scholarly journals Physiological regulation of bud burst in grapevine

2018 ◽  
Author(s):  
Santiago Signorelli ◽  
Jeremy Shaw ◽  
Dina Hermawaty ◽  
Zi Wang ◽  
Pieter Verboven ◽  
...  
Keyword(s):  
Pore Size ◽  
Vascular Development ◽  
Structural Heterogeneity ◽  
Eosin Y ◽  
List Type ◽  
Bud Burst ◽  
Tissue Oxygen ◽  
Long Distance ◽  
Oxygen Status ◽  
Grapevine Buds

AbstractThe physiological constraints on bud burst in woody perennials, including the prerequisite for vascular development remain unresolved. Both light and tissue oxygen status have emerged as important cues for vascular development in other systems, however, light requirement appears to be facultative in grapevine, and the information related to the spatial variability of oxygen in buds is unclear. Here, we analysed apoplastic development at early stages of grapevine bud burst and combined molecular modelling with histochemical techniques to determine the pore size of cell walls in grapevine buds. The data demonstrate that quiescent grapevine buds were impermeable to apoplastic dyes (acid fuchsin and eosin Y) until after bud burst was established. The molecular exclusion size was calculated to be 2.1 nm, which would exclude most macromolecules except simple sugars and phytohormones. In vivo experiments show that grapevine buds were able to resume growth even following excision from the cane, and that the outer scales of grapevine buds may participate in the biochemical repression of bud burst. Furthermore, we demonstrate that the tissue oxygen partial pressure data correlated well with structural heterogeneity within the bud and differences in tissue density. These data consolidate evidence that the meristematic core becomes rapidly oxygenated during bud burst. Taken together, and when put in the context of earlier studies, these data provide solid evidence that the physiological and biochemical events that initiate bud burst reside within the bud, and question the role of long distance signalling in this developmental transition.HighlightsThe apoplastic pore size between the grapevine bud and the mother vine is dynamically regulated in the transition to bud burst.The molecular exclusion size of the apoplastic connection between the bud and cane is calculated 2.1 nm prior to the initiation of bud burst.The structural heterogeneity of the bud explains the spatial variance in tissue oxygen status, and the meristematic core is oxygenated during the initiation of bud burst.Long distance maternal signals are not a requirement for bud burst.

On the concentration dependence of surface diffusion coefficients in capillary porous materials

1991 ◽  
Vol 434 (1891) ◽  
pp. 317-340 ◽  
Keyword(s):  
Experimental Data ◽  
Carbon Dioxide ◽  
Pore Size ◽  
Surface Diffusion ◽  
Diffusion Coefficients ◽  
Physical Adsorption ◽  
Structural Heterogeneity ◽  
Size Dependent ◽  
Chemical Potentials ◽  
Uniform Pore Size

The influence of structural heterogeneity, in the form of a non-uniform pore size distribution, on the isotherms and surface diffusion coefficients for monolayer physical adsorption is studied. A pore size dependent langmuirian isotherm is used along with consideration of equality of chemical potentials at the pore mouths at an intersection. The diffusion is modelled by a recently developed random walk formulation. It is found that the surface diffusion coefficients are strongly influenced by the heterogeneity and have a stronger increase with overall coverage than that predicted by the Darken equation. The results are found to match the experimental data of P. C. Carman and F. A. Raal on the diffusion of carbon dioxide in carbon black without the use of a fitting parameter.

scholarly journals Dynamism and context dependency in the diversification of the megadiverse plant genus Solanum L. (Solanaceae)

2018 ◽  
Author(s):  
Susy Echeverrĩa-Londoño ◽  
Tiina Särkinen ◽  
Isabel S Fenton ◽  
Sandra Knapp ◽  
Andy Purvis
Keyword(s):  
Climatic Changes ◽  
Context Dependency ◽  
List Type ◽  
Geological Time ◽  
Long Distance ◽  
Climatic Trend ◽  
Constituent Species ◽  
Dispersal Events ◽  
Diverse Plant

SummaryExplosive radiations have been considered one of the most intriguing diversification patterns across the Tree of Life, but the subsequent change, movement and extinction of the constituent species makes radiations hard to discern or understand as geological time passes.We synthesised phylogenetic and distributional data for an ongoing radiation — the mega-diverse plant genus Solanum L. — to show how dispersal events and past climatic changes have interacted to shape diversification.We found that despite the vast diversity of Solanum lineages in the Neotropics, lineages in the Old World are diversifying more rapidly. This recent explosive diversification coincides with a long-distance dispersal event from the Neotropics, at the time when, and to places where, major climatic changes took place. Two different groups of Solanum have migrated and established in Australia, but only the arid-adapted lineages experienced significant increases in their diversification, which is consistent with adaptation to the continent’s long-term climatic trend and the diversification of other arid-adapted groups.Our findings provide a clear example of how successful colonisation of new areas and niches can – but do not always – drive explosive radiations.

scholarly journals Chitin-induced systemic disease resistance in rice requires both OsCERK1 and OsCEBiP and is mediated via perturbation of cell-wall biogenesis in leaves

2021 ◽  
Author(s):  
Momoko Takagi ◽  
Kei Hotamori ◽  
Keigo Naito ◽  
Sumire Matsukawa ◽  
Mayumi Egusa ◽  
...  
Keyword(s):  
Immune Response ◽  
Cell Wall ◽  
Disease Resistance ◽  
Transcriptome Analysis ◽  
Systemic Disease ◽  
Cell Wall Composition ◽  
List Type ◽  
Local Immune Response ◽  
Long Distance ◽  
Cell Wall Biogenesis

SummaryChitin is a well-known elicitor of disease resistance whose recognition by plants is crucial to perceive fungal infections. Chitin can induce both a local immune response and a systemic disease resistance when provided as a supplement in soils. Unlike local immune responses, how chitin-induced systemic disease resistance is deployed has not been studied in detail.In this study, we evaluated systemic disease resistance against the fungal pathogen Bipolaris oryzae by performing a transcriptome analysis and monitoring cell-wall composition in rice plants grown in chitin-supplemented soils. We also examined the local immune response to chitin by measuring the production of reactive oxygen species in leaves.Chitins induced both local immune response and systemic disease resistance with differing requirements for the receptors OsCERK1 and OsCEBiP. Transcriptome analysis suggested that a perturbation in cell-wall biogenesis is involved in the induction of systemic disease resistance, an idea which was supported by the induction of disease resistance by treatment with a cellulose biosynthesis inhibitor and alterations of cell-wall composition.These findings suggest that chitin-induced systemic disease resistance in rice is caused by a perturbation of cell-wall biogenesis in leaves through long-distance signalling after recognition of chitins by OsCERK1 and OsCEBiP.

scholarly journals Recreational fisheries as a driver of salmonid population conservation

2019 ◽  
Author(s):  
Thomas A. Worthington ◽  
Ian Worthington ◽  
Ian P. Vaughan ◽  
Steve J Ormerod ◽  
Isabelle Durance
Keyword(s):  
Nature Conservation ◽  
Ecosystem Service ◽  
Species Abundance ◽  
List Type ◽  
Long Distance ◽  
Recreational Angling ◽  
Population Conservation ◽  
Two Measures ◽  
Service Paradigm ◽  
Juvenile Density

ABSTRACTThe need to monitor and protect biodiversity has never been greater, yet resources are often constrained economically. The ecosystem service paradigm could promote nature conservation while sustaining economic activity and other societal benefits, but most efforts to assess biodiversity-ecosystem service (B-ES) links have focused on diversity measures, with little attention on how species abundance relates to the magnitude of ES provision.Here, we utilised four national scale, multi-decadal, Atlantic salmon (Salmo salar) datasets to investigate links between juvenile density, the abundance of returning adults, and two measures of recreational angling provision: rod catches and angling effort.Recreational rod catches only tracked juvenile density and returning adult numbers in catchments where juvenile and adult numbers were decreasing, implying important early-warning of ES decline. In contrast, angling effort declined consistently through time.Synthesis and applications. These data illustrate i) the difficulty in measuring ES in ways that explicitly relate human resource use to nature conservation, and ii) the need for better quantification of populations at all life stages that determine ES provision, particularly in species where long-distance movements bring exposure to multiple global pressures. We suggest additional opportunities (e.g., monitoring of smolts, eDNA and citizen science initiatives) to facilitate conservation efforts and increase capacity to monitor ecosystem service sustainability.

scholarly journals Conservation of N-hydroxy-pipecolic acid-mediated systemic acquired resistance in crop plants

2019 ◽  
Author(s):  
Eric C. Holmes ◽  
Yun-Chu Chen ◽  
Elizabeth Sattely ◽  
Mary Beth Mudgett
Keyword(s):  
Systemic Acquired Resistance ◽  
Acquired Resistance ◽  
Signal Propagation ◽  
Crop Plants ◽  
Pipecolic Acid ◽  
List Type ◽  
In Planta ◽  
Long Distance ◽  
Plant Kingdom ◽  
Promising Strategy

SUMMARYSignal propagation and the coordination of whole-organism responses in plants rely heavily on small molecules. Systemic acquired resistance (SAR) is one such process in which long-distance signaling activates immune responses in uninfected tissue as a way to limit the spread of a primary, localized infection. Recently, N-hydroxy pipecolic acid (NHP) was discovered and shown to coordinate SAR in Arabidopsis. Here, we provide metabolic and biochemical evidence that NHP is conserved across the plant kingdom and demonstrate a role for NHP in mediating SAR responses in tomato and pepper. We reconstituted the NHP biosynthetic pathway in planta and show that transient expression of two NHP biosynthetic genes in tomato induces enhanced resistance to a bacterial pathogen in distal tissue. Our results suggest engineering strategies to induce NHP-mediated SAR are a promising route to improve broad-spectrum pathogen resistance in crops.IN BRIEFEngineering NHP production is a promising strategy to enhance disease resistance in crops.HIGHLIGHTSArabidopsis N-hydroxy-pipecolic acid (NHP) pathway is conserved across the plant kingdomApplication of NHP to tomato and pepper plants induces a robust SAR responseMetabolic engineering of the Arabidopsis NHP pathway in Solanum lycopersicum leads to enhanced NHP production and defense primingGenetic engineering for enhanced NHP production is a promising strategy to protect crop plants from multiple pathogens

scholarly journals Visualization of seasonal shifts of phosphorus re-translocation and overwintering recycling in a shortened annual cycle system of the deciduous poplar tree (Populus alba L.)

2020 ◽  
Author(s):  
Yuko Kurita ◽  
Satomi Kanno ◽  
Ryohei Sugita ◽  
Atsushi Hirose ◽  
Miwa Ohnishi ◽  
...  
Keyword(s):  
Annual Cycle ◽  
Tissue Level ◽  
Deciduous Trees ◽  
List Type ◽  
Bud Burst ◽  
Populus Alba ◽  
Cycle System ◽  
Poplar Trees ◽  
Whole Plant ◽  
Key Points

Summary(1) the research conducted, including the rationalePhosphorus (P) is an essential macronutrient for plant growth. In deciduous trees, P is remobilized from senescing leaves and stored in perennial tissues during winter for further growth. To clarify how deciduous trees utilize the internal P through a year, seasonal re-translocation routes and the reuse of P over winter were investigated.(2) methodsWe analyzed the seasonal re-translocation and accumulation of P in poplar trees (Populus alba. L) cultivated under “a shortened annual cycle system”, which mimicked seasonal phenology in a laboratory. The real-time radioisotope imaging and the macro- and micro-autoradiography with 32P and 33P were used to reveal the organ and tissue level P allocation.(3) key resultsThe direction of phosphate re-translocation changed seasonally. In the growing season, P was mainly re-translocated from a leaf to upper parts via phloem. During senescence, P was re-translocated to lower perennial parts, and also to inner xylem parenchyma cells. Phloem-xylem exchange of re-translocated P occurred in the stem. After bud burst in spring, stored P was re-translocated to the whole plant and mainly accumulated in new shoots.(4) the main conclusion, including the key points of discussionPoplar trees change the routes of P re-translocation longitudinally and radially depending on the season, and recycle internal P throughout the year.

scholarly journals The initiation of bud burst in grapevine features dynamic regulation of the apoplastic pore size

2019 ◽  
Vol 71 (2) ◽  
pp. 719-729 ◽  
Author(s):  
Santiago Signorelli ◽  
Jeremy Shaw ◽  
Dina Hermawaty ◽  
Zi Wang ◽  
Pieter Verboven ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Pore Size ◽  
Molecular Modelling ◽  
Bud Burst ◽  
Micro Computed Tomography ◽  
Dynamic Regulation

Molecular modelling, histochemistry, and micro-computed tomography reveal that the apoplastic pore size is dynamically regulated during bud burst in grapevine, and associated with oxygenation of the meristematic core.

scholarly journals Light responses of melanopsin-expressing ganglion cells in the foetal mammalian retina

2019 ◽  
Author(s):  
Jan Verweij ◽  
Shawnta Y. Chaney ◽  
Derek Bredl ◽  
Shruti Vemaraju ◽  
Gabriele M. König ◽  
...  
Keyword(s):  
Ganglion Cells ◽  
Vascular Development ◽  
Critical Role ◽  
Light Sensitivity ◽  
In Utero ◽  
Calcium Currents ◽  
List Type ◽  
Light Activation ◽  
Specific Expression ◽  
Light Responses

AbstractSensory stimulation plays a critical role in the maturation of sensory organs and systems. For example, when deprived of light before birth, foetal mouse pups in utero exhibit altered ocular vascular development. Normal vascular development depends on light excitation of melanopsin, a non-rod, non-cone photopigment that is expressed in a subset of ganglion cells (mRGCs) in the retina. However, there is no direct evidence that mRGCs in foetal eyes are light-responsive. Very little is known about how light absorption leads to excitation in these foetal neurons. Using mRGC-specific expression of the calcium indicators GCaMP3 and GCaMP6, we report that foetal mouse mRGCs respond to light as early as 4 days before birth. Further, two distinct Gq/11-G protein family antagonists, FR9000359 and YM-254890, abolish these light responses. TTX, a blocker of voltage-activated sodium channels, reversibly represses light responses, and FPL6417 and L-cis-diltiazem, which modify L-type calcium channels, respectively increase and reduce light responses. Electrophysiological patch pipette recordings show that embryonic mRGCs respond to light of intensity as low as 2.9 × 1012 photons/cm2/s. The present findings demonstrate a heretofore unproven but postulated light sensitivity in the retinas of foetal mice and identify the transduction pathways involved. Surprisingly, mRGCs do not function as completely independent photoreceptors but are electrotonically coupled with other mRGCs. Given that melanopsin is expressed in foetal human retinas, these findings support the idea that the eyes of foetal and early preterm infants are likely to exhibit functional photosensitivity.Key pointsMelanopsin is a light-excitable photopigment expressed in a subset of ganglion cell neurons (mRGCs) in the retinas of many different species of vertebrates. In mature animals, light activation of mRGCs modulates many visual adaptive functions including pupil constriction, entrainment of circadian rhythms, mood and learning. In neonatal pups at ages prior to the developmental onset of visual signalling from rods and cones, melanopsin cells mediate photoaversive behaviour. In foetal pups, light activation of melanopsin cells accelerates maturation of the ocular vasculature. Here, we describe and physiologically characterize the light responses of melanopsin ganglion cells in the retinas of foetal pups.MRGCs in embryonic retinas respond to light at least four days prior to birth and exhibit responses to light of intensity as low as 3 × 1012 photons/cm2/s.Phototransduction mechanisms include melanopsin activation of Gq/11 – G proteins, voltage-activated sodium currents, and voltage-gated L-type calcium currents.MRGCs are electrotonically coupled to other mRGCs in foetal retinas.We propose that melanopsin-expressing ganglion cells are excited by light while in utero and that this excitation relies, for the most part, on phototransduction pathways that have been described in postnatal retinas. Furthermore, we propose that foetal mRGCs have the requisite properties to modulate light-regulated maturation of the ocular vasculature and, perhaps, the development of visual pathways.

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