Diurnal changes in xylem pressure and mesophyll cell turgor pressure of the lianaTetrastigma voinierianum: The role of cell turgor in long-distance water transport

PROTOPLASMA ◽  
1999 ◽  
Vol 206 (1-3) ◽  
pp. 152-162 ◽  
Author(s):  
F. Th�rmer ◽  
J. J. Zhu ◽  
N. Gierlinger ◽  
H. Schneider ◽  
R. Benkert ◽  
...  
Keyword(s):  
Water Transport ◽  
Turgor Pressure ◽  
Mesophyll Cell ◽  
Diurnal Changes ◽  
Long Distance ◽  
Xylem Pressure ◽  
Cell Turgor

Phloem water relations and root growth

2000 ◽  
Vol 27 (6) ◽  
pp. 539 ◽  
Author(s):  
Jeremy Pritchard ◽  
Sam Winch ◽  
Nick Gould
Keyword(s):  
Cell Expansion ◽  
Control Point ◽  
Turgor Pressure ◽  
Significant Proportion ◽  
Physiological Data ◽  
Solute Flux ◽  
Root Cells ◽  
Cell Turgor ◽  
The Relationship

In this paper the biophysical basis of cell expansion is described, paying particular attention to the waterrelations that underpin the process. The connection of growing root cells to the rest of the plant will be addressed and possible control points in the hardware identified. Examples of environmental modification of root extension, and therefore water and solute import, are given, and the relationship with current accepted theories of solute translocation discussed. The opportunities for delivery of solutes and water to be regulated by the growing root itself will be considered, in particular the dual role of cell wall loosening in decreasing both sink cell turgor and water potential. We conclude that a significant proportion of the water for cell expansion can enter growing root cells through the phloem. The physiological data presented rule out alterations in the turgor pressure difference between sieve element and cell as a modulator of solute flux. The plasmodesmata are identified as the major control point of solute flux along the symplastic pathway.

Mechanisms of long-distance water transport in plants: a re-examination of some paradigms in the light of new evidence

1993 ◽  
Vol 341 (1295) ◽  
pp. 19-31 ◽  
Keyword(s):  
Water Transport ◽  
Pressure Probe ◽  
Nmr Imaging ◽  
Long Distance ◽  
Indirect Methods ◽  
Xylem Pressure ◽  
Direct Measurements ◽  
Xylem Pressure Probe ◽  
Cohesion Theory ◽  
New Evidence

According to the widely accepted Cohesion Theory, water is pulled by transpiration from the roots through the xylem to the leaves. It is believed that this process results in the development of large tensions (negative pressures) in the xylem. In this chapter we re-examine some of the indirect methods that were used to support the formulation of this theory. We conclude that because of ambiguities inherent in the interpretation of the results obtained by these approaches the evidence in support of the Cohesion Theory is not conclusive. Direct measurements of xylem pressure in herbaceous plants and tall trees have yielded values of tensions that are inconsistent with the Cohesion Theory. In the light of the data from the xylem pressure probe and nuclear magnetic resonance (NMR)-imaging, we believe that several forces may be responsible for long-distance water transport in plants. These include tension, osmotic pressure, capillary and air-water interfacial forces.

Attachment Styles, Physical Proximity, and Relational Satisfaction

2014 ◽  
Vol 4 (2) ◽  
pp. 106-112
Author(s):  
Anita Shrivastava ◽  
Andrea Burianova
Keyword(s):  
Attachment Styles ◽  
Romantic Relationship ◽  
Distinct Type ◽  
Relational Satisfaction ◽  
Long Distance ◽  
Avoidant Attachment ◽  
Geographic Separation ◽  
Relationship Of ◽  
Attachment Dimensions

This study aimed to explore the relationships between attachment styles, proximity, and relational satisfaction. This was achieved by assessing a distinct type of long distance romantic relationship of flying crews, compared with proximal (non-flying crew) romantic relationships. The responses of 139 expatriate professionals revealed significant associations between proximity and anxious and avoidant attachment dimensions. The role of the avoidant dimension in comparison with that of the anxious dimension was found to be a significant predictor of relational satisfaction. This study contributes significantly toward addressing the role of proximity and attachment in relational satisfaction in a new context of geographic separation.

Trade, Commerce, and the State in the Roman World

2017 ◽  
Keyword(s):  
Roman Empire ◽  
The State ◽  
Market Regulation ◽  
External Trade ◽  
Long Distance ◽  
Legal Structures ◽  
The City ◽  
Political Character ◽  
Different Sources

This interdisciplinary volume presents nineteen chapters by Roman historians and archaeologists, discussing trade in the Roman Empire in the period c.100 BC to AD 350, and in particular the role of the Roman state, in shaping the institutional framework for trade within and outside the Empire, in taxing that trade, and in intervening in the markets to ensure the supply of particular commodities, especially for the city of Rome and for the army. The chapters in this volume address facets of the subject on the basis of widely different sources of evidence—historical, papyrological, and archaeological—and are grouped in three sections: institutional factors (taxation, legal structures, market regulation, financial institutions); evidence for long-distance trade within the Empire, in wood, stone, glass, and pottery; and trade beyond the frontiers, with the East (as far as China), India, Arabia, and the Red Sea, and the Sahara. Rome’s external trade with realms to the east emerges as being of particular significance to the fisc. But in the eastern part of the Empire at least, the state appears, in collaboration with the elite holders of wealth, to have adapted the mechanisms of taxation, both direct and indirect, to support its need for revenue. On the other hand, the price of that collaboration, which was in effect a fiscal partnership, in slightly different forms in East and West, in the longer term fundamentally changed the political character of the Empire.

scholarly journals Prevalence of ACSL (rs6552828) polymorphism among runners

2019 ◽  
Vol 24 ◽  
pp. 121-128
Author(s):  
Sigal Ben-Zaken ◽  
Yoav Meckel ◽  
Dan Nemet ◽  
Alon Eliakim
Keyword(s):  
Single Nucleotide Polymorphism ◽  
Genetic Basis ◽  
Maximal Oxygen Consumption ◽  
Professional Athletes ◽  
Distance Runners ◽  
Nucleotide Polymorphism ◽  
Long Distance ◽  
Single Nucleotide ◽  
The Common

The ACSL A/G polymorphism is associated with endurance trainability. Previous studies have demonstrated that homozygotes of the minor AA allele had a reduced maximal oxygen consumption response to training compared to the common GG allele homozygotes, and that the ACSL A/G single nucleotide polymorphism explained 6.1% of the variance in the VO2max response to endurance training. The contribution of ACSL single nucleotide polymorphism to endurance trainability was shown in nonathletes, however, its potential role in professional athletes is not clear. Moreover, the genetic basis to anaerobic trainability is even less studied. Therefore, the aim of the present study was to examine the prevalence of ACSL single nucleotide polymorphism among professional Israeli long distance runners (n=59), middle distance runners (n=31), sprinters and jumpers (n=48) and non-athletic controls (n=60). The main finding of the present study was that the ACSL1 AA genotype, previously shown to be associated with reduced endurance trainability, was not higher among sprinters and jumpers (15%) compared to middle- (16%) and long-distance runners (15%). This suggests that in contrast to previous studies indicating that the ACSL1 single nucleotide polymorphism may influence endurance trainability among non-athletic individuals, the role of this polymorphism among professional athletes is still not clear.

scholarly journals Shoot–root carbon allocation, sugar signalling and their coupling with nitrogen uptake and assimilation

2016 ◽  
Vol 43 (2) ◽  
pp. 105 ◽  
Author(s):  
Lu Wang ◽  
Yong-Ling Ruan
Keyword(s):  
Growth And Development ◽  
Carbon Allocation ◽  
Dynamic Balance ◽  
Shoot Development ◽  
Long Distance ◽  
Root Carbon ◽  
Organ Systems ◽  
New Findings ◽  
Sugar Signalling

Roots and shoots are distantly located but functionally interdependent. The growth and development of these two organ systems compete for energy and nutrient resource, and yet, they keep a dynamic balance with each other for growth and development. The success of such a relationship depends on efficient root-shoot communication. Aside from the well-known signalling processes mediated by hormones such as auxin and cytokinin, sugars have recently been shown to act as a rapid signal to co-ordinate root and shoot development in response to endogenous and exogenous clues, in parallel to their function as carbon and energy resources for biomass production. New findings from studies on vascular fluids have provided molecular insights into the role of sugars in long-distance communications between shoot and root. In this review, we discussed phloem- and xylem- translocation of sugars and the impacts of sugar allocation and signalling on balancing root–shoot development. Also, we have taken the shoot–root carbon–nitrogen allocation as an example to illustrate the communication between the two organs through multi-layer root–shoot–root signalling circuits, comprising sugar, nitrogen, cytokinin, auxin and vascular small peptide signals.

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