Sustained and significant negative water pressure in xylem
Article Abstract:
Negative xylem pressure can be maintained for long periods with little or no cavitation unless the pressure falls below a species-specific threshold, supporting the cohesion-tension theory of water transport in plants. Xylem pressure-probe and z-tube experiments indicate that the xylem pressures are limited to above -0.5 MPa. The induction of negative pressures between -0.5 and -3.5 MPa in intact stem cells has little effect on the water in the xylem and conductance levels which range from -1.2 to -3.5 MPa depending on the species. The conduction of water by xylem is unaffected when stems are air-filled or injected with air.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1995
User Contributions:
Comment about this article or add new information about this topic:
The real water-bearer
Article Abstract:
The Infrared Space Observatory has detected water in the planetary nebula NGC7027, which may account for some of the oxygen in interstellar space, predicted by cosmological models, that appears to be missing. Oxygen in interstellar space is usually found as carbon monoxide in such carbon rich planetary nebula. These findings open up new avenues for the study of interstellar chemistry.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1996
User Contributions:
Comment about this article or add new information about this topic:
Between water and land
Article Abstract:
The oldest known fossils that illustrate the transition from water to land are those of Ichthyostega from the Upper Devonian of East Greenland. The lineage that includes Ichthyostega seems to have undergone the transition from water to land through changes that would have increased the facility for movement in both environments.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 2005
User Contributions:
Comment about this article or add new information about this topic:
- Abstracts: Molecular variation and evolutionarily significant units in the endangered Gila topminnow. Evolutionary significant units, distinct population segments, and the Endangered Species Act: reply to pennock and Dimmick
- Abstracts: Eradication of rabies in Europe. Europe's water-wars
- Abstracts: Marine litter keeps increasing. The work keeps turning. Iodine oxide in the marine boundary layer
- Abstracts: Flawed understanding of the scientific process. The ends of understanding. Pity poor understanding
- Abstracts: Neutralizing antibody to human rhinovirus 14 penetrates the receptor-binding canyon. Snapshots along the pathway