Volker Stiller

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gests that the humidity response is actually a transpiration response (Mott & Parkhurst 1991) mediated by complex negative feedback via the water status of cells associated with the stomatal apparatus (Cowan 1995; Franks, Cowan & Farquhar 1997; Mott & Buckley 1998; see also Dewar 1995; Monteith 1995). Studies have shown that this response can occur without(More)
Although cavitation and refilling cycles could be common in plants, it is unknown whether these cycles weaken the cavitation resistance of xylem. Stem or petiole segments were tested for cavitation resistance before and after a controlled cavitation-refilling cycle. Cavitation was induced by centrifugation, air drying of shoots, or soil drought. Except for(More)
about the hydraulic properties of the plant vascular system. The traditional view of plant hydraulics being domSoil and xylem are similar hydraulically. An unsaturated conductivinated by resistances of endodermis and root cortex ity curve for soil is called a vulnerability curve for xylem—but the (Boyer, 1985; Philip, 1966) is expanding to include well(More)
BACKGROUND To study the mechanisms of passive sensitization of patients receiving plasma containing IgE antibodies to a defined allergen. METHODS When required for medical reasons, regular donor plasma with IgE antibodies to timothy grass allergen (8-205 kU(A)/l), was given. Kinetics of IgE antibodies in the recipients' serum and his/her basophil allergen(More)
We investigated the role of xylem cavitation, plant hydraulic conductance, and root pressure in the response of rice (Oryza sativa) gas exchange to water stress. In the field (Philippines), the percentage loss of xylem conductivity (PLC) from cavitation exceeded 60% in leaves even in watered controls. The PLC versus leaf water potential relationship(More)
Embolism reversal in rice plants was studied by testing the plant's ability to refill embolized conduits while xylem pressures were substantially negative. Intact, potted plants were water-stressed to a xylem pressure of -1.88 ± 0.1 MPa and a 66.3 ± 3.8% loss of xylem conductivity (PLC) by cavitation. Stressed plants were carefully rewatered, allowing xylem(More)
We investigated the role of hydraulic conductivity, wood density, and xylem cavitation in the response of baldcypress (Taxodium distichum) seedlings to increased soil salinity and drought. One-year-old, greenhouse-grown seedlings were irrigated daily with a 100 mM (≈6‰) salt solution or once per week with fresh water (drought). Controls were irrigated daily(More)
Woody plants native to mesic habitats tend to be more vulnerable to drought-induced cavitation than those in xeric habitats. Cavitation resistance in herbaceous plants, however, is rarely studied and whether or not annual plants in arid habitats conform to the trends observed in woody plants is unknown. This question is addressed by comparing the hydraulic(More)
BACKGROUND Prospective studies of the epidemiology and clinical significance of low plasminogen activator inhibitor type 1 (PAI-1) activity are lacking. OBJECTIVE To evaluate the prevalence of low PAI-1 activity in patients with a bleeding tendency in comparison with a normal population. METHODS In 586 consecutive patients, referred because of bleeding(More)
"Cavitation fatigue" is the increased susceptibility of a xylem conduit to cavitation as a result of its prior cavitation. It was investigated whether cavitation fatigue induced in vivo could be repaired in intact plants. Sunflowers (Helianthus annuus L.) were subjected to soil drought in the greenhouse. Native embolism and vulnerability to cavitation was(More)