scholarly journals Dormancy and germination of the trimorphic achenes of a cold desert annual: spreading the risk over time

AoB Plants ◽  
2020 ◽  
Vol 12 (6) ◽  
Author(s):  
Juanjuan Lu ◽  
Wenjing Dong ◽  
Dunyan Tan ◽  
Carol C Baskin ◽  
Jerry M Baskin
Keyword(s):  
Seedling Emergence ◽  
Dispersal Ability ◽  
Dormancy Breaking ◽  
Cold Desert ◽  
Standard Procedures ◽  
Emergence Percentage ◽  
Desert Annual ◽  
The Relationship ◽  
Over Time ◽  
Temporal Dispersal

Abstract Many studies have been done on the relationship between variation in morphology, dispersal ability and degree of dormancy of heterocarpic species with dimorphic diaspores. However, there are far fewer such studies on species that produce trimorphic diaspores. Our aim was to compare dormancy and germination of achenes from peripheral, intermediate and central positions in the capitulum of the diaspore-trimorphic cold desert annual Asteraceae species Heteracia szovitsii, an important component of plant communities in the cold deserts of NW China. Dormancy breaking/germination responses of the three achene morphs and of seeds isolated from the pericarp were tested in the laboratory using standard procedures, and seedling emergence phenology of the achene morphs was monitored under natural cold desert temperature conditions in an experimental garden with and without supplemental watering. Depth of dormancy of the three achene morphs was peripheral > intermediate > central. Seedlings from the three morphs emerged in spring and in autumn. Cumulative seedling emergence percentage from achenes during 47 months of burial was central > intermediate > peripheral. Central achene morphs emerged over a period of ~12 months after sowing, while intermediate and peripheral achene morphs did so for ~40 and 47 months, respectively. Thus, H. szovitsii exhibits a temporal dispersal strategy. No viable central or intermediate achene morphs were present after 16 and 40 months, respectively, but ~60 % of the non-emerged peripheral achenes morphs were viable after 47 months. Based on our results on diaspore dormancy and those of a previous study of diaspore spatial dispersal of H. szovitsii, we conclude that this species has a high–intermediate–low risk diaspore dispersal/dormancy strategy that likely increases the chances for population persistence over time and space.

scholarly journals Ácido sulfúrico na quebra de dormência de sementes e na emergência e morfologia de plântulas de Canna edulis

2016 ◽  
Vol 22 (2) ◽  
pp. 221
Author(s):  
Rogério Gomes Pêgo ◽  
Daniela Sousa da Silva ◽  
Sebastião Martins Filho ◽  
Jose Antonio Saraiva Grossi
Keyword(s):  
Sulfuric Acid ◽  
Digital Images ◽  
Seedling Emergence ◽  
Dry Weight ◽  
Shoot Length ◽  
Average Weight ◽  
Dormancy Breaking ◽  
Emergence Percentage ◽  
Purple Coloration

he objective of this study was to evaluate the efficiency of time scarification of seeds in sulfuric acid to break the dormancy of seeds, seedling emergence and post-seminal morphology of C. edulis. This way, were determined biometric characteristics of seeds with the help of pachymeter and digital balance. To dormancy breaking, the seeds were immersed in sulfuric acid during 0.0, 0.5, 1.0, 1.5, 2.0 and 2.5 hours and sown in sand in a condition greenhouse. After 21 days emergence percentage, emergence speed index (IVE), shoot length and seedling dry weight of plants were recorded. At 0, 2, 4, 8, 12, 16, 20 days after sowing, the seedlings taken digital images and post-seminal morphology was characterized. The fruit of C. edulis contains an average of 19.27 globoses seeds of black coloration measuring about 5.62 mm in diameter, the average weight of 1000 seeds is 128.8 grams. The highest percentage of seedling emergence of 60% and 90% are obtained from seed treated with 0.5 hours in sulfuric acid at 10 and 21 days after sowing, respectively. The seeds have hypogeal germination with development of fasciculate roots with root axes differentiated at 4 days after sowing. The protophyll is observed from the eighth day and the seedlings have intense purple coloration at 16 days after sowing.

Investment Traits and Intelligence in Adulthood

2013 ◽  
Vol 34 (2) ◽  
pp. 82-89 ◽  
Author(s):  
Sophie von Stumm
Keyword(s):  
Individual Differences ◽  
Personality Traits ◽  
Fluid Intelligence ◽  
Need For Cognition ◽  
Openness To Experience ◽  
Intelligence Tests ◽  
Crystallized Intelligence ◽  
New Knowledge ◽  
The Relationship ◽  
Over Time

Intelligence-as-knowledge in adulthood is influenced by individual differences in intelligence-as-process (i.e., fluid intelligence) and in personality traits that determine when, where, and how people invest their intelligence over time. Here, the relationship between two investment traits (i.e., Openness to Experience and Need for Cognition), intelligence-as-process and intelligence-as-knowledge, as assessed by a battery of crystallized intelligence tests and a new knowledge measure, was examined. The results showed that (1) both investment traits were positively associated with intelligence-as-knowledge; (2) this effect was stronger for Openness to Experience than for Need for Cognition; and (3) associations between investment and intelligence-as-knowledge reduced when adjusting for intelligence-as-process but remained mostly significant.

Power Values and Power Distance Moderate the Relationship Between Workplace Supervisory Power and Job Satisfaction

2020 ◽  
Vol 19 (3) ◽  
pp. 135-141
Author(s):  
Kenneth D. Locke
Keyword(s):  
Job Satisfaction ◽  
Multilevel Modeling ◽  
Power Distance ◽  
European Social Survey ◽  
Social Survey ◽  
The Relationship ◽  
Workplace Power ◽  
Over Time

Abstract. Person–job (or needs–supplies) discrepancy/fit theories posit that job satisfaction depends on work supplying what employees want and thus expect associations between having supervisory power and job satisfaction to be more positive in individuals who value power and in societies that endorse power values and power distance (e.g., respecting/obeying superiors). Using multilevel modeling on 30,683 European Social Survey respondents from 31 countries revealed that overseeing supervisees was positively associated with job satisfaction, and as hypothesized, this association was stronger among individuals with stronger power values and in nations with greater levels of power values or power distance. The results suggest that workplace power can have a meaningful impact on job satisfaction, especially over time in individuals or societies that esteem power.

Emotional Impact Feedback Changes How We Remember Negative Autobiographical Experiences

2010 ◽  
Vol 57 (5) ◽  
pp. 354-359 ◽  
Author(s):  
Melanie K. T. Takarangi ◽  
Deryn Strange
Keyword(s):  
Well Being ◽  
The Other ◽  
Personal Perspective ◽  
Emotional Impact ◽  
Potential Mechanism ◽  
Negative Experiences ◽  
Negative Memory ◽  
The Relationship ◽  
Negative Memories ◽  
Over Time

When people are told that their negative memories are worse than other people’s, do they later remember those events differently? We asked participants to recall a recent negative memory then, 24 h later, we gave some participants feedback about the emotional impact of their event – stating it was more or less negative compared to other people’s experiences. One week later, participants recalled the event again. We predicted that if feedback affected how participants remembered their negative experiences, their ratings of the memory’s characteristics should change over time. That is, when participants are told that their negative event is extremely negative, their memories should be more vivid, recollected strongly, and remembered from a personal perspective, compared to participants in the other conditions. Our results provide support for this hypothesis. We suggest that external feedback might be a potential mechanism in the relationship between negative memories and psychological well-being.

Rethinking social remittances and the migration-development nexus from the perspective of time

2013 ◽  
Vol 10 (1) ◽  
pp. 11-22 ◽  
Author(s):  
Peggy Levitt ◽  
Deepak Lamba-Nieves
Keyword(s):  
Social Influence ◽  
Change Over Time ◽  
Social Remittances ◽  
The Relationship ◽  
Migration And Development ◽  
Over Time

This article explores how the conceptualization, management, and measurement of time affect the migration-development nexus. We focus on how social remittances transform the meaning and worth of time, thereby changing how these ideas and practices are accepted and valued and recalibrating the relationship between migration and development. Our data reveal the need to pay closer attention to how migration’s impacts shift over time in response to its changing significance, rhythms, and horizons. How does migrants’ social influence affect and change the needs, values, and mind-frames of non-migrants? How do the ways in which social remittances are constructed, perceived, and accepted change over time for their senders and receivers?

Changing Places: Rock Art and Holocene Landscapes in the Wadi al-Ajal, South-West Libya

2014 ◽  
Vol 12 (2) ◽  
pp. 165-182 ◽  
Author(s):  
Tertia Barnett ◽  
Maria Guagnin
Keyword(s):  
Spatial Analysis ◽  
Surface Water ◽  
Rock Art ◽  
Human Settlement ◽  
Gis Model ◽  
South West ◽  
Settlement Location ◽  
Central Sahara ◽  
The Relationship ◽  
Over Time

This article examines the relationship between rock art and landscape use by pastoral groups and early settled communities in the central Sahara from around 6000 BC to 1000 AD. During this period the region experienced significant climatic and environmental fluctuations. Using new results from a systematic survey in the Wadi al-Ajal, south-west Libya, our research combines data from over 2000 engraved rock art panels with local archaeological and palaeoenvironmental evidence within a GIS model. Spatial analysis of these data indicates a correspondence between the frequency of rock art sites and human settlement over time. However, while changes in settlement location were guided primarily by the constraints on accessibility imposed by surface water, the distribution of rock art relates to the availability of pasture and patterns of movement through the landscape. Although the reasons for these movements undoubtedly altered over time, natural routes that connected the Wadi al-Ajal and areas to the south continued to be a focus for carvings over several thousand years.

Soil and Stream Water Chemistry During Spring Snowmelt

1992 ◽  
Vol 23 (1) ◽  
pp. 13-26 ◽  
Author(s):  
W. H. Hendershot ◽  
L. Mendes ◽  
H. Lalande ◽  
F. Courchesne ◽  
S. Savoie
Keyword(s):  
Stream Water ◽  
Base Cations ◽  
Stream Chemistry ◽  
Stream Water Chemistry ◽  
The Matrix ◽  
Adsorption Desorption ◽  
The Relationship ◽  
Best Fit ◽  
Spring Snowmelt ◽  
Over Time

In order to determine how water flowpath controls stream chemistry, we studied both soil and stream water during spring snowmelt, 1985. Soil solution concentrations of base cations were relatively constant over time indicating that cation exchange was controlling cation concentrations. Similarly SO4 adsorption-desorption or precipitation-dissolution reactions with the matrix were controlling its concentrations. On the other hand, NO3 appeared to be controlled by uptake by plants or microorganisms or by denitrification since their concentrations in the soil fell abruptly as snowmelt proceeded. Dissolved Al and pH varied vertically in the soil profile and their pattern in the stream indicated clearly the importance of water flowpath on stream chemistry. Although Al increased as pH decreased, the relationship does not appear to be controlled by gibbsite. The best fit of calculated dissolved inorganic Al was obtained using AlOHSO4 with a solubility less than that of pure crystalline jurbanite.

Introduction

2018 ◽  
Author(s):  
Marko Geslani
Keyword(s):  
Comparative Study ◽  
Royal Power ◽  
History Of ◽  
Historical Developments ◽  
The Comparative Study ◽  
The Relationship ◽  
Over Time ◽  
Indian Religion

The introduction reviews the historiographic problem of the relation between fire sacrifice (yajña) and image worship (pūjā), which have traditionally been seen as opposing ritual structures serving to undergird the distinction of “Vedic” and “Hindu.” Against such an icono- and theocentric approach, it proposes a history of the priesthood in relation to royal power, centering on the relationship between the royal chaplain (purohita) and astrologer (sāṃvatsara) as a crucial, unexplored development in early Indian religion. In order to capture these historical developments, it outlines a method for the comparative study of ritual forms over time.

Assessing the Development of Operator Trust in Automation: A Longitudinal Study of an Autonomous Campus Shuttle

2020 ◽  
Vol 64 (1) ◽  
pp. 1421-1425
Author(s):  
Margaret Fowler ◽  
Farzan Sasangohar ◽  
Bob Brydia
Keyword(s):  
Longitudinal Study ◽  
Significant Relationship ◽  
Autonomous Vehicle ◽  
Student Population ◽  
Tier 1 ◽  
Trust In Automation ◽  
Operational Issues ◽  
The Relationship ◽  
Over Time

A large public tier-1 university hosted an autonomous vehicle on campus for a 12-week demonstration. Throughout the deployment, the vehicle was operated autonomously and used 5 safety operators from the student population to take over shuttle operations, as necessary. Daily and weekly surveys as well as pre-and post-study interviews were used to investigate how operators’ trust developed and changed over time as well as the relationship between trust and operational issues that varied in severity. Results revealed that there was not a significant relationship between trust and severity of operational issues. Trust levels appeared to remain relatively consistent before, during and after the deployment.

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