When 14C02 was supplied to a limited area of a mature illuminated leaf of soybean, the radioactive compounds appeared rapidly in the root, the apex of the shoot, and in young unexpanded leaves. Translocation to these "sinks" took place in the light, during photosynthesis at the source.

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In a recent ptTblication, Bennet-Clark and Bexon (1943) have described investigations on beet tissue which considerably increase onr knowledge of the respiratory metabolism of plant cells. Somewhat similar work is in progress here on carrot tissue and it has become clear that in both tissues the respiration reacts in somewhat the same way, for example to certain organic acids. "We also know a good deal about the uptake of ions by carrot tissue and its relation to respiration, and it seems useful to enquire whether carrot and beet tissue are similar in this respect. The data of Bennet-Clark and Bexon concerning respiratory drift with time and with salt solutions suggest that the two tissues are different in some ways. The methods they used for beet also differed somewhat from ours and we have therefore investigated beet tissue, using precisely the methods that we have developed for carrot tissue. MATERIAL AND METHODS.Eed beetroot, unknown variety, waa purchased in the dormant stage-and slices of 0-8 em. diam. and 0-25, 0-5 and 1 mm. tliiek were used for experiment. Tbe roots were well waslied and peeled thickly. For some experiments cylinders wor.? cut vertically from the roots with a cork borer and cut by hand into discs 1 mm. thick. Por the other experiments, cylinders were cut into a block of boet and left in the block. This was then clamped into a microtome and diaca either l-O, 0-5 or 0-'25 mm. in thickness were cut from it. All discs were immediately rinaed eeveral times in distilled water and then aoratod in distilled water until required. Slices were used at periods varying from 1-640 hours after cutting.Respiration rate waa determined at 25° G. by measuring the oxygen uptake of 1-5 gm. to 2*0 gm. of tisane in Warburg vcaaels shaken at 100 oscillations per minute. Tissue to be uaed was lightly blotted dry, weighed and transferred to vesaela with distilled water; the volume of water in the different experiments was varied when different amounts of tissue were nsed so that the tissue-aolution volume ratio remained practically constant. After a steady respiratory drift was reached in distilled water, potasainm chloride solution waa added from the side arm. The concentration of the potassium .chloride added was sufficient to give a concentration of O-Ol M, 0-02 M or 0-04 M, as reqiiii'Dd, in contact with the tissue. In controls the same volume of distilled water was added from the side arm. Tho potassium cyanide waa added, when desired, by stopping the experiment temporarily, removing the vessels from the manometers and adding the required amount of potassium cyanide to the solution in contact with the tissue: the potassium hydroxide in the centre tube of the vessel was replaced with potassium hydroxide containing the appropriate quantity of potassium cyanide to give a vapour pressure of hydrogen cyanide in equilibrium with that in the solution (Krebs, 1935).Salt accumulation waa measured with replicate sets of tissue held in flasks in the thermostat and attached to the Warburg ahaker to ensure aeration. A g...

(i) An extract containing glyceraldehyde phosphate dehydrogenases was prepared from the chloroplasts of silver beet. Diphosphopyridine nucleotide (DPN) and triphosphopyridine nucleotide (TPN) functioned as cofactorS for the enzyme activity.