External Mechanical Cues Reveal a Katanin-Independent Mechanism behind Auxin-Mediated Tissue Bending in Plants

1. Download : Download high-res image (194KB)
2. Download : Download full-size image

     

Mechanochemical feedback mediates tissue bending required for seedling emergence

1. Download : Download high-res image (137KB)
2. Download : Download full-size image

     

Tissue oxygen measurements in delayed skin flaps: a reconsideration of the mechanisms of the delay phenomenon

The delay phenomenon was studied by measuring tissue oxygen tension (PsqO2) for 3 weeks in delayed flaps and normal adjacent contralateral skin in seven mongrel dogs. The PsqO2 fell after elevation of a bipedicle flap and rose again to normal by day 14. Delivery of oxygen to this flap was improved by surgical delay, so that when the bipedicle flap was reelevated on day 14 and its distal pedicle divided, minimal changes in PsqO2 occurred. When the control area was elevated on day 14 as a random-pattern flap, it had higher PsqO2 values than measured in the bipedicle flap on day 0, and therefore, it too had participated in the delay phenomenon, even though only its midline edge had been incised. An anatomic explanation for the findings was sought in wounds made in 10 rabbit ear chambers. After injury, blood flow was seen to be rerouted parallel to the incision line and was increased first by vasodilation and then also by angiogenesis until about day 14. Rerouting of blood by injury, inflammation, and angiogenesis due to repair appears to account for a significant portion of the delay phenomenon.     

Descent of European silver eels, Anguilla anguilla L., in a Norwegian watercourse

Seaward migration of silver eels occurred at nights during autumn at decreasing water temperature. Maximum migration-rate occurred mid-October at medium and decreasing water discharge. Most eels descended in the first quarter of the lunar cycle, few eels descended at full moon. Most males and small females migrated earlier in the season than the larger females. The migration speed of silver eels in fresh water was independent of body length.     

A sensitive method for the determination of plasma catecholamines using liquid chromatography with electrochemical detection

Simple and sensitive methods for the determination of plasma catecholamines are of great interest since the level of catecholamines in plasma reflects the activity of the sympatho-adrenal system. In the present work a previously described procedure based on high pressure liquid chromatography with electrochemical detection has been adapted for assay of plasma catecholamines. This method permits simultaneous detection of noradrenaline, adrenaline and dopamine in concentrations down to 0.1 nmol/1 in less than one ml plasma.     

NIR spectroscopy,mineral nitrogen analysis and soil incubations for the prediction of crop uptake of nitrogen during the growing season

To predict the amount of N taken up in above-ground plant parts during the growing season, initial mineral soil N, a soil incubation method, soil organic matter and NIR data were compared as predictors. Soil samples were taken from 15 plots cropped with winter wheat on a farm in south-western Sweden. The plots were not fertilized with N during the 1997 growing season. N contents in above-ground plant parts were measured in mid-June and in mid-August. All methods were capable of predicting the crop uptake of N reasonably well. NIR data gave at least as good predictions as the best traditional method, initial soil NO₃-N. The most important wavelengths, around 1400 and 1700 nm, and above 2000 nm, coincide with the wavelengths reported earlier to be important for the prediction of soil organic matter. However, the data suggest that other soil components influencing mineralization are also spectrally active. Since very few samples were taken, the studies need to be extended in order to be able to use the method in practice. It is recommended that further studies be instigated for the possibility of using the same NIR calibration over several years and to clarify the spatial regions that the calibrations can cover. This revised version was published online in June 2006 with corrections to the Cover Date.