Larkum, AWD 1969, 'Some observations with a new potometer on the absorption of water by young barley plants', Journal of Experimental Botany, vol. 20, no. 1, pp. 25-33.
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A potometer, working on a syphon principle, is described for use with single, small plants where it is undesirable to flood the stem base. It has been shown that anoxia has very little effect on the water absorption of roots of intact barley plants, apart from an initial inhibition of short duration. The action of 1 × 10-5 M dinitrophenol (pH 6.0) is similar. Neither treatment kills the roots. It is possible that permeability is maintained by fermentation reactions © 1962 Oxford University Press.
Considerable uptake of phosphate by both the shoot and root has been demonstrated for young barley plants with their roots in anoxic culture solution at concentrations of 1 to 10 μM orthophosphate. Consideration of the free space and passive transpirational uptake indicates an accumulatory process, and the immediate efflux caused by respiratory inhibitors supports this. Shoot uptake is much less at higher external concentrations of phosphate and at o.I mM was only 14 per cent of the control. The root accumulation process was unimpaired at an external concentration of 1 μM phosphate when the whole plant was subjected to anaerobic conditions (shoot illuminated) but under similar conditions at a concentration of 100 μM a considerable efflux of phosphate occurred. Analysis of the fate of phosphate taken up from anoxic solution of phosphate (10 μM) indicated that there was a reduction in the level of inorganic phosphate after 4.5 h and steady rise in sugar phosphates up to 6 h with a marked increase in the levels of glucose-6-phosphate, fructose-6-phosphate, and the phosphoglycerate fraction. © 1962 Oxford University Press.