SummaryThe xylem sap in cucumbers (Cucumis sativus L.) which were or were not grafted onto figleaf gourd (Cucurbita ficifolia Bouche) was collected after decapitation from the cut end of the stems hourly. The exudation rate was highest in the first one hour collection regardless of grafting, and then decreased rapidly with time. However, there was a diurnal change in the exudation rate with the maxima occurring at 1 : 00 to 3 : 00 PM and the minima at 7 : 00 to 8 : 00 AM, irrespective of decapitation time. The grafted cucumbers were smaller in amplitude than the nongrafted ones.The rate of xylem exudation and the concentrations of N03-N, P, Ca and Mg in the first one hour exudate were higher in the grafted cucumbers than in the nongrafted ones.Only the K concentration was higher in the non-grafted cucumbers. The mineral concentration in the exudate changed remarkably with time after decapitation ; the N03-N, K and Ca concentrations decreased and the P concentration increased rapidly for the first several hours.The Mg concentration scarcely changed. Thereafter, the N03-N and K concentrations of the exudate in the grafted cucumbers fell below the N03-N and K concentrations in the nutrient solution, while in the non-grafted cucumbers the former was kept always above the latter. From these results, the grafted cucumbers were considered to be superior to the non-grafted ones, in water uptake and nutrient absorption except for K and also to depend more intensely in N03-N and K absorptions on some metabolities from the upper parts of the plants.

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Mineral absorption and oxygen consumption were investigated in comparison of ownroot cucumber (Cucumis salivars L. cv. Tokiwa-hikari No. 3) and grafted cucumber on figleaf gourd (Cucurbita ficifolia Bouche).Mineral concentrations in the nutrient solution at the end of culturing experiments under a vinyl-coverd greenhouse in winter were expressed in percent of those in the solution without plants. N03-N, P, Ca and Mg concentrations evaluated as the contents of mineral absorbed per unit volume of water absorbed were higher in grafted plants than own-root plants, but with K the reverse was the case. These results coincided with the previous report on xylem sap analysis. In the present experiments, no differences between grafted plants and own-root plants were found in water uptake per unit top weight.Such tendency of mineral absorption as mentioned above was also found except for K at 10'C, 16'C and 20"C in growth chamber.In particular, the P absorbed per unit volume of water absorbed by own-root cucumber plants decreased remarkably at 10"C.The quantity of 02 consumption in roots excised from grafted plants and own-root plants was almost the same at 16°C and 24"C, but it was 1.5 times higher at 12'C in grafted plants than own-root plants. A similar result Was also obtained in comparison of roots of young figleaf gourd and young cucumber plants.

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