scholarly journals Two Origins, Two Functions: The Discovery of Distinct Secretory Ducts Formed during the Primary and Secondary Growth in Kielmeyera

Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 877
Author(s):  
Ellenhise R. Costa ◽  
Marcelo M. P. Tangerina ◽  
Marcelo J. P. Ferreira ◽  
Diego Demarco
Keyword(s):  
Vascular Plants ◽  
Biosynthetic Pathway ◽  
A Priori ◽  
Secondary Growth ◽  
First Report ◽  
Metabolic Alteration ◽  
Tropical Environments ◽  
Structure And Metabolism ◽  
Secretory Ducts

Secretory ducts have been reported for more than 50 families of vascular plants among primary and secondary tissues. A priori, all ducts of a plant are of the same type, and only slight variations in the concentration of their compounds have been reported for few species. However, two types of secretion were observed in primary and secondary tissues of Kielmeyera appariciana, leading us to investigate the possible influence of duct origins on the structure and metabolism of this gland. Kielmeyera appariciana has primary ducts in the cortex and pith and secondary ducts in the phloem. Both ducts are composed of uniseriate epithelium surrounded by a sheath and a lumen formed by a schizogenous process. Despite their similar structure and formation, the primary ducts produce resin, while the secondary ducts produce gum. This is the first report of two types of ducts in the same plant. The distinct origin of the ducts might be related to the metabolic alteration, which likely led to suppression of the biosynthetic pathway of terpenoids and phenolics in the secondary ducts. The functional and evolutionary implications of this innovation are discussed in our study and may be related to the diversification of Kielmeyera and Calophyllaceae in tropical environments.

scholarly journals Variability of contemporary vegetation around Petuniabukta, central Spitsbergen

2012 ◽  
Vol 33 (4) ◽  
pp. 383-394 ◽  
Author(s):  
Karel Prach ◽  
Jitka Klimešová ◽  
Jiří Košnar ◽  
Olexii Redčenko ◽  
Martin Hais
Keyword(s):  
High Latitude ◽  
Vascular Plants ◽  
Native Species ◽  
Spatial Scales ◽  
A Priori ◽  
Vegetation Pattern ◽  
Svalbard Archipelago ◽  
Species Lists ◽  
Phytosociological Relevés ◽  
First Time

Abstract Vegetation was described in various spatial scales in the area of 37.8 km2 including distinguishing vegetation units, vegetation mapping, recording phytosociological relevés (53), and completing species lists of vascular plants (86), mosses (124) and lichens (40). Phytosociological relevés were elaborated using ordination methods DCA and CCA. The relevés formed clusters corresponding well to a priori assigned vegetation units. Slope and stoniness significantly influenced the vegetation pattern. Despite the high latitude (nearly 80° N), the vegetation is rather rich in species. Non-native species do not expand. The moss Bryum dichotomum is reported for the first time from Svalbard archipelago.

scholarly journals Structure of Panax quinquefolius L. (Araliaceae) Roots with Emphasis on Secretory Duct Formation

1998 ◽  
Vol 123 (5) ◽  
pp. 798-801 ◽  
Author(s):  
R. Larry Peterson ◽  
Gregory T. Varney ◽  
Shannon Binns
Keyword(s):  
Lateral Roots ◽  
Primary Root ◽  
Secondary Growth ◽  
Panax Quinquefolius ◽  
Secondary Phloem ◽  
Primary Xylem ◽  
Casparian Bands ◽  
Transmission Electron ◽  
Anatomical Localization ◽  
Secretory Ducts

Primary and first-order lateral roots of Panax quinquefolius L. (American ginseng) were collected from plants in an experimental garden during their second year of growth and processed for light and transmission electron microscopy. Roots in primary growth had either a diarch or triarch primary xylem pattern, a pericycle, an endodermis with Casparian bands and subsequently a suberized cell wall, and a cortex of variable thickness with a suberized hypodermal layer. Both root types underwent rapid secondary growth and the primary root particularly formed a fleshy storage organ. The secondary phloem and secondary xylem had abundant parenchyma and few conducting elements. Secretory ducts differentiated in tissue derived from the pericycle and in the secondary phloem. Each schizogenous duct consisted of six to eight epithelial cells, which possessed dense, globular deposits but lacked starch. A phellogen, which produced several layers of suberized phellem, was initiated in the periphery of tissue derived from the pericycle. The results of this study clarify the anatomical localization of secretory duets in roots of this species.

scholarly journals Novel South African Rare Actinomycete Kribbella speibonae Strain SK5: A Prolific Producer of Hydroxamate Siderophores Including New Dehydroxylated Congeners

Molecules ◽  
2020 ◽  
Vol 25 (13) ◽  
pp. 2979
Author(s):  
Kojo Sekyi Acquah ◽  
Denzil R. Beukes ◽  
Digby F. Warner ◽  
Paul R. Meyers ◽  
Suthananda N. Sunassee ◽  
...  
Keyword(s):  
South African ◽  
Biosynthetic Pathway ◽  
Relevant Literature ◽  
2D Nmr ◽  
Molecular Network ◽  
First Report ◽  
Desferrioxamine B ◽  
Nmr Data ◽  
Hydroxamate Siderophores ◽  
Fragmentation Patterns

In this paper, we report on the chemistry of the rare South African Actinomycete Kribbella speibonae strain SK5, a prolific producer of hydroxamate siderophores and their congeners. Two new analogues, dehydroxylated desferrioxamines, speibonoxamine 1 and desoxy-desferrioxamine D1 2, have been isolated, together with four known hydroxamates, desferrioxamine D1 3, desferrioxamine B 4, desoxy-nocardamine 5 and nocardamine 6, and a diketopiperazine (DKP) 7. The structures of 1–7 were characterized by the analysis of HRESIMS and 1D and 2D NMR data, as well as by comparison with the relevant literature. Three new dehydroxy desferrioxamine derivatives 8–10 were tentatively identified in the molecular network of K. speibonae strain SK5 extracts, and structures were proposed based on their MS/MS fragmentation patterns. A plausible spb biosynthetic pathway was proposed. To the best of our knowledge, this is the first report of the isolation of desferrioxamines from the actinobacterial genus Kribbella.

scholarly journals Plant hydraulic architecture through time: lessons and questions on the evolution of vascular systems

IAWA Journal ◽  
2019 ◽  
Vol 40 (3) ◽  
pp. 387-420 ◽  
Author(s):  
Anne-Laure Decombeix ◽  
Anaïs Boura ◽  
Alexandru M. F. Tomescu
Keyword(s):  
Vascular Plants ◽  
Vascular Plant ◽  
Secondary Growth ◽  
Single Type ◽  
Dominant Type ◽  
Vascular Tissues ◽  
Regulatory Constraints ◽  
Plant Groups ◽  
Different Types ◽  
Plant Hydraulic Architecture

ABSTRACTStudies of anatomically preserved fossils provide a wealth of information on the evolution of plant vascular systems through time, from the oldest evidence of vascular plants more than 400 million years ago to the rise of the modern angiosperm-dominated flora. In reviewing the key contributions of the fossil record, we discuss knowledge gaps and major outstanding questions about the processes attending the evolution of vascular systems. The appearance and diversification of early vascular plants in the late Silurian-Devonian was accompanied by the evolution of different types of tracheids, which initially improved the hydraulics of conduction but had less of an effect on mechanical support. This was followed in the Devonian and Carboniferous by an increase in complexity of the organization of primary vascular tissues, with different types of steles evolving in response to mechanical, hydraulic, and developmental regulatory constraints. Concurrently, secondary vascular tissues, such as wood, produced by unifacial or bifacial cambia are documented in a wide array of plant groups, including some that do not undergo secondary growth today. While wood production has traditionally been thought to have evolved independently in different lineages, accumulating evidence suggests that this taxonomic breadth reflects mosaic deployment of basic developmental mechanisms, some of which are derived by common ancestry. For most of vascular plant history, wood contained a single type of conducting element: tracheids (homoxyly). However, quantitative (e.g. diameter and length) and qualitative (e.g. pitting type) diversity of these tracheids allowed various taxa to cover a broad range of hydraulic properties. A second type of conducting elements, vessels, is first documented in an extinct late Permian (c. 260 Ma) group. While the putative hydraulic advantages of vessels are still debated, wood characterized by presence of vessels (heteroxyly) would become the dominant type, following the diversification of angiosperms during the Cretaceous.

scholarly journals Linking the Evolution of Development of Stem Vascular System in Nyctaginaceae and Its Correlation to Habit and Species Diversification

2021 ◽  
Author(s):  
Israel L. Cunha Neto ◽  
Marcelo Rodrigo Pace ◽  
Rebeca Hernández-Gutiérrez ◽  
Veronica Angyalossy
Keyword(s):  
Developmental Stages ◽  
Vascular System ◽  
A Priori ◽  
Secondary Growth ◽  
Stem Anatomy ◽  
Species Diversification ◽  
Successive Cambia ◽  
The Family ◽  
Interxylary Phloem ◽  
Cambial Variants

Abstract Background: The presence of alternative patterns of secondary growth in stems of Nyctaginaceae has been known for a long time. Still, the interpretation of types of cambial variants are controversial. The knowledge on stem anatomical diversity in Nyctaginaceae, which is diverse also in habits, offers the unique opportunity not only to investigate the evolution of complex developments, but also to address how these anatomies shifted within habits and how the acquisition of novel cambial variants and habit transitions impacted the diversification of the family. Methods: We integrated developmental data with a phylogenetic framework to investigate the diversity and evolution of stem anatomy in Nyctaginaceae using phylogenetic comparative methods, reconstructing ancestral states, and examining whether anatomical shifts correspond to species diversification rate shifts in the family. Results: Two types of cambial variants, interxylary phloem and successive cambia, were recorded in Nyctaginaceae, which result from four different ontogenies. These ontogenetic trajectories depart from two distinct primary vascular structures (regular or polycyclic eustele) yet, they contain shared developmental stages which generate stem morphologies with deconstructed boundaries of morphological categories (continuum morphology). Unlike our a priori hypotheses, interxylary phloem is reconstructed as the ancestral character for the family, with three ontogenies characterized as successive cambia evolving in few taxa. Cambial variants are not contingent in habits, and their transitions are independent from species diversification.Conclusions: Our findings suggests that multiple developmental mechanisms, such as heterochrony and heterotopy generate the transitions between interxylary phloem and successive cambia. Intermediate between these two extremes are present in Nyctaginaceae, suggesting a continuum morphology across the family as a generator of anatomical diversity.

scholarly journals Integrating continuous hypermutation with high-throughput screening for optimization of cis,cis-muconic acid production in yeast

2020 ◽  
Author(s):  
Emil D. Jensen ◽  
Francesca Ambri ◽  
Marie B. Bendtsen ◽  
Alex A. Javanpour ◽  
Chang C. Liu ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Directed Evolution ◽  
High Throughput ◽  
High Throughput Screening ◽  
Biosynthetic Pathway ◽  
A Priori ◽  
Enzymatic Reaction ◽  
Search Space ◽  
Muconic Acid ◽  
Metabolic Reactions

SummaryDirected evolution is a powerful method to optimize proteins and metabolic reactions towards user-defined goals. It usually involves subjecting genes or pathways to iterative rounds of mutagenesis, selection, and amplification. While powerful, systematic searches through large sequence-spaces is a labor-intensive task, and can be further limited by a priori knowledge about the optimal initial search space, and/or limits in terms of screening throughput. Here we demonstrate an integrated directed evolution workflow for metabolic pathway enzymes that continuously generates enzyme variants using the recently developed orthogonal replication system, OrthoRep, and screens for optimal performance in high-throughput using a transcription factor-based biosensor. We demonstrate the strengths of this workflow by evolving a ratelimiting enzymatic reaction of the biosynthetic pathway for cis,cis-muconic acid (CCM), a precursor used for bioplastic and coatings, in Saccharomyces cerevisiae. After two weeks of simply iterating between passaging of cells to generate variant enzymes via OrthoRep and high-throughput sorting of best-performing variants using a transcription factor-based biosensor for CCM, we ultimately identified variant enzymes improving CCM titers >13-fold compared to reference enzymes. Taken together, the combination of synthetic biology tools as adopted in this study, is an efficient approach to debottleneck repetitive workflows associated with directed evolution of metabolic enzymes.

scholarly journals Denitrification and associated nitrous oxide and carbon dioxide emissions from the Amazonian wetlands

2020 ◽  
Vol 17 (16) ◽  
pp. 4297-4311
Author(s):  
Jérémy Guilhen ◽  
Ahmad Al Bitar ◽  
Sabine Sauvage ◽  
Marie Parrens ◽  
Jean-Michel Martinez ◽  
...  
Keyword(s):  
Carbon Dioxide Emissions ◽  
Large Scale ◽  
Amazon Basin ◽  
A Priori ◽  
Open Water ◽  
Model Parameters ◽  
N2o Emissions ◽  
Tropical Wetlands ◽  
Tropical Environments ◽  
Amazonian Wetlands

Abstract. In this paper, we quantify the CO2 and N2O emissions from denitrification over the Amazonian wetlands. The study concerns the entire Amazonian wetland ecosystem with a specific focus on three floodplain (FP) locations: the Branco FP, the Madeira FP and the FP alongside the Amazon River. We adapted a simple denitrification model to the case of tropical wetlands and forced it by open water surface extent products from the Soil Moisture and Ocean Salinity (SMOS) satellite. A priori model parameters were provided by in situ observations and gauging stations from the HYBAM Observatory. Our results show that the denitrification and the trace gas emissions present a strong cyclic pattern linked to the inundation processes that can be divided into three distinct phases: activation, stabilization and deactivation. We quantify the average yearly denitrification and associated emissions of CO2 and N2O over the entire watershed at 17.8 kgN ha−1 yr−1, 0.37 gC-CO2 m−2 yr−1 and 0.18 gN-N2O m−2 yr−1 respectively for the period 2011–2015. When compared to local observations, it was found that the CO2 emissions accounted for 0.01 % of the integrated ecosystem, which emphasizes the fact that minor changes to the land cover may induce strong impacts on the Amazonian carbon budget. Our results are consistent with the state of the art of global nitrogen models with a positive bias of 28 %. When compared to other wetlands in different pedoclimatic environments we found that the Amazonian wetlands have similar emissions of N2O with the Congo tropical wetlands and lower emissions than the temperate and tropical anthropogenic wetlands of the Garonne (France), the Rhine (Europe) and south-eastern Asia rice paddies. In summary our paper shows that a data-model-based approach can be successfully applied to quantify N2O and CO2 fluxes associated with denitrification over the Amazon basin. In the future, the use of higher-resolution remote sensing products from sensor fusion or new sensors like the Surface Water and Ocean Topography (SWOT) mission will permit the transposition of the approach to other large-scale watersheds in tropical environments.

scholarly journals On the hydraulic conductance of three woody Devonian plants

IAWA Journal ◽  
2019 ◽  
Vol 40 (3) ◽  
pp. 446-465 ◽  
Author(s):  
B. Cascales-Miñana ◽  
P. Gerrienne ◽  
B. Sirjacq ◽  
P. Steemans
Keyword(s):  
Water Transport ◽  
Vascular Plants ◽  
Evolutionary History ◽  
New Genus ◽  
Secondary Xylem ◽  
Secondary Growth ◽  
Hydraulic Conductance ◽  
Plant Fossils ◽  
History Of ◽  
Fossil Site

ABSTRACTMost evolutionary innovations in plant vascular tissues, including secondary growth, occurred during the Devonian period (~420 to 360 million years ago). Such innovations had a major impact on land colonisation by plants and on their biodiversity. Here, we show the hydraulic conductance of the secondary xylem of three shrubby or arborescent plant fossils (a probably new genus of Cladoxylopsida, the archaeopteridalean genus Callixylon and the stenokolean genus Brabantophyton). Evidences come from the Ronquières fossil site (Belgium). This site is considered mid-late Givetian/earliest Frasnian in age. Results reveal that hydraulic conductivity of these early woody plants is more or less similar to that of modern gymnosperms, meaning that water transport was already as efficient in Devonian plants as it is in living plants. Our results further suggest that tracheids with features helping for optimised water transport were quickly selected in the evolutionary history of vascular plants.

scholarly journals Anatomical investigations on Turkish critically endangered species: Achillea sivasica Çelik et Akpulat (Asteraceae)

2020 ◽  
Vol 80 (1) ◽  
Author(s):  
Mehmet Tekin ◽  
Şeyda Akdere
Keyword(s):  
Cross Section ◽  
Vascular Bundle ◽  
Early Stage ◽  
Secondary Growth ◽  
Critically Endangered ◽  
Secretory Cells ◽  
Leaf Lamina ◽  
Critically Endangered Species ◽  
Secretory Ducts ◽  
Leaf Midrib

In this study, root, stem, leaf midrib and leaf lamina anatomy and achene micromorphology of Turkish critically endangered endemic Achillea sivasica were investigated for the first time. In this study, the root was found in late primary growth and in early secondary growth stage. It has large cortex layer consisting of 12-16 cell rows beneath the periderm. Secretory ducts formed by 5-12 secretory cells embedded in the cortex and located near vascular bundle were found at the root that is in early stage of secondary development. The stem was circular-pentagonal shaped in cross-section. There was lamellar collenchyma beneath epidermis of pentagon corners, and cortex parenchyma between corners. Secretory ducts located near the phloem, between the cortex and endodermis on the interfascicular region, were also observed. Endodermis layer was evident and its cells have indentations and protrusions where they touch adjacent endodermis cells, which strengthen the connection between them. In addition, casparian strips was conspicuous in many endodermis cells. Leaf midrib area was triangular shaped in cross section. There were secretory ducts, consisting of 4-5 secretory cells observed on both sides of the sclerenchymatous fibers which accompaning xylem. The leaf lamina was amphistomatic and stomata type was anomocytic. Mesophyll layer was equifacial. There was a large secretory duct and its diameter is bigger than the nearest main lamina vascular bundle. Achene shape was lanceolate-oblong and its surface was ribbed and glabrous of A. sivasica.

Adaptations of root structure in relation to biotic and abiotic factors

1992 ◽  
Vol 70 (4) ◽  
pp. 661-675 ◽  
Author(s):  
R. L. Peterson
Keyword(s):  
Vascular Plants ◽  
Apical Meristem ◽  
Abiotic Factors ◽  
Apical Cell ◽  
Secondary Growth ◽  
Cluster Roots ◽  
Root Structure ◽  
Symbiotic Interactions ◽  
Cambium Activity ◽  
Phylogenetic Origin

Roots are discussed less frequently than other plant organs in terms of their phylogenetic origin and evolutionary specialization because of limited paleobotanical information and few broad comparative studies of root structure and development. There is considerable diversity, however, in root structure among the major groups of vascular plants. Roots of many extinct and extant seedless vascular plants have a simple apical meristem (i.e., an apical cell), limited secondary growth, and in some genera, branching is accomplished by a true dichotomy of the apical meristem. Roots of seed plants evolved more complex apical meristems, branching from subterminal tissues, and in some groups extensive vascular cambium activity. Evolutionary developments related to nutrient availability include symbiotic interactions with soil fungi to form mycorrhizae, soil bacteria and cyanobacteria to form nitrogen-fixing nodules, and the modification of branching to form cluster roots. Concomitant with these specializations, root hair frequency and structure are often modified. All roots possess a suberized layer, the endodermis, and in many species, particularly among the angiosperms, a specialized suberized exodermis is present. Roots of aquatic species have evolved mechanisms either to tolerate or to avoid anaerobiosis. Roots growing in continuously wet environments possess constitutive aerenchyma whereas roots of periodically flooded plants are able to respond by forming lysigenous or schizogenous aerenchyma. Key words: roots, evolution, adaptations, structure, symbioses.

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