Some Cretaceous long-looped terebratulide brachiopods analysed in the light of the diversity observed in the ontogeny of Recent representatives

2003 ◽  
Vol 174 (3) ◽  
pp. 261-269 ◽  
Author(s):  
Danièle Gaspard
Keyword(s):  
Early Ontogeny ◽  
Early Growth ◽  
Growth Stages ◽  
Serial Sections ◽  
Median Septum ◽  
Wide Range ◽  
Growth Types ◽  
Fossil Records ◽  
Similar Growth ◽  
Main Growth

Abstract The shape of the loop is of prime importance in brachiopod terebratulide classification and has been widely discussed and revised [Williams et al., 1996]. In the Rhynchonelliforma, we have focused our attention on the Terebratellidina, long-looped brachiopods with a wide-range diversity. The observation of its internal structure in recent representatives, investigated from the early growth stages, using the Scanning Electron Microscope (S.E.M.), demonstrates the complexity of its growth. Two main growth types of the descending branches are expressed during early ontogeny [Gaspard, 2002], followed in both cases by forward growth in opposite directions, with a brachial ribbon attached or unattached to the median septum. The purpose of such observations is to find in the fossil records similar growth types. An approach from the recent representatives allows a better knowledge of the Cretaceous taxa considered, even if the only way to recognise the loop is by means of transverse serial sections. The study of the recent terebratellidine loop facilitates the establishment of links between species from different geological periods. It helps to determine superfamilial distinctions and to find possible ancestors of recent terebratellidines.

scholarly journals Metabolic Responses of Two Contrasting Lentil Genotypes to PEG-Induced Drought Stress

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1190
Author(s):  
Chrysanthi Foti ◽  
Ioannis F. Kalampokis ◽  
Konstantinos A. Aliferis ◽  
Ourania I. Pavli
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Metabolic Response ◽  
Early Growth ◽  
Metabolic Responses ◽  
Economic Losses ◽  
Growth Stages ◽  
Wide Range ◽  
Research Findings ◽  
Post Transcriptional Regulation

Among abiotic stresses, drought is undoubtedly one of the most severe environmental factors for a wide range of major crops, leading to considerable yield and economic losses. The adverse effects in crop yield reflect the result of a series of morphological and physiological changes but also changes in signaling pathways, transcriptional and post-transcriptional regulation of stress-responsive genes, and metabolic adaptations. Despite the exhausting studies elucidating plants’ metabolic response to drought, there is a knowledge gap in the biochemical mechanisms governing drought tolerance in lentil (Lens culinaris Medik.). The present study aimed to determine the fluctuations of the metabolite profiles of lentil genotypes with contrasting drought tolerance to discover possible biomarkers for screening tolerant genotypes at early growth stages. Lentil seedlings were subjected to osmotic drought stress, induced by polyethylene glycol, at two stress levels (2.5% and 5.0% PEG-6000) for a period of 20 days, while untreated plants were also included as controls. GC/ΕΙ/MS-mediated metabolic profiling was employed to monitor changes in response to osmotic drought stress. The data was subjected to OPLS-DA and OPLS-HCA for the discrimination between treatments and the discovery of trends and corresponding biomarkers. In total, the analysis yielded 150 metabolite features with highly reproducible patterns, of which the vast majority belonged to carbohydrates, carboxylic acids, and amino acids. Overall, findings highlight the differential accumulation of a series of compounds, and more importantly, the variable accumulation of certain metabolites, namely D-fructose, α,α-trehalose, myo-inositol, and L-tryptophan, in the contrasting genotypes, indicating that the adaptive metabolic responses to osmotic drought stress operate under strong genotypic dependency in lentil. Research findings provide insights into various aspects of lentil’s metabolism under drought and further offer the possibility of applying such knowledge towards effectively screening for drought-tolerant lentil germplasm at early growth stages.

scholarly journals Influence of 24-epibrassinolide on seedling growth and distribution of mineral elements in two maize hybrids

2017 ◽  
Vol 71 (3) ◽  
pp. 201-209 ◽  
Author(s):  
Hadi Waisi ◽  
Andjelka Petkovic ◽  
Bogdan Nikolic ◽  
Bojan Jankovic ◽  
Vera Raicevic ◽  
...  
Keyword(s):  
Seedling Growth ◽  
Photosynthetic Apparatus ◽  
Mineral Elements ◽  
Early Growth ◽  
Growth Potential ◽  
Growth Stages ◽  
Maize Hybrids ◽  
Stage Of Development ◽  
Seedling Biomass ◽  
Wide Range

In this study, influence of wide range of 24-epibrassinolide (24-EBL) on early growth potential of two maize hybrids (ZP 434 and ZP 704) was examined. Paper concerns germination, seedling biomass, important chlorophylls content, and redistribution of elements (heavy metals and microelements), in a seedlings of the maize hybrids, as influenced by different 24-EBL concentrations. It was found that hybrids react differently to exogenously applied hormone. The biggest differences between two examined maize hybrids considering the germination level were reached with the lowest values at 86% for ZP 704 and 72% for ZP 434, gained at the highest applied concentration of 24-EBL. Seedlings of hybrid ZP 434 reacted positively moderately in the case of shoot length and biomass under the influence of 24-EBL, but seedlings of hybrid ZP 704 had lower values of these parameters under the influence of the phytohormone. Chlorophyll a/b ratios showed that photosynthetic apparatus of seedlings of the hybrids is not active in this stage of development. It was established that 24-EBL affects seedling growth and re-allocation of naturally present mineral elements in early growth stages and that could be one of the reason for poorer growth of ZP 704 treated with various concentrations of 24-EBL, comparing to control. When applied in lower concentrations, 24-EBL is blocking toxic elements such as chromium and nickel to relocate to vital parts of plant, what was case in hybrid ZP704. In case of ZP 434, lower concentrations of 24-EBL are affecting re-allocation of Cu and Cr and these findings suggest that maize hybrid seedlings treated with lower concentrations of 24-EBL could survive and be successful in polluted areas.

scholarly journals Osmotic Stress or Ionic Composition: Which Affects the Early Growth of Crop Species More?

Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 435
Author(s):  
Agnieszka Ludwiczak ◽  
Monika Osiak ◽  
Stefany Cárdenas-Pérez ◽  
Sandra Lubińska-Mielińska ◽  
Agnieszka Piernik
Keyword(s):  
Osmotic Stress ◽  
Stress Responses ◽  
Ionic Composition ◽  
Degradation Process ◽  
Early Growth ◽  
Cultivated Plants ◽  
C3 Plants ◽  
Growth Stages ◽  
Crop Species ◽  
Ionic Salt

Salinization is a key soil degradation process. An estimated 20% of total cultivated lands and 33% of irrigated agricultural lands worldwide are affected by high salinity. Much research has investigated the influence of salt (mainly NaCl) on plants, but very little is known about how this is related to natural salinity and osmotic stress. Therefore, our study was conducted to determine the osmotic and ionic salt stress responses of selected C3 and C4 cultivated plants. We focused on the early growth stages as those critical for plant development. We applied natural brine to simulate natural salinity and to compare its effect to NaCl solution. We assessed traits related to germination ability, seedlings and plantlet morphology, growth indexes, and biomass and water accumulation. Our results demonstrate that the effects of salinity on growth are strongest among plantlets. Salinity most affected water absorption in C3 plants (28% of total traits variation), but plant length in C4 plants (17–27%). Compensatory effect of ions from brine were suggested by the higher model plants’ growth success of ca 5–7% under brine compared to the NaCl condition. However, trait differences indicated that osmotic stress was the main stress factor affecting the studied plants.

scholarly journals Coastal Mangrove Response to Marine Erosion: Evaluating the Impacts of Spatial Distribution and Vegetation Growth in Bangkok Bay from 1987 to 2017

2020 ◽  
Vol 12 (2) ◽  
pp. 220 ◽  
Author(s):  
Han Xiao ◽  
Fenzhen Su ◽  
Dongjie Fu ◽  
Qi Wang ◽  
Chong Huang
Keyword(s):  
Spatial Distribution ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Mangrove Ecosystem ◽  
Early Growth ◽  
Growth Stages ◽  
Human Disturbances ◽  
Vegetation Growth ◽  
Two Parameters ◽  
The Impact

Long time-series monitoring of mangroves to marine erosion in the Bay of Bangkok, using Landsat data from 1987 to 2017, shows responses including landward retreat and seaward extension. Quantitative assessment of these responses with respect to spatial distribution and vegetation growth shows differing relationships depending on mangrove growth stage. Using transects perpendicular to the shoreline, we calculated the cross-shore mangrove extent (width) to represent spatial distribution, and the normalized difference vegetation index (NDVI) was used to represent vegetation growth. Correlations were then compared between mangrove seaside changes and the two parameters—mangrove width and NDVI—at yearly and 10-year scales. Both spatial distribution and vegetation growth display positive impacts on mangrove ecosystem stability: At early growth stages, mangrove stability is positively related to spatial distribution, whereas at mature growth the impact of vegetation growth is greater. Thus, we conclude that at early growth stages, planting width and area are more critical for stability, whereas for mature mangroves, management activities should focus on sustaining vegetation health and density. This study provides new rapid insights into monitoring and managing mangroves, based on analyses of parameters from historical satellite-derived information, which succinctly capture the net effect of complex environmental and human disturbances.

scholarly journals Effect of sodium silicate on early growth stages of wheat under drought stress

2020 ◽  
Vol 63 (1) ◽  
Author(s):  
Sang Gyu Lee ◽  
Hyeri Lee ◽  
Byung Cheon Lee ◽  
Hojoung Lee ◽  
Jun Cheol Moon ◽  
...  
Keyword(s):  
Drought Stress ◽  
Sodium Silicate ◽  
Early Growth ◽  
Growth Stages

A Neoclassical Growth Model for Population Dynamics in a Homogeneous Habitat

2001 ◽  
Author(s):  
Peter Vadasz ◽  
Alisa S. Vadasz
Keyword(s):  
Experimental Data ◽  
Growth Model ◽  
Logistic Growth ◽  
Lag Phase ◽  
Growth Stages ◽  
Initial Growth ◽  
Neoclassical Model ◽  
Wide Range ◽  
Logistic Growth Model ◽  
Special Case

Abstract A neoclassical model is proposed for the growth of cell and other populations in a homogeneous habitat. The model extends on the Logistic Growth Model (LGM) in a non-trivial way in order to address the cases where the Logistic Growth Model (LGM) fails short in recovering qualitative as well as quantitative features that appear in experimental data. These features include in some cases overshooting and oscillations, in others the existence of a “Lag Phase” at the initial growth stages, as well as an inflection point in the “In curve” of the population size. The proposed neoclassical model recovers also the Logistic Growth Curve as a special case. Comparisons of the solutions obtained from the proposed neoclassical model with experimental data confirm its quantitative validity, as well as its ability to recover a wide range of qualitative features captured in experiments.

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