scholarly journals Increased salinity stress changes plant productivity and biomass by altering the top‐down controls in eelgrass beds

Ecosphere ◽  
2021 ◽  
Vol 12 (12) ◽  
Author(s):  
Mizuho Namba ◽  
Masahiro Nakaoka
Keyword(s):  
Salinity Stress ◽  
Plant Productivity ◽  
Top Down ◽  
Stress Changes ◽  
Eelgrass Beds

Effects of Salinity Stress on Growth and Phenolics of Rice (Oryza sativa L.)

2016 ◽  
Vol 57 ◽  
pp. 1-10 ◽  
Author(s):  
Luong The Minh ◽  
Do Tan Khang ◽  
Pham Thi Thu Ha ◽  
Phung Thi Tuyen ◽  
Truong Ngoc Minh ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Ferulic Acid ◽  
Salinity Stress ◽  
Protocatechuic Acid ◽  
Total Phenolics ◽  
Susceptible Cultivar ◽  
Coumaric Acid ◽  
Rice Varieties ◽  
Stress Changes ◽  
Chemical Contents

This study was conducted to determine the correlation between of salinity stress on growth and phenolic compounds in rice. It was observed that salinity stress caused a significant decrease in shoot lengths, fresh and dry weights of all rice varieties. Under salinity stress, changes of chemical contents also differed among phenolic compounds and rice cultivars. Total phenolics and flavonoids, and contents of vanillin and protocatechuic acid in tolerant varieties were strongly increased, whereas in contrast, they were markedly reduced in the susceptible cultivar. Ferulic acid and p-coumaric acid were detected only in tolerance rice. Vanillin and protocatechuic acid may play a role, but ferulic acid and p-coumaric acid may be much involved in the tolerant mechanism against salinity stress. Ferulic acid and p-coumaric acid and their derivatives are able to be exploited as promising agents to reduce detrimental effects of salinity stress on rice production.

scholarly journals Fisiologia da percepção do estresse salino em híbridos de tangerineira “Sunki Comum” sob solução hidropônica salinizada

2015 ◽  
Vol 6 (4) ◽  
pp. 463 ◽  
Author(s):  
Francisco Vanies da Silva Sá ◽  
Marcos Eric Barbosa Brito ◽  
Luderlândio de Andrade Silva ◽  
Romulo Carantino Lucena Moreira ◽  
Pedro Dantas Fernandes ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Gas Exchange ◽  
Salinity Stress ◽  
Salinity Tolerance ◽  
Saline Water ◽  
Water Solution ◽  
Block Design ◽  
Saline Stress ◽  
Randomized Block Design ◽  
Stress Changes

In order to study the physiology of perception of saline stress in ‘Common Sunki’ mandarin hybrids, an experiment was realized in a greenhouse at the CCTA - UFCG, Pombal, PB, Brazil,using using a randomized block design with a 2x4 factorial , with two levels of salinity (0.3 and 4.0 dS m-1) and four ‘Common Sunki’ mandarin hybrids (1 - TSKC x CTARG–019; 2 - TSKC x CTSW–028; 3 - TSKC x CTSW–033 and 4 - TSKC x CTSW-041), with three replications and four plants per plot. The plants were grown hydroponically and 90 days after sowing, a saline water solution was applied on rootstocks and evaluations of gas exchange and chlorophyll fluorescence were carried out 24 and 48 hours after saline stress. Changes on physiologic conditions were observed in the hybrids TSKC x CTSW - 028, TSKC x CTSW - 033 and TSKC x CTSW - 041 during the first 24 hours of saline stress. Fot the hybrid TSKC x CTARG – 019, changes were observed after 48 hours od salinity stress. According to salinity tolerance, the hybrids could be classified as follows: TSKC x CTARG - 019 > TSKC x CTSW - 028 = TSKC x CTSW – 041 > TSKC x CTSW - 033.

Top-Down Processing and Visual Reorientation Illusions in a Virtual Reality Environment

2004 ◽  
Vol 63 (3) ◽  
pp. 143-149 ◽  
Author(s):  
Fred W. Mast ◽  
Charles M. Oman
Keyword(s):  
Virtual Reality ◽  
Visual Processing ◽  
Line Length ◽  
Perceptual Cues ◽  
Virtual Reality Environment ◽  
Top Down ◽  
Test Conditions ◽  
The Subject ◽  
Processing Mechanisms

The role of top-down processing on the horizontal-vertical line length illusion was examined by means of an ambiguous room with dual visual verticals. In one of the test conditions, the subjects were cued to one of the two verticals and were instructed to cognitively reassign the apparent vertical to the cued orientation. When they have mentally adjusted their perception, two lines in a plus sign configuration appeared and the subjects had to evaluate which line was longer. The results showed that the line length appeared longer when it was aligned with the direction of the vertical currently perceived by the subject. This study provides a demonstration that top-down processing influences lower level visual processing mechanisms. In another test condition, the subjects had all perceptual cues available and the influence was even stronger.

Functional Anatomy of Intensity Aspects of Attention

2003 ◽  
Vol 14 (3) ◽  
pp. 181-190 ◽  
Author(s):  
Walter Sturm
Keyword(s):  
Right Hemisphere ◽  
Functional Anatomy ◽  
Fmri Data ◽  
Functional Networks ◽  
Top Down ◽  
Stimulus Modality ◽  
Spatial Orienting ◽  
Phasic Alertness ◽  
Co Activation ◽  
Attention System

Abstract: Behavioral and PET/fMRI-data are presented to delineate the functional networks subserving alertness, sustained attention, and vigilance as different aspects of attention intensity. The data suggest that a mostly right-hemisphere frontal, parietal, thalamic, and brainstem network plays an important role in the regulation of attention intensity, irrespective of stimulus modality. Under conditions of phasic alertness there is less right frontal activation reflecting a diminished need for top-down regulation with phasic extrinsic stimulation. Furthermore, a high overlap between the functional networks for alerting and spatial orienting of attention is demonstrated. These findings support the hypothesis of a co-activation of the posterior attention system involved in spatial orienting by the anterior alerting network. Possible implications of these findings for the therapy of neglect are proposed.

Auswirkungen eines Aufmerksamkeitstrainings auf die aphasische Symptomatik bei Schlaganfallpatienten

2011 ◽  
Vol 22 (1) ◽  
pp. 21-32 ◽  
Author(s):  
Julia Graf ◽  
Hartwig Kulke ◽  
Christa Sous-Kulke ◽  
Wilfried Schupp ◽  
Stefan Lautenbacher
Keyword(s):  
Top Down

Aufmerksamkeit kann als Kontrollsystem neuronaler Aktivität verstanden werden, welches Neuroplastizität top-down modulieren hilft. Bisher wurde selten versucht, durch deren gezielte Förderung Funktionswiederherstellungen nach Hirnschädigung zu begünstigen. In vorliegender Studie wurde dies am Beispiel der Aphasie erprobt. 15 Schlaganfallpatienten erhielten ein dreiwöchiges Training der selektiven Aufmerksamkeit mit den PC-Programmen CogniPlus und „Konzentration“ bei fünf Sitzungen pro Woche zusätzlich zur Standardtherapie, 13 weitere bildeten eine Kontrollgruppe ohne Aufmerksamkeitstraining. Zur Effektivitätskontrolle dienten zwei Versionen des Untertests Go/Nogo (Testbatterie zur Aufmerksamkeitsprüfung) und die Kurze Aphasieprüfung. Nach dem Training manifestierte sich zwischen den Untersuchungsgruppen kein Unterschied in Aufmerksamkeits- und Sprachfunktionen; das zusätzliche Aufmerksamkeitstraining war also wirkungslos. Allerdings zeigten Patienten mit deutlichen Aufmerksamkeitsverbesserungen tendenziell weniger Aphasie-Symptome, was die Hypothese aufmerksamkeitsvermittelter Plastizitätsmodulation nach Hirnschädigung partiell stützt.

Aufmerksamkeitswechsel und Konzentration: Von den Funktionen zum Mechanismus

2001 ◽  
Vol 209 (1) ◽  
pp. 34-53 ◽  
Author(s):  
Rainer Bösel
Keyword(s):  
Top Down ◽  
Eeg Alpha

Zusammenfassung. Aufmerksamkeit wird sowohl als Selektivität in der bewußter Verarbeitung oder auch als selektive neuronale Aktivierung verstanden. Die neuronalen Strukturen, die Objektdiskrimination ermöglichen, erlauben eine Interaktion von datengetriebenen und endogenen top-down Prozessen, die zu einer selektiven Bereitstellung von Verarbeitungs-Ressourcen führen. Zielgerichtetes Verhalten erfordert manchmal einen Wechsel in der Ressourcen-Bereitstellung und eine Konzentration von mentaler Aktivität. Aufmerksamkeitswechsel kann als ein zweiphasiger Prozeß verstanden werden, der aus einer breiten Mobilisierung von Gedächtnis-Ressourcen besteht (angezeigt durch EEG-Theta), gefolgt von einer re-organisierenden Einengung neuronaler Aktivität (angezeigt durch langsames EEG-Alpha). Dieser Beitrag unterstützt die Annahme, daß die Analyse des gekoppelten Wechselspiels aus Mobilisierung und Konzentration in bestimmten Teilen der posterioren und anterioren Rindenregionen ein Schlüssel für das Verständnis von Aufmerksamkeitswechsel sein könnte.

Psychology and Culture: Top Down Versus Bottom Up?

PsycCRITIQUES ◽  
2005 ◽  
Vol 50 (19) ◽  
Author(s):  
Michael Cole
Keyword(s):  
Top Down ◽  
Bottom Up
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