Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 23
Filter
Add more filters










Publication year range
1.
Mol Phylogenet Evol ; 141: 106626, 2019 12.
Article in English | MEDLINE | ID: mdl-31526848

ABSTRACT

Studies about the drivers of angiosperm clade diversifications have revealed how the environment continuously alters the species chances to adapt or to go extinct. This process depends on complex interactions between abiotic and biotic factors, conditioned to the geological and tectonic settings, the genetic variability of species and the rate at which speciation occurs. In this study, we aim to elucidate the timing of diversification of the Lithospermeae, the second largest tribe within Boraginaceae, and to identify the possible morphological and ecological characters associated with shifts in diversification rates of the most species-rich clades. Lithospermeae includes ca. 470 species and 26 genera, among which are some of the largest genera of the family such as Onosma (150 spp.), Echium (60 spp.), and Lithospermum (80 spp.). An exhaustive study of the whole clade is not available to date and its evolutionary history and diversification rates are incompletely known. In the present study, we provide the most comprehensive phylogeny of the group so far, sampling 242 species and all 26 genera. We found that crown-groups and diversification rates of Lithospermeae largely date back to the Mid-Miocene, with high diversification rates in the largest genera, though only significantly high in Onosma. Our analysis fails to associate any of the functional or morphological traits considered with significant shifts in diversification rates. The timing of the diversification of the species-rich clades corresponds with Miocene tectonic events and global climate changes increasing aridity across Eurasia and western North America. These results suggest a causal link between known ecological features of Lithospermeae (i.e., pre-adaptation to arid, open habitats, and mineral soils) and their diversification. Future studies should expand the sampling of individual subclades and detailed functional analyses to identify the contribution of adaptations to arid conditions and pollinator shifts.


Subject(s)
Biodiversity , Boraginaceae/classification , Phylogeny , Phylogeography , Base Sequence , Boraginaceae/anatomy & histology , DNA, Chloroplast/genetics , DNA, Ribosomal Spacer/genetics , North America , Species Specificity , Time Factors
2.
Microsc Res Tech ; 82(6): 786-802, 2019 Jun.
Article in English | MEDLINE | ID: mdl-30801847

ABSTRACT

Foliar and stem epidermal anatomical features of the tribe Cynoglosseae have been studied in detail for the taxonomic identification using light microscopy (LM) and scanning electron microscopic (SEM) techniques. A comparative study was conducted on different plant parts (leaf and stem epidermal anatomy) of 25 species belonging to eight genera of the tribe Cynoglosseae (Boraginaceae) collected from different phytogeographical regions of Iran for the first time. Different qualitative and quantitative characteristics were observed in detail using LM and SEM. Results showed that although generally the stem and leaf anatomical traits were similar, but some diagnostic features were examined for distinguishing the closely related genera in the tribe. The ratio of cortex/diameter of stem and phloem/xylem, the average row number of collenchyma, palisade and spongy cells, structure of trichomes, type of indumentum and palisade arrangement were found taxonomically important. The anatomical characters were statistically analyzed using cluster analysis and principal component analysis. The study found that stem and leaf eccentrics are variable in the genus but constant within species of the same genus. Most species had typical isobilateral leaves, but some showed an incipient dorsoventrally symmetry with a layer of abaxial palisade tissue. Eglandular trichomes were observed found in all the studied species, which were recognized based on structure and function. In present study some novel characters have been observed which are of great interest to the taxonomist for the correct identification some genera delimitations. The characters studied here are of less taxonomic value and delimitating at species level.


Subject(s)
Boraginaceae/anatomy & histology , Plant Epidermis/cytology , Plant Leaves/anatomy & histology , Plant Stems/anatomy & histology , Biometry , Iran , Microscopy , Microscopy, Electron, Scanning
3.
An. acad. bras. ciênc ; 90(1): 59-71, Mar. 2018. tab, graf
Article in English | LILACS | ID: biblio-886898

ABSTRACT

ABSTRACT Varronia curassavica, a subshrubby medicinal species associated with restinga in the Atlantic Forest, has been exploited by local people and the pharmaceutical industry. Indeed, restingas have experienced a continuous process of degradation, and thus, with species and ecosystem both at risk, efforts to support conservation actions are required. The present study aimed to evaluate aspects of V. curassavica reproductive biology. To accomplish this, morphological characterization was performed by monitoring flowering events. The availability of nectar and pollen, as well as the frequency and behavior of floral visitors and dispersers, was also evaluated. This species exhibits both heterostyly and protogyny. Anthesis is diurnal, and flowers last less than a day. The high number of flower and fruit abortions suggests that mechanisms, such as self-incompatibility intra-morphs and easily detached flowers, contribute to reduced fruit production. The high diversity of floral visitors indicate a generalist pollination syndrome. Diptera, Hymenoptera and Lepidoptera were the main pollinators, and nectar was the main resource sought by these insects. Fruits were dispersed by birds and ants. It can be concluded that the interaction of V. curassavica with several species is a key factor in its own survival and for maintaining the biological diversity of restinga.


Subject(s)
Boraginaceae/anatomy & histology , Boraginaceae/physiology , Flowers/anatomy & histology , Flowers/physiology , Plants, Medicinal/physiology , Reference Values , Reproduction/physiology , Species Specificity , Time Factors , Biodiversity , Pollination/physiology , Plant Dispersal
4.
An Acad Bras Cienc ; 90(1): 59-71, 2018.
Article in English | MEDLINE | ID: mdl-29424392

ABSTRACT

Varronia curassavica, a subshrubby medicinal species associated with restinga in the Atlantic Forest, has been exploited by local people and the pharmaceutical industry. Indeed, restingas have experienced a continuous process of degradation, and thus, with species and ecosystem both at risk, efforts to support conservation actions are required. The present study aimed to evaluate aspects of V. curassavica reproductive biology. To accomplish this, morphological characterization was performed by monitoring flowering events. The availability of nectar and pollen, as well as the frequency and behavior of floral visitors and dispersers, was also evaluated. This species exhibits both heterostyly and protogyny. Anthesis is diurnal, and flowers last less than a day. The high number of flower and fruit abortions suggests that mechanisms, such as self-incompatibility intra-morphs and easily detached flowers, contribute to reduced fruit production. The high diversity of floral visitors indicate a generalist pollination syndrome. Diptera, Hymenoptera and Lepidoptera were the main pollinators, and nectar was the main resource sought by these insects. Fruits were dispersed by birds and ants. It can be concluded that the interaction of V. curassavica with several species is a key factor in its own survival and for maintaining the biological diversity of restinga.


Subject(s)
Boraginaceae/anatomy & histology , Boraginaceae/physiology , Flowers/anatomy & histology , Flowers/physiology , Biodiversity , Plant Dispersal , Plants, Medicinal/physiology , Pollination/physiology , Reference Values , Reproduction/physiology , Species Specificity , Time Factors
5.
Plant Biol (Stuttg) ; 20 Suppl 1: 112-117, 2018 Jan.
Article in English | MEDLINE | ID: mdl-28945318

ABSTRACT

Dimorphism in style height has evolved repeatedly in flowering plants, with some individuals having short and others long styles; in the case of distylous species, stigma position varies reciprocally with that of the anthers. Distyly can be associated with divergence in the functional gender between long- and short-styled individuals, but gender divergence has rarely been investigated in species with a simple stigma height polymorphism in the absence of reciprocal dimorphism in anther position. To evaluate the relation between stigma height polymorphism and gender, I measured the dimensions of floral morphology and seed production for the two morphs of a large population of the Iberian species Lithodora fruticosa (Boraginaceae). Results confirm the existence of a stigma height polymorphism in L. fruticosa, with long- and short-styled individuals at a 1:1 ratio in the studied population. Long-styled individuals produced substantially more seeds than did short-styled individuals, pointing to strong divergence in functional gender between the two morphs. The results of this study are puzzling in light of recent work that suggests that L. fruticosa has a multi-allelic self-incompatibility system. I discuss the significance of gender divergence in L. fruticosa and evaluate hypotheses that might explain it.


Subject(s)
Boraginaceae/anatomy & histology , Flowers/anatomy & histology , Sex Characteristics , Boraginaceae/genetics , Boraginaceae/growth & development , Flowers/genetics , Fruit/growth & development , Mediterranean Region , Seeds/growth & development
6.
Am J Bot ; 104(1): 50-61, 2017 Jan.
Article in English | MEDLINE | ID: mdl-28039130

ABSTRACT

PREMISE OF THE STUDY: Populations of heterostylous species are characterized by two or three floral morphs with reciprocal positioning of stigmas and anthers. Theoretical models predict equal morph frequencies (isoplethy) when disassortative mating is prevalent in populations, but biased morph ratios may occur when variation in the expression of heterostyly causes deviations from intermorph mating. METHODS: We explore the role of sex-organ deployment in governing morph ratios in two closely related genera of Boraginaceae, exhibiting striking variation in floral traits associated with the heterostylous syndrome. We sampled 66 populations of six species of Glandora and 39 populations of three species of Lithodora across their distributional range in the Mediterranean. In each population we estimated morph ratios and measured several floral traits. We used phylogenetically corrected and noncorrected regressions to test the hypothesis that differences in sex-organ reciprocity and herkogamy are associated with deviations from isoplethy. KEY RESULTS: Biased morph ratios occurred in 24% of populations, particularly in Lithodora. Populations biased for the long-styled morph (L-morph) were more frequent than the short-styled morph (S-morph). Distylous species were less likely to exhibit biased ratios than species with stigma-height dimorphism. In Lithodora fruticosa, a species lacking reciprocity, decreased herkogamy in the S-morph was associated with increasing L-morph bias, perhaps resulting from self-interference. CONCLUSION: Striking variation in the expression of heterostyly in Glandora and Lithodora is associated with biased morph ratios, which probably result from pollinator-mediated mating asymmetries within populations.


Subject(s)
Boraginaceae/physiology , Flowers/physiology , Pollen/physiology , Pollination/physiology , Biological Evolution , Boraginaceae/anatomy & histology , Boraginaceae/classification , Flowers/anatomy & histology , Geography , Mediterranean Region , Models, Anatomic , Pollen/anatomy & histology , Reproduction/physiology , Species Specificity
7.
Microsc Res Tech ; 80(2): 231-238, 2017 Feb.
Article in English | MEDLINE | ID: mdl-27726230

ABSTRACT

Investigation of mortuary ritual is an important method to reconstruct many aspects of past societies. Due to the lack of relevant analytical work, little evidence related to organic materials in a burial can be found in China. Here we report materials collected from a burial during the excavation of the Shengedaliang site. The recovered materials were analyzed using Raman spectroscopy and plant analysis: flotation, pollen and phytolith analysis. The red pigments found scattered over the human remains were identified as cinnabar. Extracted phytoliths associated with the burial are mainly leaves from the Boraginaceae family. This is the first time that a covering of leaves have been identified with a burial in Neolithic China. The presence of "special" leaves fossil may indicate a type of "plant worship" and the identification of an important plant used in traditional Chinese medicine. The finding of the two materials allows us to better identify indicators of funerary ritual and its relationship to social inequality.


Subject(s)
Boraginaceae/anatomy & histology , Burial/history , Ceremonial Behavior , Pigments, Biological/history , Plant Leaves/chemistry , Boraginaceae/chemistry , China , Fossils/history , History, Ancient , Humans , Mercury Compounds/chemistry , Mercury Compounds/history , Radiometric Dating , Spectrum Analysis, Raman/methods
8.
Am J Bot ; 102(12): 2108-15, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26681356

ABSTRACT

PREMISE OF THE STUDY: The Paleogene deposits of the Hamada of Méridja, southwestern Algeria, are currently dated as lower-to-middle Eocene in age based on fossil gastropods and charophytes. Here we report the presence of fruits that can be assigned to the Boraginaceae s.str., apparently representing the first fossil record for this family in Africa, shedding new light on the historical biogeography of this group. METHODS: Microscopic studies of the fossil nutlets were carried out and compared to extant Boraginaceae nutlets, and to types reported in the literature for this family. KEY RESULTS: The fossils are strikingly similar in general size and morphology, particularly in the finer details of the attachment scar and ornamentation, to nutlets of extant representatives of the Boraginaceae tribe Echiochileae, and especially the genus Ogastemma. We believe that these nutlets represent an extinct member of this lineage. CONCLUSIONS: The Ogastemma-like fossils indicate that the Echiochileae, which are most diverse in northern Africa and southwestern Asia, have a long history in this region, dating back to the Eocene. This tribe corresponds to the basal-most clade in Boraginaceae s.str., and the fossils described here agree well with an assumed African origin of the family and the Boraginales I, providing an important additional calibration point for dating the phylogenies of this clade.


Subject(s)
Biological Evolution , Boraginaceae/classification , Fossils/anatomy & histology , Algeria , Boraginaceae/anatomy & histology , Fruit/anatomy & histology , Fruit/classification
9.
Am J Bot ; 102(10): 1647-58, 2015 Oct.
Article in English | MEDLINE | ID: mdl-26453596

ABSTRACT

PREMISE OF THE STUDY: Investigations of recently derived and edaphically (soil) defined plant systems have provided insight into important mechanisms of ecological divergence. We investigated the impact of edaphic adaptation on recent divergence between two Colorado Plateau endemics: the gypsum facultative Oreocarya revealii (Boraginaceae) and its more generalist sister species O. paradoxa. We assessed morphological stability, genetic identity, and soil chemistry to determine whether O. revealii is a distinct lineage edaphically adapted from O. paradoxa, as has been described in the literature. METHODS: We genotyped 21 populations throughout the ranges of both species using 11 microsatellite markers and three plastid regions (trnL-F, trnT-L, trnQ-rps16) for haplotype analysis. We compared these data with soil chemistry (Ca and S concentrations, indicating gypsum levels), location, and morphological identity of populations. KEY RESULTS: Soil chemistry failed to explain genetic or morphological identity in either taxon. Haplotype analysis suggests ancestral variation in the more geographically restricted O. revealii, along with regional geographic isolation. A discontinuity was identified between the morphological and genetic identity in several populations, suggesting incomplete lineage sorting and the nonfixation of identifying morphological traits. CONCLUSIONS: Oreocarya revealii is unlikely to have arisen via edaphic selection, because soil chemistry of population sites, morphology of individuals, and genetic identity are not strongly correlated. The nonfixation of identifying traits is likely a result of recent divergence in this system, and the potentiality of such discrepancies should be considered when investigating recently diversified gypsum-associated groups.


Subject(s)
Biological Evolution , Boraginaceae/anatomy & histology , Boraginaceae/genetics , Chloroplast Proteins/genetics , Soil/chemistry , Calcium/metabolism , Chloroplast Proteins/metabolism , Colorado , Ecosystem , Microsatellite Repeats , Molecular Sequence Data , Sequence Analysis, DNA , Species Specificity , Sulfur/metabolism
10.
Rev. bras. plantas med ; 17(4): 562-569, out.-dez. 2015. tab, graf
Article in Portuguese | LILACS | ID: lil-763217

ABSTRACT

RESUMOO conhecimento do sistema reprodutivo é fundamental para a conservação e manejo de uma espécie. O objetivo deste trabalho foi descrever a fenologia da floração, a antese, registrar os insetos visitantes no período de floração, determinar as características morfométricas das flores e o sistema reprodutivo da erva-baleeira, em um ambiente de Cerrado do Norte de Minas Gerais. Entre maio a dezembro de 2012 foi caracterizado o comportamento fenológico da floração. Na análise da fenologia floral foi determinado: o crescimento da inflorescência, o número de flores e frutos por inflorescências. Utilizou-se seis acessos que tiveram dez inflorescências marcadas em cada acesso, totalizando 60 inflorescências. A antese foi determinada utilizando quatro inflorescências em duas plantas. Os visitantes florais foram observados in loco e capturados em três dias consecutivos de coleta. As características morfométricas foram determinadas com paquímetro utilizando 20 flores, sendo cinco flores de quatro acessos. Para determinar o sistema reprodutivo utilizou-se a razão pólen:óvulo (P:O), utilizando 50 flores, sendo 10 flores de cinco acessos em pré-antese. Nas condições de Montes Claros, o crescimento das inflorescências de erva-baleeira ocorreu entre meados de agosto e início de outubro, totalizando 45 dias. O florescimento foi observado entre meados de setembro e final de outubro, enquanto a frutificação ocorreu de meados de outubro a início de dezembro, sendo que ambos ocorreram de forma irregular. A antese floral de erva-baleeira, neste estudo, ocorre entre 7:00 e 11:00 horas. Os insetos visitantes pertencem as ordens Coleoptera, Hemiptera, Diptera e Hymenoptera. As flores apresentaram o diâmetro de 2,13 ± 0,05 (mm), o comprimento de 3,29 ± 0,08 (mm), diâmetro do ovário de 0,70 ± 0,02 (mm), o comprimento do ovário de 2,48 ± 0,12 (mm), o diâmetro da antera de 0,67 ± 0,01(mm) e o comprimento da antera de 0,93 ±0,02 (mm), quatro óvulos e cinco anteras por flor. A razão P:O foi de 576,542, indicando que a espécie é alógama facultativa.


ABSTRACTThe knowledge of the reproductive system is essential for the conservation and management of the species. This study aimed on several procedures, as follows: to describe the phenology of flowering, the anthesis; to record the visiting insects during flowering and to determine the morphometric characteristics of the flowers and the reproductive system of the "erva-baleeira", in an environment of Northern Cerrado in the State of Minas Gerais. From May to December 2012, the flowering phenology of six access was characterized. In the analyzes of floral phenology it were determined the growth of the inflorescence and the number of flowers and fruits per inflorescence by using six access which had ten inflorescences marked in each access l, totalizing sixty inflorescences. The anthensis was assessed using four inflorescences in two plants. The flower`s visitors were observed live and captured in three consecutive days of sampling. The morphometric characteristics were determined with a caliper using 20 flowers, with five flowers from four access. In order to determine the reproductive system it was employed a ratiopollen: ovule (P: O) with 50 flowers and 10 of them belonging to five accesses in the pre-anthesis. Under the conditions of Montes Claros, the growth of inflorescences from Cordia occurred between mid-August and early October, totalizing 45 days. The flowering was observed between mid-September and late October, and the fruiting occurred from mid-October to early December. Both phases happened irregularly. The anthesis of the Cordia, in this study, occurred between 7:00 and 11:00 o`clock.. The visiting insects identified were from the orders of Coleoptera, Hemiptera, Diptera and Hymenoptera. The flowers exhibited a diameter of 2.13 ± 0.05 (mm), length of 3.29 ± 0.08 (mm), diameter of 0.70 ± 0.02 Ovarian (mm), the length of the ovary was 2.48 ± 0.12 (mm), the diameter of the anther 0.67 ± 0.01 (mm) and the length anther was 0.93 ± 0.02 (mm), with five anthers and four ovules per flower. The reason P: O was 576.542, indicating that the species is facultative allogamous.


Subject(s)
Cordia/anatomy & histology , Flowers/anatomy & histology , Plants, Medicinal/classification , Boraginaceae/anatomy & histology , Insecta/classification
11.
J Exp Bot ; 63(17): 6115-23, 2012 Oct.
Article in English | MEDLINE | ID: mdl-23028018

ABSTRACT

For many plant species, nutrient availability induces important anatomical responses, particularly the production of low-density tissues to the detriment of supporting tissues. Due to the contrasting biomechanical properties of plant tissues, these anatomical responses may induce important modifications in the biomechanical properties of plant organs. The aim of this study was to determine the effects of nutrient enrichment on the anatomical traits of two freshwater plant species and its consequences on plant biomechanical performance. Two plant species were grown under controlled conditions in low versus high nutrient levels. The anatomical and biomechanical traits of the plant stems were measured. Both species produced tissues with lower densities under nutrient-rich conditions, accompanied by modifications in the structure of the aerenchyma for one species. As expected, nutrient enrichment also led to important modifications in the biomechanical properties of the stem for both species. In particular, mechanical resistance (breaking force and strength) and stiffness of stems were significantly reduced under nutrient rich conditions. The production of weaker stem tissues as a result of nutrient enrichment may increase the risk of plants to mechanical failure, thus challenging plant maintenance in mechanically stressful or disturbed habitats.


Subject(s)
Boraginaceae/anatomy & histology , Mentha/anatomy & histology , Plant Stems/anatomy & histology , Boraginaceae/growth & development , Boraginaceae/metabolism , Fertilizers , Fresh Water , Mentha/growth & development , Mentha/metabolism , Nitrogen/analysis , Nitrogen/metabolism , Phosphorus/analysis , Phosphorus/metabolism , Plant Stems/growth & development , Plant Stems/metabolism , Stress, Mechanical
12.
Oecologia ; 170(1): 147-57, 2012 Sep.
Article in English | MEDLINE | ID: mdl-22349860

ABSTRACT

Although florivores can destroy significant amounts of sexual tissues and indirectly affect pollination, little is known about their preferences, which could shape the evolution of floral traits or defense. In this study, we used a gynodioecious plant Nemophila menziesii, and its main florivore Platyprepia virginalis, to test which floral characteristics are associated with florivory in the field and with florivore choice in the laboratory. Hermaphrodite flowers consistently received more damage than nearby females in the field. In the laboratory setting, florivores also preferred unmanipulated hermaphrodites versus unmanipulated females. Systematic evaluation of hermaphrodite traits, such as corolla size, anther presence, and corolla color, revealed that corolla diameter was the main determinant of florivore preference in this system. Here, we discuss the implications of both pollinator and florivore choice in the evolution of corolla size and sex ratio in gynodioecious species with cytoplasmic male sterility and emphasize the need for more information on the preferences of florivores.


Subject(s)
Boraginaceae/physiology , Flowers , Food Preferences , Herbivory , Animals , Boraginaceae/anatomy & histology , Disorders of Sex Development , Moths , Plants, Edible , Pollination , Reproduction
13.
Vet Clin North Am Food Anim Pract ; 27(2): 419-28, ix, 2011 Jul.
Article in English | MEDLINE | ID: mdl-21575778

ABSTRACT

Pyrrolizidine alkaloid (PA)-containing plants are found throughout the world and are probably the most common plant cause of poisoning of livestock, wildlife, and humans. PAs are potent liver toxins that under some conditions can be carcinogenic. This article briefly introduces high-risk North American PA-containing plants, summarizing their toxicity and subsequent pathology. Current diagnostic techniques, treatments, and strategies to avoid losses to PA poisoning are also reviewed.


Subject(s)
Boraginaceae/chemistry , Crotalaria/chemistry , Plants, Toxic/chemistry , Pyrrolizidine Alkaloids/toxicity , Senecio/chemistry , Animals , Boraginaceae/anatomy & histology , Boraginaceae/classification , Crotalaria/anatomy & histology , Crotalaria/classification , Humans , Pyrrolizidine Alkaloids/chemistry , Pyrrolizidine Alkaloids/pharmacokinetics , Pyrrolizidine Alkaloids/pharmacology , Senecio/anatomy & histology , Senecio/classification
14.
Ann Bot ; 108(1): 1-12, 2011 Jul.
Article in English | MEDLINE | ID: mdl-21515606

ABSTRACT

BACKGROUND AND AIMS: In sub-alpine habitats, patchiness in snowpack produces marked, small-scale variation in flowering phenology. Plants in early- and late-melting patches are therefore likely to experience very different conditions during their flowering periods. Mertensia fusiformis is an early-flowering perennial that varies conspicuously in style length within and among populations. The hypothesis that style length represents an adaptation to local flowering time was tested. Specifically, it was hypothesized that lower air temperatures and higher frost risk would favour short-styled plants (with stigmas more shielded by corollas) in early-flowering patches, but that the pollen-collecting behaviour of flower visitors in late-flowering patches would favour long-styled plants. METHODS: Floral morphology was measured, temperatures were monitored and pollinators were observed in several matched pairs of early and late populations. To evaluate effects of cold temperatures on plants of different style lengths, experimental pollinations were conducted during mornings (warm) and evenings (cool), and on flowers that either had or had not experienced a prior frost. The effectiveness of different pollinators was quantified as seed set following single visits to plants with relatively short or long styles. KEY RESULTS: Late-flowering populations experienced warmer temperatures than early-flowering populations and a different suite of pollinators. Nectar-foraging bumble-bee queens and male solitary bees predominated in early populations, whereas pollen-collecting female solitary bees were more numerous in later sites. Pollinators differed significantly in their abilities to transfer pollen to stigmas at different heights, in accordance with our prediction. However, temperature and frost sensitivity did not differ between long- and short-styled plants. Although plants in late-flowering patches tended to have longer styles than those in early patches, this difference was not consistent. CONCLUSIONS: Seasonal change in pollinator-mediated selection on style length may help maintain variation in this trait in M. fusiformis, but adaptation to local flowering time is not apparent. The prevalence of short styles in these populations requires further explanation.


Subject(s)
Bees/physiology , Boraginaceae/anatomy & histology , Flowers/anatomy & histology , Pollination/physiology , Adaptation, Physiological , Animals , Bees/anatomy & histology , Boraginaceae/genetics , Cold Temperature , Colorado , Female , Flowers/genetics , Male , Phenotype , Pollen , Quantitative Trait, Heritable , Seasons
15.
New Phytol ; 191(1): 173-183, 2011 Jul.
Article in English | MEDLINE | ID: mdl-21434929

ABSTRACT

• The desert flora possesses diverse root architectures that result in fast growth in response to precipitation. We introduce the short root, a previously undescribed second-order root in the aridland chamaephyte Cryptantha flava, and explore fine root production. • We describe the short root anatomy and associated fine roots, correlate standing fine root crop with soil moisture, and explore the architectural level - the short root, third-order lateral roots, or the whole root system - at which fine roots are induced by watering and the amount of water required. • We show that short roots are borne at intervals on lateral roots and produce fine roots at their tips; new fine roots are white and have root hairs, while brown and black fine roots are apparently dead; and fine root production is triggered at the level of lateral roots and with relatively low precipitation (≤ 2 cm). • Short roots are suberized and thus are probably not capable of water uptake themselves, but serve as initiation sites for fine roots that grow rapidly in response to rainfall. Thus, C. flava should be a beneficiary of projected precipitation increases in habitats where rainfall is pulsed.


Subject(s)
Boraginaceae/growth & development , Rain , Boraginaceae/anatomy & histology , Ecosystem , Plant Roots/anatomy & histology , Plant Roots/growth & development , Seasons
16.
New Phytol ; 189(1): 229-40, 2011 Jan.
Article in English | MEDLINE | ID: mdl-20831647

ABSTRACT

• While great attention has been paid to the mechanisms controlling plant growth, much less is known about why and how plants shrink. The modular design of plants may facilitate the independence of modules if the xylem vasculature is hydraulically sectored. We examined the hydraulic connectivity of modules comprising juveniles and adults of the aridland chamaephyte Cryptantha flava (Boraginaceae), motivated by the observation that rosette mortality is spatially aggregated in adults, but not in juveniles. • We explored spatial patterns of leaf wilting after clipping a single lateral root, tracked physiological dyes taken up by a single root, and measured within-plant variation in leaf water potentials after watering a portion of the root system. We then measured xylem anatomical features related to hydraulic connectivity. • Our approaches revealed hydraulic integration in juveniles but hydraulic sectoriality in adults. We attribute such developmental changes to increasing distances between xylem bundles, and larger xylem lumen and heartwood areas as plants age. • We have demonstrated functional sectoriality in a desert chamaephyte, and report the mechanism by which sectoriality occurs, offering a hydraulic explanation for the death of whole plant portions resulting in shrinkage of large plants, and for the high occurrence of this design in deserts.


Subject(s)
Boraginaceae/physiology , Water/metabolism , Boraginaceae/anatomy & histology , Plant Leaves/metabolism , Plant Leaves/physiology , Plant Roots/metabolism , Plant Roots/physiology , Xylem/anatomy & histology , Xylem/physiology
17.
Plant Biol (Stuttg) ; 13 Suppl 1: 7-18, 2011 Jan.
Article in English | MEDLINE | ID: mdl-21134082

ABSTRACT

Interest in reciprocal floral polymorphisms, such as heterostyly, has increased in recent decades because they can be used as suitable model systems to study mechanisms of outbreeding and disassortative mating in plants. Heterostylous plants are characterised by the presence of discrete morphs that differ in sex organ position and in some other ancillary traits. As regards sex organ deployment, different types of polymorphisms have been described, depending on number and type of discrete classes present in populations and degree of reciprocity between them. However, a clear-cut characterisation of stylar polymorphisms does not appear to be the best approach when there is great variability among populations because of continuous variation of some of traits examined. A recent study in Lithodora sensu lato (recently split into two separate genera, Lithodora and Glandora) showed a wide variation in sex organ position across species in the genus, which warrants precise population analysis of stylar polymorphism and its reciprocity. We provide a detailed morphometric analysis of flower sexual traits and include those considered to be ancillary characters. We report a wide variation in these traits in populations of Lithodora s.l. and highlight the subjectivity of the former characterisation of style polymorphism based on visual inspection. Ancillary traits appear repeatedly in Lithodora and Glandora, particularly in the latter. The appearance of these traits seems to be related to greater reciprocity between sexual whorls in Glandora, with the exception of G. prostrata. These results agree with evolutionary steps proposed in the build-up of heterostyly according to some evolutionary models. We also examined variation in polymorphisms in light of current models for evolution of heterostyly, and, more specifically, we sought to verify the prediction that flower traits as a whole (i.e., flower integration) respond to selective pressure to assure the exact location of pollen on the pollinator body. Most reciprocal populations and species, where between-morph pollen transfer is expected to be higher, would show greater integration. Our results confirm this hypothesis.


Subject(s)
Boraginaceae/genetics , Flowers/anatomy & histology , Flowers/genetics , Polymorphism, Genetic , Biological Evolution , Boraginaceae/anatomy & histology , Genetic Variation , Models, Biological , Pollen/genetics , Pollination/physiology , Reproduction/genetics
18.
Cell Biol Int ; 34(5): 537-42, 2010 Apr 08.
Article in English | MEDLINE | ID: mdl-20055759

ABSTRACT

The present study highlights the importance of preculture time and concentration of TDZ (thidiazuron) for direct regeneration from in vitro leaves (attached to shoots) in Arnebia euchroma. Shoot buds proliferated to form multiple shoots on MS medium (Murashige and Skoog medium) with 5.0 microM Kn. Different additives viz. ascorbic acid, PVP (polyvinylpyrrolidone), PVPP (polyvinylpolypyrrolidone) or activated charcoal (50, 100 and 250 mg/l each) were used to check the phenolic exudations. Direct shoot regeneration was obtained when shoots were initially precultured for 40 days on medium with a higher concentration of TDZ (20.0 muM) and then transferred to a lower concentration (5.0 microM TDZ). The identity of shoot buds was confirmed by histological studies. Regenerated shoots were cultured for 30 days on medium containing Kn (5.0 microM) for proliferation and then transferred to IBA (0.25 microM)-containing medium for rooting. Rooted plantlets were transferred to greenhouse with 45-50% survival.


Subject(s)
Boraginaceae , Culture Techniques/methods , Phenylurea Compounds/pharmacology , Plant Leaves , Plant Shoots , Regeneration , Thiadiazoles/pharmacology , Boraginaceae/anatomy & histology , Boraginaceae/drug effects , Boraginaceae/physiology , Phenols/metabolism , Plant Leaves/drug effects , Plant Leaves/physiology , Plant Roots/physiology , Plant Shoots/drug effects , Plant Shoots/physiology , Plants, Medicinal/cytology , Plants, Medicinal/drug effects , Plants, Medicinal/physiology , Regeneration/drug effects , Regeneration/physiology
19.
Am Nat ; 174(5): 660-72, 2009 Nov.
Article in English | MEDLINE | ID: mdl-19778167

ABSTRACT

Life-history theory makes several key predictions about reproductive strategies on the basis of demographic vital rates, particularly the relationship between juvenile and adult survival. Two such predictions concern the optimal time to begin reproducing and whether semelparity or iteroparity is favored. I tested these life-history predictions and explored how they might differ between the native and introduced ranges of the monocarpic perennial Cynoglossum officinale. I first compared vital rates between ranges. I then used these vital rates to parameterize integral projection models to calculate the population growth rate (lambda) and net reproductive rate (R(0)) as surrogates for fitness to compare strategies within and between ranges. I found that both survival and growth were higher in the introduced range, where size at flowering was larger and iteroparity was much more common than in the native range. The observed and predicted strategies for size at flowering were similar in the native range. In the introduced range, however, even though plants flowered at a larger size, the observed size was not as large as the optimum predicted by lambda or the higher optimum predicted by R(0). Iteroparity conferred higher fitness in both ranges, as measured by both fitness metrics, suggesting that severe constraints, potentially specialist herbivores, prevent this strategy from becoming more common in the native range.


Subject(s)
Boraginaceae/physiology , Adaptation, Physiological , Boraginaceae/anatomy & histology , Boraginaceae/growth & development , Environment , Flowers/growth & development , Flowers/physiology , Models, Biological , Reproduction , Time Factors
20.
J Evol Biol ; 21(5): 1281-9, 2008 Sep.
Article in English | MEDLINE | ID: mdl-18631213

ABSTRACT

Theory predicts that morph ratios in heterostylous populations are governed by negative frequency-dependent selection typically resulting in equal morph ratios at equilibrium. Previous work on the distylous perennial herb Pulmonaria officinalis, however, showed asymmetric mating between floral morphs and a weak self-incompatibility system, with the long-styled morph (L-morph) producing significantly higher seed set following intramorph crosses and even selfing than the short-styled morph (S-morph), two aspects thought to affect female fecundity and morph-ratio variation. Here, we evaluated morph ratios and population size of all known P. officinalis populations in the northern part of Belgium. Morph ratios deviated significantly from 1:1 (range 0.09-1 L-morph frequency, mean = 0.58). Relative fecundity of the S-morph (i.e. mean seed set of the S-morph/mean seed set of the L-morph) was on average 0.73, was positively related to the frequency of the L-morph, and reached 1 (similar levels of female fecundity) at an average L-morph frequency of 0.66 in the population. As some small populations had the S-morph in majority, our results suggest that local morph ratios are influenced both by the relative fecundity of L- and S-morph individuals and by stochastic processes in small populations.


Subject(s)
Boraginaceae/physiology , Flowers/physiology , Pollination , Boraginaceae/anatomy & histology , Fertility , Flowers/anatomy & histology , Genetics, Population , Population Density
SELECTION OF CITATIONS
SEARCH DETAIL
...