise of research. Conservation of plant species often requires ex situ (off-site) cultivation of living collections. Cycads constitute the most imperiled major group of plants, and ex situ collections are an important part of conservation planning for this group, given seed recalcitrance, difficulties with tissue culture, and ongoing in situ threats. Very little is known about the genetics of ex situ conservation collections of cycads. Thus, this study seeks to illuminate how well an ex situ collection of a cycad can capture the diversity in a wild population.Methodology. A model species, Zamia decumbens, was chosen on the basis of geographic isolation and detailed census knowledge, which allowed near-total sampling of in situ plants. Overall, 375 in situ plants were compared to 205 ex situ plants via 10 microsatellite markers.Pivotal results. Genetic-distance analysis shows high fidelity of the ex situ collections to their in situ source populations as well as clustering of ex situ progeny by accessio...
68 citations
TL;DR: Bees could identify whether a flower offered pollen and could quantify the number of pollen-rewarding flowers, which suggests that selection of floral display size by pollinators may differ between plants with different mating systems.
Abstract: Premise of research. The size of floral display, flower, and reward can influence pollinator foraging behavior. However, the importance of correlations between floral traits and rewards in affectin...
34 citations
TL;DR: The results indicate that the Tehuantepec Isthmus, the Nicaraguan Depression, and the Panamanian IsthMus have acted as important barriers to the dispersal of oak species, influencing species diversity, biogeographic patterns, and niche divergence.
Abstract: Premise of research. The most important diversity hot spot of genus Quercus (Fagaceae) in America is situated in southern Mexico. From this area down to the Colombian Andes, oak species diversity decreases considerably, but the pattern of species distribution and turnover has not been analyzed. This study aimed at determining geographical patterns of species turnover, species distribution, and endemism for Neotropical Quercus species.Methodology. Occurrence records for 58 oak species belonging to the Quercus and Lobatae sections were obtained. Patterns of species turnover were determined by comparing species composition among latitudinal/longitudinal units. Areas of endemism were determined using weighted networks. The potential distribution of oak species was determined using ecological niche models. Finally, a principal component analysis was used to identify changes in the oak species’ ecological niche across areas.Pivotal results. The species composition analysis indicated that the Tehuantepec Isthmus...
32 citations
TL;DR: A phylogenetic framework of Blepharis is presented and hypotheses of where and when C4 photosynthesis evolved in the genus are presented, suggesting that it evolved two or three times in southern Africa and Asia between 1 and 5 million years ago.
Abstract: Premise of research. Plants with C4 photosynthesis are able to produce carbohydrates more efficiently than plants with C3 photosynthesis in warm climates when levels of atmospheric CO2 are reduced. The C4 pathway has evolved multiple times in distantly related lineages, but it is not known whether the same physiological transitions occurred in all lineages. Species with intermediate C3-C4 physiology and anatomy offer the opportunity to study how plants transition from C3 to C4. It is thus vital to characterize phylogenetic relationships and photosynthetic pathways in groups with C3-C4 intermediate species, as well as C3 and C4 species.Methodology. We assessed photosynthetic pathway evolution in the Afro-Asian genus Blepharis (Acanthaceae) by sampling 99 species for carbon isotope ratios, 18 species for leaf anatomy, and 36 species for phylogenetic analysis. We estimated when Blepharis clades diverged using a BEAST molecular dating analysis, and we estimated ancestral distributions using BioGeoBEARS. We al...
31 citations
TL;DR: The data suggest that Haberlea rhodopensis may have acted as a persistent refugial area in southeast Europe since the mid-Tertiary, and shed light on historic and current phylogenetic and phylogeographic events that shaped the flora of the Balkan Peninsula.
Abstract: Premise of research. Even though the Balkan Peninsula is a biodiversity hot spot in southeastern Europe harboring many endemic plants, very little is known about the temporal extent of the phylogeographic history and the contemporary genetic diversity of the endemics there. Haberlea rhodopensis is one of the European Gesneriaceae species occurring in this region and represents appropriate study material to address these questions.Methodology. We generated fossil-dated molecular phylogenies (atpB-rbcL, trnH-psbA, trnLF, ITS) across the Lamiales to determine the origin and age of H. rhodopensis and conducted phylogeographic (trnH-psbA, ITS) and population genetic (ISSRs) analyses on 17 populations from Bulgaria and Greece, covering the entire distribution range of the species, to investigate their biogeographic history, present-day genetic diversity, and differentiation levels.Pivotal results. The European Gesneriaceae genera have a Tertiary origin in the early Oligocene, while the Haberlea lineage emerged ...
29 citations
TL;DR: The results—coupled with previous demonstrations of chemotype-influenced differential herbivory and parasitism—illustrate the complex influences of genetic variability on multispecies interactions and the individuality of species responses to toxic chemicals.
Abstract: Thymus vulgaris has a chemical polymorphism in which individual plants have an essential oil dominated by either nonphenolic (geraniol, -terpineol, cis-sabinene hydrate, linalool, or 1,8-cineole) or phenolic (carvacrol and thymol) monoterpenes. Using the geraniol, cis-sabinene hydrate, and the two phenolic chemotypes, we tested three hypotheses: (1) chemotypes vary in their influences on germination and growth of associated plant species, (2) associated species respond differentially to individual chemotypes, and (3) soils under thyme canopies will influence associated species differently than do sterile soils. The study was done in Montpellier, France, in settings mimicking natural conditions. In one experiment, survival of both monocots and dicots from the seed bank was lower in soils collected from under thyme plants of the phenolic chemotypes. In a second experiment, we sowed seeds of Daucus carota, Nigella damascena, and Bromus madritensis into soil collected from under thyme plants and covered with ...
29 citations
TL;DR: Krassilovia mongolica provides evidence of the additional diversity of extinct voltzian conifers and shows that some persisted to inhabit forest-moor swamp environments in eastern Asia during the Early Cretaceous.
Abstract: Premise of research. Abundant fossil and molecular evidence suggests that all extant conifer families were established by the Early Cretaceous. However, the recognition and understanding of the lineages that lead to the evolution of these extant families remain incomplete. Late Paleozoic to Early Mesozoic Voltziales conifers—also known as transitional conifers, usually with multilobed ovuliferous scales—have been hypothesized to be among the stem lineages of modern crown conifers. This article describes an exquisitely preserved voltzian seed cone from the Aptian-Albian of Mongolia that introduces new taxonomic diversity and morphological data into the complex pattern of conifer evolution.Methodology. Bulk lignite samples collected from the Tevshiin Govi locality were disaggregated in water, cleaned with hydrochloric and hydrofluoric acids, washed, and dried in air. Fossils were examined using LM, SEM, and X-ray microtomography.Pivotal results. Krassilovia mongolica gen. et sp. nov. has seed cones with hel...
28 citations
TL;DR: Advances in flowering times were comparable to those in other north temperate studies, as was the large change in spring-flowering species, and results of simulations and comparisons across studies suggest that sampling error may contribute substantially to reported variation among species.
Abstract: Premise of research. Flowering times are sensitive indicators of climate change. This study explores important methodological issues in the use of samples of phenological records, quantifies change in flowering times, and examines causes of variability among species.Methodology. I used Monte Carlo simulations to explore effects of sample size on estimates of phenological statistics. I documented 60 yr of change in temperature and flowering times of forbs in Worcester County, Massachusetts, a largely nonurban area, using a combination of herbarium specimens and observations, and I tested several hypotheses using these data. I also compared changes in flowering times in eastern North America from several published studies.Pivotal results. Average spring temperatures increased 1.4°C (0.24°C/decade) during the last 60 yr. Mean and median flowering dates were most robust for small sample sizes, while early and late flowering dates and ranges were least stable. Mean flowering time advanced 2.9 d (0.4°C/decade),...
28 citations
TL;DR: These Miocene fossils are the first confirmed occurrence of this genus in the Southeast Asian fossil record, and supports the possibility that southeastern Yunnan was already experiencing frost-free winters and seasonal precipitation with wet summers and relatively dry winters.
Abstract: Premise of research. Burretiodendron Rehder is a genus of six species that are mainly found on limestone in Southeast Asian mountain forests with a monsoonal climate. Recent molecular evidence supports its placement in Malvaceae s.l. Presently, two species of Burretiodendron have been classified as vulnerable according to the International Union for the Conservation of Nature. Fossil Burretiodendron is also extremely rare in the record, and little is known about its evolutionary history.Methodology. Fossil fruits and leaves were collected from upper Miocene sediments in Yunnan (SW China). Their macro and micro morphology were studied and compared with all extant species of Burretiodendron and with species of fossil and extant Craigia W.W. Sm. & W.E. Evans having somewhat similar fruits.Pivotal results. We recognize fossil remains of Burretiodendron on the basis of fruits described as Burretiodendron parvifructum sp. nov. and associated leaves of Burretiodendron miocenicum sp. nov.Conclusions. These Miocen...
28 citations
TL;DR: It is argued that high genetic diversity of populations might represent increased probability of possessing alleles or allele combinations that are advantageous or more capable in terms of average response capacities to environmental change, and genetic diversity might be an important property of plant populations for their short-term response capability against adverse effects of climate change.
Abstract: Premise of research In the future, ecosystems will have to deal with climate warming in combination with increasing frequency and magnitude of extreme weather events such as drought Adaptive phenotypic plasticity enables plants to respond to environmental variability and is likely to buffer impacts of climate change Therefore, factors that influence the phenotypic plasticity of plant populations must be identified to assess climate change outcomes and support conservation measures Genetic diversity in many temperate plant species is known to vary among regions and populations, largely as a result of their phylogeographic history during the late Pleistocene and Holocene Here, we argue that high (neutral) genetic diversity of populations might represent increased probability of possessing alleles or allele combinations that are advantageous or more capable in terms of average response capacities to environmental change Methodology We test this idea for European beech (Fagus sylvatica) by investigatin
TL;DR: The topography and components identified in the secretion of the colleters suggests that such structures may be involved in the protection of developing leaves and flowers in Chamaecrista.
Abstract: Premise of research. Colleters are structures that secrete a sticky product that covers and protects the shoot apex and floral buds. In Chamaecrista, colleters have been reported in the cotyledons of three species and on the leaves of all species belonging to sect. Absus subsect. Baseophyllum. Anatomical studies using taxonomic and phylogenetic approaches are necessary to evaluate the presence, diversity, and importance of colleters for Chamaecrista.Methodology. We analyzed 55 species of Chamaecrista belonging to five of the six sections of the genus. Samples from both herbarium- and field-collected material of young vegetative and reproductive meristems were used. The material was subjected to standard anatomical study by light microscopy and SEM, and secretion was evaluated by histochemical analyses.Pivotal results. Histochemical analyses for the total proteins, total polysaccharides, acid mucopolysaccharides, pectins/mucilage, and lipids generated positive results. Six types of colleters are described ...
TL;DR: This clade represents only a moderate-sized radiation of the Caribbean clade; however, the convergent nature of character evolution and the lack of unique synapomorphies for subclades underscore the lability of morphological characters in this group and the difficulty in recognizing these clades from a purely morphological standpoint.
Abstract: Premise of research. The Sandpaper clade comprises a group of taxa endemic to the Greater Antilles and forms a subgroup of a larger Caribbean assemblage of Miconieae. Numerous species within this monophyletic group share striking morphological characters and thus traditionally have been considered close relatives. Recent phylogenetic work has shown that not all of these species are each other’s closest relatives, and they actually form three distinct clades: the Lima, Paralima, and Pseudolima clades. We reconstructed a phylogeny of these poorly known species to test patterns of morphological evolution and the biogeographic history of the clade.Methodology. We reconstructed a phylogeny of the Sandpaper clade using two plastid intergenic spacers (accD-psaI, psbK-psbL) and two nuclear ribosomal spacers (ITS, ETS) and then sequenced three more plastid spacers for the Lima clade (rpl32-trnL, trnV-ndhC, trnH-psbA) to provide better resolution among those species. The biogeographic history and the evolution of m...
TL;DR: This review attempts to show how, by using this “next-generation evo-devo” approach, insights into both developmental biology and evolutionary biology can be gained.
Abstract: Evolutionary developmental biology has come to prominence in the past two decades, in both the plant kingdom and the animal kingdom, particularly following the description of homeotic genes linked to key morphological transitions. A primary goal of evolutionary developmental biology (“evo-devo”) is to define how developmental programs are modified to generate novel or labile morphologies. This requires an understanding of the molecular genetic basis of these programs and of the evolutionary changes they have undergone. The past decade has seen the establishment of a common language and common standards, and these changes have greatly improved the integration of evo-devo. Recently, a more comparative approach has been added to mechanistic developmental biology. In this review we attempt to show how, by using this “next-generation evo-devo” approach, insights into both developmental biology and evolutionary biology can be gained. Although the concepts we discuss are more broadly applicable, we have focused ...
TL;DR: Observations clearly indicate that glands on the inflorescence axis of C. glandulosus are resin-secreting colleters that may have important protective functions, and is the first report of the occurrence of colleters onThe inflorescences of a Croton species.
Abstract: Premise of research. Croton glandulosus L. is a ruderal annual species of Euphorbiaceae native to the American tropics and widespread in urban and rural areas in Brazil. We investigated the structure, histochemistry, and ultrastructure of glands on the inflorescence axis of C. glandulosus to explore the relationship between their structure and function.Methodology. Reproductive apexes were prepared according to standard methods for plant anatomy, SEM, and TEM. Histochemical tests were performed using fresh material.Pivotal results. Mature glands are bowling pin shaped and are differentiated into a single-layered secretory epidermis arranged radially around a parenchymatous central axis supplied with xylem. In the neck region of the glands, the epidermal cells present structural components typical of lipophilic secretion, whereas the parenchyma cells are specialized in the production of hydrophilic compounds. The resinous secretion is released by cuticle pores occurring exclusively on the tip of the gland....
TL;DR: A new, morphologically distinct, anatomically preserved conifer assignable to the basal Cupressaceae, which was subject to arthropod infestation during life, is discovered within a marine carbonate concretion from the Coniacian (Late Cretaceous) Eden Main locality of Vancouver Island, British Columbia.
Abstract: Premise of research. A new, morphologically distinct, anatomically preserved conifer assignable to the basal Cupressaceae, which was subject to arthropod infestation during life, has been discovered within a marine carbonate concretion from the Coniacian (Late Cretaceous) Eden Main locality of Vancouver Island, British Columbia.Methods. Specimens were studied from anatomical sections prepared using the classic cellulose acetate peel technique.Pivotal results. This plant, described as Acanthostrobus edenensis gen. et sp. nov., has helically arranged needle leaves and terminal seed cones composed of numerous helically arranged bract/scale complexes dominated by the bract. Both vegetative leaves and bracts display exceptionally long, narrow tips that may have been involved in predator deterrence. The seed cone has diminutive ovuliferous scales with free distal margins; bract/scale complexes bear two to four small, secondarily inverted ovules. Cone tissues contain arthropod feeding galleries surrounded by nec...
TL;DR: The high diversity of growth forms observed in Piperales is linked to frequent shifts in cambial activity and changes in habit-related features within the different lineages, suggesting a single origin of wood in the order.
Abstract: Premise of research. Piperales displays a wide diversity of growth forms that appears to be linked with differences in cambial activity and subsequent derived wood production. To date, no overall s...
TL;DR: Floral ontogeny in Amburana deviates considerably from the unidirectional pathway that is a common pattern among more derived papilionoid lineages and contributes to a better understanding of early-branching papilionoids and their systematic relationships.
Abstract: Premise of research. We present a detailed analysis of the floral ontogeny of Amburana cearensis, which is an early-branching papilionoid legume with an unusual floral morphology. Especially the reduced one-petalled corolla is noteworthy and stimulates the question about the ontogenetic background of this reduction. Are all five petals initiated and later reduced, or are four petals completely lost (i.e., without any primordia evident)? Ontogenetic studies of early-branching papilionoids provide important insights for the understanding of relationships down to caesalpinioid legumes and up to derived papilionoid lineages.Methodology. We analyzed inflorescences, flowers, and flower buds with the SEM using standard procedures.Pivotal results. Sepals and petals are initiated bidirectionally, which is a rare character among papilionoid legumes. The reduced one-petalled corolla is the result of early suppression of four petal primordia. Stamen formation is in reversed unidirectional order starting from the adax...
TL;DR: The micromorphologies and anatomical features of crested sepals are diverse even though convergences in terms of epidermal topology and the occurrence of vascular tissues in elaborate structures also occur among independently evolved crested lineages in Iris.
Abstract: Premise of research. The Iris flower is considered to be a pseudoinflorescence by having three pollination units, each acting as a labiate flower. The sepal provides the entrance, “floor,” and “walls” of the pollination tunnel and is sometimes adaxially elaborated with various structures, such as ridges, crests, and protuberances. Crested sepals have a prominent median crest that lies along the proximal-distal axis of the pollination tunnel and sometimes also have various lateral structures on the entrance, floor, or walls of the pollination tunnel, suggesting that they may play a role in pollination. Crested sepals are morphologically diverse and have evolved at least five times in Iris. Understanding their micromorphology and anatomy will shed light on the diversification of perianth and provide insights into flower-pollinator interaction.Methodology. Micromorphologies of the adaxial epidermis and anatomical characteristics of selected crested sepals representing different patterns of structural elabora...
TL;DR: The results reveal an important effect of temperature on increasing floral maintenance costs, imposing selective pressures on flower size, and longevity in large-flowered Mediterranean plants.
Abstract: Premise of research. Larger and longer-lived flowers are more frequently pollinated, but they are associated with high maintenance costs due to greater water usage. The Mediterranean climate limits plant reproduction and maximizes resource use efficiency, so smaller and short-lived flowers are potentially advantageous under hot and dry conditions.Methodology. We experimentally evaluated the relationship between the floral longevity of Cistus ladanifer, a large-flowered Mediterranean shrub, and pollination, flower size, and temperature at two different altitudes with contrasting climatic conditions. We hypothesized that flower size and longevity would be reduced in the drier and hotter conditions of the lower-altitude site. In addition, we expected that floral longevity would decrease with experimental pollen deposition, flower size, and temperature. We pollinated and capped flowers to evaluate the variation in floral longevity by comparing actual and potential floral longevity at low and high altitudes.Pi...
TL;DR: The phylogeny, biogeographical history, and evolution of edaphic association in Sempervivum and Jovibarba (Crassulaceae), two oreophytic genera of the mountain flora of Europe and adjacent areas, were reconstructed and it was showed that SemperVivumand JovIBarba are monophyletic sister genera.
Abstract: Premise of research. We reconstructed the phylogeny, biogeographical history, and evolution of edaphic association in Sempervivum and Jovibarba (Crassulaceae), two oreophytic genera of the mountain flora of Europe and adjacent areas.Methodology. Using two nuclear markers (internal transcribed spacer and parts of intergenic spacer) and three chloroplast DNA markers (atpI-atpH, rps16-intron, trnQ-rps16) for 44 of the 48 species recognized in the two genera, we obtained a molecular phylogenetic hypothesis on relationships between and within the two genera. This phylogeny was dated and used for the reconstruction of ancestral distribution areas and the evolution of edaphic association.Pivotal results. Our analyses showed that Sempervivum and Jovibarba are monophyletic sister genera. Several well-supported intrageneric clades were recovered in our nuclear phylogeny, which generally were not supported by our chloroplast data. This incongruence most likely results from hybridization. The split between the two ge...
TL;DR: The structural development and morphology of these adhesive pads of Passiflora discophora are investigated and the underlying structure-function relationship of the attachment process is understood to understand the general strategies of this mode of attachment.
Abstract: Premise of research. Passiflora discophora is exceptional among passion flowers for its climbing strategy, using branched tendrils with terminal adhesive pads instead of coiling tendrils as typical within this family. This article investigates the structural development and morphology of these adhesive pads and aims to understand the underlying structure-function relationship of the attachment process. Based on our results, we discuss possible mechanical consequences of the tendril structure and compare our findings with similar attachment systems in unrelated species in order to identify general strategies of this mode of attachment.Methodology. We investigated the temporal development of the attachment process, including detailed studies of the morphology and anatomy of the adhesive pads, using LM with different staining procedures and SEM.Pivotal results. Young tendrils establish initial contact with a supporting substrate by interlocking with their hook-shaped tips. Touch stimuli induce the tips to de...
TL;DR: The polybotryoid fern clade, which consists of Cyclodium, Maxonia, Olfersia, Polybotrya, and Polystichopsis, was strongly supported as monophyletic, as were its component genera.
Abstract: Premise of research. The polybotryoid fern clade is completely Neotropical and consists of Cyclodium, Maxonia, Olfersia, Polybotrya, and Polystichopsis. It has never received a detailed phylogenetic analysis. We performed such an analysis to examine the relationships among species and genera and to map the evolution of their morphological and anatomical characters.Methodology. Our study included 46 (77%) of the 60 species in the clade. It also included 37 outgroup species from 19 genera. We sequenced four plastid DNA markers (rbcL, rps4-trnS, trnG-trnR, and trnL-trnF) and analyzed the data with maximum likelihood and Bayesian inference. One anatomical and 11 morphological characters were mapped on the resulting phylogenetic trees using the criterion of maximum parsimony.Pivotal results. The polybotryoid clade was strongly supported as monophyletic, as were its component genera. Nearly all its species have long-creeping rhizomes. Polystichopsis was resolved sister to the other polybotryoid genera. Its mono...
TL;DR: The murundus function as critical bases for the maintenance of species diversity in this extensive floodplain, thereby deserving recognition among ecosystems with high conservation priorities.
Abstract: Premise of research. This represents one of the first studies of the ecology, diversity, and structure of campos de murundus termite savannas in the vast seasonal wetlands of southern Amazonia. We aimed to improve understanding of this threatened system by assessing species richness, abundance, and co-occurrence among trees and herbs of murundus (earth mounds), investigating the environmental and biological mechanisms underlying these patterns, and discussing implications for biodiversity conservation.Methodology. We identified every tree, shrub, subshrub, and herb on 373 murundus across 11 ha at Araguaia State Park, southern Amazonia. We constructed species abundance distributions of trees and herbs, assessed best-fit models, and tested for nonrandom patterns of species co-occurrence using checkerboard scores. Using detrended correspondence analysis (DCA), we assessed the affinities among tree species and their positions in murundus.Pivotal results. A total of 166 species, 123 genera, and 49 families occ...
TL;DR: The results suggest that the small balsam, Impatiens parviflora, generally copes well with shady conditions and shows physiological traits that allow plant growth under contrasting and stressful environments.
Abstract: Premise of research. Invasive plants usually have growth and reproductive abilities that allow them to cope with new habitats and environments. The small balsam, Impatiens parviflora, is one of the most widespread annual invasive species in Europe. As no precise physiological assessment for this species has been performed, we compared physiological traits linked to growth performance in contrasting environments.Methodology. Plants were cultivated in growth chambers under four different treatments varying by light and water conditions. We assessed the impact of water stress and low light levels on traits related to plant growth, leaf physiology, photosynthesis, and water status.Pivotal results. Tolerance of low light level was reflected by several morphological and physiological characteristics. The number of leaves initiated was not affected by light condition, whereas specific leaf area increased for plants grown under low light. In addition, the chlorophyll fluorescence parameters revealed that low ligh...
TL;DR: It is demonstrated that both resistance and tolerance increase with ontogeny and that the cost of tolerance and a pronounced trade-off between resistance andolerance faded through ontogenY.
Abstract: Premise of research. As plants grow and develop larger roots and leaves, their access to resources increases. Consequently, reproductive plants should be able to invest in defense against herbivores more than younger plants. However, because plant defense may occur through resistance (traits that reduce herbivore damage) or tolerance (traits that reduce the negative effects of damage on plant fitness), ontogenetic changes in the pattern of resource allocation to growth, defense, and reproduction are likely to influence the relative investment in resistance and tolerance. Currently, many mechanisms of resistance are known, while mechanisms of tolerance are still rather unexplored. We investigated whether resistance and tolerance increase with ontogeny, whether tolerance is costly (i.e., lower seed production in the absence of damage), whether the relative investment into these two modes of defense changes with ontogeny, and whether plant growth rate and certain biomass allocation patterns are associated wi...
TL;DR: Eocene Ginkgoites patagonica was present in plant communities, and it is the last representative of a still poorly understood southern ginkgophyte lineage that was distinct from the ancestors of G. biloba of the Northern Hemisphere.
Abstract: Premise of research. The ginkgophytes are an ancient group of gymnosperms with a long history starting during the late Paleozoic and reaching the present with the unique species Ginkgo biloba L. In order to better characterize the early and middle Eocene (ca. 52.2 and 47.7 Ma) leaf species Ginkgo patagonica Berry from northwest Patagonia, Argentina, new specimens were studied, focusing on their morphological and anatomical characters.Methodology. The specimens were studied with LM, epifluorescence, SEM, and TEM.Pivotal results. The diagnosis of the species Ginkgoites patagonica comb. nov. is enlarged to include anatomical and ultrastructural epidermal characters. Herein, the species Ginkgo patagonica is shown to have characteristics that clearly separate it from the genus Ginkgo L., and it is therefore recombined to the genus Ginkgoites Seward.Conclusions. Eocene Ginkgoites patagonica was present in plant communities, and it is the last representative of a still poorly understood southern ginkgophyte line...
TL;DR: Elevated temperature, UV, and temperature-UV interactions affect peatmoss biomass, wall chemistry, and anatomy in ways that could influence environmental roles and Functionally important traits affected by temperature or UV are recommended for assessment in field studies.
Abstract: Premise of research. Sphagnum peatmosses strongly influence local and regional hydrology and biotic communities and based on high abundance at high latitudes also play a global environmental role in maintaining atmospheric chemistry and climate homeostasis. Previous field research suggests that elevated temperature linked to global climate change or elevated UV related to ozone depletion at high latitudes affects aspects of peatmoss productivity or external morphology hypothesized to influence environmental roles. However, changes in microscopic anatomy or potential temperature-UV interaction effects have not previously been investigated. Controlled environments offer advantages for assessing anatomical impacts of temperature and UV variation and detecting temperature-UV interactions.Methodology. Clonal cultures of experimentally tractable Sphagnum compactum were treated for a 2-mo period with environmentally relevant temperature levels (10°, 20°, and 30°C) and two levels of UV-A + UV-B found in a pilot s...
TL;DR: The results of this study support the idea that established populations can persist through cloning and that migration can occur over large physical distances.
Abstract: Premise of research. If sexual reproduction is necessary for maintaining genotypic diversity, then plant populations lacking sex might be expected to exhibit less genotypic diversity than sexually reproducing populations. This pattern could be particularly pronounced in mosses of harsh environments, where haploid gametophytes persist in the apparent absence of sex, presumably through vegetative cloning. Here we compare genetic diversity in four Mojave Desert populations of the moss Syntrichia caninervis to assess the degree to which sexual reproduction is associated with genotypic diversity. This study helps define the role of reproductive modes in producing and maintaining genetic diversity.Methodology. Eight microsatellite loci were used to genotype four Mojave Desert populations of S. caninervis, which consisted of two sites with lower environmental stress and sexual reproduction and two sites with higher stress and no apparent sexual reproduction.Pivotal results. Of 341 ramets that amplified successfu...
TL;DR: A study of efficacy of different antibiotics for management of bacterial blight disease of pomegranate caused by Xanthomonas axonopodis pv.
Abstract: A study of efficacy of different antibiotics for management of bacterial blight disease of pomegranate caused by Xanthomonas axonopodis pv. punicae was conducted during the year 2010-12 at College of Agriculture, Osmanabad. In vitro study revealed that antibiotic streptocycline showed maximum inhibition zone of 22.21 and 31.60 per cent at 250 and 500 ppm concentrations against X. axonopodis pv . punicae , followed by tetracycline (18.26 and 27.53 %) and bacterinol (17.40 and 27.15 %) the least inhibition of bacterial growth was observed in cefaclore (13.08 and 17.53 %), respectively. Among seven botanicals neem oil showed maximum inhibition at all concentration (5, 10, 15 and 20 %) followed by garlic, neem leaf extract, tulasi leaf extract, ginger extract, guava leaf extract and aloe vera, respectively. The bacterial antagonistic viz., Pseudomonas fluorescens and Bacillus substilis were found effective in inhibiting the test pathogen at 15.43 and 12.71 per cent, respectively. Based on the efficacy of these different antibiotics, bioagents and plant extracts, the best one were applied in integrated management schedule for mitigating bacterial blight of pomegranate. The schedule was applied at five different locations in Marathwada region of Maharashtra. At the time of adoption of orchards, the per cent disease severity observed in the orchard at Kelewadi, Wagholi, Sakanewadi, Hol and Killari were 16.44, 16.56, 17.85, 11.50 and 26.32 which was reduced to 3.5, 8.23, 8.14 and 9.53 and 9.04, respectively at harvest.