Co-Authors:
ACHITUV, M., Agricultural Research Organization, Volcani Center, P.O.B.6, Bet Dagan, Israel
BAR‐AKIVA, A., Agricultural Research Organization, Volcani Center, P.O.B.6, Bet Dagan, Israel
Abstract:
Phosphorus deficiency in citrus leaves resulted in reduced glutamic‐oxaloacetic transaminase (GOT) activity and low pyridoxal‐phosphate (PLP) content. GOT activity was estimated in crude enzyme extracts by spectrophotometry PLP content was detected colorimetrically in water‐alcoholic extracts. K and Cu deficiencies increased; ‐N, ‐S and ‐Zn decreased and ‐Mg, ‐Fe and ‐Mn did not affect GOT activity in citrus leaves. Experiments were conducted to restore enzyme activity either by direct addition of PLP to the reaction mixture or by infiltration of PLP or KH2PO4 to detached, intact leaves. The infiltration was carried out in vacuo and the leaves were incubated on wet paper for 26 h, after which enzyme activity was estimated. Transamination activity of ‐P leaves more restored by PLP than by KH2PO4 treatments. In zinc‐deficient leaves the enzyme activity was not restored by infiltration of KH2PO4. Copyright © 1976, Wiley Blackwell. All rights reserved