柑橘砧穗關係與養料吸收及運移之研究（應用放射性磷、硫及鈣為顯跡劑）

Studies on the Absorption and Translocation of Nutrients by Citrus as Influenced by Stock-scion Relationshinps, Using Psa, Sas And Ca45 as Tracers

目前臺灣省普遍栽植且具商業價值之柑桔類果樹，品屬繁多，然果農均沿襲舊俗，不論栽植任何品屬之柑桔，泰半採用酸桔（Citrus reticulata var. Sunki Hort,）為砧木。事實上，酸桔雖為一種優良砧木，但並非完全適宜於所有柑桔品屬，且極易感染黃龍病（Tristeza）。枳殼（Poncirus trifoliata Raf）為砧木，任何品屬之柑桔雖能預防黃龍病之侵襲，惜樹形小，結果期短，淺根為其缺點。

Since trifoliate orange when used as a rootstock for Citrus has been found to have resistance to tristeza, it is said that this species would and the ideal rootstock for replacing the traditional Sunki for citrus in Taiwan. When choosing of a rootstock for any citrus variety, the most emphatic characters always focused on soil and climatic adaptability, disease resistance, longevity, yield and quality. Little attention has been paid to the stionic influence on nutrients absorption and subsequent translocatiou through the budunion region. In the present experiments, radioactive P32, S35 and,Ca45 were used as tracers in the attempt to elucidate the iufluences of stionic variation on nutritional aspects, and special emphasis was made on the difference and suitability between trifoliate and sunki rootstocks. The laboratory work was carried out from October 1963 to May 1964. Radioassay and autoradiography were used, and specific activity of leaves and roots of samples were analyzed. The results from these studies may be summarized as follows: 1.Among 11 kinds of rootstocks budded with ponkan, there were ronounced stionic variations on Ca45 absorption and subsequent translocation. the use of tri­ioliate as rootstooks wasn't so disappointed as far as the nutritional point of view is concerned. 2.Sufficient amount of P32 and S35 was absorbed by both Sunki and trifoliate rootstocks budded with ponkan, tankan and Satsuma orange, and the accumulation of nutrients was even more pronounced in the case of Sunki. How ever when the tock was Sunki, the nutrient contents of the leaves of the scions were strikingly lower as compared with that of trifoliate. It seemed that the stionic variations showed a tendency in interfering the transportation of nutrients through the budunions, and this situation was more pronounced than that in the case of nutrient .absorption by the roots. 3.In the case of different scions with the same stook, no apparent differences were found on the absorption of nutrients by the stock. 4.From the viewpoint of nutrient supply, the effect of trifoliate oranges stock seems satisfactory.