scholarly journals An Analysis of the Water Potential Isotherm in Plant Tissue

1969 ◽  
Vol 22 (1) ◽  
pp. 35 ◽  
Author(s):  
I Noy-Meir ◽  
B Z Ginzburg
Keyword(s):  
Water Potential ◽  
Water Content ◽  
Filter Paper ◽  
Plant Tissue ◽  
Quadratic Function ◽  
Living Tissue ◽  
Static Potential ◽  
Plane Tree ◽  
Poten Tials ◽  
The Matrix

The water potential isotherms of leaves of carob (a sclerophyllic xerophyte), plane tree (a mesophyte), and saltbush (a semisucculent xero-halophyte) were measured by vapour equilibration with filter paper. The isotherm of the living tissue was partitioned into components by measuring the isotherms of killed tissue and of isolated matrix fractions. Empirical functions were fitted by regression to each of the components. The isotherm of the matrix fractions fitted best to a function of the form 'P = -a/w2+b/w and the isotherms of killed tissue, whether before or after subtraction of the matrix, to a function of the form 'P = -a/w2-b/w. The first term indicates non-ideality of the tissue solution. The water potential difference between living and killed tissue, which is an approximation of the hydro-static potential, was far from linear with water content; either a quadratic function or two discontinuous linear ones could be fitted to it. Negative hydrostatic poten-tials were measured, the highest values (20 atm) being attained in carob. A hyster-etic component was measured both in the entire tissue and in the matrix fractions.

scholarly journals An Analysis of the Water Potential Isotherm in Plant Tissue I. The Theory

1967 ◽  
Vol 20 (4) ◽  
pp. 695 ◽  
Author(s):  
I Noy-Meir ◽  
B Z Ginzburg
Keyword(s):  
Free Energy ◽  
Water Potential ◽  
Water Content ◽  
Plant Tissue ◽  
Specific Free Energy

The water potential isotherm is the function relating the water potential (specific free energy of water) in a given system to its water content.

Spectral assessments of wheat plants grown in pots and containers under saline conditions

2013 ◽  
Vol 40 (4) ◽  
pp. 409 ◽  
Author(s):  
Harald Hackl ◽  
Bodo Mistele ◽  
Yuncai Hu ◽  
Urs Schmidhalter
Keyword(s):  
Water Potential ◽  
Water Content ◽  
Aboveground Biomass ◽  
Leaf Water ◽  
Leaf Water Content ◽  
Spectral Indices ◽  
Fresh Weight ◽  
Normalised Difference Vegetation Index ◽  
Spectral Sensing ◽  
Reflectance Ratio

Spectral measurements allow fast nondestructive assessment of plant traits under controlled greenhouse and close-to-field conditions. Field crop stands differ from pot-grown plants, which may affect the ability to assess stress-related traits by nondestructive high-throughput measurements. This study analysed the potential to detect salt stress-related traits of spring wheat (Triticum aestivum L.) cultivars grown in pots or in a close-to-field container platform. In two experiments, selected spectral indices assessed by active and passive spectral sensing were related to the fresh weight of the aboveground biomass, the water content of the aboveground biomass, the leaf water potential and the relative leaf water content of two cultivars with different salt tolerance. The traits were better ascertained by spectral sensing of container-grown plants compared with pot-grown plants. This may be due to a decreased match between the sensors’ footprint and the plant area of the pot-grown plants, which was further characterised by enhanced senescence of lower leaves. The reflectance ratio R760 : R670, the normalised difference vegetation index and the reflectance ratio R780 : R550 spectral indices were the best indices and were significantly related to the fresh weight, the water content of the aboveground biomass and the water potential of the youngest fully developed leaf. Passive sensors delivered similar relationships to active sensors. Across all treatments, both cultivars were successfully differentiated using either destructively or nondestructively assessed parameters. Although spectral sensors provide fast and qualitatively good assessments of the traits of salt-stressed plants, further research is required to describe the potential and limitations of spectral sensing.

Carbon balance in relation to drying in four epiphytic mosses growing in different vertical ranges

1979 ◽  
Vol 57 (19) ◽  
pp. 1994-1998 ◽  
Author(s):  
Peter L. Tobiessen ◽  
Nancy G. Slack ◽  
Keith A. Mott
Keyword(s):  
Water Potential ◽  
Water Content ◽  
Carbon Balance ◽  
The Other ◽  
Moss Species ◽  
Relationship Of ◽  
The Relationship ◽  
Neckera Pennata ◽  
Lower Water Content ◽  
Photosynthesis And Respiration

The response of photosynthesis and respiration to drying was measured in four species of epiphytic mosses, Ulota crispa (Hedw.) Brid., Neckera pennata Hedw., Anomodon rugellii (C. Mull.) Keissl., and Plagiomnium cuspidatum (Hedw.) T. Kop., from habitats along a desiccation gradient. There was little difference among the mosses in these responses. The relationship of water content to water potential did differ among the mosses, with Plagiomnium, the facultative epiphyte, showing a typical response of more mesic species and the other three showing a more xeric response, i.e., water potential does not begin to fall steeply until a lower water content is reached in Ulota, Neckera, and Anomodon. Both photosynthesis and respiration in all four moss species were quite sensitive to moderate water stress.

scholarly journals Growth and physiological response of two biomass sorghum (Sorghum bicolor (L.) Moench) genotypes bred for different environments, to contrasting levels of soil moisture

2015 ◽  
Vol 10 (4) ◽  
pp. 208 ◽  
Author(s):  
Lorenzo Barbanti ◽  
Ahmad Sher ◽  
Giuseppe Di Girolamo ◽  
Elio Cirillo ◽  
Muhammad Ansar
Keyword(s):  
Soil Moisture ◽  
Stomatal Conductance ◽  
Water Potential ◽  
Water Content ◽  
Aboveground Biomass ◽  
Relative Water Content ◽  
Physiological Response ◽  
Field Capacity ◽  
Biomass Sorghum ◽  
Relative Water

A better understanding of plant mechanisms in response to drought is a strong premise to achieving high yields while saving unnecessary water. This is especially true in the case of biomass crops for non-food uses (energy, fibre and forage), grown with limited water supply. In this frame, we investigated growth and physiological response of two genotypes of biomass sorghum (<em>Sorghum bicolor</em> (L.) Moench) to contrasting levels of soil moisture in a pot experiment carried out in a greenhouse. Two water regimes (high and low water, corresponding to 70% and 30% field capacity) were applied to JS-2002 and Trudan-8 sorghum genotypes, respectively bred for dry sub-tropical and mild temperate conditions. Two harvests were carried out at 73 and 105 days after seeding. Physiological traits (transpiration, photosynthesis and stomatal conductance) were assessed in four dates during growth. Leaf water potential, its components and relative water content were determined at the two harvests. Low watering curbed plant height and aboveground biomass to a similar extent (ca. 􀀀70%) in both genotypes. JS-2002 exhibited a higher proportion of belowground to aboveground biomass, <em>i.e</em>., a morphology better suited to withstand drought. Despite this, JS-2002 was more affected by low water in terms of physiology: during the growing season, the average ratio in transpiration, photosynthesis and stomatal conductance between droughty and well watered plants was, respectively, 0.82, 0.80 and 0.79 in JS-2002; 1.05, 1.08 and 1.03 in Trudan-8. Hence Trudan-8 evidenced a ca. 20% advantage in the three traits. In addition, Trudan-8 could better exploit abundant moisture (70% field capacity), increasing aboveground biomass and water use efficiency. In both genotypes, drought led to very low levels of leaf water potential and relative water content, still supporting photosynthesis. Hence, both morphological and physiological characteristics of sorghum were involved in plant adaptation to drought, in accordance with previous results. Conversely, the common assumption that genotypes best performing under wet conditions are less suited to face drought was contradicted by the results of the two genotypes in our experiment. This discloses a potential to be further exploited in programmes of biomass utilization for various end uses, although further evidence at greenhouse and field level is needed to corroborate this finding.

scholarly journals Application of microbial risk assessment on a residentially-operated Bio-toilet

2006 ◽  
Vol 4 (4) ◽  
pp. 479-486 ◽  
Author(s):  
Naoko Nakagawa ◽  
Hana Oe ◽  
Masahiro Otaki ◽  
Katsuyoshi Ishizaki
Keyword(s):  
Risk Assessment ◽  
Water Content ◽  
Risk Level ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Infectious Risk ◽  
The Matrix ◽  
Pathogenic Viruses ◽  
Scale Experiment ◽  
Time Required

The Sustainable Sanitation System is a new wastewater treatment system that incorporates a non-flushing toilet (Bio-toilet) that converts excreta into a reusable resource (as fertilizer or humus for organic agriculture) and reduces the pollution load to environments of the rivers, the lakes, and the sea. However, the risk of exposure to pathogens should be considered, because excrement is stored in the Bio-toilet. The aim of the present work is to analyze the health risk of dealing with the matrix (excreta and urine mixed with sawdust) of the Bio-toilet. Therefore, the fate of pathogenic viruses was investigated using coliphages as a virus index, and the modeling of the die-off rate in matrix was introduced. Then the microbial risk assessment was applied to a Bio-toilet that was actually used in a residential house; the infection risks of rotavirus and enterovirus as reference pathogens were calculated. According to the lab-scale experiment using coliphages for investing the die-off rate of viruses in the Bio-toilet, Qβ had a higher die-off, which was greatly influenced by the water content and temperature. On the other hand, T4 showed a lower rate and was independent of water content. Therefore, these two phages' data were used as critical examples, such as viruses having high or low possibilities of remaining in the Bio-toilet during the risk assessment analysis. As the result of the risk assessment, the storage time required for an acceptable infectious risk level has wide variations in both rotavirus and enterovirus cases depending on the phage that was used. These were 0–260 days' and 0–160 days' difference, respectively.

Relative water content and water potential of tissue 1

1995 ◽  
Vol 46 (1) ◽  
pp. 111-118 ◽  
Author(s):  
J.C. Diaz-Pérez ◽  
K.A. Shackel ◽  
E.G. Sutter
Keyword(s):  
Water Potential ◽  
Water Content ◽  
Relative Water Content ◽  
Relative Water
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