ZINC NUTRITION AND LEVELS OF ENDOGENOUS INDOLE-3-ACETIC-ACID IN RADISH SHOOTS

Radish (Raphanus sativus cv. Akamaru-Hatsukadaikon) was grown for seve ral experiments in a glasshouse with zinc (Zn) supply in the nutrient solution. Lack of Zn resulted in stunted growth and reduced leaf of ra dish shoots were observed. Two-dimensional thin layer chromatography ( TLC) and gas chromatography-mass spectrometry (GC-MS) analysis reveale d the presence of endogenous indole-3-acetic acid (IAA) in Zn-deficien t radish shoots. An estimate has been made of alkali-labile (1 and 7N NaOH) IAA in Zn-deficient radish shoots with the use of gas chromatogr aphy (GC). The level of 7N NaOH-labile IAA (peptidic + ester + free) a nd 1N NaOH-labile IAA (ester + free) in Zn-deficient radish shoots was almost the same as that of control radish shoots. These results sugge st that Zn nutrition did not affect the level of endogenous IAA in rad ish shoots.