scholarly journals From spatio-temporal morphogenetic gradients to rhythmic patterning at the shoot apex

2018 ◽  
Author(s):  
Carlos S. Galvan-Ampudia ◽  
Guillaume Cerutti ◽  
Jonathan Legrand ◽  
Romain Azais ◽  
Géraldine Brunoud ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Shoot Apex ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Plant Hormone ◽  
Temporal Dynamics ◽  
Quantitative Imaging ◽  
Transport Network ◽  
High Definition ◽  
Spatio Temporal

AbstractRhythmic patterning is central to the development of eukaryotes, particularly in plant shoot post-embryonic development. The plant hormone auxin drives rhythmic patterning at the shoot apical meristem, but the spatio-temporal dynamics of the auxin gradients is unknown. We used quantitative imaging to demonstrate that auxin provides high-definition graded information not only in space but also in time. We provide evidence that developing organs are auxin-emitting centers that could self-organize spatio-temporal auxin gradients through a transport network converging on the meristem center. We further show that a memory of the exposition of cells to auxin allows to differentiate temporally sites of organ initiation, providing a remarkable example of how the dynamic redistribution of a morphogenetic regulator can be used to create rhythmicity.

scholarly journals Temporal integration of auxin information for the regulation of patterning

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Carlos S Galvan-Ampudia ◽  
Guillaume Cerutti ◽  
Jonathan Legrand ◽  
Géraldine Brunoud ◽  
Raquel Martin-Arevalillo ◽  
...  
Keyword(s):  
Shoot Apex ◽  
Temporal Dynamics ◽  
Quantitative Imaging ◽  
Temporal Integration ◽  
Positional Information ◽  
High Definition ◽  
Auxin Concentration ◽  
Spatio Temporal ◽  
High Auxin ◽  
Multicellular Organisms

Positional information is essential for coordinating the development of multicellular organisms. In plants, positional information provided by the hormone auxin regulates rhythmic organ production at the shoot apex, but the spatio-temporal dynamics of auxin gradients is unknown. We used quantitative imaging to demonstrate that auxin carries high-definition graded information not only in space but also in time. We show that, during organogenesis, temporal patterns of auxin arise from rhythmic centrifugal waves of high auxin travelling through the tissue faster than growth. We further demonstrate that temporal integration of auxin concentration is required to trigger the auxin-dependent transcription associated with organogenesis. This provides a mechanism to temporally differentiate sites of organ initiation and exemplifies how spatio-temporal positional information can be used to create rhythmicity.

scholarly journals Spatio-temporal Dynamics of the Patterning of Arabidopsis Flower Meristem

2020 ◽  
Author(s):  
José Díaz ◽  
Elena R. Álvarez-Buylla
Keyword(s):  
Flower Development ◽  
Apical Meristem ◽  
Temporal Dynamics ◽  
Positional Information ◽  
Floral Organ ◽  
Necessary Condition ◽  
Sufficient Condition ◽  
Abc Model ◽  
Flower Meristem ◽  
Spatio Temporal

AbstractThe qualitative model presented in this work recovers the onset of the four fields that correspond to those of each floral organ whorl of Arabidopsis flower, suggesting a mechanism for the generation of the positional information required for the differential expression of the A, B and C identity genes according to the ABC model for organ determination during early stages of flower development. Our model integrates a previous model for the emergence of WUS pattern in the apical meristem, and shows that this pre-pattern is a necessary but not sufficient condition for the posterior information of the four fields predicted by the ABC model. Furthermore, our model predicts that LFY diffusion along the L1 layer of cells is not a necessary condition for the patterning of the floral meristem.

scholarly journals Does Shoot Apical Meristem Function as the Germline in Safeguarding Against Excess of Mutations?

2021 ◽  
Vol 12 ◽  
Author(s):  
Agata Burian
Keyword(s):  
Cell Fate ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Cell Lineage ◽  
Temporal Distribution ◽  
Tissue Level ◽  
Protective Mechanisms ◽  
Genetic Continuity ◽  
Spatio Temporal ◽  
Living Organisms

A genetic continuity of living organisms relies on the germline which is a specialized cell lineage producing gametes. Essential in the germline functioning is the protection of genetic information that is subjected to spontaneous mutations. Due to indeterminate growth, late specification of the germline, and unique longevity, plants are expected to accumulate somatic mutations during their lifetime that leads to decrease in individual and population fitness. However, protective mechanisms, similar to those in animals, exist in plant shoot apical meristem (SAM) allowing plants to reduce the accumulation and transmission of mutations. This review describes cellular- and tissue-level mechanisms related to spatio-temporal distribution of cell divisions, organization of stem cell lineages, and cell fate specification to argue that the SAM functions analogous to animal germline.

scholarly journals Diversity of phyllotaxis in land plants in reference to the shoot apical meristem structure

2016 ◽  
Vol 85 (4) ◽  
Author(s):  
Edyta M. Gola ◽  
Alicja Banasiak
Keyword(s):  
Pattern Formation ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Land Plants ◽  
Phyllotactic Pattern ◽  
Lateral Organs ◽  
Spatio Temporal

Regularity and periodicity in the arrangements of organs in all groups of land plants raise questions about the mechanisms underlying phyllotactic pattern formation. The initiation of the lateral organs (leaves, flowers, etc.), and thus, their spatio-temporal positioning, occurs in the shoot apical meristem (SAM) and is related to the structure and organogenic activity of the meristem. In this review, we present some aspects of the diversity and stability of phyllotactic patterns in the major lineages of land plants, from bryophytes to angiosperms, in which SAM structures differ significantly. In addition, we discuss some of the possible mechanisms involved in the formation of the recurring arrangement of the lateral organs.

Developmental potentialities of leaf primordia of Osmunda cinnamomea. VI. The expression of P1

1971 ◽  
Vol 49 (11) ◽  
pp. 1941-1945 ◽  
Author(s):  
Thomas H. Haight ◽  
Charles Carroll Kuehnert
Keyword(s):  
Phase I ◽  
Phase Ii ◽  
Shoot Apex ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Leaf Primordia ◽  
Phase Iii ◽  
Developmental Phase ◽  
Experimental Conditions ◽  
Three Phases

Data from culture experiments presented strongly suggest that the development of leaf primordia at the shoot apex may be divided into three phases in Osmunda cinnamomea. Phase I lasts from inception (Im) to some point in time during P1. Phase II probably begins somewhere between Im and I1, and may be retained as long as P9. Phase III is evident as early as P1 and continues through the entire primordial sequence to include Pn. In nature, or under experimental conditions where physiological continuity between the primordium and shoot apical meristem complex is maintained, O. cinnamomea primordial expression is phase III expression (leaf only). However, if the primordia produced at the shoot apex are removed from certain external biological influences (specifically the shoot apical meristem and certain older primordia) terminal expression of the primordia may be either phase I, phase II, or phase III depending upon the developmental phase of the primordia at the time of their isolation.

scholarly journals Plastid Osmotic Stress influences cell differentiation at the Plant Shoot Apex

2016 ◽  
Author(s):  
Margaret E. Wilson ◽  
Matthew Mixdorf ◽  
R. Howard Berg ◽  
Elizabeth S. Haswell
Keyword(s):  
Stem Cell ◽  
Cell Differentiation ◽  
Osmotic Stress ◽  
Shoot Apex ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Retrograde Signaling ◽  
Cell Identity ◽  
Callus Production ◽  
Stress Influences

ABSTRACTThe balance between proliferation and differentiation in the plant shoot apical meristem is controlled by regulatory loops involving the phytohormone cytokinin and stem cell identity genes. Concurrently, cellular differentiation in the developing shoot is coordinated with the environmental and developmental status of plastids within those cells. Here we employ an Arabidopsis thaliana mutant exhibiting constitutive plastid osmotic stress to investigate the molecular and genetic pathways connecting plastid osmotic stress with cell differentiation at the shoot apex. msl2 msl3 mutants exhibit dramatically enlarged and deformed plastids in the shoot apical meristem, and develop a mass of callus tissue at the shoot apex. Callus production in this mutant requires the cytokinin receptor AHK2 and is characterized by increased cytokinin levels, down-regulation of cytokinin signaling inhibitors ARR7 and ARR15, and induction of the stem cell identity gene WUSCHEL. Furthermore, plastid stress-induced apical callus production requires elevated plastidic ROS, ABA biosynthesis, the retrograde signaling protein GUN1, and ABI4. These results are consistent with a model wherein the cytokinin/WUS pathway and retrograde signaling control cell differentiation at the shoot apex.SUMMARY STATEMENTPlastid osmotic stress influences differentiation at the plant shoot apex. Two established mechanisms that control proliferation, the cytokinin/WUSCHEL stem cell identity loop and a plastid-to-nucleus signaling pathway, are implicated.

The development of cotyledon and shoot apex in monocotyledons

1984 ◽  
Vol 62 (6) ◽  
pp. 1316-1318 ◽  
Author(s):  
J.-L. Guignard
Keyword(s):  
Shoot Apex ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Central Zone ◽  
Differential Growth ◽  
Lateral Shoot

Monocotyledonous embryos have a single cotyledon which is initiated very early. During development the differential growth in the cotyledon results in a lateral shoot apical meristem; its quiescent central zone, at first axial as in Palmae, becomes more lateral in the course of evolution owing to earlier development of the cotyledon. One can establish a phyletic sequence from a dicotyledonous embryo to an advanced monocotyledonous embryo through the Palmae.

Spatial and temporal dynamics of Pacific capelin Mallotus catervarius in the Gulf of Alaska: implications for ecosystem-based fisheries management

2020 ◽  
Vol 637 ◽  
pp. 117-140 ◽  
Author(s):  
DW McGowan ◽  
ED Goldstein ◽  
ML Arimitsu ◽  
AL Deary ◽  
O Ormseth ◽  
...  
Keyword(s):  
Temporal Dynamics ◽  
Marine Ecosystem ◽  
Gulf Of Alaska ◽  
Data Series ◽  
Limited Information ◽  
Important Species ◽  
Multiple Data ◽  
Spatial And Temporal Dynamics ◽  
Spawning Areas ◽  
Spatio Temporal

Pacific capelin Mallotus catervarius are planktivorous small pelagic fish that serve an intermediate trophic role in marine food webs. Due to the lack of a directed fishery or monitoring of capelin in the Northeast Pacific, limited information is available on their distribution and abundance, and how spatio-temporal fluctuations in capelin density affect their availability as prey. To provide information on life history, spatial patterns, and population dynamics of capelin in the Gulf of Alaska (GOA), we modeled distributions of spawning habitat and larval dispersal, and synthesized spatially indexed data from multiple independent sources from 1996 to 2016. Potential capelin spawning areas were broadly distributed across the GOA. Models of larval drift show the GOA’s advective circulation patterns disperse capelin larvae over the continental shelf and upper slope, indicating potential connections between spawning areas and observed offshore distributions that are influenced by the location and timing of spawning. Spatial overlap in composite distributions of larval and age-1+ fish was used to identify core areas where capelin consistently occur and concentrate. Capelin primarily occupy shelf waters near the Kodiak Archipelago, and are patchily distributed across the GOA shelf and inshore waters. Interannual variations in abundance along with spatio-temporal differences in density indicate that the availability of capelin to predators and monitoring surveys is highly variable in the GOA. We demonstrate that the limitations of individual data series can be compensated for by integrating multiple data sources to monitor fluctuations in distributions and abundance trends of an ecologically important species across a large marine ecosystem.

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