YUSUKE SUMIKI 



and 

 AKIRA KAWARADA 



University of Tokyo 



Occurrence of G 'LbbereUin. Ai in the 

 Water Sprouts of Citrus 



In 1951, the occurrence of a new phytohormone which greatly stimu- 

 lated stem elongation in immature bean seeds was reported by 

 Mitchell, Skaggs, and Anderson (3). It was the first description of the 

 occurrence of a gibberellin-like substance in higher plants. West and 

 Phinney (8) reported the occurrence of gibberellin-like substances 

 from species of several different families of flowering plants. Since 

 then a number of reports (4, 5, 6, 7) related to gibberellins or gib- 

 berellin-like substances have been published. 



Last year, MacMillan and Suter (2) obtained gibberellin A^ from 

 the immature seeds of runner bean, Phaseolus multiflorus, which was 

 the first successful isolation of one of the known gibberellins. 



In our laboratory, the constituents of water sprouts of mandarin 

 orange were examined, and gibberellin A^ was obtained in pure crys- 

 talline form. 



The material used in this experiment was a bud variation of Citrus 

 imshiu, first found by K. Furusato (1) in Shizuoka Prefecture in 1949. 

 In spring, many long twigs sprout from its apex like a witches'-broom 

 of the cherry tree. The leaves are lighter green and smaller than those 

 of the normal branches and flowering is not initiated. In this paper, 

 the procedure of isolation and identification of gibberellin A^ from 

 the elongated water sprouts is described. 



EXPERIMENTAL 



The elongated water sprouts (ca. 1.8 kg.), harvested in November, 

 1957, were divided into leaves (0.6 kg.) and shoots (1.14 kg.), and the 

 latter portion was cut, ground by the blender, immersed in 1.5 1. of 50 

 per cent aqueous acetone, and extracted overnight at room tempera- 

 ture. After the extraction was repeated, the eluates were combined 



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